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Title:
NUCLEOSIDE TRIPHOSPHATE AND NUCLEOSIDE TRIPHOSPHATE ANALOGUE PRODRUGS
Document Type and Number:
WIPO Patent Application WO/2018/100137
Kind Code:
A1
Abstract:
The invention relates to nucleoside triphosphate and nucleoside triphosphate analogue prodrugs. It is an object of the present invention to provide improved nucleoside triphosphate or nucleoside triphosphate analogue prodrugs. To achieve the object, the present invention provides in one aspect non-symmetrically double modified nucleoside triphosphate compounds, or their analogues, wherein the modification is carried out at the terminal, i.e. the γ-phosphate, or the corresponding analogous group, and wherein the first modification is adding a moiety A being intracellular stable, and the second modification is adding an intracellular labile mask B, which is cleaved within the cell, such that a nucleoside triphosphate or analogue thereof mono-modified with the intracellularly stable moiety A is released in the cell.

Inventors:
MEIER CHRIS (DE)
NACK TOBIAS (DE)
DINIS DE OLIVEIRA THIAGO (DE)
ZHAO CHENGLONG (DE)
Application Number:
PCT/EP2017/081140
Publication Date:
June 07, 2018
Filing Date:
December 01, 2017
Export Citation:
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Assignee:
UNIV HAMBURG (DE)
International Classes:
A61K47/54; A61K31/7072; A61K31/708; A61P31/12; A61P31/16; A61P31/18; C07H19/10; C07H19/207
Domestic Patent References:
WO2016026493A12016-02-25
WO2009129798A22009-10-29
WO2016026493A12016-02-25
Foreign References:
US7608600B22009-10-27
Other References:
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TRISTAN GOLLNEST ET AL: "THE TriPPPro-APPROACH: DEVELOPMENT OF NUCLEOSIDE TRIPHOSPHATE PRODRUGS", 1 January 2014 (2014-01-01), XP055396684, Retrieved from the Internet [retrieved on 20170807]
CHRIS MEIER: "Developing Prodrugs of antivirally active Nucleoside Triphosphates -Against all odds, it works!", 17 April 2015 (2015-04-17), XP055396835, Retrieved from the Internet [retrieved on 20170808]
B. A. MULDER ET AL: "Nucleotide modification at the -phosphate leads to the improved fidelity of HIV-1 reverse transcriptase", NUCLEIC ACIDS RESEARCH, vol. 33, no. 15, 1 September 2005 (2005-09-01), pages 4865 - 4873, XP055111673, ISSN: 0305-1048, DOI: 10.1093/nar/gki779
CHRIS MEIER: "Nucleoside diphosphate and triphosphate prodrugs - An unsolvable task?", ANTIVIRAL CHEMISTRY & CHEMOTHERAPY., vol. 25, no. 3, 1 December 2017 (2017-12-01), GB, pages 69 - 82, XP055458335, ISSN: 0956-3202, DOI: 10.1177/2040206617738656
BALZARINI, P. HERDEWIJN; E. DE CLERCQ: "Differential Patterns of intracellular Metabolism of 2',3'-Didehydro-2',3'-dideoxythymidine and 3'-Azido-2',3 '-dideoxythymidine, two potent Anti-human Immunodeficiency Virus Compounds", J. BIOL. CHEM., vol. 264, 1989, pages 6127 - 6133
RJ SAWCHUK; Z. YANG: "Investigation of distribution, transport and uptake of anti-HIV drugs to the central nervous system", ADVANCED DRUG DELIVERY REVIEWS, vol. 39, 1999, pages 5 - 31
A. POMPON; I. LEFEBVRE; J.-L. IMBACH; S. KHAN; D. FARQUHAR: "Decomposition Pathways of the Mono-(Pivaloyloxymethyl) and Bis-(Pivaloyloxymethyl) Esters of Azidothymidine-5'-Monophosphate in Cell Extract and in Tissue-Culture Medium - An Application of the Online Isrp-Cleaning HPLC Technique", ANTIVIRAL CHEM. CHEMOTHER., vol. 5, 1994, pages 91 - 98
I. LEFEBVRE; C. PERIGAUD; A. POMPON; A.-M. AUBERTIN; J.-L. GIRARDET; A. KIM; G. GOSSELIN; J.-L. IMBACH: "Mononucleoside Phosphotriester Derivates with S Acyl-2-thioethyl Bioreversible Phosphate-Protecting Groups: Intracellular Delivery of 3'-Azido-2',3'-dideoxythymidine-5'-monophosphate", J. MED. CHEM., vol. 38, 1995, pages 3941 - 3950, XP002293734, DOI: doi:10.1021/jm00020a007
W. THOMSON; D. NICHOLLS; W. J. IRWIN; J. S. AL-MUSHADANI; S. FREEMAN; A. KARPAS; J.PETRIK; N. MAHMOOD; A. J. HAY: "Synthesis, Bioactivation and Anti-HIV Activity of the Bis(4-acyloxybenzyl) and Mono(4-acyloxybenzyl) Esters of the 5'-Monophosphate of AZT", J. CHEM. SOC., PERKIN TRANS., vol. 1, 1993, pages 1239 - 1245, XP009120657
THOMSON, D. NICHOLLS; W. J. IRWIN; J. S. AL-MUSHADANI; S. FREEMAN; A. KARPAS; J.PETRIK; N. MAHMOOD; A. J. HAY: "Synthesis, Bioactivation and Anti-HIV Activity of the Bis(4-acyloxybenzyl) and Mono(4-acyloxybenzyl) Esters of the 5'-Monophosphate of AZT", J. CHEM. SOC., PERKIN TRANS., vol. 1, 1993, pages 1239 - 1245, XP009120657
A. ROUTLEDGE; I. WALKER; S. FREEMAN; A. HAY; N. MAHMOOD: "Synthesis, Bioactivation and Anti-HIV Activity of 4-Acyloxybenzyl Bis(Nucleosid-5-yl) Phosphates", NUCL. NUCL., vol. 14, 1995, pages 1545 - 1558, XP009120656, DOI: doi:10.1080/15257779508009491
C. MEIER: "CycloSal Phosphates as Chemical trojan Horses for the intracellular Nucleotide and Glycosylmonophosphate Delivery - Chemistry meets Biology", EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 2006, pages 1081 - 1102, XP002554869
H.J. JESSEN; T. SCHULZ; J. BALZARINI; C. MEIER: "Bioreversible protection of nucleoside diphosphates", ANGEWANDTE CHEMIE INTERNATIONAL EDITION, vol. 47, 2008, pages 8719 - 8722, XP002538710, DOI: doi:10.1002/anie.200803100
T. SCHULZ; J. BALZARINI; C. MEIER: "The DiPPro Approach: Synthesis, Hydrolysis, and Antiviral Activity of Lipophilic d4T Diphosphate Prodrugs", CHEMMEDCHEM, vol. 9, 2014, pages 762 - 75, XP055207340, DOI: doi:10.1002/cmdc.201300500
SCHULZ, T.: "doctoral thesis", 2012, UNIVERSITY OF HAMBURG, article "Synthese und Untersuchung von Nucleosiddi-phosphat Prodrugs"
L. WEINSCHENK; DOMINIQUE SCHOLS; JAN BALZARINI; CHRIS MEIER: "Nucleoside Diphosphate Prodrugs: Non-symmetric DiPPro-Nucleotides", J. MED. CHEM., vol. 58, 2015, pages 6114 - 6130
LA ALEXANDROVA; AY SKOBLOV; MV JASKO; LS VICTOROVA: "AA Krayevsky, 2'-Deoxy-nucleosides 5' -triphosphates modified at a-, β- and y-phosphates as substrates for DNA polymerases", NUCLEIC ACIDS RES., vol. 26, 1998, pages 778 - 786
LS VICTOROVA; DG SEMIZAROV; EA SHIROKOVA; LA ALEXANDROVA; AA ARZUMANOV; MV JASKO; AA KRAYEVSKY, HUMAN DNA POLYMERASES AND RETROVIRAL REVERSE TRANSCRIPTASES: SELECTIVITY IN RESPECT TO DNTPS MODIFIED AT TRIPHOSPHATE RESIDUES, vol. 18, 1999, pages 1031 - 1032
MULDER BA; ANAYA S; YU P ET AL.: "Nucleotide modification at the y-phosphate leads to the improved fidelity of HIV-1 reverse transcriptase", NUCL. ACIDS RES., vol. 33, no. 15, 2005, pages 4865 - 4873, XP055111673, DOI: doi:10.1093/nar/gki779
PERTUSATI: "Medicinal Chemistry of Phosphonate Prodrugs for Antiviral Therapy", ANTIVIR. CHEM. CHEM., vol. 22, 2012, pages 181 - 203, XP055275047, DOI: doi:10.3851/IMP2012
A. HOFER; GS CREMOSNIK; AC MILLER; R. GIAMBRUNO; C. TREFZER; G. SUPERTI-FURGA; KL BENNETT; HJ JESSEN: "A Modular Synthesis of Modified Phosphoanhydrides", CHEM. EUR. J., vol. 21, 2015, pages 10116 - 10122, XP055396615, DOI: doi:10.1002/chem.201500838
T. GOLLNEST; T. D. DE OLIVEIRA; D. SCHOLS; J. BALZARINI; C. MEIER: "Lipophilic prodrugs of nucleoside triphosphates as biochemical probes and potential antivirals", NAT COMMUN, 2015, pages 6
J. L. SESSLER; B. WANG; A. HARRIMAN, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 117, 1995, pages 704 - 714
A. HOFER; G. S. CREMOSNIK; A. C. MULLER; R. GIAMBRUNO; C. TREFZER; G. SUPERTI-FURGA; K. L. BENNETT; H. J. JESSEN, CHEMISTRY - A EUROPEAN JOURNAL, vol. 21, 2015, pages 10116 - 10122
L. WEINSCHENK; D. SCHOLS; J. BALZARINI; C. MEIER, JOURNAL OF MEDICINAL CHEMISTRY, vol. 58, 2015, pages 6114 - 6130
Attorney, Agent or Firm:
STÜVEN, Ralf et al. (DE)
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Claims:
CLAIMS

1. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug, or a

pharmaceutically acceptable salt thereof, having covalently bound to its terminal phosphate or analogous group a lipophilic moiety A and a lipophilic moiety B, the lipophilic moieties

A and B being different from each other, A being an intracellular stable lipophilic moiety, and B being an intracellular labile lipophilic moiety.

2. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug having the general formula I

or a pharmaceutically acceptable salt thereof, wherein

A and B are different lipophilic moieties, A being an intracellular stable lipophilic moiety, and

B being an intracellular labile lipophilic moiety,

U is, independently from each other, O, S, Se, or BH3, preferably O,

V is, independently from each other, O, CH2, NH, CHF, CHCl, CHBr, CF2, CC12, CBr2 or

CFC1, preferably O,

and wherein

R1 is nucleoside or nucleoside analogue.

3. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to claim 1 or 2, wherein

a) A is a residue according to formula II

(Π), wherein

RA1 , RA2 and RA4 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

Z is Y or CRA6RA7Y, Y being O, S, NH or CRA9RA10, and wherein

RA6, RA7, RA9 and RA10 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

RA3 and RA5 are, independently from each other, H or C(X)RA8, but are not both H, wherein X is O, S or NH, and

RA8 is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or

heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or

b) A is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue.

4. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to claim 3, wherein

a) RA1 , RA2 and RA4

i. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3_2o heteroaromatic residue, or an electron acceptor, or

ii. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3_i2 heteroaromatic residue, or an electron acceptor, or

iii. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or

unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 heteroalkenynyl, substituted or unsubstituted C5-24 Aryl, substituted or unsubstituted C3-24 heteroaryl, and electron acceptor, or

iv. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C2-10 alkenyl, substituted or

unsubstituted C2-10 alkynyl, substituted or unsubstituted C4-10 alkenynyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 cycloalkenyl, substituted or unsubstituted C5-10 cycloalkynyl, substituted or unsubstituted C5-10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C2-10 heteroalkenyl, substituted or unsubstituted C2-10 heteroalkynyl, substituted or unsubstituted C4-10 heteroalkenynyl, substituted or unsubstituted C5_12 aryl, substituted or unsubstituted C3-12 heteroaryl, and electron acceptor, or

v. are all H,

b) RA8

i. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3-20 heteroaromatic residue, or

ii. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3-12 heteroaromatic residue, or

iii. is selected from the group consisting of substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 heteroalkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, preferably Ci_2o alkyl or Ci_2o alkenyl, and c) RA6, RA7, RA9 and RA10

i. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, a substituted or unsubstituted C5-20 aromatic or C3_2o heteroaromatic residue, or an electron acceptor, or ii. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3_i2 heteroaromatic residue, or an electron acceptor, or

iii. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-2o alkenyl, substituted or

unsubstituted C2-2o alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, and electron acceptor, or

iv. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C2-10 alkenyl, substituted or

unsubstituted C2-10 alkynyl, substituted or unsubstituted C4-10 alkenynyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 cycloalkenyl, substituted or unsubstituted C5-10 cycloalkynyl, substituted or unsubstituted C5-10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C2-10 heteroalkenyl, substituted or unsubstituted C2-10 heteroalkynyl, substituted or unsubstituted C4-10 hetero alkenynyl, substituted or unsubstituted C5_12 aryl, substituted or unsubstituted C3-12 heteroaryl, and electron acceptor, or

v. are all H, or

vi. are an electron acceptor or H, with the proviso that residues at the same carbon atom are not both electron acceptors, or

d) A

i. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3-20 heteroaromatic residue, or

ii. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3-12 heteroaromatic residue, or iii. is selected from the group consisting of substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2_2o alkenyl, substituted or unsubstituted C2_2o alkynyl, substituted or unsubstituted C4_2o alkenynyl, substituted or unsubstituted C3_2o cycloalkyl, substituted or unsubstituted C3_2o cycloalkenyl, substituted or unsubstituted C5-2o cycloalkynyl, substituted or unsubstituted C5-2o cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2_2o heteroalkenyl, substituted or unsubstituted C2_2o heteroalkynyl, substituted or unsubstituted C4_2o hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3_24 heteroaryl, preferably Ci_2o alkyl or Ci_2o alkenyl, 5. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to one of claims 3 or 4, wherein Z is CRA6RA7Y, and wherein Y is O, S or NH, preferably O, the residues RA1, RA2, RA4, RA5, RA6 and RA7 are each H, and RA3 is C(X)RA8, wherein X is O, S or NH, preferably O, and wherein RA8 is as defined above. 6. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to one of the preceding claims, wherein B is a residue according to the following formula III

wherein

RB1, RB2 and RB4 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

RB6 and RB7 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

RB3 and RB5 are, independently from each other, H or WC(X)RB8, but are not both H, wherein W and X are, independently from each other, O, S or NH, preferably both O, and

RB8 is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or

heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue.

7. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to claim 6, wherein

f) RB1, RB2 and RB4

i. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3_2o heteroaromatic residue, or an electron acceptor, or

ii. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3_i2 heteroaromatic residue, or an electron acceptor, or

iii. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or

unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, and electron acceptor, or

iv. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C2-10 alkenyl, substituted or

unsubstituted C2-10 alkynyl, substituted or unsubstituted C4-10 alkenynyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 cycloalkenyl, substituted or unsubstituted C5-10 cycloalkynyl, substituted or unsubstituted C5-10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C2-10 heteroalkenyl, substituted or unsubstituted C2-10 heteroalkynyl, substituted or unsubstituted C4-10 hetero alkenynyl, substituted or unsubstituted C5_12 aryl, substituted or unsubstituted C3-12 heteroaryl, and electron acceptor, or

v. are all H,

g) RB8 i. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3-20 heteroaromatic residue, or

ii. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3-12 heteroaromatic residue, or

iii. is selected from the group consisting of substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, preferably Ci_2o alkyl or Ci_2o alkenyl, h) RB6 und RB7

i. are, independently from each other, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_2o aliphatic or Ci_2o heteroaliphatic residue, a substituted or unsubstituted C5-20 aromatic or C3_2o heteroaromatic residue, or an electron acceptor, or

ii. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C5_12 aromatic or C3_i2 heteroaromatic residue, or an electron acceptor, or

iii. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_2o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or

unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_2o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, and electron acceptor, or

iv. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C2_10 alkenyl, substituted or unsubstituted C2_10 alkynyl, substituted or unsubstituted C4_10 alkenynyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 cycloalkenyl, substituted or unsubstituted C5_10 cycloalkynyl, substituted or unsubstituted C5_10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C2_10 heteroalkenyl, substituted or unsubstituted C2_10 heteroalkynyl, substituted or unsubstituted C4-10 hetero alkenynyl, substituted or unsubstituted C5_12 aryl, substituted or unsubstituted C3-12 heteroaryl, and electron acceptor, or

v. are all H, or

vi. are an electron acceptor or H, with the proviso that RB6 is H and RB7 is an electron acceptor, or RB7 is H and RB6 is an electron acceptor.

8. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to claim 7, wherein the nucleoside triphosphate or nucleoside triphosphate analogue prodrug is a compound according to the following formula If

or a pharmaceutically acceptable salt thereof, wherein Z is Y or CR R Y, preferably C¾Y, aanndd wwhheerreeiinn YY iiss OO,, SS,, NNHH oorr CCRAyRA , preferably O, and X is O, S or NH, preferably O, and W is O, S or NH, preferably O.

9. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to one of claims 1 to 8 for use as a medicament.

10. Nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to one of claims 1 to 8 for use as an antiviral medicament, preferably as an antiretroviral medicament, medicament for treating an HIV infection, hepatitis infection, influenza or hemorrhagic fever.

11. Pharmaceutical composition or dosage form comprising a nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to one of claims 1 to 8 and a

pharmaceutically acceptable carrier.

Description:
NUCLEOSIDE TRIPHOSPHATE AND NUCLEOSIDE TRIPHOSPHATE ANALOGUE PRODRUGS

The invention relates to compounds that can be used as nucleoside triphosphate or nucleoside triphosphate analogue prodrugs.

In the treatment of, for example, viral infectious diseases such as herpes or hepatitis infections or the immune deficiency disease AIDS (Acquired Immunodeficiency Syndrome), but also in cancer, nucleoside analogues are used, which can be incorporated into DNA. After

incorporation, the nucleoside analogues in general act as chain terminators, i.e. there is no further elongation in the 3'-direction (Balzarini, P. Herdewijn, E. De Clercq; Differential Patterns of intracellular Metabolism of 2 ' ,3 ' -Didehydro-2 ' ,3 ' -dideoxythymidine and 3 ' -Azido- 2 ' ,3 ' -dideoxythymidine, two potent Anti-human Immunodeficiency Virus Compounds; J. Biol. Chem. 1989, 264, 6127-6133). However, the nucleoside analogues must be present as triphosphates (NTP), so that they can be incorporated into the DNA strand for chain extension.

In the form of their mono-, di- or triphosphates (NMP, NDP, NTP), nucleoside analogues can not penetrate the cell membrane under physiological conditions due to their charge. It is also not possible to pass the blood brain barrier (BBB) to treat diseases affecting the brain.

Therefore, nucleoside analogues must either be intracellularly converted into their triphosphates by more or less specific kinases in several stages, or phosphorylated nucleoside analogues must be designed or modified so as to be able to pass through the cell membrane or BBB.

For this purpose, the lipophilicity of the drugs has usually to be increased (e.g. RJ Sawchuk, Z. Yang, Investigation of distribution, transport and uptake of anti-HIV drugs to the central nervous system, Advanced Drug Delivery Reviews 1999, 39, 5-31). One possibility of increasing the lipophilicity of known drugs is the use of prodrug systems. Prodrugs are precursors of an active agent, releasing the active agent at the desired site of action after biotransformation, e.g. detachment of masking groups. In addition to increased lipophilicity, further preconditions for prodrugs are sufficient stability in extracellular medium and the release of non-toxic masks. Enzymatically activatable prodrug systems for nucleoside monophosphates (NMP) have already been described (A. Pompon, I. Lefebvre, J.-L. Imbach, S. Khan, D. Farquhar;

Decomposition Pathways of the Mono-(Pivaloyloxymethyl) and Bis-(Pivaloyloxymethyl) Esters of Azidothymidine-5'-Monophosphate in Cell Extract and in Tissue-Culture Medium - An Application of the Online Isrp-Cleaning HPLC Technique; Antiviral Chem. Chemother. 1994, 5, 91-98; I. Lefebvre, C. Perigaud, A. Pompon, A.-M. Aubertin, J.-L. Girardet, A. Kim, G. Gosselin, J.-L. Imbach; Mononucleoside Phosphotriester Derivates with S Acyl-2-thioethyl Bioreversible Phosphate-Protecting Groups: Intracellular Delivery of 3'-Azido-2',3'- dideoxythymidine-5'-monophosphate; J. Med. Chem. 1995, 38, 3941-3950; W. Thomson, D. Nicholls, W. J. Irwin, J. S. Al-Mushadani, S. Freeman, A. Karpas, J.Petrik, N. Mahmood, A. J. Hay, Synthesis, Bioactivation and Anti-HIV Activity of the Bis(4-acyloxybenzyl) and Mono(4- acyloxybenzyl) Esters of the 5 '-Monophosphate of AZT, J. Chem. Soc, Perkin Trans., 1993, 1, 1239-1245; Thomson, D. Nicholls, W. J. Irwin, J. S. Al-Mushadani, S. Freeman, A. Karpas, J.Petrik, N. Mahmood, A. J. Hay, Synthesis, Bioactivation and Anti-HIV Activity of the Bis(4- acyloxybenzyl) and Mono(4-acyloxybenzyl) Esters of the 5 '-Monophosphate of AZT, J. Chem. Soc, Perkin Trans., 1993, 1 , 1239-1245; A. Routledge, I. Walker, S. Freeman, A. Hay, N. Mahmood, Synthesis, Bioactivation and Anti-HIV Activity of 4-Acyloxybenzyl Bis(Nucleosid- 5-yl) Phosphates; Nucl. Nucl, 1995, 14, 1545-1558; C. Meier, CycloSal Phosphates as

Chemical trojan Horses for the intracellular Nucleotide and Glycosylmonophosphate Delivery - Chemistry meets Biology; European Journal of Organic Chemistry 2006, 1081-1102).

However, although a few nucleoside monophosphate prodrug systems are known and are successfully applied, e.g. Sofosbuvir against Hepatitis C, the disadvantage of using NMP prodrugs is that the necessary subsequent phosphorylation to diphosphates and triphosphates in the cell can still be inhibited or completely suppressed. For example, in the case of the nucleoside analogue azidothymidine (AZT), a known anti-HIV drug, the phosphorylation to the AZTDP (DP = diphosphate) is inhibited. In addition, numerous side effects are attributed to the corresponding monophosphate AZTMP (MP = monophosphate).

A suitable masking of nucleoside triphosphates (NTP) and analogues thereof is therefore desirable. In contrast to NMPs, in NTPs not only one phosphate group is present, but two energy-rich phosphoric acid anhydride bonds, which must be reversibly masked in the form of the pyrophosphate unit without causing a cleavage in the anhydride bond(s). When the pyrophosphate moiety is unmasked, no reaction must take place at the phosphorus atom as this can lead to a break in the pyrophosphate bridge. This essentially differentiates NDP and NTP prodrugs from their NMP relatives. Hydrolysis reactions on the phosphorus atom can also take place. Nucleoside triphosphates, in particular, may be dephosphorylated very rapidly intracellularly. In addition, there is still the risk that, besides the microbial (pathogen) polymerases (viruses, bacteria or parasites), cell-specific polymerases are also inhibited. This can potentially lead to a toxico logical problem.

WO 2009/129798 A2 describes symmetrically masked nucleoside diphosphates and triphosphates as well as a process for their preparation. "Symmetric" in this context means that the masks used for masking the charges of the terminal phosphate have the same structure. However, it has been found that the percentage of the desired diphosphate or triphosphate species of the active ingredient released during the chemical or enzymatic hydrolysis depends on the rate of cleavage of the first mask releasing the monomasked intermediate. The corresponding hydrolysis products of the pyrophosphate group were detected as a byproduct, the corresponding nucleoside monophosphates in the case of the nucleoside diphosphate prodrugs, and the corresponding nucleoside diphosphates and the nucleoside monophosphates in case of the nucleoside triphosphates. This ultimately results in a merely nonselective release of the desired target compounds.

Jessen et al. 2008 and Schulz et al. 2014 (H.J. Jessen, T. Schulz, J. Balzarini, C. Meier, Bio- reversible protection of nucleoside diphosphates; Angewandte Chemie International Edition 2008, 47, 8719-8722; T. Schulz, J. Balzarini, C. Meier, The DiP ro Approach: Synthesis, Hydrolysis, and Antiviral Activity of Lipophilic d4T Diphosphate Prodrugs; ChemMedChem 2014, 9, 762-75; see also Schulz, T., 2012, Synthese und Untersuchung von Nucleosiddi- phosphat Prodrugs, doctoral thesis, University of Hamburg) also describe first examples of symmetrically masked nucleoside triphosphates. In addition, Schulz et al. 2014 describe the non-symmetric masking of a nucleoside diphosphate analogue (l-[(2R,5S)-5-(hydroxymethyl)- 2,5-dihydrofuran-2-yl]-5-methylpyrimidine-2,4-dion, Stavudine, d4T) with a acyloxybenzyl group and a β-cyanoethyl group. The β-cyanoethyl group was rapidly cleaved in biological media. In WO 2016/026493 Al, nucleoside and triphosphate compounds are described, which are bioreversibly non-symmetrically masked at the terminal phosphate group, one mask being more labile than the other and, thus, being cleaved more rapidly (see also L. Weinschenk, Dominique Schols, Jan Balzarini, Chris Meier, Nucleoside Diphosphate Prodrugs: Non- symmetric DiP ro-Nucleotides. J. Med. Chem. 2015, 58, 6114-6130).

It is an object of the present invention to provide improved nucleotide or nucleotide analogue prodrugs. The problem is solved according to the invention by a non-symmetric chemical modification of nucleoside triphosphate compounds, or analogues thereof, at the terminal phosphate group or the respective analogous group containing a γ-phosphorus atom, one modification being covalently attaching an intracellularly labile moiety acting as a prodrug masking moiety, while the other modification is covalently attaching an intracellularly stable moiety, which is not supposed to be cleaved neither (photo-)chemically nor enzymatically within the cell.

The invention provides nucleotide or nucleotide analogue prodrugs, which are converted intracellularly to γ-phosphate-mono-modified nucleotides or nucleotide analogues. By means of the non-symmetric modification used according to the invention, nucleoside triphosphates (NTP) or their analogues can be successfully introduced into the cell, but instead of releasing the respective NTP or analogue in the cell as such, γ-mono -modified NTPs or analogues thereof are released from the prodrug, which are stable in the intracellular environment. The mono-modified compounds are particularly suitable for the selective inhibition of microbial or viral polymerases, e.g. reverse transcriptase of the human immunodeficiency virus. The modification is carried out only at the terminal phosphate, i.e. at the γ-phosphate. Additional modification of the internal phosphate(s) can be dispensed with.

It has been described in the literature that γ-modified nucleoside triphosphates with one methyl ester unit on the γ-phosphate or an arylphosphonate instead of the γ-phosphate of the nucleo- side triphosphates can be substrates for the viral HIV polymerase in primer extension assays. Moreover, it has been shown that the use of such mono-y-modified nucleoside triphosphates with small aliphatic or aromatic residues can lead to differentiation between different polyme- rases. In contrast to viral reverse transcriptase, mono-y-modified nucleoside triphosphates are much less or not at all recognized as a substrate by the human DNA polymerases (see, for example, LA Alexandrova, AY Skoblov, MV Jasko, LS Victorova, AA Krayevsky, 2'-Deoxy- nucleosides 5' -triphosphates modified at α-, β- and γ-phosphates as substrates for DNA poly- merases, Nucleic Acids Res. 1998, 26, 778-786, LS Victorova, DG Semizarov, EA Shirokova, LA Alexandrova, AA Arzumanov, MV Jasko, AA Krayevsky, Human DNA Polymerases and retroviral reverse transcriptases: Selectivity in respect to dNTPs modified at triphosphate residues, 1999, 18, 1031-1032; Mulder BA, Anaya S, Yu P, et al. Nucleotide modification at the γ-phosphate leads to the improved fidelity of HIV- 1 reverse transcriptase. Nucl. Acids Res. 2005, 33(15):4865-4873. doi:10.1093/nar/gki779). However, the published compounds were not and could not be used as potential virostatic agents, since they were too polar for a membrane passage. No prodrugs of such compounds have been reported or discussed yet.

In a first aspect the present invention provides a nucleoside triphosphate or nucleoside triphosphate analogue prodrug, or a pharmaceutically acceptable salt thereof, having covalently bound to its terminal phosphate or analogous group a lipophilic moiety A and a lipophilic moiety B, the lipophilic moieties A and B being different from each other, A being an intracellular stable lipophilic moiety, and B being an intracellular labile lipophilic moiety. The nucleoside triphosphate or nucleoside triphosphate analogue prodrug according to the first aspect of the invention is cell-penetrating and permits the intracellular release of an active compound, for example an antivirally or an antitumoral active compound. In the compounds according to the invention, the moieties A and B at the terminal phosphorus atom differ by their stability within the cell. One of the moieties is intracellularly labile (and is therefore also called mask), for example enzymatically cleavable, e.g. by means of esterases, while the other moiety is intracellularly stable, so that after e.g. enzymatic cleavage of the labile moiety (mask) in the cell a mono-modified nucleotide or nucleotide analogue results. The resulting stably mono-modified compound has high resistance to nucleophilic attack on the phosphoanhydride bond(s) and enzymatic cleavage of the stable moiety A. Both the mask B and the moiety A are lipophilic and thus ensure the necessary lipophilicity in order to ensure entry into the cell. The adjustment of the lipophilicity of these two moieties is known to a person skilled in the art and can, if necessary, be determined by routine experimentation. For example, the lipophilicity of the mask (moiety B) and the stable moiety A can be manipulated by the size or length of a hydrocarbon residue. The stability of the moieties can also be influenced, for example, by the incorporation of heteroatoms. In addition, the selection of a suitable stable modification at the γ-phosphorus atom of a nucleoside triphosphate or analogue also allows a differentiation in the property of the mono-modified compound resulting after removal of the mask to function as a substrate of microbial/viral and endogenous polymerases. Particularly advantageous is, for example, a γ-mono -modified nucleoside triphosphate analogue, which is used at least predominantly or specifically only by microbial/viral polymerases and not or insignificantly by endogenous polymerases as substrate, as a result of which possible adverse effects on the cell can be avoided or reduced.

The compounds according to the invention allow the introduction of nucleotides and nucleotide analogues at the level of stably mono-modified triphosphates or triphosphate analogues into the cell. In particular, nucleoside triphosphates and analogues thereof can be introduced directly into the cell, in which they will be released and can also be enriched in a stably mono-modified form so that they can directly be used as a substrate of e.g. viral polymerases. As a result, side effects which are caused, for example, by monophosphates can be avoided. By intracellular release of stably mono-modified triphosphate analogues, which selectively serve as substrate for microbial/viral, but not or only marginally for cellular enzymes, side effects can be avoided which are caused by endogenous cellular enzymes using the introduced compounds as substrate leading to incorporation of the nucleoside triphosphate analogue into cellular

R A/DNA, e.g. by the mitochondrial DNA polymerase γ. The compounds according to the invention can, for example, find advantageous use in medicinal products both as antiviral and as antitumoral agents. They are particularly suitable as drugs for the treatment of infections by viruses, in particular retroviruses such as HI viruses, influenza, hemorrhagic fever and hepatitis viruses.

The intracellularly stable moiety A is thus preferably selected in such a way that it particularly provides for a specificity of the mono-modified compound, i.e. the compound having only the stable moiety A, as a substrate for, for example, viral/microbial enzymes, preferably polymerases, for example reverse transcriptases (EC 2.7.7.49), such as those of the HI virus. In contrast, the intracellularly for example enzymatically cleavable mask B ensures in particular for sufficient cell uptake of the original dimodified compound and the intracellular formation of the mono-modified compound. In addition, the stable moiety A also preferably improves cell membrane penetration by virtue of its lipophilicity.

The compounds according to the invention are generally present as salts under physiological conditions. In the following, a triphosphate compound or triphosphate analogue la is shown by way of example, where Cat + means cation, for example ammonium, sodium or potassium cation. Nucl stands for nucleoside or nucleoside analogue.

The term "nucleoside triphosphate or nucleoside triphosphate analogue" refers to nucleoside triphosphates or analogues thereof, a nucleoside triphosphate being a compound according to the following general formula VI

0 0 0

I I I I 1 1

HO- pP——Oo-— -Pp——O— -pP—— N

| β o- ucleoside (VI),

I\ Yy | β 1| a<X

OOHH OOHH OOHH

and a "nucleoside triphosphate analogue" being an analogue of a nucleoside triphosphate. Nucleoside triphosphates are composed of a base component (nucleobase), a sugar component, e.g. a pentose like ribose or deoxyribose, and a triphosphate residue (sometimes also termed "triphosphate bridge") attached to an O atom of the sugar component, e.g. an O atom bound to the 5' atom of a pentose. The term "triphosphate analogue" refers to compounds not being triphosphates in a strict sense, because they do not contain three phosphate groups, i.e. groups having a phosphorus atom bound to four oxygen atoms, but contain groups analogous to phosphate groups, e.g. phosphonate groups, instead of one or two phosphate groups. A

"nucleoside triphosphate analogue" is a chemical compound, which is structurally and/or functionally similar to a nucleoside triphosphate such that an enzyme, e.g. a viral polymerase, having a nucleoside triphosphate naturally occurring in, for example, a human cell as a substrate would also use said compound as a substrate, analogous to the naturally occurring nucleoside triphosphate. A nucleoside triphosphate analogue may, in relation to a naturally occurring nucleoside triphosphate, be modified in one, two or in each of the above-mentioned components, i.e. the base component, the sugar component or the triphosphate component. The latter may, for example, be modified in that the bridging O atoms are replaced by, e.g. CH 2 , CF 2 , NH etc., or in that the non-bridging O atoms are replaced, e.g. by O, S or BH 3 . The term "terminal phosphate or analogous group" refers to the terminal or γ-phosphate (γ- phosphoryl) group of the triphosphate group, or to the group, e.g. phosphonate, phosphoro- thioate, phosphoroselenoate or boranophosphate group, being analogous to the terminal phosphate group, i.e. the terminal group not being a phosphate group but containing a phosphorus atom. The term "γ-phosphorus atom" as used herein relates to the phosphorus atom of the terminal phosphorus containing group of the triphosphate component or the component being analogous thereto.

A "non-symmetrically modified nucleoside triphosphate or nucleoside triphosphate analogue prodrug" is understood to mean a nucleoside triphosphate or nucleoside triphosphate analogue being twice, but non-symmetrically, modified at the γ-phosphorus atom thereof, by covalently attaching two different lipophilic groups A and B at the group containing the γ-phosphorus atom. Group B is an intracellularly labile moiety, while group A is intracellularly stable moiety. A non-symmetrically modified nucleoside triphosphate or nucleoside triphosphate analogue prodrug" may thus be a compound according to the following general formula I

in which A and B stand for different chemical structures, U is, independently from each other, O, S, Se, or BH 3 , for example O, V is, independently from each other, O, CH 2 , NH, CHF, CHC1, CHBr, CF 2 , CC1 2 , CBr 2 or CFC1, for example O, and R 1 is nucleoside or nucleoside analogue. The terminal phosphorus atom, i.e. the γ-phosphorus atom, thus forms a stereogenic centre. The chemical structures A, B neutralize the negative electric charges at the single- bonded oxygen atoms of the terminal phosphate under physiological conditions. In the case of the stable moiety A, an oxygen atom otherwise bound to the terminal phosphorus atom can also be replaced by S or NH. The two organic groups A and B themselves are also not charged under physiological conditions. The term "mono -modified" used here in relation to a nucleoside triphosphate or nucleoside triphosphate analogue exclusively relates to compounds comprising the intracellularly stable moiety A only at the terminal phosphate or the group analogous to the terminal phosphate group, e.g. a terminal phosphonate group. According to the invention, mono-modified triphosphate compounds or triphosphate analogues are released within a cell, e.g. a mammalian cell, by cellular activity, e.g. enzymatically, from a compound of the invention having, at the terminal phosphate or analogues group, both an intracellularly stable moiety A and an intracellularly labile moiety (mask) B. The latter compounds, i.e. triphosphate compounds or analogues thereof carrying, at their terminal phosphate or analogous group, both the mask B and the stable moiety A, may be referred to as being "dimodified" or as being "monomasked plus mono-modified".

An "intracellularly labile moiety", which may also be referred to as "mask", or as an

"intracellularly labile group", "enzymatically cleavable moiety", "enzymatically cleavable group", or the like, is understood here to be a chemical group which is, e.g. hydrolytically, cleavable under conditions prevailing in a target cell, preferably a eukaryotic, for example human cell, for example in terms of temperature, pH, salt content, etc., with the aid of enzymes present or, as the case may be, inducible in the target cell. The term also encompasses photolabile, i.e. photocleavable moieties, e.g. groups that can be cleaved by irradiation with UV or near-UV light. The term also encompasses those cases in which a mask is degraded in several steps, for example cascade-like, and at least one degrading step takes place

enzymatically. For example, the initial attack can be carried out enzymatically, while the further degradation steps occur spontaneous. In particular, a moiety is considered to be intracellularly labile, if the compound masked therewith has a comparatively low half-life in the cell, for example a half-life of < 4 h, preferably < 3 h, < 2 h, < 1 h, < 45 min or < 30 min.

Under an "intracellularly stable moiety", which may also be referred to as "intracellularly stable modification", "intracellularly stable group", "intracellularly stable protecting group" or similar terms, is to be understood a modification which is not or at least essentially not cleaved under intracellular conditions, and which is also not cleaved photo chemically. In particular, an "intracellularly stable moiety" is understood to be an intracellularly stable modification if the compound modified with it has a high half-life in the cell, for example a half-life of >24 h, preferably >36, >48, >60, >72, >84, >96, >108 or >120 h.

By "nucleoside" are meant organic molecules consisting of a sugar residue (sugar component) linked to an organic base (base component), e.g. a heterocyclic organic base, in particular a nitrogen-containing heterocyclic organic base (nucleobase), which are linked via a glycosidic bond. The sugar moiety is often a pentose, e.g. deoxyribose or ribose, but may also be another sugar, e.g. a C 3 -, C 4 - or C 6 -sugar. Frequently, but not exclusively, nucleobases are purines (R) or pyrimidines (Y). Examples of naturally occurring purines are guanine (G) and adenine (A), examples of naturally occurring pyrimidines are cytosine (C), thymine (T) and uracil (U). In particular, a nucleoside is therefore a compound of the following general formula

wherein B is a nitrogen-containing heterocyclic organic base, e.g. a nucleobase, and R 2 and R 3' are, independently from each other, H or OH. Phosphorylated nucleosides, for example nucleoside monophosphates (NMP), nucleoside diphosphates (NDP) and nucleoside triphosphates (NTP), are also referred to as nucleotides. The phosphate, diphosphate

(pyrophosphate) or triphosphate group is generally linked to the O atom attached to the 5'-C atom of the sugar component of the nucleoside. However, the invention also encompasses compounds in which the phosphate group(s) is(are) bound to a 2'- or 3'-OH group.

A "nucleoside analogue" (or "nucleoside analog") is to be understood here as an organic compound which is naturally not present in the human body but which is structurally similar to a nucleoside occurring naturally in the human body so that it can be used, for example, by the cell and/or viral enzymes essentially corresponding to the natural nucleoside, for example phosphorylated and incorporated into an RNA or DNA strand. A nucleoside analogue can itself be a nucleoside. However, for example, it may also be another compound having the above characteristics, for example a compound of a heterocyclic base and an acyclic residue and/or a residue which is not a sugar, or a compound of a carbocyclic compound and a heterocyclic base. In the case of carbocyclic nucleoside analogues, for example, the ring oxygen in the sugar component is replaced by a carbon (a methylene group or a substituted methylene group). In the sugar component, for example, a carbon atom may also be replaced by a heteroatom, for example the 3 '-carbon atom by sulfur. Further, the 5' hydroxyl group of the sugar component may be replaced by another group, e.g. an amino group, or substituted. A nucleoside analogue may also be composed of a sugar like ribose or deoxyribose and a nucleobase analogue.

Examples of nucleobase analogues are 5-bromouracil, 6-azathymine, 5-fluorouracil and N 6 - hydroxy adenine. Nucleoside analogues are either themselves nucleosides in the above sense or structurally and/or functionally analogous to nucleosides. Since nucleoside analogues do not necessarily have to contain a sugar or base component in the narrow sense, the terms

"component analogous to the (naturally occurring nucleo)base" (base analogue) or "component analogous to the sugar component" (sugar analogue) may also be used here. If a sugar component or base component is mentioned here, the corresponding analogous components of nucleoside analogues are also encompassed, unless the context clearly indicates otherwise. Numerous nucleoside analogues are known to the person skilled in the art. Known examples are AZT (3'-azido-2',3'-dideoxythimidine, azidothymidine), 2',3'-dideoxyinosine (didanosine), 2',3'-dideoxycytidine (zalticabine), P-L-2',3'-dideoxythiacytidine (lamivudine, 3TC), L- thymidine, 2'-methyl-("up")-2'-hydroxyl-("down")-uridine/-cytidine), 2'-Methyl-(„up")-2'- fluoro-(„down")-uridine/-cytidine (see, for example, US Pat. No. 7608600 Bl), 2-amino-9-((2- hydroxyethoxy)methyl)-lH-purine-6(9H)-one (Acyclovir). Nucleoside analogues which inhibit reverse transcriptase from retroviruses such as human immunodeficiency virus (HIV) are also referred to as NRTIs (nucleoside reverse transcriptase inhibitors).

A "nucleoside phosphate analogue" is understood to mean an analogue to a phosphorylated nucleoside, i.e. a nucleotide analogue. The term "nucleoside monophosphate analogue" is, for example, understood to mean an analogue to a nucleoside monophosphate. Examples of nucleoside monophosphate analogues are nucleoside phosphonates, such as, for example, 3- hydroxy-2-phosphonomethoxypropyl (HPMP), 2-phosphonomethoxyethyl (PME), 2',3'- didehydro-2',3'-dideoxythymidine phosphonate (d4TP), (S)9-(3-hydroxy-2- phosphonylmethoxypropyl) adenine (HPMP A) and 9-(2-phosphonylmethoxyethyl) adenine (PMEA, adefovir). Nucleoside phosphonates are known to the person skilled in the art, contain a C-P linkage instead of the P-0 linkage of nucleoside phosphates, and can contain, for example, a nucleobase, an acyclic or cyclic aliphatic sugar-analogous component and a phosphonomethyl group CH 2 P(0)(OH) 2 group (see, for example, Pertusati et 2012, Medicinal Chemistry of Phosphonate Prodrugs for Antiviral Therapy, Antivir. Chem. Chem. 22: 181-203, doi: 10.3851 / IMP2012). Phosphorylated nucleoside analogues, for example phosphorylated nucleosides with a modified nucleobase, also fall under the terms "nucleoside phosphate analogue" or "nucleotide analogue."

If the abbreviation "Nucl" is used here, it encompasses both nucleosides and nucleoside analogues. The abbreviations "NMP", "NDP" and "NTP" encompass not only nucleoside monophosphates, nucleoside diphosphates and nucleoside triphosphates, but also

corresponding analogues, i.e. nucleoside monophosphate analogues, nucleoside diphosphate analogues and nucleoside triphosphate analogs, unless explicitly stated otherwise.

For the purposes of the present invention, the indication of a range such as " 1-10", for example, is to be understood as meaning that each intermediate value is also disclosed. In the case of an indication which can only affect integers, such as, for example, a number of C atoms, this means, of course, that only integers are disclosed. Any narrower range from a broader range is also meant to be disclosed by indicating the broader range, the narrower range also including ranges not comprising any of the boundary values of the broader range (e.g. a range of 2-5 from a range of 1-10).

The term "C n -C m " or "C n _ m ", where n and m are each positive integers and m is greater than n, means a range indicating the number of carbon atoms of a compound or residue. The expression here expressly includes all integer intermediate values between the range boundaries n and m, in each case independently of one another. The expression "C 1 -10 " (n = 1 , m = 10) therefore means, for example, a compound, group or residue having 1-10, i.e. 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. "C 1 -10 " therefore also comprises, for example, "C 2 _6 M , i.e. 2, 3, 4, 5 or 6 carbon atoms, or "C ", i.e. 1 , 2, 3 or 4 carbon atoms, or "C4-9", i.e. 4, 5, 6, 7, 8 or 9 carbon atoms. Correspondingly, the term "Ci_ 2 o-alkyl" means, for example, an alkyl group having 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18 , 19 or 20 carbon atoms and comprises all combinations of the values of n and m, which lie in the range from n = 1 to m = 20, for example "C 1 -10 alkyl", i.e., an alkyl having 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms, or "C5-7 alkyl", i.e. an alkyl having 5, 6 or 7 carbon atoms. Correspondingly, this also applies to terms such as "C 2-10 alkenyl", "C4-20 alkenynyl", and the like.

The term "aliphatic residue" comprises cyclic or acyclic linear (straight chain) or branched, saturated or unsaturated carbon compound residues, other than aromatic residues. The term "heteroaliphatic residue" means aliphatic residues in whose carbon skeleton one or more C atoms are replaced by heteroatoms, for example oxygen, sulfur, nitrogen or phosphorus.

The term "alkyl" comprises saturated aliphatic (non-aromatic) groups including straight-chain (linear) alkyl groups (e.g. methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl), and branched alkyl groups (e.g. isopropyl, tert-butyl, isobutyl). The term also encompasses O, N, S or P alkyl groups (e.g., -O-methyl), i.e. alkyl groups which are bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. The term "alkenyl" comprises unsaturated aliphatic (non-aromatic) groups having at least one C-C double bond, including straight-chain and branched alkenyl groups. The term also includes 0-, N-, S- or P-alkenyl groups (e.g., -O-propenyl), i.e. alkenyl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. The term "alkynyl" (or "alkinyl") includes unsaturated aliphatic (non-aromatic) groups having at least one C-C triple bond, including straight-chain and branched alkynyl groups. The term also includes O, N, S or P alkynyl groups (e.g., -O-butinyl), i.e. alkynyl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. The term "alkenynyl" (or "alkeninyl") includes unsaturated aliphatic (non-aromatic) groups having at least one C-C double bond and at least one C-C triple bond, including straight-chain and branched alkenynyl groups. The term also includes 0-, N-, S-, or P-alkenynyl groups, i.e. alkenynyl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom.

The term "cycloalkyl" includes compounds containing an alicyclic group, i.e. a ring-shaped saturated aliphatic (non-aromatic) group, e.g. cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl group. The term also includes 0-, N-, S- or P-cycloalkyl groups, i.e. cycloalkyl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. The terms "cycloalkenyl", "cycloalkynyl" and "cycloalkenynyl" mean correspondingly ring- shaped aliphatic (non-aromatic) alkenyls, alkynyls or alkenynyls as defined above, the double and/or triple bond(s) being present within or outside the ring or ring system.

The term "heteroalkyl" refers to alkyl groups in which one or more carbon atoms of the hydrocarbon structure are replaced by other atoms (heteroatoms), e.g. oxygen, nitrogen, sulfur or phosphorus atoms. The term also includes 0-, N-, S- or P-heteroalkyl groups, i.e.

heteroalkyl groups which are bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. The term "heteroalkyl" also includes cycloalkyls in which one or more carbon atoms of the hydrocarbon structure are replaced by other atoms, e.g. oxygen, nitrogen, sulfur or phosphorus atoms. The terms "heteroalkenyl", "heteroalkynyl", "heteroalkeninyl" mean corresponding alkenyls, alkynyls and alkeninyls, as well as cycloalkenyls, cycloalkynyls and cycloalkeninyls, in which one or more carbon atoms of the hydrocarbon skeleton are replaced by other atoms (heteroatoms), e.g. oxygen, nitrogen, sulfur or phosphorus atoms. For example, the term "Ci_2o-heteroalkyl" means an alkyl group having 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms and at least one heteroatom. The same also applies to heteroalkenyls, hetero alkynyls and heteroalkenynyls. By "aryl" are meant groups with aromaticity, including multi-membered aromatic single ring groups and multicyclic systems with at least one aromatic ring. Examples of aryl groups include benzene, phenyl and naphthalene. The term also includes 0-, N-, S- or P-aryl groups, i.e. aryl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom. By "heteroaryl" are meant aryl groups having at least one heteroatom in the ring structure, i.e. in which one or more carbon atoms in the ring structure are replaced by other atoms

(heteroatoms), e.g. b oxygen, nitrogen, sulfur or phosphorus atoms. Examples of heteroaryls are pyrrole, furan, thiophene, thiazole, isothiazole, imidazole, triazole, tetrazole, pyrazole, oxazole, pyridine, pyrazine, pyridazine and pyrimidine. The term also includes multicyclic, e.g. bicyclic and tricyclic, aryl groups, e.g. benzoxazole, benzodioxazole, benzothiazole, benzoimidazole, benzothiophene, methylenedioxyphenyl, quinoline, isoquinoline, indole, benzofuran, purine or benzofuran. The term also includes 0-, N-, S- or P-heteroaryl groups, i.e. heteroaryl groups bound to a compound via an oxygen, nitrogen, sulfur or phosphorus atom.

By the term "halogen" is meant chlorine (CI), fluorine (F), bromine (Br) and iodine (I), particular chlorine (CI) and fluorine (F).

The term "substituted" means that one or more substituents are present, which replace a hydrogen atom on one or more carbon atoms of the hydrocarbon structure or on one or more heteroatoms in the carbon skeleton. Examples of such substituents are oxo, hydroxyl, phosphate, cyano, azido and amino groups, but also e.g. halogens (e.g., F, CI, Br), acyl, acyloxy, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl and heteroaryl groups. Instead of the term "substituent" also the terms "residue" or "moiety" may be used here.

An "electron acceptor" is understood here to be a compound, compound residue or functional group which accepts, attracts or withdraws electrons and thus causes a charge displacement, i.e. a polarization, in a compound. Electron acceptors or electron acceptor groups are known to a person skilled in the art and have, for example, a negative inductive or mesomeric effect. Examples of electron acceptor groups are MeS0 2 , =0, C(0)H, COOH, C0 2 R, CN, S0 3 H, ketones, esters or the ester group, N0 2 and halogen (e.g. F, CI). Me stands for methyl.

A nucleoside triphosphate or nucleoside triphosphate analogue according to the first aspect of the invention preferably is a compound according to the following general formula I

or a pharmaceutically acceptable salt thereof, wherein

A and B are different lipophilic moieties, A being an intracellular stable lipophilic moiety, and

B being an intracellular labile lipophilic moiety,

U is, independently from each other, O, S, Se, or BH 3 , preferably O,

V is, independently from each other, O, CH 2 , NH, CHF, CHC1, CHBr, CF 2 , CC1 2, CBr 2 or

CFC1, preferably O, and wherein nucleoside or nucleoside analog.

Preferably, U and V are each O. A nucleoside triphosphate or nucleoside triphosphate analogue according to this preferred embodiment has a structure according to the following general formula la:

The residue R 1 is, in the case of a nucleoside or nucleoside analogue, preferably bound via the sugar component or the component analogous to the sugar component, for example via an oxygen atom, e.g. the oxygen atom bound to the 5'-C atom of a pentose. The residue may, however, also be bound to the phosphorus atom via a C atom, preferably a C atom of the sugar component or sugar component analogue, e.g. a 5'-C atom of a pentose or pentose analogue, thus forming a phosphonate group, or via another suitable atom or group, e.g. NH or S. The residue R 1 may, for example, also be bound via an oxygen atom at the 2'- or 3'-carbon atom of a pentose.

In a preferred embodiment of the invention

a) A is a residue according to formula II

wherein

R A1 , R A2 and R A4 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

Z is Y or CR A6 R A7 Y, Y being O, S, NH or CR A9 R A10 , and wherein R , R , R and R are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

R A3 and R A5 are, independently from each other, H or C(X)R A8 , but are not both H, wherein X is O, S or NH, and

R A8 is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or

heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or

b) A is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or

heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue.

Non-limiting examples of electron acceptors are N0 2 , CN, SO 3 H, ketone, and halogen.

A compound according to the invention can thus, for example, be a compound according to the following general formulas Ibl or Ib2:

(Ibl) (Ib2)

Y can be O, S, NH or CR R , and is preferably O.

In a preferred embodiment of the invention the residues R , R and R are, in a compound according to the above formula I, independently from each other H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_ 2 o aliphatic or Ci_ 2 o heteroaliphatic residue, or a substituted or unsubstituted C 5 - 2 o aromatic or C 3 - 2 o heteroaromatic residue, or an electron acceptor, especially preferred, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C 5 _ 12 aromatic or C 3 -12 heteroaromatic residue, or an electron acceptor. In a further preferred embodiment of the invention R A1 , R A2 and R A4 are, in a compound of the invention according to the formula I above, independently from each other selected from the group consisting of H, substituted or unsubstituted Ci_ 2 o alkyl, substituted or unsubstituted C 2 _ 20 alkenyl, substituted or unsubstituted C 2 _ 2 o alkynyl, substituted or unsubstituted C 4 -20 alkenynyl, substituted or unsubstituted C 3 -20 cycloalkyl, substituted or unsubstituted C 3 -20 cycloalkenyl, substituted or unsubstituted C 5 -20 cycloalkynyl, substituted or unsubstituted C 5 -20 cycloalkenynyl, substituted or unsubstituted Ci_ 2 o heteroalkyl, substituted or unsubstituted C 2 _ 20 heteroalkenyl, substituted or unsubstituted C 2 _ 2 o heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 Aryl, substituted or unsubstituted C3-24 heteroaryl, or an electron acceptor.

Further preferred, R A1 , R A2 and R A4 are, in a compound of the invention according to the formula I above, independently from each other selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C 2 _io alkenyl, substituted or unsubstituted C 2 _io alkynyl, substituted or unsubstituted C 4 -10 alkenynyl, substituted or unsubstituted C 3 -10 cycloalkyl, substituted or unsubstituted C 3 -10 cycloalkenyl, substituted or unsubstituted C 5 -10 cycloalkynyl, substituted or unsubstituted C 5 -10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C 2 _io heteroalkenyl, substituted or unsubstituted C 2 _io heteroalkynyl, substituted or unsubstituted C 4 -10 hetero alkenynyl, substituted or unsubstituted C 5 _ 12 aryl, substituted or unsubstituted C 3 -12 heteroaryl, or an electron acceptor. Especially preferred R A1 , R A2 and R A4 are all H.

Preferably, R A8

i. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_ 2 o aliphatic or Ci_ 2 o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3-20 heteroaromatic residue, or ii. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C 5 _ 12 aromatic or C3-12 heteroaromatic residue, or

iii. is selected from the group consisting of substituted or unsubstituted Ci_ 2 o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_ 2 o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, preferably Ci_ 2 o alkyl or Ci_ 2 o alkenyl.

The residues R A6 , R A7 , R A9 and R A1 ° preferably

i. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_ 2 o aliphatic or Ci_ 2 o heteroaliphatic residue, a substituted or unsubstituted C5-20 aromatic or C3_ 2 o heteroaromatic residue, or an electron acceptor, or

ii. are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C 5 _ 12 aromatic or C3_i 2 heteroaromatic residue, or an electron acceptor, or

iii. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_ 2 o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or

unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_ 2 o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 hetero alkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, or an electron acceptor, or

iv. are, independently from each other, selected from the group consisting of H, substituted or unsubstituted Ci_io alkyl, substituted or unsubstituted C 2 _ 10 alkenyl, substituted or

unsubstituted C 2 _ 10 alkynyl, substituted or unsubstituted C 4 _ 10 alkenynyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 cycloalkenyl, substituted or unsubstituted C 5 _ 10 cycloalkynyl, substituted or unsubstituted C 5 _ 10 cycloalkenynyl, substituted or unsubstituted Ci_io heteroalkyl, substituted or unsubstituted C 2 _ 10 heteroalkenyl, substituted or unsubstituted C 2 _ 10 heteroalkynyl, substituted or unsubstituted C4-10 heteroalkenynyl, substituted or unsubstituted C 5 _ 12 aryl, substituted or unsubstituted C3-12 heteroaryl, or an electron acceptor, or

v. are all H, or

vi. are an electron acceptor or H, with the proviso that residues at the same carbon atom are not both an electron acceptor, i.e. R A6 and R A7 are not both an electron acceptor, and R A9 and R A1 ° are not both an electron acceptor.

In a further embodiment of the invention the moiety A i. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_ 2 o aliphatic or Ci_ 2 o heteroaliphatic residue, or a substituted or unsubstituted C5-20 aromatic or C3-20 heteroaromatic residue, or

ii. is a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_io aliphatic or Ci_io heteroaliphatic residue, or a substituted or unsubstituted C 5 _ 12 aromatic or C3-12 heteroaromatic residue, or

iii. is selected from the group consisting of substituted or unsubstituted Ci_ 2 o alkyl, substituted or unsubstituted C2-20 alkenyl, substituted or unsubstituted C2-20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C5-20 cycloalkynyl, substituted or unsubstituted C5-20 cycloalkenynyl, substituted or unsubstituted Ci_ 2 o heteroalkyl, substituted or unsubstituted C2-20 heteroalkenyl, substituted or unsubstituted C2-20 heteroalkynyl, substituted or unsubstituted C4-20 heteroalkenynyl, substituted or unsubstituted C5-24 aryl, substituted or unsubstituted C3-24 heteroaryl, preferably Ci_ 2 o alkyl or Ci_ 2 o alkenyl.

The moiety A may be bound via a heteroatom, e.g. an O, N or S atom, or via a C atom to the terminal phosphorus atom. An example of a preferred embodiment, where the moiety A is an alkyl residue bound via an O atom bound to the terminal phosphorus atom, is shown in the following formula (Icl). Alkyl

ample of this embodiment with the alkyl residue being Ci 8 H 37 , is shown below

Moiety A is not a β-cyanoethyl group -0(CH 2 ) 2 CN.

As mentioned above, an alkyl or other residue may, however, also be directly attached to the terminal phosphorus atom, i.e. via a C-atom of the residue, as shown below.

In a preferred embodiment of the compound of the invention Z is CR A6 R A7 Y, wherein Y is O, S or NH, preferably O, the residues R A1 , R A2 , R A4 , R A5 , R A6 and R A7 are each H, and R A3 is C(X)R A8 , wherein X is O, S or NH, preferably O, and wherein R A8 is as defined above.

In a particular preferred embodiment of the invention the mask B in the compound of the invention is a residue according to the following formula III

wherein

R B1 , R B2 and R B4 are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor, R and R are, independently from each other, H, a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue, or an electron acceptor,

R B3 and R B5 are, independently from each other, H or WC(X)R B8 , but are not both H, wherein W and X are, independently from each other, O, S or NH, preferably both O, and

R B8 is a substituted or unsubstituted cyclic, acyclic, linear or branched aliphatic or

heteroaliphatic residue, or a substituted or unsubstituted aromatic or heteroaromatic residue.

Non-limiting examples of electron acceptors are N0 2 , CN, SO 3 H, ketone, and halogen.

An example of a preferred embodiment of the mask B, wherein R B1 , R B2 , R B4 , R B5 , R B6 and R B are all H, and wherein R B3 is WC(X)R B8 , is shown in the following formula (Ilia)

As mentioned above, W and X are, independently from each other, O, S or NH, preferably both O.

In a preferred embodiment, the compound of the invention has a structure according to the following general formula (Id):

In a preferred embodiment the residues R A1 , R A2 , R A4 , R B1 , R B2 and R B4 , and preferably also the residues R B6 and R B7 , are all the same, preferably all H. Such a preferred embodiment, in which the residues R A5 and R B5 are also each H, has, for example, the structure according to the following general formula Ie:

Alternatively, however, the residues R Ai and R Bi can be each H and the residues R A5 and R 1

. B5

can be as defined above, but not H. R A5 can, for example, be C(X)R A8 and R^ can, for example, be W(X)R B8 . W and X can, independently from each other, and in case of X also independently for any occurrence of X, be O, S or NH. Preferably, W and X are each O. In a further preferred embodiment of the compound of the invention the residue R is

C(X)R A5 and the residue R B3 is W(X)R B5 , as shown in the following formula If:

W and X can, independently from each other, and in case of X also independently from any occurrence of X, be O, S or NH. Preferably W and X are each O.

In a further preferred embodiment, the two moieties "A" and "B" differ only in the residues R A3 and/or R A5 as well as R B3 and/or R B5 . In this embodiment Z is CR A6 R A7 Y, where Y is O. The residues R A1 and R B1 , R A2 and R B2 , R A4 and R B4 as well as the residues R A6 and R B6 , and the residues R A7 and R B7 , are identical among each other, particularly preferably all H. Particularly preferably, the two moieties differ only in their residues R A3 and R B3 or only in their residues R A5 and R B5 , particularly preferably only in their residues R A3 and R B3 . Such a preferred embodiment has, for example, the structure according to the general formula Ig:

The residues R A3 and R B3 are both not H. R A3 is preferably C(X)R A8 , the bond to the phenyl ring being via C, and the residue R is preferably W(X)R B5 , the bond to the phenyl ring being

. B3

via W. X is preferably, for each of the residues R and R ai independently from each other, O, S or NH, and W in the residue R is preferably O, S or NH. Preferably, X and W are each O.

As already indicated, in preferred embodiments of the invention, the residues R or R can have the general structure IV shown in the following to the left, and the residues R B3 or R B5 have the general structure V shown in the following on the right:

(IV) (V)

Examples of preferred residues R or R according to formula IV are given below:

(IVa) (IVb) (IVc)

Examples of preferred residues R B3 or R B5 according to formula V, in which X is O, are given below:

(Va) (Vb) (Vc) case where the moiety A has the following general structure Ila

the terms "acylbenzyl moiety" or "acylbenzyl moiety", abbreviated as ab moiety or ab group, may also be used. case where the moiety B has the following general structure Ilia

the terms„acyloxybenzyl moiety",„acyloxybenzyl group" or "acyloxybenzyl mask", abbreviated as AB moiety, AB group or AB mask, may be used. In contrast to the acylbenzyl moiety, in which the acyl group (alkanoyl group) is directly linked to the benzyl radical via the C atom of the group, the acyl group in the acyloxybenzyl mask is linked to the benzyl radical via an oxygen atom.

A preferred embodiment of the compound according to the invention is, for example, a compound according to the following general formula Ih

In a compound according to the invention in which the two moieties "A" and "B" differ only in the residues R A3 and/or R A5 as well as R B3 and/or R B5 , for example, a compound of the invention according to the general formula Ig or Ih, the residues R A8 and R B8 are preferably, each independently of one another, a substituted or unsubstituted cyclic, acyclic, linear or branched Ci_ 2 o aliphatic residue or Ci_ 2 o heteroaliphatic residue, or a substituted or

unsubstituted C5-20 aromatic residue or C3-20 heteroaromatic residue, provided that residues R A< and R B8 are different and selected such that moiety A is an intracellular stable lipophilic group and moiety B is an intracellularly labile lipophilic mask.

Especially preferred residues R A8 and R B8 are, independently from each other, selected from the group consisting of substituted or unsubstituted Ci_ 2 o alkyl, substituted or unsubstituted C 2 _ 20 alkenyl, substituted or unsubstituted C 2 -20 alkynyl, substituted or unsubstituted C4-20 alkenynyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 cycloalkenyl, substituted or unsubstituted C3-20 cycloalkynyl, substituted or unsubstituted C 5 -20 cycloalkenynyl, substituted or unsubstituted Ci_ 2 o heteroalkyl, substituted or unsubstituted C 2 -20 hetero alkenyl, substituted or unsubstituted C 2 -20 heteroalkynyl, substituted or unsubstituted C 4 _ 20 heteroalkenynyl, substituted or unsubstituted C 5 -24 aryl, substituted or unsubstituted C3-24 heteroaryl, preferably Ci_2o alkyl or Ci_2o alkenyl, with the proviso that the residues R A8 and

R B8 are different, and moiety A is an intracellularly stable lipophilic group, and moiety B is an intracellularly labile lipophilic mask. Especially preferred the residues R A8 and R B8 are selected from substituted or unsubstituted Ci_ 2 o alkyl and substituted or unsubstituted C 2 _ 2 o alkenyl, with the proviso that the residues R A8 and R B8 are different, and the moiety A is an intracellularly stable lipophilic group and the moiety B is an intracellularly labile lipophilic mask. The compounds according to the invention exhibit good cell penetrability and intracellularly release, for example, mono-modified nucleoside phosphate analogues, which are preferably selectively used by, for example, microbial or viral polymerases, e.g. the reverse transcriptase of the HI virus, as a substrate and lead to chain termination. The compounds according to the invention are thus suitable for use as drugs, in particular as antiviral drugs, for example antiretroviral drug. For example, the compounds according to the invention can advantageously be used in medications for the treatment of HIV, influenza, hepatitis C and B infections, haemorrhagic fever or cancer.

The invention therefore also relates in a second aspect to a pharmaceutical composition comprising a compound according to the invention and a pharmaceutically acceptable carrier. Pharmaceutically acceptable carriers are known to the person skilled in the art and comprise one or more liquid, semi- so lid or solid fillers, diluents or other substances suitable for administration to mammals, including humans. For the purposes of the present invention, the term "carrier" refers to any organic or inorganic, natural or synthetic substance which can be combined with the active ingredient to simplify application. Examples of such carriers include, but are not limited to organic or inorganic solvents, starch, lactose, mannitol, methylcellulose, talc, gelatin, agar agar, calcium phosphate, magnesium stearate, animal and vegetable fats, higher molecular weight fatty acids, or higher molecular weight polymers.

The term "pharmaceutically acceptable" means any substantially non-toxic material for mammals, especially humans, which does not substantially affect the effectiveness of the biological activity of the active ingredient. Such materials may include pharmaceutically acceptable concentrations of salts, buffers, preservatives, or the like. Non-limiting examples of pharmaceutically acceptable carriers include magnesium carbonate, magnesium stearate, talc, sugar, lactose, ethanol, glycerol, water, buffer solutions. The pharmaceutical composition may also comprise adjuvants and/or diluents.

In a third aspect the invention also relates to a pharmaceutical dosage form comprising a compound according to the invention and a pharmaceutically acceptable carrier. Especially preferred is a dosage form for oral administration, for example a tablet or capsule.

A preferred embodiment of a compound according to the invention can be prepared, for exam le, according to the scheme given below

The residues R 1 , R A1 7 and R B1~7 are as indicated above for the first aspect of the present invention.

The invention is explained in more detail below with reference to the accompanying figures and exemplary embodiments for illustrative purposes only.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematically the intracellular cleavage of an enzyme-cleavable mask B and intracellular formation of a compound modified with a stable moiety A from a preferred embodiment of a compound according to the invention. Nucl = nucleoside or nucleoside analogue; Cat + = cation, E = esterase; Ti /2 = half-life.

FIG. 2 Schematic representation of the template (30 nt) and primer (25 nt) used for the primer extension assays.

FIG. 3 shows results of primer extension assays with a stable mono-modified nucleoside triphosphate. A. Autoradiogram with the polymerase HIV-RT, B. Autoradiogram with the human polymerase β. C. autoradiogram with the human polymerase γ. - = primer; + = dATP, dCTP, dGTP and TTP with polymerase HIV-RT; N * = dATP, dCTP, dGTP and C9 ketone- TTP); T = only TTP; T* = only C9-ketone-TTP.

FIG. 4 shows results of primer extension assays with a compound according to the invention. A. Autoradiogram with the polymerase HIV-RT, B. Autoradiogram with the human polymerase β (with d4TTP), C. Autoradiogram with the human polymerase β (with the stable C9-ketone-d4TTP). - = primer; + = dATP, dCTP, dGTP and TTP with polymerase HIV-RT; N* = dATP, dCTP, dGTP and C9 ketone-d4TTP); Ni * = dATP, dCTP, dGTP and d4TTP; d4T = d4TTP; d4T* = = only C9-ketone-d4TTP. FIG. 5 shows HPLC chromatograms of the hydrolysis of the monomasked C9-ketone-d4TTP in CEM/0 cell extracts after different incubation times.

FIG. 1 shows, for an exemplary embodiment of a compound according to the invention, schematically its introduction as a double-modified prodrug into a cell whose cell membrane is indicated here by an arcuate line, as well as the assumed course of release of a NTP derivative, i.e. a nucleoside triphosphate mono-modified with an intracellularly stable moiety A. The two otherwise negatively charged oxygen atoms (in bold face type) of the hydroxyl groups of the terminal phosphate (γ-phosphorus atom) in the NTP prodrug are non-symmetrically substituted, i.e. modified with two different groups A and B. The mask B is here an

acyloxybenzyl derivative (AB derivative) and can be cleaved hydrolytically or enzymatically. In the cell, the labile mask B is therefore rapidly removed after enzymatic attack on the ester group by esterases (E) present in the cell and subsequent spontaneous degradation, resulting in a mono-modified product bearing the intracellularly stable group A. The labile mask B is cleaved at a rate leading to a comparatively short half- life time 12 (1) of the starting prodrug. A nucleophilic attack on the phosphorus anhydride bond(s) with a cleavage thereof does not occur, so that the unwanted formation of the mono- or diphosphate is prevented. The group A, in this case an acylbenzyl (ab-derivative), is not, or very much slower, attacked enzymatically, so that there is no or at least essentially no release of the parent nucleoside triphosphate (NTP).

Exemplary embodiments (Part I)

1. Preparation of a stably mono-modified NTP

For a preliminary test of the concept according to the invention, thymidine triphosphate was prepared with a stable acylbenzyl group A having a C9 alkyl residue (also referred to as a C9- ab group or C9 ketone group) according to the following scheme:

NuclDP

1) DC1, MeCN/DCM, RT, 40-60 min

Nucl = d4T, R A : C 17 H 35 , 27 % 2) tBuOOH, -20 °C→RT, 15-35 min

Nucl = d4U, R = C 9 H 19 , 57 % 3) 10% NEt3, MeCN, RT, 15-70 min

4) RP-18, 4) Dowex NH 4 +

Nucl = T, R A8 = C 9 H 19 , 66 %

5) RP-18

2. Polymerase assays (primer extension assays) with the C9 ketone TTP

The mono-modified TTP (C9 ketone TTP) prepared as described above was tested in primer extension assays using a 32 P-labeled primer (25 nt) and a 30 nt template for its suitability as a substrate of HIV reverse transcriptase and human polymerases (see FIG. 2).

The primer extension assays confirmed the inventive concept. FIG. 3A shows the reference samples (-,+) from the reaction with the HIV reverse transcriptase. To determine the "starting point" only the 25 nt primer and no polymerase ("-") was added to the first sample, so that no elongation of the strand occurred. In the presence of all dNTPs (+ = dATP, dCTP, dGTP and TTP), the complete elongation of the strand (30 nt) was observed in the second sample (control experiment). The incorporation of TMP from the C9 ketone nucleoside triphosphate is apparent in the third and fourth samples (N* includes the non-cleavable C9 ketone TTP instead of the natural TTP, T* includes only the C9 ketone TTP). In comparison, FIGs. 3B and 3C show the results of the reaction with the human DNA polymerases β and γ. In Figs. 3B and 3C, in the respective samples four, i.e. the samples containing only the C9 ketone TTP (T*), no incorporation of TMP out of the C9 ketone TTP is observed (corresponds to the primer, 25 nt). Consequently, the desired differentiation between viral and human polymerase could be achieved.

3. Preparation of a compound according to the present invention

A compound according to the present invention having an unstable, i.e. enzymatically cleavable, C4-acyloxybenzyl mask B (also referred to as C4-AB mask) and a stable acylbenzyl group A with C9-alkyl residue (also referred to as C9-ab group or C9-ketone group) with d4T monophosphate (d4TMP, stavudine monophosphate) as R 1 according to the scheme shown in the following figure. The γ-mono -modified C9-ketone nucleoside triphosphate was selectively generated from the resulting C9-ketone/C4-AB-d4TTP prodrug by enzymatic cleavage of the enzymatically cleavable mask B.

4. Polymerase assays with the C9-ketone d4TTP The prepared mono-modified d4TTP (C9-ketone-d4TTP) was tested for its suitability as a nucleotide analogue in primer extension assays (see FIG. 4). FIG. 4A shows the reference samples (-, +) from the reaction with the HIV reverse transcriptase. To determine the "starting point" only the 25 nt primer and no polymerase ("-") was added to the first sample, so that no elongation of the strand occurred. In the presence of all dNTPs (+), the complete elongation of the strand (30 nt) was observed in the second sample (control experiment). The incorporation of d4TTP from the C9-ketone nucleoside triphosphate is visible in the third and fourth sample (N* includes the stable C9-ketone d4TTP instead of the natural TTP; d4T* includes only the C9 ketone d4TTP).

In comparison, FIGs. 4B and 4C show the results of the reaction with the human DNA polymerases β. In FIG. 4B, starting from d4TTP, the comparatively marginal incorporation of d4TMP can be seen in samples three and four sample (Ni* includes d4TTP instead of the natural TTP; d4T includes only the d4TTP). In FIG. 4C, starting from C9-ketone-d4TTP, no incorporation can be observed (corresponds to the primer, 25 nt) for the corresponding samples three and four. Consequently, the desired substrate specificity was also observed here.

5. Hydrolysis Tests

Hydrolysis studies in CEM/0 cell extract gave information about the enzymatic release of γ- mono-modified ketone nucleoside triphosphates from prodrugs. The samples are incubated in cell extract and the incubation is stopped at different times. The hydrolysis samples were analyzed by HPLC (high-pressure liquid chromatography).

The C9-ketone d4TTP was incubated in CEM/0 cell extracts. After different incubation times, samples were tested for hydrolysis by HPLC. γ-Μοηο -modified nucleoside triphosphates had the required stability in the cell medium. In the C9-ketone d4TTP, 89% of the compound was detected after 96 h in the CEM/0 cell extract (see FIG. 5). The same applies to the stability in phosphate buffer at pH=7.3. No hydrolysis was observed after 800 h. This stability is remarkable. Neither the formation of d4TTP, d4TDP nor that of d4TMP was detected. γ-Μοηο -modified AZT triphosphates already known from literature had only a half-life of ti/ 2 (l) = 17-55 min, depending on the residue on the γ- phosphate (γ-methylphosphonate, γ-phenylphosphonate, γ-phenyltriphosphate and γ-anilido), in human serum (A. Hofer, GS Cremosnik, AC Miller, R. Giambruno, C. Trefzer, G. Superti- Furga KL Bennett, HJ Jessen, A Modular Synthesis of Modified Phosphoanhydrides, Chem. Eur. J. 2015, 21 , 10116-10122).

6. Antiviral activity

The following Table 1 shows data on the antiviral activity of compounds according to the invention according to the following general structure la.

Several compounds of the invention having different combinations of moieties A, B have been tested. The meaning of the abbreviations used in the Table 1 for the moieties A and B tested are given in the following:

Moiety A:

C9-ab C17-ab i5 H 3l Hj

C15 C18 As a control, in one experiment (see compound 2 in Table 1 below), a labile mask C17-AB according to the following general formula

C17-AB was used instead of a stable moiety A. Moiety B:

C4-AB C6-AB C17-AB

Table 1 : Antiviral activity of exemplary compounds of the invention. Comp. = compound; Nucl = nucleoside; EC50 = half maximal effective concentration; CC50= cytotoxic concentration; CEM = cells from CEM cell line; HIV-l=human deficiency virus type-1; HIV- 2= human deficiency virus type-2; TK ~ =thymidine -kinase deficient CEM cells that are HIV-2 infected

Comp. Nucl B A HIV-1 HIV-2 CEM TK HIV-2

EC50 ^M) EC50 ^M) CC50 (μΜ) EC50 (μΜ)

1 d4T (Nucl) - - 0.33±0.13 0.97±0.50 79 ± 3 150±7

2 d4T C4-AB C17-AB 0.12 ± 0.05 0.10 ± 0.03 33 ± 7 0.54±0,41 3 d4T C4-AB C9-ab 0.37±0.24 1.2±0.92 25 ± 3 2.5±1.8

4 d4T C6-AB C17-ab 0.44±0.28 1.1±0.83 34 ± 12 0.40±0.15

5 d4T C17-AB C9-ab 0.58±0.32 0.78±0.51 35 ± 6 1.1±0.75

6 d4T C17-AB C17-ab 0.42±0.18 0.83±0.43 28 ± 2 0.38±0.19

7 d4T C4-AB CI 8 0.14±0.08 0.12±0.09 13 ± 2 0.17±0.045

8 d4T C4-AB C15 0.25±0.0 0.14±0.15 22 ± 3 0.39±0.3

9 adenosine C17-AB C9-ab 10 > 10 74 ± 12 > 10

As an example, compound 3 with d4T (Stavudine) as a nucleoside, C9-ab (also called "C9 ketone") as intracellularly stable moiety A and C4-AB as mask B is depicted below:

As a further example, the structure of compound 8 having an alkyl group as moiety A is shown:

Compounds 3-9 are embodiments of compounds of the invention according to the general formula I. Compound 2 is a compound not according to the invention having two cleavable acyloxybenzyl (AB) masks. Compound 1 is the pure nucleoside d4T. In compound 9, adenosine was used as nucleoside. Exemplary embodiments (Part II)

A. H-Phosphonate Route General Procedure A: Preparation of unsymmetrical H-phosphonate

Under dry conditions, diphenyl phosphonate (1.2 eq.) was dissolved in 3 mL pyridine and cooled to 0 °C. Alkyl alcohol (1.0 eq.) was added and stirred at 0 °C for 30 min and then heated up to 38 °C. Following, Alkyl alcohol (1.0 eq.) was added and the mixture was stirred for 3 h. Then the solvent was removed in vacuo. The crude product was purified by flash column chromatography (silica) with EtO Ac/petroleum ether/ 0.5% trimethylamine as eluent.

General Procedure B: Preparation of y-modified-d4TTP from H-phosphonate The reactions were performed under dry conditions, a) H-phosphonate (1.0 eq.) was dissolved in 6 mL acetonitrile and N-chlorosuccinimide (2.0 equiv.) was added. After stirring for 2 h at room temperature, tetrabutylammonium phosphate monobasic solution (0.4 M in acetonitrile) (3.0 eq.) was added dropwise. The mixture was stirred for 1 h and the solvent was removed in vacuo. The residue was extracted with CH 2 CI 2 /H 2 O. The organic phase was dried over sodium sulfate and the solvent was removed by evaporation to afford corresponding pyrophosphate in nearly quantitative yield, b) The corresponding pyrophosphate was dissolved in acetonitrile and cooled down to 0 °C. A mixture of trifluoroacetic anhydride (TFAA, 5.0 eq.) and triethylamine (Et 3 N, 8.0 eq.) in 3 mL acetonitrile was cooled to 0 °C and added to the mixture. After stirring for 10 min, all volatile components were removed in vacuum. The residue was once again co-evaporated with 3 mL acetonitrile and subsequently dissolved in 3 mL acetonitrile at 0 °C. 1-methylimidazole (3.0 eq.) and triethylamine (Et 3 N, 8.0 eq.) was added. The suspension was allowed to warm up to room temperature and stirred for 10 min. The resulting activated imidazolidate formed and the corresponding NMP (0.7 - 1.0 eq.) in 3 mL acetonitrile was added. The reaction was stirred at room temperature for 2 - 3 h and dried in vacuum. The crude product was purified by automatic RP18 flash chromatography, and then followed by ion-exchange to the ammonium form with Dowex 50WX8 cation-exchange resin and a second RP18 chromatography purification step. Product-containing fractions were collected and the organic solvent evaporated. The remaining aqueous solutions were freeze- dried and the desired product obtained as a white solid.

e g i k m o q General Procedure A: White solid, yield 52%

1H-NMR (600 MHz, Chloroform-d): δ 7.45 (s, 0.5 H, P-H), 7.40 (d, 3 J HH = 8.3 Hz, 2H, H-2 ), 7.18 - 7.02 (m, 2H, H-3 ), 6.28 (s, 0.5 H, P-H), 5.09 (d, 3 J HH = 9.5 Hz, 2H, Ph-CH 2 ), 4.11 - 3.92 (m, 2H, H-a), 2.59 (q, 3 J HH = 7.5 Hz, 2H, H-t), 1.64 (quint, 3 J HH = 6.7 Hz, 2H, H-b), 1.45 - 1.13 (m, 33H, H-c, H-d, H-e, H-f, H-g, H-h, H-i, H-j, H-k, H-1, H-m, H-n, H-o, H-p, H-q, H-u), 0.87 (t, 3 JHH = 6.9 Hz, 3H, H-r).

13 C-NMR (151 MHz, Chloroform-d): δ 172.7 (C-s), 150.9 (C-4 " ), 133.2 (C-1 " ), 129.1 (C- 2 " ), 121.9 (C-3 " ), 66.50 (d, 2 J CP = 5.5 Hz, Ph-CH 2 ), 65.98 (d, 2 J CP = 6.1 Hz, C-a), 30.32 (d, 3 J C p = 6.2 Hz, C-b), 31.89, 29.67, 29.64, 29.63, 29.61, 29.52, 29.45, 29.33, 29.06 (C-d, C-e, C- f, C-g, C-h, C-i, C-j, C-k, C-1, C-m, C-n, C-o, C-p), 27.69 (C-t), 25.43 (C-c), 22.66 (C-q), 14.08 (C-r), 8.99 (C-u). jl P-NMR (243 MHz, Chloroform-d): δ 7.70

e g i k m o q

General Procedure A: White solid, yield 57%

1H-NMR (600 MHz, Chloroform-d): δ 7.45 (s, 0.5 H, P-H), 7.43 - 7.36 (m, 2H, H-2 ), 7.17 - 7.04 (m, 2H, H-3 ), 6.28 (s, 0.5 H, P-H), 5.09 (d, 3 J HH = 9.5 Hz, 2H, Ph-CH 2 ), 4.10 - 3.95 (m, 2H, H-a), 2.56 (t, 3 J HH = 7.5 Hz, 2H, H-t), 1.74 (quint, 3 J HH = 7.5 Hz, 2H, H-u), 1.64 (quint, 3 J HH = 7.2 Hz, 2H, H-b),1.44 (tq, 3 J HH = 7.6, 7.5 Hz, 2H, H-v), 1.38 - 1.17 (m, 30H, H-c, H-d, H-e, H-f, H-g, H-h, H-i, H-j, H-k, H-1, H-m, H-n, H-o, H-p, H-q), 0.97 (t, 3 J HH = 7.4 Hz, 3H, H-w), 0.87 (t, 3 JHH = 7.0 Hz, 3H, H-r).

13 C-NMR (151 MHz, Chloroform-d): δ 172.1 (C-s), 150.9 (C-4 " ), 133.19 (C-1 " ), 129.1 (C- 2 " ), 121.9 (C-3 " ), 66.52 (d, 2 J CP = 6.0 Hz, Ph-CH 2 ), 65.98 (d, 2 J CP = 6.0 Hz, C-a), 34.1 (C-t), 30.33 (d, 3 J C p = 6.0 Hz, C-b), 31.89, 30.35, 30.31, 29.67, 29.65, 29.63, 29.62, 29.53, 29.46, 29.33, 29.07 (C-d, C-e, C-f, C-g, C-h, C-i, C-j, C-k, C-1, C-m, C-n, C-o, C-p), 26.93 (C-u), 25.44 (C-c), 22.67 (C-q), 22.21 (C-v), 14.09 (C-r), 13.69 (C-w).

P-NMR (243 MHz, Chloroform-d): δ 7.70

e g i k m o q

General Procedure A: White solid, yield 63%

1H-NMR (600 MHz, Chloroform-d): δ 7.45 (s, 0.5 H, P-H), 7.43 - 7.36 (m, 2H, H-2 ), 7.12 - 7.04 (m, 2H, H-3 ), 6.28 (s, 0.5 H, P-H), 5.09 (d, 3 J HH = 9.6 Hz, 2H, Ph-CH 2 ), 4.10 - 3.94 (m, 2H, H-a), 2.55 (t, 3 J HH = 7.5 Hz, 2H, H-t), 1.75 (quint, 3 J HH = 7.5 Hz, 2H, H-u), 1.64 (quint, 3 J HH = 7.2 Hz, 2H, H-b),1.46 - 1.37 (m, 2H, H-v), 1.37 - 1.18 (m, 34H, H-c, H-d, H-e, H-f, H- g, H-h, H-i, H-j, H-k, H-1, H-m, H-n, H-o, H-p, H-q, H-w, H-x), 0.90 (t, 3 J HH = 6.9 Hz, 3H, H-y), 0.87 (t, 3 JHH = 7.0 Hz, 3H, H-r).

13 C-NMR (151 MHz, Chloroform-d): δ 172.1 (C-s), 150.9 (C-4 " ), 133.2 (C-1 " ), 129.1 (C- 2 " ), 121.9 (C-3 " ), 66.52 (d, 2 J CP = 5.5 Hz, Ph-CH 2 ), 65.99 (d, 2 J CP = 6.2 Hz, C-a), 34.35 (C- t), 30.33 (d, 3 J C p = 6.3 Hz, C-b), 31.90, 31.40, 29.68, 29.65, 29.64, 29.62, 29.53, 29.46, 29.34, 29.08, 25.44, 22.67, 22.45 (C-d, C-e, C-f, C-g, C-h, C-i, C-j, C-k, C-1, C-m, C-n, C-o, C-p, C-q, C-w, C-x), 28.74 (C-v), 24.84 (C-u), 14.09 (C-r), 13.99(C-y).

P-NMR (243 MHz, Chloroform-d): δ 7.70

General Procedure B: White solid, yield 63%

In order to avoid any misunderstanding, it is noted that, in the formula above, the stable moiety A is depicted below the plane of the triphosphate backbone, whereas the labile moiety B, an acyloxybenzyl (AB) moiety, is depicted above the plane of the triphosphate backbone.

1H-NMR (600 MHz, Methanol-d4): δ 7.74 -7.67 (m, 1H, H het -6), 7.50 (dt, 3 J HH = 8.6 Hz, 4 J HH = 2.7 Hz, 2H, H-2 ' ), 7.11 (d, 3 J HH = 8.1 Hz, 2H, H-3 ' ), 6.96 (dt, 3 J HH = 3.6 Hz, 4 J HH = 1.7 Hz, 1H, Η-Γ), 6.52 (dt, 3 J HH = 5.9 Hz, 4 J HH = 1.8 Hz, 1H, H-3 ), 5.85 (d, 3 J HH = 6.0 Hz, 1H, H-2 ), 5.28 - 5.16 (m, 2H, Ph-CH 2 ), 4.99 (tt, 3 J HH = 3.8 Hz, 4 J HH = 1.9 Hz, 1H, H-4 ), 4.35 - 4.17 (m, 2H, H-5 ), 4.17 - 4.08 (m, 2H, H-a), 2.62 (q, 3 J HH = 7.5 Hz, 2H, H-t), 1.93 (dd, 4 J HH = 3.7, 1.3 Hz, 3H, H h er7), 1.64 (quint, 3 J HH = 7.2 Hz, 2H, H-b), 1.39 - 1.27 (m, 30H, H-c, H-d, H-e, H-f, H-g, H-h, H-i, H-j, H-k, H-l, H-m, H-n, H-o, H-p, H-q), 1.25 (t, 3 J HH = 7.5 Hz, 3H, H-u), 0.92 (t, 3 J HH = 7.0 Hz, 3H, H-r).

13 C-NMR (151 MHz, Methanol-d4): 174.45 (C-s), 166.55 (C het -4, HMBC), 152.79 (C het -2), 152.38 (C-4 " ), 138.67 (C het -6), 135.77 (C-3 ' ), 135.14 (C-1 " ), 130.36 (d, 4 J CP = 4.2 Hz, 2* C- 2 " ), 127.18 (C-2 ' ), 122.87, 122.86 (2* C-3 " ), 112.06 (C het -5), 90.85 (C-1 ' ), 87.22 (d, 3 J CP = 9.1 Hz, C-4 ' ), 70.24 (d, 2 J CP = 5.7 Hz, C-Bn), 69.85 (d, 2 J CP = 6.2 Hz, C-a), 67.85 (d, 2 J CP = 5.8 Hz, C-5 ' ), 31.24 (d, 3 J CP = 7.4 Hz, C-b), 33.07, 30.80, 30.76, 30.73, 30.68, 30.47, 30.30, 26.56, 23.74 (C-d, C-e, C-f, C-g, C-h, C-i, C-j, C-k, C-1, C-m, C-n, C-o, C-p, C-q), 28.37 (C-t), 14.46 (C-r), 12.50 (C het -7), 9.32 (C-u). 31 P-NMR (243 MHz, Methanol-d4): δ -11.84 (d, 2 J

Hz, Ρ-γ), -23.84 (s, Ρ-β).

General Procedure B: White solid, yield 30%

In order to avoid any misunderstanding, it is noted that, in the formula above, the stable moiety A is depicted below the plane of the triphosphate backbone, whereas the labile moiety B, an acyloxybenzyl (AB) moiety, is depicted above the plane of the triphosphate backbone.

1H-NMR (600 MHz, Methanol-d4): δ 7.75 -7.67 (m, 1H, H het -6), 7.50 (dd, 3 J HH = 8.7 Hz, 4 J HH = 2.5 Hz, 2H, H-2 ), 7.10 (d, 3 J HH = 8.3 Hz, 2H, H-3 ), 6.96 (dd, 3 J HH = 3.6 Hz, 4 J HH = 1.8 Hz, 1H, Η-Γ), 6.56 -6.48 (m, 1H, H-3 ), 5.85 (d, 3 J HH = 6.1 Hz, 1H, H-2 ), 5.28 - 5.16 (m, 2H, Ph-CH 2 ), 4.99 (tt, 3 J HH = 3.7 Hz, 4 J HH = 1.9 Hz, 1H, H-4 ), 4.35 - 4.17 (m, 2H, H-5 ), 4.17 - 4.06 (m, 2H, H-a), 2.60 (t, 3 J HH = 7.4 Hz, 2H, H-t), 1.93 (dd, 4 J HH = 3.8, 1.2 Hz, 3H, H het -7), 1.73 (quint, 3 J HH = 7.6 Hz, 2H, H-u), 1.64 (quint, 3 J HH = 7.3 Hz, 2H, H-b), 1.48 (tq, 3 J HH = 7.7, 7.4 Hz, 2H, H-v), 1.38 - 1.24 (m, 30H, H-c, H-d, H-e, H-f, H-g, H-h, H-i, H-j, H-k, H-l, H- m, H-n, H-o, H-p, H-q), 1.01 (t, 3 J HH = 7.4 Hz, 3H, H-w), 0.92 (t, 3 J HH = 7.0 Hz, 3H, H-r).

13 C-NMR (151 MHz, Methanol-d4): 173.74 (C-s), 166.56 (C het -4, HMBC), 152.79 (C het -2), 152.35 (C-4 " ), 138.68 (C het -6), 135.83 (C-3 ' ), 135.16 (dd, 3 J CP = 7.3, 3.5 Hz, C-l ), 130.38 (d, 4 J C p = 4.2 Hz, 2x C-2 " ), 127.16 (C-2 ' ), 122.87, 122.86 (2x C-3 " ), 112.08 (C het -5), 90.86 (C-r), 87.23 (d, 3 J C p = 9.0 Hz, C-4 ' ), 70.25 (d, 2 J CP = 6.0 Hz, C-Bn), 69.84 (d, 2 J CP = 6.3 Hz, C-a), 67.85 (d, 2 J CP = 5.8 Hz, C-5 ' ), 34.77 (C-t), 31.24 (d, 3 J CP = 7.1 Hz, C-b), 33.07, 30.80, 30.75, 30.73, 30.67, 30.47, 30.29, 26.55, 23.73 (C-d, C-e, C-f, C-g, C-h, C-i, C-j, C-k, C-1, C- m, C-n, C-o, C-p, C-q), 28.07 (C-u), 23.25 (C-v), 14.45 (C-r), 14.10 (C-w), 12.49 (C het -7).

31 P-NMR (243 MHz, Methanol-d4): δ -11.76 (d, 2 J PP = 18.0 Hz, P-a), - 12.96 (d, 2 J PP = 16.9 Hz, Ρ-γ), -23.61- -23.70 (m, Ρ-β).

General Procedure B: White solid, yield 26%

In order to avoid any misunderstanding, it is noted that, in the formula above, the stable moiety A is depicted below the plane of the triphosphate backbone, whereas the labile moiety B, an acyloxybenzyl (AB) moiety, is depicted above the plane of the triphosphate backbone.

1H-NMR (600 MHz, Methanol-d4): δ 7.73 -7.63 (m, 1H, H het -6), 7.47 (dd, 3 J HH = 8.6 Hz, 4 J HH = 2.6 Hz, 2H, H-2 ), 7.07 (d, 3 J HH = 8.1 Hz, 2H, H-3 ), 6.93 (dq, 3 J HH = 3.3 Hz, 4 J HH = 1.5 Hz, 1H, Η-Γ), 6.49 (dt, 3 J HH = 5.9 Hz, 4 J HH = 1.8 Hz, 1H, H-3 ), 5.82 (dt, 3 J HH = 6.1 Hz, 4 J HH = 1.8 Hz, 1H, H-2 ), 5.25 - 5.13 (m, 2H, Ph-CH 2 ), 4.96 (tt, 3 J HH = 3.7 Hz, 4 J HH = 1.8 Hz, 1H, H-4 ), 4.32 - 4.15 (m, 2H, H-5 ), 4.15 - 4.03 (m, 2H, H-a), 2.57 (t, 3 J HH = 7.4 Hz, 2H, H-t), 1.90 (d, 4 J HH = 3.8 Hz, 3H, H het -7), 1.72 (quint, 3 J HH = 7.5 Hz, 2H, H-u), 1.60 (quint, 3 J HH = 6.9 Hz, 2H, H-b),1.46 - 1.39 (m, 2H, H-v), 1.39 - 1.19 (m, 34H, H-c, H-d, H-e, H-f, H-g, H- h, H-i, H-j, H-k, H-l, H-m, H-n, H-o, H-p, H-q, H-w, H-x), 0.92 (t, 3 J HH = 6.9 Hz, 3H, H-y),

0.89 (t, 3 J HH = 7.0 Hz, 3H, H-r).

13 C-NMR (151 MHz, Methanol-d4): 173.72 (C-s), 166.58 (C het -4, HMBC), 152.79 (C het -2), 152.35 (C-4 " ), 138.69 (C het -6), 135.80 (C-3 ' ), 135.15 (dd, 3 J CP = 7.2, 3.6 Hz, C-l ), 130.40 (d, 4 J C p = 4.2 Hz, 2x C-2 " ), 127.16 (C-2 ' ), 122.87, 122.86 (2* C-3 " ), 112.07 (C het -5), 90.86 (C-r), 87.23 (d, 3 J C p = 9.1 Hz, C-4 ' ), 70.25 (d, 2 J CP = 7.3 Hz, C-Bn), 69.84 (d, 2 J CP = 6.3 Hz, C-a), 67.85 (d, 2 J CP = 5.7 Hz, C-5 ' ), 35.05 (C-t), 31.23 (d, 3 J CP = 7.3 Hz, C-b), 33.08, 32.67, 30.82, 30.81, 30.77, 30.74, 30.68, 30.48, 30.30, 26.55, 23.74, 23.59 (C-d, C-e, C-f, C-g, C-h, C-i, C-j, C-k, C-l, C-m, C-n, C-o, C-p, C-q, C-w, C-x), 29.87 (C-v), 25.94 (C-u), 14.46 (C- r), 14.40 (C-y), 12.50 (C het -7)

31 P-NMR (243 MHz, Methanol-d4): δ -11.75 (d, 2 J PP = 19.0 Hz, P-a), - 12.94 (d, 2 J PP = 17.0 Hz, Ρ-γ), -23.63 (t, 2 J PP = 17.9 Hz, Ρ-β).

B. Phosphoramidite Route

1. Syntheses and characterization The syntheses and characterization of 4-(hydroxymethyl)phenylalkanoates la-k were described previously (T. Gollnest, T. D. de Oliveira, D. Schols, J. Balzarini, C. Meier, Lipophilic prodrugs of nucleoside triphosphates as biochemical probes and potential antivirals. Nat Commun 2015, 6.). The synthesis and characterization of 4-(((tert-

Butyldimethylsilyl)oxy)methyl)phenol 2 was described previously (J. L. Sessler, B. Wang, A. Harriman, Journal of the American Chemical Society 1995, 117, 704-714). The synthesis and characterization of (FmO)P(N(i-Pr) 2 ) 2 3 was described previously (A. Hofer, G. S. Cremosnik, A. C. Miiller, R. Giambruno, C. Trefzer, G. Superti-Furga, K. L. Bennett, H. J. Jessen, Chemistry - A European Journal 2015, 21, 10116-10122). The syntheses procedure of non- symmetric (AB,ab)-phosphoramidites were adapted to a literature known procedure (L.

Weinschenk, D. Schols, J. Balzarini, C. Meier, Journal of Medicinal Chemistry 2015, 58, 6114-6130). In the following, the abbreviations "AB" and "ab" are used for denoting an acyloxybenzyl moiety (AB) or an acylbenzyl (ab) moiety, the ab moiety being a stable moiety A, the AB moiety being a labile moiety B. 1.1 General procedures (GP)

GP 1 : Syntheses of ketones (ab)

To a solution of N-methoxy-N-methylalkylamide (1.00 equiv.) in THF (5 mL) was added dropwise a suspension of bis(4-((tert-butyldimethylsilyl)oxymethyl)phenyl)-magnesium » LiCl 6 (0.91 M in THF/dioxane 9: 1, 1.83 mmol, 1.10 equiv.) at -20 °C and stirred for 4 h at -20 °C and 1 h at 0 °C. The reaction was aborted by adding a half sat. solution of ammonia chloride (20 mL). Ethylacetate was added (20 mL), the phases separated and the aqueous extracted with ethylacetate (2x 20 mL). The combined org. layers were washed with brine, dried over sodium sulfate and the solvent was removed in vacuo. The residue was purified by column

chromatography on silica (PE/ethylacetate 5: 1→1 : 1).

GP 2: Syntheses of non-symmetrical (Fm,ab)-phosphoramidites The protocol was adapted to a literature known procedure (A. Hofer, G. S. Cremosnik, A. C. Miiller, R. Giambruno, C. Trefzer, G. Superti-Furga, K. L. Bennett, H. J. Jessen, Chemistry - A European Journal 2015 , 21 , 10116- 10122).

(FmO)P(Ni-Pr2)2 (1.20 equiv.) and (4-(hydroxymethyl)phenyl)-alkylketone (1.00 Equiv.) were dissolved in THF (5 mL). A solution of 4,5-dicyanoimidazol (0.25 M in MeCN, 4.00 mL,

1.00 mmol, 1.00 equiv.) was added dropwise at 0 °C and the suspension was stirred for 1 h at 0 °C. After removal of the solvent in vacuo, the residue was purified by column

chromatography on silica (n-hexan/ethylacetate 9: 1 + 1% NEt 3 ).

GP 3: Syntheses of non symmetric (AB,ab)-TriP ro-NTPs (n-Bu 4 N) 2 -Nucl-DP (1.0 Equiv.) was coevaporated with MeCN, dried in addition to (AB,ab)- phosphoramidite (1.0-2.0 Equiv.) 1-2 h in vacuo and dissolved in MeCN (1-2 mL). To this solution was added a solution of 4,5-dicyanoimidazol (0.25 M in MeCN, 1.2-1.8 equiv.) at rt and stirred for 20-120 min. t-BuOOH (5.5 M in n-decane, 1.2-2.00 equiv.) was subsequently added dropwise at -20- -30 °C and the solution was stirred for 30 min at rt. The solvent was removed via cold distillation. The residue was purified by using automated flash-RP-CC (H 2 0/MeCN 90: 10→30:70) and transformed into the corresponding ammonia-form by cation exchanger. In most cases a further purification step was necessary by using automated flash- RP-CC (H 2 0/MeCN).

GP 4: Syntheses of Mono-modified (ab)-TriP ro-NTPs

(n-Bu 4 N) 2 dTDP (1.0 Equiv.) and (Fm/ab-C9)-phosphoramidite (1.3 equiv.) were dissolved in MeCN/DCM (1/2 mL) and a solution of 4,5-dicyanoimidazol (0.25 M in MeCN, 1.1 equiv.) was added dropwise in two portions over 5 min at rt and stirred for 20-40 min. t-BuOOH (5.5 M in n-decane, 1.3 equiv.) was subsequently added dropwise at -20 °C and the solution was stirred for 30 min at rt. The solvent was removed via cold distillation. The residue was suspended in MeCN (2 mL) and stirred with NEt 3 (10% v/v) for 30-90 min at rt. After removal of the solvent the residue was purified by using automated flash-RP-CC (H 2 0/MeCN

90: 10→30:70) and transformed into the corresponding ammonia-form by cation exchanger. In most cases a further purification step was necessary by using automated flash-RP-CC

(H 2 0/MeCN).

1.2 Preparation of the ketones (ab)

1.2.1 Syntheses of N-methoxy-N-methylalkyamids

N-methoxy-N-methyldecanamide 4 N,O-Dimethylhydroxylaminehydrochloride (879 mg, 9.20 mmol, 1.00 equiv.) was dissolved in DCM (24 mL) and cooled to 0 °C. Abs. pyridine (1.65 mL, 20.3 mmol, 2.20 equiv.) and decanoylchloride (1.93 mL, 9.20 mmol, 1.00 equiv.) were added and the solution was stirred for 3 h at 0 °C. Afterwards water and DCM were added, the phases were separated and the aqueous phase extracted with DCM. The combined org. layers were washed with brine, dried over sodium sulfat and the solvent was removed in vacuo. The crude product was purified by column chromatography on silica (PE/ethylacetate 2: 1). yield: 1.91 g (8.88 mmol, 96%) as a colorless oil. TLC: Rf= 0.4 (PE/ethylacetate 1 : 1, Iodine). 1H-NMR (300 MHz, CDC1 3 ):

δ [ppm] = 3.67 (s, 3 H, OMe), 3.17 (s, 3 H, N-Me), 2.40 (t, J= 7.6 Hz, 2 H, 2-H), 1.74 - 1.50 (m, 2 H, 3-H), 1.41 - 1.17 (m, 12 H, 4-H-9-H), 0.97 - 0.79 (m, 3 H, 10-H). 13 C-NMR

(75 MHz, CDC1 3 ): δ [ppm] = 174.8 (C-l, HMBC), 61.3 (OMe), 32.1, 32.0 (C-2, NMe), 29.6, 29.6, 29.4 (C-4, C-5, C-6, C-7, C-8), 24.8 (C-3), 22.8 (C-9), 14.2 (C-10). IR (film): v [cm "1 ] = 2923, 2853, 1667, 1462, 1381, 1176, 1001, 495. HRMS (ESI + ): mlz = calc: 216.1958

[M+H] + , found: 216.1964 [M+H] + . C 12 H 25 O 2 (M= 215.34 g/mol).

N-methoxy-N-methyloctadecanamid 5

N,O-Dimethylhydroxylaminehydrochloride (595 mg, 6.10 mmol, 1.00 Equiv.) was dissolved in DCM (30 mL) and cooled to 0 °C. Abs. Pyridine (1.04 mL, 12.8 mmol, 2.10 Equiv.) and

Decanoylchloride (2.10 mL, 6.30 mmol, 1.00 Equiv.) were added and the solution was stirred for 2.5 h at 0 °C. Afterwards water and DCM were added, the phases were seperated and the aqueous phase extracted with DCM (20 mL). The combined org. layers were washed with brine, dried over sodiumsulfat and the solvent was removed in vacuo. The crude product was purified by column chromatography on silica (PE/Ethylacetate 2: 1→1 : 1). yield: 1.92 g

(5.85 mmol, 96%) as a colorless solid. TLC: R 0.5 (PE/Ethylacetate 2: 1, Iodine). 1H-NMR (300 MHz, CDC1 3 ): δ [ppm] = 3.67 (s, 3 H, OMe), 3.17 (s, 3 H, N-Me), 2.40 (t, J= 7.6 Hz,

2 H, 2-H), 1.62 (p, J= 7.3 Hz, 2 H, 3-H), 1.41 - 1.17 (m, 28 H, 4-H-17-H), 0.97 - 0.82 (m,

3 H, 18-H). C-NMR (75 MHz, CDC1 3 ): δ [ppm] = 174.9 (C-l, HMBC), 61.3 (OMe), 32.1 (C-2, NMe), 29.8, 29.8, 29.8, 29.7, 29.6, 29.6, 29.5 (C-4-C-16), 24.8 (C-3), 22.8 (C-17), 14.3 (C-18). IR (film): v [cm "1 ] = 2921, 2852, 1670, 1463, 1412, 1381, 1176, 1381, 999, 721. HRMS (ESI + ): mlz = calc: 328.3210 [M+H] + , found: 328.3217 [M+H] + .

C20H41NO2 (M= 327.55 g/mol).

1.2.2 Synthesis of the Grignard reagent -((tert-butyldimethylsilyl)oxymethyl)phenyl)magnesium » LiCl 6

Preparation of the reagent z ' PrMgCl'LiCl:

A solution of LiCl (0.5 M in THF, 11.6 mL, 5.81 mmol, 1.00 Equiv.) was mixed with a solution of z ' PrMgCl (2 M in THF, 2.9 mL, 5.81 mmol, 1.00 Equiv.) at rt. The concentration was determined to 0.4 M.

Br-/Mg-exchange : OTBS-4-Bromobenzylicalcohol (1.20 mL, 1.38 g, 4.59 mmol, 1.00 Equiv.) was added to a solution of z ' PrMgCl'LiCl (0.4 M in THF, 12.0 mL, 4.8 mmol, 1.05 Equiv.) and 1,4-dioxane (10 vol%, 1.2 mL) and stirred 16-30 h at rt until consumption of the bromide. The gained suspension was used within 24 h. 1.2.3 Synthesis of the ketones

(4-((tert-butyldimethylsilyl)oxymethyl)phenyl)nonanylketo ne 8

GP 1, using N-methoxy-N-methyldecanamid 4 (358 mg, 1.66 mmol, 1.00 Equiv.) in THF (5 mL) and Bis(4-((tert-butyldimethylsilyl)oxymethyl)phenyl)-magnesium » LiCl 6 (0.91 M in THF/Dioxan 9: 1, 1.83 mmol, 1.10 Equiv.). Yield: 437 mg (1.16 mmol, 70%) as a colorless oil.

TLC: Rf= 0.5 (PE/Ethylacetate 3: 1, VSS). 1H-NMR (300 MHz, CDC1 3 ): δ [ppm] = 7.93 (d, J = 8.3 Hz, 2 H, 3-H), 7.40 (d, J= 8.5 Hz, 2 H, 2-H), 4.79 (s, 2 H, 1-CH 2 0), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 1.73 (p, J= 7.4 Hz, 2 H, 7-H), 1.44 - 1.22 (m, 12 H, 8-H, 9-H, 10-H, 11-H, 12-H, 13-H), 0.95 (s, 9 H, OTBDMS), 0.93 - 0.82 (m, 3 H, 14-H), 0.11 (s, 6 H, OTBDMS). 13 C-

NMR (75 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 146.9 (C-l), 136.0 (C-4), 128.3 (C-3), 126.0 (C-2), 64.7 (1-CH 2 0), 38.8 (C-6), 32.0 (C-12), 29.6 (C-8 - C-l 1), 29.6, 29.6, 29.4, 26.1 (OTBDMS), 24.6 (C-7), 22.8 (C-13), 18.5 (OTBDMS), 14.3 (C-14), -5.1 (OTBDMS). IR

(Film): v [cm "1 ] = 2955, 2928, 2855, 1686, 1610, 1463, 1256, 1094, 839, 778. HRMS (ESI + ): mlz = calc: 377.2870 [M+H] + , found: 377.2881 [M+H] + . C23H40O2S1 (M= 376.28 g/mol).

(4-((tert-butyldimethylsilyl)oxymethyl)phenyl)heptadecany lketone 9

GP 1, using Bis(4-((tert-butyldimethylsilyl)oxymethyl)phenyl)-magnesium » LiCl 6 (0.4 M in THF/Dioxane 9: 1, 4.59 mmol, 1.20 Equiv.) and N-methoxy-N-methyloctadecanamid 5 (1.25 g, 3.82 mmol, 1.00 Equiv.) in THF (8 mL). Yield: 1.12 g (2.48 mmol, 65%) as a colorless oil.

TLC: ?i= 0.3 (PE/DCM 3: 1, VSS: orange). 1H-NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.93 (d, J= 8.3 Hz, 2 H, 3-H), 7.40 (d, J= 8.7 Hz, 2 H, 2-H), 4.79 (s, 2 H, 1-CH 2 0), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 1.73 (p, J= 7.3 Hz, 2 H, 7-H), 1.43 - 1.21 (m, 28 H, 8-H - 21-H), 0.95 (s, 9 H, OTBDMS), 0.91 - 0.85 (m, 3 H, 22-H), 0.11 (s, 3 H, OTBDMS). C-NMR (101 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 146.9 (C-1), 136.0 (C-4), 128.3 (C-3), 126.0 (C-2), 64.7 (1- CH 2 0), 38.8 (C-6), 32.1 (C-20), 29.9, 29.8, 29.8, 29.8, 29.7, 29.6, 29.6, 29.5 (C-8 - C-19), 26.1 (OTBDMS), 24.6 (C-7), 22.8 (C-21), 18.5 (OTBDMS), 14.3 (C-22), -5.1 (OTBDMS). C 3 iH 5 60 2 Si (M= 488.87 g/mol).

(4-(Hydroxymethyl)phenyl)nonanylketone 10

To a solution of Silylether 8 (434 mg, 1.15 mmol, 1.00 Equiv.) in THF (10 mL) was added TBAF (1 M in THF, 1.7 mL, 1.73 mmol, 1.50 Equiv.) at 0 °C and stirred at rt for 45 min. The solvent was removed in vacuo subsequently. The residue was purified by column

chromatography on silica (PE/Ethylacetate 2:1). Yield: 297 mg (1.13 mmol, 98%) as a colorless solid.

TLC: R f = 0.5 (PE/Ethylacetate 1 : 1, VSS). 1H-NMR (600 MHz, CDC1 3 ): δ [ppm] = 7.95 (d, J = 8.3 Hz, 2 H, 3-H), 7.45 (d, J= 8.2 Hz, 2 H, 2-H), 4.77 (s, 2 H, 1-CH 2 0), 2.96 (ι¾, 2 H, 6-H), 1.83 (s, OH), 1.73 (p, J= 7.5 Hz, 2 H, 7-H), 1.44 - 1.20 (m, 12 H, 8-H, 9-H, 10-H, 11-H, 12-H, 13-H), 0.88 (t, J= 7.0 Hz, 3 H, 14-H). 13 C-NMR (151 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 146.0 (C-1), 136.5 (C-4), 128.5 (C-3), 126.8 (C-2), 64.8 (1-CH 2 0), 38.8 (C-6), 32.0 (C-12), 29.6, 29.6, 29.5, 29.4 (C-8 - C-11), 24.6 (C-7), 22.8 (C-13), 14.2 (C-14). HRMS (ESI + ): mlz = calc: 263.2006 [M+H] + , found: 263.1974 [M+H] + . d 7 H 26 0 2 (M= 262.39 g/mol).

(4-(Hydroxymethyl)phenyl)heptadecanylketone 11

For procedure see ketone 10. Silylether 9 (1.91 g, 2.44 mmol, 1.00 Equiv.) in THF (19 mL) and TBAF (1 M in THF, 3.65 mL, 3.65 mmol, 1.50 Equiv.). Yield: 870 mg (2.32 mmol, 95%) as a colorless solid. TLC: Rf= 0.4 (PE/Ethylacetate 2:1, VSS: orange). 1 H-NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.95 (d, J= 8.3 Hz, 2 H, 3-H), 7.45 (d, J= 8.1 Hz, 2 H, 2-H), 4.77 (s, 2 H, 1-CH 2 0), 2.95 (m e , 2 H, 6-H), 1.73 (m, 2 H, 7-H), 1.49 - 1.17 (m, 28 H, 8-H - 21-H), 0.91- 0.85 (m, 3 H, 22-H). 13 C-NMR (101 MHz, CDC1 3 ): δ [ppm] = 200.4 (C-5), 146.0 (C-l), 136.5 (C-4), 128.5 (C-3), 126.8 (C-2), 64.8 (1-CH 2 0), 38.8 (C-6), 32.1 (C-12), 29.8, 29.8, 29.8, 29.8, 29.7, 29.6, 29.5, 29.5 (C-8 - C-19), 24.6 (C-7), 22.8 (C-21), 14.3 (C-22). HRMS (ESI + ): mlz = calc: 375.3258 [M+H] + , found: 375.3237 [M+H] + . C25H42O2 (M= 374.32 g/mol).

1.3 Syntheses of non-symmetric (AB,ab)-phosphoramidites 0'-(4'-pentanoyloxybenzyl)-0-(4-decanoylbenzyl)-N,N-diiso-pr opylphosphoramidite

-C 4 /ab-C 9 ) 12

Yield: 100 mg (167 μιηοΐ, 37%) as a colorless oil. TLC: R 0.6 (PE/NEt 3 9:1, VSS). 1H- NMR (300 MHz, CDC1 3 ): δ [ppm] = 7.92 (d, J= 8.3 Hz, 2 H, 3-H), 7.42 (d, J= 8.7 Hz, 2 H, 2-H), 7.35 (d, J= 8.5 Hz, 2 H, 2'-H), 7.03 (d, J= 8.6 Hz, 2 H, 3 * -H), 4.86 - 4.63 (m, 4 H, I-CH 2 O, r-CH 2 0), 3.78 - 3.62 (ι¾, 2 H, l"a-H), 2.99 - 2.88 (m, 2 H, 6-H), 2.59 - 2.53 (m, 2 H, 6 * -H), 1.81 - 1.65 (m, 4 H, 7-H, 7 * -H), 1.54 - 1.16 (m, 26 H, 8'-H, 8-H, 9-H, 10-H, 11-H, 12-H, 13-H, 2"a-H, 2"b-H), 0.97 (t, J= 7.3 Hz, 3 H, 9 * -H), 0.92 - 0.84 (m, 3 H, 14-H). 13 C- NMR (151 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 172.5 (C-5'), 150.1 (C-4'), 144.9 (d, 3 J CP = 7.2 Hz, C-l), 137.0 (d, 3 J CP = 7.3 Hz, C-l'), 136.3 (C-4), 128.3 (C-2), 128.2 (C-2'), 126.9 (C- 3), 121.5 (C-3'), 65.1 (d, 2 J CP = 18.5 Hz, I-CH 2 O), 65.0 (d, 2 J CP = 18.3 Hz, l'-C¾0 . 43.3 (d, 2 J CP = 12.4 Hz, 2x C-l M a), 38.8 (C-6), 34.3 (C-6'), 32.0 (C-12), 29.6, 29.6, 29.6, 29.4 (C-8, C-9, C-10, C-ll), 27.2 (C-7'), 24.9 (C-7), 24.8, 24.8, 24.6 (2x C-2 M a, 2x C-2 M b), 22.8 (C-13), 22.4 (C-8'), 14.3 (C-14), 13.9 (C-9'). 31 P-NMR (243 MHz, CDC1 3 ): δ [ppm] = 148.4. C 35 H 54 N0 5 P (599.79 g/mol).

0'-(4'-heptanoyloxybenzyl)-0-(4-octadecanoylbenzyl)-N,N-d iiso-propylphosphoramidit (AB-

Yield: 345 mg (466 μηιοΐ, 89%) as a colorless solid. TLC: 0.8 (PE/NEt 3 9:1, VSS:

orange). 1H-NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.92 (d, J= 8.3 Hz, 2 H, 3-H), 7.42 (d, J= 8.1 Hz, 2 H, 2-H), 7.35 (d, J= 8.5 Hz, 2 H, 2'-H), 7.03 (d, J= 8.5 Hz, 2 H, 3 * -H), 4.90 - 4.61 (m, 4 H, I-CH 2 O, r-CHzO), 3.70 K, 2 H, l"a-H), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 2.55 (t, J= 7.5 Hz, 2 H, 6 * -H), 1.81 - 1.67 (m, 4 H, 7-H, 7 * -H), 1.47 - 1.17 (m, 46 H, 8'-H, 9'-H, IO'-Η, 8-H - 21- H, 2"a-H, 2"b-H), 0.94 - 0.85 (m, 6 H, 1 Γ-Η, 22-H). 13 C-NMR (101 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 172.5 (C-5'), 150.1 (C-4'), 144.8 (d, 3 J CP = 7.5 Hz, C-l), 136.3 (C-l'), 136.3

(C-4), 128.3 (C-2), 128.2 (C-2'), 126.9 (C-3), 121.5 (C-3'), 65.1 (d, 2 J CP = 18.5 Hz, I-CH 2 O),

65.0 (d, 2 J C p = 18.2 Hz, l'-C¾0 . 43.3 (d, 2 J CP = 12.5 Hz, 2x C-l M a), 38.8 (C-6), 34.6 (C-6'),

32.1 (C-20), 31.6 (C-10'), 29.9, 29.8, 29.8, 29.7, 29.7, 29.6, 29.5, 28.9 (C-8', C-8, C-9, C-10, C-11, C-12, C-13, C-14, C-15, C-16, C-17, C-18, C-19), 25.1, 24.9, 24.8, 24.8, 24.8, 24.6 (C-7, C-7', 2x C-2 M a, 2x C-2 M b), 22.8 (C-21), 22.6 (C-10'), 14.3 (C-11'), 14.2 (C-22). 31 P- NMR (162 MHz, CDC1 3 ): δ [ppm] = 148.4. C 45 H 74 NO s P (740.06 g/mol). 0'-(4'-octadecanoyloxybenzyl)-0-(4-decanoylbenzyl)-N,N-diiso -propylphosphoramidit (AB- -C 9 ) 14

Yield: 599 mg (766 μηιοΐ, quant.) as a colorless solid. TLC: 0.8 (PE/NEt 3 9: 1, VSS).

1H-NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.92 (d, J= 8.3 Hz, 2 H, 3-H), 7.42 (d, J= 8.2 Hz, 2 H, 2-H), 7.35 (d, J= 8.5 Hz, 2 H, 2'-H), 7.03 (d, J= 8.5 Hz, 2 H, 3 * -H), 4.86 - 4.62 (m, 4 H, I-CH 2 O, r-CHzO), 3.70 (m e , 2 H, l"a-H), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 2.54 (t, J= 7.5 Hz, 2 H, 6 * -H), 1.82 - 1.66 (m, 4 H, 7-H, 7 * -H), 1.46 - 1.15 (m, 52 H, 8-H, 9-H, 10-H, 11-H, 12-H, 13-H, 8'-H - 21 '-H, 2"a-H, 2"b-H), 0.88 (t, J= 6.7 Hz, 6 H, 22'-H, 14-H). 13 C-NMR

(101 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 172.5 (C-5'), 150.1 (C-4'), 144.9 (d, 3 J CP = 7.2 Hz, C-1), 136.3 (C-4), 128.3 (C-2), 128.2 (C-2'), 126.9 (C-3), 121.5 (C-3'), 65.2, 65.1, 65.0, 64.9 (I-CH2O, l'-CHiO), 43.4, 43.3 (2x C-l M a), 38.8 (C-6), 34.6 (C-6'), 32.1 (C-20'), 32.0 (C-12), 29.9, 29.8, 29.8, 29.8, 29.7, 29.6, 29.6, 29.5, 29.4, 29.4, 29.3 (C-8 - C-ll, C-8' - C-19'), 25.1, 24.9, 24.8, 24.8, 24.8, 24.6 (C-7, C-7', 2x C-2 M a, 2x C-2 M b), 22.8 (C-13), 22.8 (C-21'), 14.3 (C-22'), 14.3 (C-14). 31 P-NMR (162 MHz, CDC1 3 ): δ [ppm] = 148.4.

C 48 H 8 oN0 5 P (782.14 g/mol).

0'-(4'-octadecanoyloxybenzyl)-0-(4-octadecanoylbenzyl)-N, N-diiso-propylphosphoramidit

Yield: 350 mg (391 μηιοΐ, quant.) as a colorless solid. TLC: 0.7 (PE/NEt 3 9: 1, VSS). 1H- NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.92 (d, J= 8.1 Hz, 2 H, 3-H), 7.42 (d, J= 8.2 Hz, 2 H, 2-H), 7.35 (d, J= 8.3 Hz, 2 H, 2'-H), 7.03 (d, J= 8.4 Hz, 2 H, 3 * -H), 4.86 - 4.64 (m, 4 H, I-CH 2 O, r-CHzO), 3.70 (m e , 2 H, l"a-H), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 2.54 (t, J= 7.5 Hz, 2 H, 6 * -H), 1.82 - 1.66 (m, 4 H, 7-H, 7 * -H), 1.48 - 1.12 (m, 68 H, 8-H - 21-H, 8'-H - 21 '-H, 2"a-H, 2"b-H), 0.88 (t, J= 6.7 Hz, 6 H, 22'-H, 22-H). 13 C-NMR (101 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 172.5 (C-5'), 150.1 (C-4'), 144.9 (d, 3 J CP = 7.3 Hz, C-1), 137.0 (d, 3 J CP = 7.3 Hz, C-1'), 136.3 (C-4), 128.3 (C-2), 128.2 (C-2'), 126.9 (C-3), 121.5 (C-3'), 65.2, 65.1, 65.0, 64.9 (I-CH 2 O, l'-CHiO), 43.4, 43.3 (2x C-l M a), 38.8 (C-6), 34.6 (C-6'), 32.1 (C-20, C-20'), 29.9, 29.8, 29.8, 29.8, 29.7, 29.7, 29.6, 29.6, 29.5, 29.4, 29.3 (C-8 - C-19, C-8' - C-19'), 25.1, 24.9, 24.8, 24.8, 24.8, 24.6 (C-7, C-7', 2x C-2 M a, 2x C-2 M b), 22.9 (C-21, C-21'), 14.3 (C-22'), 14.3 (C-22). 31 P-NMR (162 MHz, CDC1 3 ): δ [ppm] = 148.4. C 56 H 94 N0 5 P (892.34 g/mol).

1.4 Syntheses of non-symmetrical (Fm,ab)-phosphoramidites

0'-l-((9H-fluoren-9-yl)methoxy-0-(4-decanoylbenzyl)-N,N-d iiso-propylphosphoramidite

GP 2, using (FmO)P(Nz- r 2 ) 2 (515 mg, 1.21 mmol, 1.21 Equiv.) and

(4-(Hydroxymethyl)phenyl)nonanylketon 10 (263 mg, 1.00 mmol, 1.00 Equiv.) in THF (5 mL) and 4,5-Dicyanoimidazol (0.25 M in MeCN, 4.00 mL, 1.00 mmol, 1.00 Equiv.) Yield: 633 mg (935 mmol, 93%) as a colorless oil. The final compound was contaminated with 5%> (via 31 P- NMR) phosphoramidite (FmO) 2 PNz ' - r 2 and with 23% dibenzofulvene. TLC: Rf= 0.7

(PE/Ethylacetate 2: 1 + 1% NEt 3 , VSS).1H-NMR (600 MHz, CDC1 3 ): δ [ppm] = 7.93 (d, J = 8.3 Hz, 2 H, 3-H), 7.78 - 7.68 (m, 2 H, Fm), 7.66 (d, J = 7.5 Hz, 1 H, Fm), 7.61 (d, J = 7.6 Hz, 1 H, Fm), 7.42 (d, J= 8.1 Hz, 2 H), 7.40 - 7.36 (m, 2 H, Fm), 7.34 - 7.25 (m, 2 H, Fm), 4.75 (dd, J= 13.5, 8.1 Hz, 1 H, l-CH^O), 4.69 (dd, J= 13.6, 8.5 Hz, 1 H, l-CH^O), 4.21 (t, J = 7.1 Hz, 1 H, Fm-2'-H), 4.09 - 4.03 (m, 1 H, Fm-1 '-Ha), 3.89 - 3.83 (m, 1 H, Fm-1 '-H b ), 3.69 (m, 2 H, l"a-H), 2.94 (t, J = 7.4 Hz, 2 H, 6-H), 1.73 (p, J = 7.4 Hz, 2 H, 7-H), 1.42 - 1.23 (m, 12 H, 8-H - 13-H), 1.20 (d, J = 6.8 Hz, 6 H, 2"a-H), 1.17 (d, J = 6.8 Hz, 6 H, 2"b-H), 0.91 - 0.87 (m, 3 H, 14-H).

13 C-NMR (151 MHz, CDC1 3 ): δ [ppm] = 200.5 (C-5), 145.0 (C-l), 145.0 (Fm), 144.7 (Fm), 141.5 (Fm), 141.4 (Fm), 136.2 (C-4), 128.9, 128.3 (C-2), 127.6 (Fm), 127.2 (Fm), 127.0 (Fm), 127.0 (Fm), 126.9 (C-3), 125.5 (Fm), 125.3 (Fm), 120.0 (Fm), 1 19.9 (Fm), 66.2 (d, 2 J CP = 18.2 Hz, Fm-1 '), 64.8 (d, 2 J CP = 17.3 Hz, 1-CH 2 0), 49.4 (d, 3 J CP = 7.7 Hz, Fm-2'), 43.3 (d, 2 J CP = 12.3 Hz, 2x C-l"a), 38.8 (C-6), 32.0 (C-12), 29.7, 29.6, 29.6, 29.4 (C-8, C-9, C-10, C-1 1), 24.9 (C-7), 24.8, 24.8, 24.7, 24.6 (2x C-2"a, 2x C-2"b), 22.8 (C-13), 14.3 (C-14). 31 P-NMR (162 MHz, CDC1 3 ): δ [ppm] = 147.7. C 37 H 50 NO 3 P (587.78 g/mol). 0'-l-((9H-fluoren-9-yl)methoxy-0-(4-octadecanoylbenzyl)-N,N- diiso-propylphosphoramidit -Civ) 17

GP 2, using (FmO)P(Nz- r 2 ) 2 (522 mg, 1.22 mmol, 1.80 Equiv.) and

(4-(Hydroxymethyl)phenyl)heptadecanylketon 11 (250 mg, 667 μιηοΐ, 1.00 Equiv.) in

DCM/THF (8/10 mL). 4,5-Dicyanoimidazol (0.25 M in MeCN, 3.50 mL, 875 μmol,

1.30 Equiv.) Yield: 546 mg (780 μιηοΐ, quant.) as a colorless solid. The compound was contaminated with 22% (via 31 P-NMR) phosphoramidite (FmO) 2 PNz ' - r 2 . TLC: Rf= 0.8 (PE/Ethylacetate 2: 1 + 1% NEt 3 , VSS). 1H-NMR (400 MHz, CDC1 3 ): δ [ppm] = 7.93 (d, J = 8.3 Hz, 2 H, 3-H), 7.79 - 7.75 (m, 2 H, Fm), 7.69 - 7.56 (m, 2 H, Fm), 7.47 - 7.34 (m, h H, 2-H, Fm), 7.33 - 7.24 (m, 2 H, Fm), 4.76 (dd, J= 13.6, 8.2 Hz, 1 H, l-CH^O), 4.69 (dd, J = 13.6, 8.5 Hz, 1 H, l-CH^O), 4.25 - 4.15 (m, 1 H, Fm-2'-H), 4.11 - 3.96 (m, 1 H, Fm-1 '-H a ), 3.90 - 3.77 (m, 1 H, Fm-1 '-H b ), 3.75 - 3.61 (ni c , 2 H, l"a-H), 2.94 (t, J= 7.4 Hz, 2 H, 6-H), 1.73 (p, J = 7.4 Hz, 2 H, 7-H), 1.43 - 1.17 (m, 40 H, 8-H - 21-H, 2"a-H, 2"b-H), 0.98 - 0.83 (m, 3 H, 22-H). 13 C-NMR (151 MHz, CDC1 3 ): δ [ppm] = 200.4 (C-5), 145.1, 145.0, 144.8 (2x Fm, C-1), 141.5 (Fm), 141.4 (Fm), 136.2 (C-4), 128.3 (C-2), 127.6 (Fm), 127.5 (Fm), 127.0 (Fm), 127.0 (Fm), 126.9 (C-3), 125.5 (Fm), 125.3 (Fm), 120.0 (Fm), 119.9 (Fm), 66.2 (d, 2 J CP = 17.1 Hz, Fm-Γ), 64.8 (d, 2 J CP = 18.2 Hz, 1-CH 2 0), 49.3 (d, 3 J CP = 7.7 Hz, Fm-2'), 43.3 (d, 2 J C p = 12.7 Hz, 2x C-l"a), 38.8 (C-6), 32.1 (C-20), 31.7, 29.8 (m), 29.7, 29.7, 29.6, 29.5 (C-8, C-9, C-10, C-11, C-12, C-13, C-14, C-15, C-16, C-17, C-18, C-19), 24.9, 24.8, 24.8, 24.7, 24.6 (C-7, 2x C-2"a, 2x C-2"b), 22.9, 22.8 (C-21), 14.3 (C-22).

31 P-NMR (162 MHz, CDC1 3 ): δ [ppm] = 147.7. C 45 H 6 6 0 3 P (700.00 g/mol).

1.5 Non symmetric (AB,ab)-TriP ro-NTPs -C 4 H 9 ,ab-C 9 Hi 9 )-TriPPPro-d4TTP

General procedure 3 using (rc-Bu 4 N) 2 -d4TDP (61.0 mg, 74.0 μηιοΐ, 1.00 Equiv.), (AB-C 4 /ab- C9)-phosphoramidite (90.0 mg, 149 μιηοΐ, 1.80 Equiv.), 4,5-Dicyanoimidazol (0.25 M in

MeCN, 533 pL, 134 μιηοΐ, 1.81 Equiv.) and t-BuOOH (5.5 M in n-Decan, 27.0 pL, 150 μιηοΐ, 2.00 Equiv.). Yield: After freeze drying 35.5 mg (38.0 μτηοΐ, 51%) were obtained as a colorless cotton. 1H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 7.93 (dd, J= 8.4, 1.8 Hz, 2 H, 3"-H), 7.68 (m e , 1 H, 6-H), 7.45 (dd, J= 8.4, 2.8 Hz, 2 H, 2"-H), 7.40 (dd, J= 8.6, 3.2 Hz, 2 H, 2" '-H), 7.03 (dd, J= 8.7, 2.3 Hz, 2 H, 3"'-H), 6.92 (m c , 1 H, l '-H), 6.49 (ι¾, 1 H, 3'-H), 5.80 1 H, 2'-H), 5.22 (d, 3 J H p = 8.1 Hz, 2 H, 1 "-CH 2 0), 5.20 (d, 3 J H p = 8.4 Hz, 2 H, 1 "'- CH 2 0), 4.94 (m e , 1 H, 4'-H), 4.29 (m, 1 H, 5'-H a ), 4.20 (m, 1 H, 5'-H b ), 3.00 (ι¾, 2 H, 6"-H), 2.58 2 H, 6" '-H), 1.91 - 1.85 (m, 3 H, 5-CH 3 ), 1.76 - 1.66 (m, 4 H, 7"-H, 7"'-H), 1.50 - 1.42 (m, 2 H, 8"'-H), 1.42 - 1.26 (m, 12 H, 8"-H-13"-H), 0.99 (t, J= 7.4 Hz, 3 H, 9"'-H), 0.93 - 0.87 (m, 3 H, 14"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.5 (C-5), 173.7 (C-5' "), 166.5 (C-4), 152.8 (C-2), 152.4 (C-4' "), 141.3 (C-l "*, HMBC), 138.7 (C-6), 138.1 (C-4"*), 135.8 (C-3'), 135.0 (d, 3 J CP = 7.4 Hz, C-l ' "*), 130.5 (d, 4 J CP = 5.4 Hz, C-2' "), 129.4 (C-3"), 128.9 (d, 4 J C p = 6.0 Hz, C-2"), 127.1 (C-2'), 122.8 (d, 4 J CP = 2.3 Hz, C-3' "), 112.1 (C-5), 90.8 (C-l '), 87.3 (d, 3 J CP = 9.1 Hz, C-4'), 70.5 (m, 1 "-CH 2 0), 70.1 (m, 1 " '-CH 2 0), 67.9 (d, 2 J C p = 5.8 Hz, C-5'), 39.6 (C-6"), 34.8 (C-6' "), 33.1 (C-12"), 30.7, 30.6, 30.4, 30.4 (C-8"-l l "), 28.1 (C-7' "), 25.6 (C-7"), 23.7 (C-13"*), 23.3 (C-8' "*), 14.4 (C-14"), 14.1 (C- 9"'), 12.5 (5-CH 3 ). 31 P-NMR (162 MHz, MeOH-d 4 ): δ [ppm] = -11.84 (d, 2 J PP = 20.2 Hz, Ρ γ ), -13.26 (d, 2 J PP = 17.3 Hz, P a ), -23.82 (dd, 2 J PP = 22.2, 17.4 Hz, P p ). HRMS (ESI ): mlz = calc: 448.1231 [M-H] " , found: 448.1235 [M-2H] 2" fur CsgHssNzOigPs- C 3 9H 5 9 4 Oi6P3 (M= 932.83 g/mol). -C 6 Hi 3 ,ab-Ci 7 H 35 )-TriPPPro-d4TTP

General procedure 3 using (/?-Bu 4 N) 2 -d4TDP (100 μηιοΐ, 1.00 Equiv.), (AB-C 6 Hi 3 ,ab- Ci 7 H 35 )-phosphoramidite 13 (127 mg, 172 μηιοΐ, 1.70 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 680 pL, 170 μηιοΐ, 1.70 Equiv.) and t-BuOOH (5.5 M inn-Decane, 31.0 pL, 170 μηιοΐ, 1.70 Equiv.). Yield: After freeze drying 56.0 mg (52.0 μηιοΐ, 52%) were obtained as a colorless cotton.1H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 7.92 (dd, J= 8.4, 1.7 Hz, 2 H, 3"-H), 7.67 K, 1 H, 6-H), 7.44 (dd, J = 8.4, 2.8 Hz, 2 H, 2"-H), 7.39 (dd, J = 8.6, 3.1 Hz, 2 H,2"'-H), 7.03 (dd, J = 8.6, 2.4 Hz, 2 H, 3"'-H), 6.96 - 6.89 (ι¾, 1 H, l'-H), 6.51 - 6.45 (Γ¾, 1 H, 3'-H), 5.83 -5.79 (ni c , 1 H, 2'-H), 5.21 (d, 3 J ffP =8.2 Hz, 2 H, 1"-CH 2 0), 5.18 (d, 3 J H p = 8.5Hz,2H, 1"'-CH 2 0), 4.96 -4.92 (m e , 1 H, 4'-H), 4.29 (ddd, J = 11.7, 6.8, 3.3 Hz, 1 H, 5'- H a ), 4.24- 4.16 (m, 1 H, 5'-H b ), 3.00 (Γ¾, 2 H, 6"-H), 2.58 (Γ¾, 2 H, 6"'-H), 1.88 (s, 3 H,

5-CH 3 ), 1.77 - 1.65 (m, 4 H, 7"-H, 7"'-H), 1.48 - 1.23 (m, 34 H, 8"-H-21"-H, 8"'-H-10"'- H), 0.96 - 0.92 (m, 3 H, 11 "-H), 0.90 (t, J = 7.0 Hz, 3 H, 22"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.4 (C-5), 173.7 (C-5'"), 166.5 (C-4), 152.8 (C-2), 152.4 (C-4'"), 142.6 (C-1", HMBC), 138.7 (C-6), 138.1 (C-4"), 135.8 (C-3'), 134.9 (C-1'", HMBC), 130.5 (d, 4 J C p = 5.4 Hz, C-2'"), 129.4 (C-3"), 128.9 (d, 4 J CP = 6.3 Hz, C-2"), 127.1 (C-2'), 122.8 (d, 4J C p = 2.5 Hz, C-3'"), 112.1 (C-5), 90.8 (C-1'), 87.2 (d, 3 J CP = 8.9 Hz, C-4'), 70.5 (m, 1"- CH 2 0), 70.1 (m, 1"'-CH 2 0), 67.9 (d, 2 J CP = 5.8 Hz, C-5'), 39.6 (C-6"), 35.0 (C-6'"), 33.1 (C- 20"), 32.7 (C-10"), 30.8, 30.8, 30.8, 30.7, 30.7, 30.5, 30.4, 29.9 (C-8'", C-9'", C-8"-19"), 25.9 (C-7'"), 25.6 (C-7"), 23.7 (C-21"*), 23.6 (C-10'"*), 14.4 (C-22"), 14.4 (C-ll'"), 12.5 (5-CH 3 ). 31 P-NMR (243 MHz, MeOH-d 4 ): δ [ppm] = -11.83 (d, 2 J PP = 20.0 Hz, Ρ γ ), -13.19 (d, 2 JP P = 17.0 Hz, P a ), -23.81 (t, 2 J PP = 18.5 Hz, P p ). C 49 H 79 4 Oi6P3 (M= 1073.10 g/mol). -Ci 7 H 35 ,ab-C 9 Hi 9 )-TriPPPro-d4TTP

General procedure 3 using (n-Bu 4 N) 2 -d4TDP (100 μιηοΐ, 1.00 Equiv.), Phosphoramidite 14 (132 mg, 169 μιηοΐ, 1.70 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 680 μΐ,, 170 μιηοΐ, 1.70 Equiv.) and t-BuOOH (5.5 M inn-Decan, 31.0 μΕ, 170 μιηοΐ, 1.70 Equiv.). Yield:

51.0 mg (45.7 μιηοΐ, 46%) as a colorless cotton.1H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 7.92 (dd, J= 8.4, 1.7 Hz, 2 H, 3"-H), 7.67 (η¾, 1 H, 6-H), 7.43 (dd, J = 8.3, 3.1 Hz, 2 H, 2"- H), 7.39 (dd, J = 8.5, 3.1 Hz, 2 H, 2"'-H), 7.02 (dd, J = 8.6, 2.5 Hz, 2 H, 3"'-H), 6.94 - 6.91 (me, 1 H, l'-H), 6.50-6.45 (ι¾, 1 H, 3'-H), 5.83 - 5.75 (ι¾, 1 H, 2'-H), 5.21 (d, ^=8.2 Hz,2H, 1"-CH 2 0), 5.18 (d, ^=8.7 Hz, 2 H, 1"'-CH 2 0), 4.96 - 4.93 (ι¾, 1 H, 4'-H), 4.29 (ddd, J= 11.6, 6.9, 3.2 Hz, 1 H, 5'-H a ), 4.20 (ddd,J= 11.6,5.5,3.1 Hz, 1 H, 5'-¾), 3.00 (η¾, 2 H, 6"-H), 2.57 (ι¾, 2 H, 6"'-H), 1.88 (s, 3 H, 5-CH 3 ), 1.77 - 1.66 (m, 4 H, 7"-H, 7"'-H), 1.48 - 1.25 (m, 40 H, 8"-H-13"-H, 8"'-H-21"'-H), 0.90 (ι¾, 6 H, 14"-H, 22"'-H). 13 C- NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.4 (C-5), 173.7 (C-5'"), 166.5 (C-4), 152.8 (C-2), 152.4 (C-4'"), 142.6 (C-1", HMBC), 138.7 (C-6), 138.0 (C-4"), 135.8 (C-3'), 134.9 (C-1'", HMBC), 130.5 (d, 4 J CP = 5.4 Hz, C-2'"), 129.4 (C-3"), 128.9 (d, 4 J CP = 6.3 Hz, C-2"), 127.2 (C-2'), 122.8 (d, 5 J CP = 2.5 Hz, C-3'"), 112.1 (C-5), 90.8 (C-1'), 87.2 (d, 3 J CP = 8.9 Hz, C-4'), 70.5 (m, 1"-CH 2 0), 70.1 (m, 1"'-CH 2 0), 67.9 (d, 2 J CP = 6.1 Hz, C-5'), 39.6 (C-6"), 35.0 (C- 6"'), 33.1 (C-12", C-20'"), 30.8, 30.8, 30.8, 30.7, 30.7, 30.7, 30.6, 30.5, 30.5, 30.4, 30.2 (C- 8"'-C-19"', C-8"-ll"), 26.0 (C-7'"), 25.6 (C-7"), 23.8 (C-21'"*), 23.7 (C-13"*), 14.5 (C- 22"), 14.5 (C-14'"), 12.5 (5-CH 3 ). 31 P-NMR (243 MHz, MeOH-d 4 ): δ [ppm] = -11.82 (d, 2 JPP = 20.1 Hz, Ρ γ ), -13.17 (ι¾, Ρ α ), -23.80 (t, 2 J PP = 18.5 Hz, P p ). C 52 H 85 N 4 Oi 6 P 3 (M= 1115.19 g/mol).

(AB-Ci 7 H3 5 ,ab-Ci 7 H 35 )-TriPPPro-d4TTP

General procedure 3 using (n-Bu 4 N) 2 -d4TDP (88 mg, 100 μηιοΐ, 1.00 Equiv.),

Phosphoramidit 15 (136 mg, 153 μιηοΐ, 1.50 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 612 μΕ, 153 μιηοΐ, 1.50 Equiv.) and t-BuOOH (5.5 M inn-Decan, 28.0 μί, 150 μmol, 1.50 Equiv.). Yield: 15.2 mg (12.4 μιηοΐ) of the NH 4 -form and 32.2 mg (19.8 μιηοΐ) of the n- Bu 4 N-form as a colorless solid, overallyield: 63%.1H-NMR (600 MHz, THF-d 8 ): δ [ppm] = 10.12 - 9.95 (m, 1 H, NH), 8.04 (ι¾, 1 H, 6-H), 7.93 (d, J = 8.1 Hz, 2 H, 3"-H), 7.68 - 7.49 (m, 4 H, 2"-H, 2"'-H), 7.03 (d, J = 8.1 Hz, 2 H, 3"'-H), 6.98 - 6.93 (!¾, 1 H, l'-H), 6.74 - 6.62 1 H, 3'-H), 5.63 -5.55 (m, 1 H, 2'-H), 5.47-5.23 (m, 1"-CH 2 0, 1"'-CH 2 0) 4.84- 4.79 (m e , 1 H,4'-H), 4.56 -4.31 (m, 1 H, 5'-H a ), 4.17 - 3.99 (m, 1 H, 5'-H b ), 3.54 - 3.38 (m, 16 H, n-Bu 4 N), 2.98 (t, J = 7.3 Hz, 2 H, 6"-H), 2.56 (t, J = 7.5 Hz, 2 H, 6"'-H), 2.03 - 1.93 (m, 3 H, 5-CH 3 ), 1.83 - 1.64 (m, 16 H, n-Bu 4 N), 1.52 - 1.29 (m, 72 H, 8"-H-21"-H, 8"'-H- 21"'-H n-Bu 4 N), 0.98 (t, J = 7.3 Hz, 24 H), 0.95 - 0.90 (m, 6 H, 22"-H, 22"'-H). 13 C-NMR (151 MHz, THF-ds): δ [ppm] = 199.3 (C-5), 172.1 (C-5'"), 152.1 (C-2), 151.7 (C-4'"), 138.5 (C-6), 137.6 (C-4"), 130.2 (d, 4 J CP = 4.8 Hz, C-2'"), 128.7 (C-3"), 128.6 (d, 4 J CP = 5.0 Hz, C-2"), 125.9 (C-2'), 122.2 (C-3'"), 111.3 (C-5), 90.1 (C-l'), 88.1 (d, 3 J CP = 7.9 Hz, C-4'),

59.2 (n-Bu 4 N), 39.2 (C-6"), 34.9 (C-6'"), 33.1 (C-20", C-20'"), 30.8, 30.8, 30.7, 30.5, 30.5,

30.3 (C-8"'-C-19"\ C-8"-19"), 25.3 (C-7"*), 25.0 (C-7'"*), 23.7 (C-21"*, C-21'"*, n-Bu 4 N), 20.8 (rc-Bu 4 N), 14.6, 14.4 (n-Bu 4 N, C-22", C-22'"), 12.7 (5-CH 3 ). 31 P-NMR (162 MHz, THF-ds): δ [ppm] = -11.90 (d, 2 J PP = 20.8 Hz, Ρ γ ), -12.97 (d, 2 J PP = 19.8 Hz, P a ), - 21.85 (m, P p ).

C 9 2H 165 4 Oi6P3 (M= 1679.27 g/mol). AB-Ci 7 H35,ab-C 9 Hi 9 )-TriPPPro-ATTP

General procedure 3 using ADP (/?-Bu 4 N) 2 (71.0 mg, 73.0 μηιοΐ, 1.00 Equiv.) in DMF

(1 mL) and Phosphoramidite 14 (100 mg, 109 μιηοΐ, 1.50 Equiv.) in DCM (2 mL), BTT (0.3 M in MeCN, 487 μΕ, 146 μιηοΐ, 2.00 Equiv.), t-BuOOH (5.5 M in n-Decan, 27.0 μΕ, 146 μmol, 2.00 Equiv.) at 0 °C. The residue was a several times purified by auto Flash RP-CC

(H 2 0/MeCN), transformed via cation exchange in die Triethyl ammonia form and purified by auto Flash RP-CC (H 2 0/MeCN). Yield: After freeze drying 31.0 mg (24.5 μιηοΐ, 34%) were obtained as a colorless strong hygroscopic cotton. 1H-NMR (400 MHz, MeOH-d 4 /CDCl 3 2:1 v/v): δ [ppm] = 8.67 (s, 1 H, 8-H), 8.16 (s, 1 H, 2-H), 7.88 - 7.78 (m, 2 H, 3"-H), 7.41 - 7.24 (m, 4 H, 2"-H, 2" '-H), 7.01 - 6.88 (m, 3 H, 3"'-H), 6.01 (ι¾, 1 H, l '-H), 5.20 - 5.09 (m, 4 H, 1 "-CH 2 0, 1 " '-CH 2 0), 4.50 - 4.42 (m, 2 H, 2'-H, 3'-H), 4.42 - 4.34 (m, 1 H, 4'-H), 4.32 - 4.23 (m, 2 H, 5'-H), 3.01 - 2.85 (ι¾, 2 H, 6"-H), 2.53 (t, J= 7.4 Hz, 2 H, 6"'-H), 1.79 - 1.59 (m, 4 H, 7"-H, 7" '-H), 1.48 - 1.17 (m, 40 H, 8"-H-13"-H, 8" '-H-21 " '-H), 0.85 (t, J= 6.8 Hz, 6 H, 14"-H, 22" '-H). 31 P-NMR (162 MHz, MeOH-d 4 /CDCl 3 2:1 v/v): δ [ppm] = -11.27 (d, 2 J PP = 17.2 Hz, Ρ γ ), -12.86 (d, 2 J PP = 15.7 Hz, P a ), -22.65 (t, 2 J PP = 16.6 Hz, Pp.

C 5 2H 78 5 a 2 Oi6P3 (M= 1168.12 g/mol).

1.6 Mono-modified (ab)-TriP ro-NTPs ab-C 9 Hi 9 )-TriPPPro-d4TTP

(AB-C 4 H 9 ,ab-C 9 Hi 9 )-Tri ro-d4TTP (5.0 mg, 5.4 μηιοΐ, 1.0 Equiv.) dissolved in water (200 μΐ,) and porcine liver esterase (3mg/mL in 50 mM PBS, 0.3→0.8 mL, 41 U) were incubated for 11 h at 37 °C in a thermomixer. The solvent was removed by freeze drying. The residue was purified by using automated Flash-RP-CC (H 2 0/MeCN 90: 10→30:70). yield: After freeze drying 2.2 mg (2.9 μιηοΐ, 53%) were obtained as a colorless solid. 1 H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 7.94 (d, J= 8.3 Hz, 2 H, 3"-H), 7.71 (Γ¾, 1 H, 6-H), 7.58 (d, J= 8.2 Hz, 2 H, 2"-H), 6.93 (π¾., 1 H, l '-H), 6.54 (ι¾, 1 H, 3'-H), 5.81 (π¾., 1 H, 2'-H), 5.14 (d, 3 J H p = 6.0 Hz, 2 H, l "-CH 2 0), 4.97 (m c , 1 H, 4'-H), 4.32 - 4.26 (m, 1 H, 5'-H a ), 4.19 - 4.15 (m,

1 H, 5'-H b ), 3.00 (t, J= 7.4 Hz, 2 H, 6"-H), 1.95 - 1.87 (m, 3 H, 5-CH 3 ), 1.69 (p, J= 7.4 Hz,

2 H, 7"-H), 1.44 - 1.23 (m, 12 H, 8"-H-13"-H), 0.90 (t, J= 7.0 Hz, 3 H, 14"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.8 (C-5", HMBC), 166.7 (C-4, HMBC), 145.8 (C-l ",

HMBC), 138.8 (C-4"), 135.6 (C-3', HSQC), 129.2 (C-3"), 128.3 (C-2"), 126.4 (C-2', HSQC), 112.2 (C-5, HMBC), 90.3 (C-l ', HSQC), 87.0 (C-4', HSQC), 67.5 (1 "-CH 2 0, HSQC), 67.3 (C-5', HSQC), 39.5 (C-6"), 33.0 (C-12"), 30.6, 30.6, 30.4, 30.4 (C-8"-l l "), 25.7 (C-7"), 23.7 (C-13"*), 14.4 (C-14"), 12.5 (5-CH . 3_). 31 P-NMR (243 MHz, MeOH-d 4 ): δ [ppm] = -10.03 (d, 2 J PP = 16.7 Hz, Ρ γ ), -10.25 (d, 2 J PP = 16.6 Hz, P a ), -20.43 (m, P p ).

C 27 H 37 N 2 Oi 4 P 3 (M= 752.49 g/mol).

General procedure 4, using (/?-Bu 4 N) 2 dTDP (46 umol, 1.0 Equiv.), (Fm/ab-Cg)- phosphoramidite (39 mg, 60 μηιοΐ, 1.3 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 0.20 mL, 51 μιηοΐ, 1.1 Equiv.) and t-BuOOH (5.5 M in n-Decan, 11.0 μί, 60 μιηοΐ,

1.3 Equiv.). Yield: After freeze drying 23.1 mg (30.3 μιηοΐ, 66%) were obtained as a colorless solid. 1H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 7.94 (d, J= 8.3 Hz, 2 H, 3"-H), 7.82 (s, 1 H, 6-H), 7.57 (d, J= 8.1 Hz, 2 H, 2"-H), 6.29 (π¾., 1 H, l '-H), 5.14 (d, 3 J H p = 6.4 Hz, 2 H, 1 "-CH 2 0), 4.64 - 4.58 (m, 1 H, 3'-H), 4.31 - 4.25 (m, 1 H, 5 '-H a ), 4.23 - 4.15 (m, 1 H, 5'-

H b ), 4.00 (m e , 1 H, 4'-H), 3.00 (t, J= 7.3 Hz, 2 H, 6"-H), 2.25 (ddd, J= 13.5, 7.4, 6.1 Hz, 1 H, 2'-H a ), 2.19 (ddd, J= 13.5, 6.2, 3.6 Hz, 1 H, 2'-H b ), 1.92 (d, J= 1.2 Hz, 3 H, 5-CH 3 ), 1.69 (p, J = 7.3 Hz, 2 H, 7"-H), 1.42 - 1.25 (m, 12 H, 8"-H - 14"-H), 0.90 (t, J= 7.0 Hz, 3 H, 14"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.7 (C-5), 166.5 (C-4), 152.4 (C-2), 145.5 (C-1 "), 138.2 (C-6), 137.4 (C-4"), 129.2 (C-3"), 128.2 (C-2"), 111.9 (C-5), 87.4 (C-4'), 86.0 (C-1 '), 72.0 (C-3'), 68.1, (d, 2 J CP = 5.3 Hz, 1 "-CH 2 0), 66.6 (C-5'), 40.7 (C-2'), 39.5 (C-6"),

33.1 (C-12"), 30.7, 30.6, 30.4, 30.4 (C-8"-l l "), 25.7 (C-7"), 23.7 (C-13"), 14.4 (C-14"). 31 P-NMR (243 MHz, MeOH-d 4 ): δ [ppm] = -11.12 (d, 2 J PP = 19.0 Hz, Ρ γ ), -11.40 (d, 2 J PP =

19.2 Hz, P a ), -22.31 (t, 2 J PP = 19.1 Hz, P p ). C 27 H 47 N 4 Oi 5 P 3 (M= 760.61 g/mol). -C 9 Hi 9 )-TriPPPro-dATTP

General procedure 4, using dADP-(/?-Bu 4 N) 2 (50.0 μηιοΐ, 1.00 Equiv.) in DMF (1 mL),

Phosphoramidit 16 (49.0 mg, 75.0 μηιοΐ, 1.50 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 300 μΐ,, 75.0 μιηοΐ, 1.50 Equiv.) and t-BuOOH (5.5 M in n-Decan, 14.0 μΕ, 75.0 μιηοΐ, 1.50 Equiv.) Yield: After freeze drying 14.5 mg (18.9 μιηοΐ, 38%) were obtained as a colorless cotton.1H-NMR (600 MHz, MeOH-d 4 ): δ [ppm] = 8.75 (s, 1 H, 8-H), 8.17 (s, 1 H, 2-H), 7.83 (d,J=8.3Hz,2H, 3"-H), 7.50 (d,J= 8.1 Hz, 2 H, 2"-H), 6.39 (t, J= 6.3 Hz, 1 H, l'-H), 5.13 (d,J=6.4Hz,2H, 1"-CH 2 0), 4.76 -4.66 (ι¾, 1 H, 3'-H), 4.42 - 4.34 (m, 1 H, 5'-H a ), 4.31 -4.26 (m, 1 H, 5'-H b ), 4.18 - 4.14 (m, 1 H, 4'-H), 2.93 (t,J=7.2 Hz, 1 H, 6"-H), 2.64 - 2.57 (m, 1 H,2'-H a ), 2.49- 2.42 (m, 1 H, 2'-H b ), 1.65 (p,J=7.2 Hz, 2 H, 7"-H), 1.40-1.24 (m, 12 H, 8"-H-13"), 0.89 (t, J= 6.9 Hz, 3 H, 14"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.4 (C-5"), 152.8 (C-6, HMBC), 149.1 (C-4), 145.2 (d, 3 J CP = 8.9 Hz, C-l"), 143.0 (C-8), 137.2 (C-4"), 129.1 (C-3"), 128.2 (C-2"), 119.2 (C-5), 88.0 (d, 3 J CP = 9.0 Hz, 4'- H), 85.6 (C-l'), 71.9 (3'-H), 68.0 (d, 2 J CP = 5.1 Hz, 1"-CH 2 0), 66.4 (d, 2 J CP = 5.9 Hz, C-5'), 42.1 (C-2'), 39.5 (C-6"), 33.1 (C-12"), 30.7, 30.6, 30.4, 30.4 (C-8"-ll"), 25.6 (C-7"), 23.7 (C-13"), 14.4 (C-14"). 31 P-NMR (162 MHz, MeOH-d 4 ): δ [ppm] = -10.91 (d, 2 J PP = 17.8 Hz, Ρ γ ), -11.19 (d, 2 J PP = 17.8 Hz, P a ), -21.75 (t, 2 J PP = 17.8 Hz, P p ). C 27 H 46 N 7 NOi 3 P 3 (M=

769.62 g/mol). (ab-Ci 7 H 35 )-TriPPPro-d4TTP

General procedure 4, using (/?-Bu 4 N) 2 -d4TDP (95.0 μηιοΐ, 1.00 Equiv.), Phosphoramidit 17 (100 mg, 143 μιηοΐ, 1.50 Equiv.), 4,5-Dicyanoimidazol (0.25 M in MeCN, 570 μΐ,, 1.5 Equiv.) and t-BuOOH (5.5 M in n-Decan, 26.0 μί, 143 μmol, 1.50 Equiv.) Yield: After freeze drying 22.1 mg (25.9 μιηοΐ, 27%) were obtained as a colorless solid. 1H-NMR (600 MHz, MeOH- d 4 ): δ [ppm] = 7.95 (d, J= 8.3 Hz, 2 H, 3"-H), 7.69 (ι¾, 1 H, 6-H), 7.57 (d, J= 8.2 Hz, 2 H, 2"-H), 6.93 (m e , 1 H, l '-H), 6.53 (ι¾, 1 H, 3'-H), 5.82 (!¾, 1 H, 2'-H), 5.14 (d, ^ = 6.4 Hz, 2 H, 1 "-CH 2 0), 4.97 (ι¾, 1 H, 4'-H), 4.30 (ddd, J= 11.7, 6.8, 3.3 Hz, 1 H, 5'-H a ), 4.18 (ddd, J = 11.6, 5.4, 3.1 Hz, 1 H, 5'-H b ), 3.01 (t, J= 7.3 Hz, 2 H, 6"-H), 1.90 (s, 3 H, 5-CH 3 ), 1.69 (p, J = 7.3 Hz, 2 H, 7"-H), 1.43 - 1.22 (m, 28 H, 8"-H-21 "-H), 0.90 (t, J= 7.0 Hz, 3 H, 22"-H). 13 C-NMR (151 MHz, MeOH-d 4 ): δ [ppm] = 202.7 (C-5"), 166.6 (C-4), 152.8 (C-2), 145.5 (C-1 ", HMBC), 138.7 (C-6), 137.4 (C-4"), 136.0 (C-3'), 129.2 (C-3"), 128.3 (C-2"), 127.0 (C-2'), 112.0 (C-5), 90.9 (C-1 '), 87.3 (d, 3 J CP = 9.3 Hz, C-4'), 68.1 (d, 2 J CP = 5.5 Hz, 1 "-

CH 2 0), 67.7 (d, 2 J C p = 5.9 Hz, C-5'), 39.5 (C-6"), 33.1 (C-20"), 30.8, 30.8, 30.8, 30.7, 30.7, 30.7, 30.5, 30.4 (C-8"-13"), 25.7 (C-7"), 23.7 (C-21 "), 14.4 (C-22"), 12.5 (5-CH 3 ). 31 P- NMR (243 MHz, MeOH-d 4 ): δ [ppm] = -11.20 (d, 2 J PP = 19.5 Hz, Ρ γ ), -11.52 (d, 2 J PP = 19.4 Hz, P a ), -22.53 (t, 2 J PP = 19.5 Hz, P p ). C 35 H 6 iN 4 Oi 5 P 3 (M= 870.81 g/mol).