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Title:
PROCESS FOR THE PRODUCTION OF OLEOCANTHAL, OLEACEIN AND THEIR ANALOGUES
Document Type and Number:
WIPO Patent Application WO/2021/121925
Kind Code:
A1
Abstract:
A process for the production of a compound according to Formula (I), such as oleocanthal or oleacein, starting from oleuropein. The process provides the dialdehyde core of oleocanthal, oleacein and their analogues having the required stereochemistry. Furthermore, the process can be used for the production of a large number of structurally diverse products by varying the structure of the alcohol moiety in the esterification step.

Inventors:
SKALTSOUNIS ALEXIOS LEANDROS (GR)
KOSTAKIS IOANNIS (GR)
GABORIAUD-KOLAR NICOLAS (FR)
CHRISTOFORIDOU NIKOLETA (GR)
SARIKAKI GEORGIA (GR)
Application Number:
PCT/EP2020/083897
Publication Date:
June 24, 2021
Filing Date:
November 30, 2020
Export Citation:
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Assignee:
NATIONAL AND KAPODISTRIAN UNIV OF ATHENS (GR)
PHARMAGNOSE S A (GR)
International Classes:
C07C67/30; C07D309/16; C12P7/00; C12P7/62
Domestic Patent References:
WO2018162769A22018-09-13
Foreign References:
ES2693177A22018-12-07
Other References:
AMOS B. SMITH ET AL: "Syntheses of (-)-Oleocanthal, a Natural NSAID Found in Extra Virgin Olive Oil, the (-)-Deacetoxy-Oleuropein Aglycone, and Related Analogues", JOURNAL OF ORGANIC CHEMISTRY, vol. 72, no. 18, 1 January 2007 (2007-01-01), US, pages 6891 - 6900, XP055548540, ISSN: 0022-3263, DOI: 10.1021/jo071146k
M. SERVILIB. SORDINIS. ESPOSTOS. URBANIG. VENEZIANII. DI MAIOR. SELVAGGINIA. TATICCHI, ANTIOXIDANTS (BASEL, SWITZERLAND, vol. 3, 2013, pages 1 - 23
M. FUENTES DE MENDOZAC. DE MIGUEL GORDILLOJ. MARIN EXPOXITOJ. SANCHEZ CASASM. MARTINEZ CANOD. MARTIN VERTEDORM. N. FRANCO BALTASAR, FOOD CHEM, vol. 141, 2013, pages 2575 - 2581
G. K. BEAUCHAMPR. S. J. KEASTD. MORELJ. LINJ. PIKAQ. HANC.-H. LEEA. B. SMITHP. A. S. BRESLIN, NATURE, vol. 437, 2005, pages 45 - 46
K.-L. PANGK.-Y. CHIN, NUTRIENTS, vol. 10, 2018, pages 570
Y. GUJ. WANGL. PENG, ONCOL. REP., vol. 37, 2017, pages 483 - 491
M. P. CHARALAMBOUST. LIGHTFOOTV. SPEIRSK. HORGANN. J. GOODERHAM, BR. J. CANCER, vol. 101, 2009, pages 106 - 115
E. MEDINAA. DE CASTROC. ROMEROM. BRENES, J. AGRIC. FOOD CHEM., vol. 54, 2006, pages 4954 - 4961
A. LACONOR. GOMEZJ. SPERRYJ. CONDEG. BIANCOR. MELIJ. J. GOMEZ-REINOA. B. 3RD SMITHO. GUALILLO, ARTHRITIS RHEUM, vol. 62, 2010, pages 1675 - 1682
H. QOSAY. S. BATARSEHM. M. MOHYELDINK. A. EL SAYEDJ. N. KELLERA. KADDOUMI, ACS CHEM. NEUROSCI., vol. 6, 2015, pages 1849 - 1859
W. LIJ. B. SPERRYA. CROWEJ. Q. TROJANOWSKIA. B. 3RD SMITHV. M.-Y. LEE, J. NEUROCHEM., vol. 110, 2009, pages 1339 - 1351
M. NARUSZEWICZM. E. CZERWINSKAA. K. KISS, CURR. PHARM. DES., vol. 21, 2015, pages 1205 - 1212
A. FILIPEKM. E. CZERWINSKAA. K. KISSM. WRZOSEKM. NARUSZEWICZ, PHYTOMEDICINE, vol. 22, 2015, pages 1255 - 1261
M. E. CZERWINSKAA. K. KISSM. NARUSZEWICZ, FOOD CHEM, vol. 153, 2014, pages 1 - 8
A. PARZONKOM. E. CZERWINSKAA. K. KISSM. NARUSZEWICZ, PHYTOMEDICINE, vol. 20, 2013, pages 1088 - 1094
A. B. SMITHQ. HANP. A. S. BRESLING. K. BEAUCHAMP, ORG. LETT., vol. 7, 2005, pages 5075 - 5078
B. J. ENGLISHR. M. WILLIAMS, TETRAHEDRON LETT., vol. 50, 2009, pages 2713 - 2715
K. TAKAHASHIH. MORITAT. HONDA, TETRAHEDRON LETT., vol. 53, 2012, pages 3342 - 3345
M. VALLIE. G. PEVIANIA. PORTAA. D'ALFONSOG. ZANONIG. VIDARI, EUROPEAN J. ORG. CHEM., vol. 2013, 2013, pages 4332 - 4336
A. B. SMITHJ. B. SPERRYQ. HAN, J. ORG. CHEM., vol. 72, 2007, pages 6891 - 6900
K. VOUGOGIANNOPOULOUC. LEMUSM. HALABALAKIC. PERGOLAO. WERZA. B. 3RD SMITHS. MICHELL. SKALTSOUNISB. DEGUIN, J. NAT. PROD., vol. 77, 2014, pages 441 - 445
N. XYNOSG. PAPAEFSTATHIOUM. PSYCHISA. ARGYROPOULOUN. ALIGIANNISA.-L. SKALTSOUNIS, J. SUPERCRIT. FLUIDS, vol. 67, 2012, pages 89 - 93
V.-I. BOKAA. ARGYROPOULOUE. GIKASA. ANGELISN. ALIGIANNISA.-L. SKALTSOUNIS, PLANTA MED., vol. 81, 2015, pages 1628 - 1635
C. SAVOURNINB. BAGHDIKIANR. ELIASF. DARGOUTH-KESRAOUIK. BOUKEFG. BALANSARD, J. AGRIC. FOOD CHEM., vol. 49, 2001, pages 618 - 621
T. MICHELI. KHLIFP. KANAKISA. TERMENTZIN. ALLOUCHEM. HALABALAKIA.-L. SKALTSOUNIS, PHYTOCHEM. LETT., vol. 11, 2015, pages 424 - 439
S. HANESSIANE. MAINETTIF. LECOMTE, ORG. LETT., vol. 8, 2006, pages 4047 - 4049
Attorney, Agent or Firm:
ROUKOUNAS, Dimitrios (DE)
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Claims:
CLAIMS

1. A process for the production of a compound according to Formula (I) wherein RiO is an alcohol moiety, wherein the process comprises the following steps: a) converting the compound of Formula II to the compound of Formula III

b) converting the compound of Formula III to the compound of Formula IV c) converting the compound of Formula IV to the compound of Formula V

wherein R20 is the same as R1O as defined above or is a protected form of R1O, d) converting the compound of Formula V to the compound of Formula VI wherein RiO is as defined above, e) subjecting the compound of Formula VI to enzymatic hydrolysis with b-glucosidase to give the compound of Formula (I).

2. The process according to claim 1 , wherein Ri is substituted or unsubstituted alkyl or alkene, or a substituted or unsubstituted aryl.

3. The process according to claim 2, wherein Ri is a C1-C15 alkyl or alkene, optionally substituted with aryl, alkoxy, acyl, hydroxyl, amino, halogen, thiol, nitrile, carboxyl.

4. The process according to claim 2, wherein Ri is aryl, optionally substituted with alkyl, alkoxy, halogen, amino, hydroxyl, thiol, nitrile, carboxyl.

5. The process according to claim 4, wherein Ri is wherein R3, R4, Rs, R6 and R7 are the same or different and are selected from hydrogen, hydroxyl, halogen, alkyl, alkoxy.

6. The process according to claim 5, wherein Ri is selected from

7. The process according to claim 6, wherein R2O is selected from

8. The process according to any one of the preceding claims, wherein step a) is carried out with NaOH in an acetonic olive leaf extract.

9. The process according to any one of the preceding claims, wherein step b) is carried out with acetic anhydride in the presence of pyridine.

10. The process according to any one of the preceding claims, wherein step c) is carried out with an alcohol of formula R2OH in the presence of triethylamine and 4- dimethylaminopyridine (DMAP), wherein R20 is as defined above.

11. The process according to any one of the preceding claims, wherein step d) is carried out with hydrazine or diethylamine in methanol.

12. The process according to any one of the preceding claims, wherein steps b) and c) are carried out without isolating the compounds of Formula IV and Formula V.

Description:
PROCESS FOR THE PRODUCTION OF OLEOCANTHAL, OLEACEIN AND THEIR

ANALOGUES Field of the invention

The present invention relates to a process for the production of certain natural products such as oleocanthal and oleacin as well as their analogues.

Background of the invention Extra virgin olive oil, a well-known source of polyphenols, has attracted scientific attention in recent years because of its biological activities and its attribution in many aspects of human health. Although olive oil primarily consists of oleic acid (up to 80 %) and other fatty acids, some minor phenolic compounds, comprising the 1-2 % of the total content, are generally considered to be responsible for the various health benefits of olive oil. The most characteristic compounds in this group are tyrosol (M. Servili, B. Sordini, S. Esposto, S. Urbani, G. Veneziani, I. Di Maio, R. Selvaggini, A. Taticchi, Antioxidants (Basel, Switzerland) 2013, 3, 1-23) and hydroxytyrosol (M. Fuentes de Mendoza, C. De Miguel Gordillo, J. Marin Expoxito, J. Sanchez Casas, M. Martinez Cano, D. Martin Vertedor, M. N. Franco Baltasar, Food Chem. 2013, 141, 2575-2581), the two glucosylated seco-iridoids Oleuropein (G. K. Beauchamp, R. S. J. Keast, D. Morel, J. Lin, J. Pika, Q. Han, C.-H. Lee, A. B. Smith, P. A. S. Breslin, Nature 2005, 437, 45-46) and Ligstroside (K.-L. Pang, K.-Y. Chin, Nutrients 2018, 10, 570); and the two corresponding decarboxymethylated aglycons Oleacein (Y. Gu, J. Wang, L. Peng, Oncol. Rep. 2017, 37, 483-491) and Oleocanthal (M. P. Charalambous, T. Lightfoot, V. Speirs, K. Horgan, N. J. Gooderham, Br. J. Cancer 2009, 101, 106-115).

Oleocanthal

Oleocanthal and oleacein are characterized by a dialdehyde core, connected by an ester moiety with tyrosol and hydroxytyrosol respectively. These two compounds, and especially oleocanthal, have been identified as the agents responsible for the pungency of extra virgin oil. Oleocanthal’s recent discovery as COX inhibitor, with similar effect to that of ibuprofen, has dramatically increased its interest both for the study of biological properties but also for the development of new non-steroidal anti-inflammatory drugs (NSAIDS) based on its structure [G. K. Beauchamp, R. S. J. Keast, D. Morel, J. Lin, J. Pika, Q. Han, C.-H. Lee, A. B. Smith, P. A. S. Breslin, Nature 2005, 437, 45-46; K.-L. Pang, K.-Y. Chin, Nutrients 2018, 10, 570] Additionally, according to many data, oleocanthal demonstrated promising anticancer [Y. Gu, J. Wang, L. Peng, Oncol. Rep. 2017, 37, 483-491 ; M. P. Charalambous, T. Lightfoot, V. Speirs, K. Horgan, N. J. Gooderham, Br. J. Cancer 2009, 101, 106-115], antimicrobial [E. Medina, A. de Castro, C. Romero, M. Brenes, J. Agric. Food Chem. 2006, 54, 4954-4961], anti-inflammatory [A. lacono, R. Gomez, J. Sperry, J. Conde, G. Bianco, R. Meli, J. J. Gomez-Reino, A. B. 3rd Smith, O. Gualillo, Arthritis Rheum. 2010, 62, 1675-1682] and neuroprotective activities [H. Qosa, Y. S. Batarseh, M. M. Mohyeldin, K. A. El Sayed, J. N. Keller, A. Kaddoumi, ACS Chem. Neurosci. 2015, 6, 1849-1859; W. Li, J. B. Sperry, A. Crowe, J. Q. Trojanowski, A. B. 3rd Smith, V. M.-Y. Lee, J. Neurochem. 2009, 110, 1339-1351], with no toxic effects. Regarding oleacein, several studies suggest that this compound possesses antimicrobial, anti-proliferative, anti-inflammatory [M. Naruszewicz, M. E. Czerwinska, A. K. Kiss, Curr. Pharm. Des. 2015, 21, 1205-1212; A. Filipek, M. E. Czerwihska, A. K. Kiss, M. Wrzosek, M. Naruszewicz, Phytomedicine 2015, 22, 1255- 1261], cardio protective [M. E. Czerwihska, A. K. Kiss, M. Naruszewicz, Food Chem. 2014, 153, 1-8] and antioxidant activity by modulating the Nrf2 pathway [A. Parzonko, M. E. Czerwinska, A. K. Kiss, M. Naruszewicz, Phytomedicine 2013, 20, 1088-1094] Thus, there is a high demand for these two dialdehydes, in order to initiate more in- depth biological studies, however, their low content in olive oil prevents large scale isolation due to apparent high-cost efficiency of the process.

The great interest of these two high-added value natural compounds triggered the development of various synthetic approaches, all involving multi-step total synthesis, with low total yields. Smith’s group was the first to report both synthesis and assignment of the absolute configuration of oleocanthal. This 12-steps strategy involved the functionalization of cyclopentanone and its oxidative opening to the dialdehyde corresponding to the natural enantiomer assigning, therefore, its stereochemistry as (-)- oleocanthal [A. B. Smith, Q. Han, P. A. S. Breslin, G. K. Beauchamp, Org. Lett. 2005, 7, 5075-5078] Later, another approach has been developed based on the opening of a secologanin derivative constructed through a tandem Michael cyclisation/Horner- Woodworth-Emmons olefination. This synthesis, though shorter (9 steps) found limitation due to the lack of control of the stereochemistry during the key cyclisation process leading to the (±)oleocanthal [B. J. English, R. M. Williams, Tetrahedron Lett. 2009, 50, 2713-2715] A third synthesis has been proposed implying the oxidative opening of a highly functionalized cyclopentane serving as a key intermediate, similar to the one developed in Smith’s synthesis, though obtained this time through Sml 2 promoted ring closure [K. Takahashi, H. Morita, T. Honda, Tetrahedron Lett. 2012, 53, 3342-3345] More recently, an 8-step approach has been proposed, implying an epoxycyclopentanone as key intermediate, though leading to the racemic mixture [M. Valli, E. G. Peviani, A. Porta, A. D’Alfonso, G. Zanoni, G. Vidari, European J. Org. Chem. 2013, 2013, 4332-4336] Regarding Oleacein, the first total synthesis was accomplished by Smith’s group [A. B. Smith, J. B. Sperry, Q. Han, J. Org. Chem. 2007 72, 6891-6900], and later, a one-step semi-synthesis was accomplished, under Krapcho decarbomethoxylation conditions [K. Vougogiannopoulou, C. Lemus, M. Halabalaki, C. Pergola, O. Werz, A. B. 3rd Smith, S. Michel, L. Skaltsounis, B. Deguin, J. Nat. Prod. 2014, 77, 441-445]

Thus, there is still a need for an improved process for the production of compounds such as oleocanthal or oleacein and their analogues, which does not have the drawbacks of the processes of the prior art.

Summary of the invention

The present invention provides a process for the production of compounds such as oleocanthal or oleacein and their analogues starting from oleuropein, an abundantly available product. The process provides in an efficient manner the dialdehyde core of oleocanthal, oleacein and their analogues having the required stereochemistry. Furthermore, the process can be easily adapted for the production of a large number of structurally diverse products by varying the structure of the alcohol moiety in the esterification step. The process involves a small number of steps, is simple, versatile, can be used on a large scale and provides optically pure products.

Detailed description of the invention

The present invention provides a process for the production of a compound according to Formula (I) wherein R1O is an alcohol moiety, wherein the process comprises the following steps: a) converting the compound of Formula II to the compound of Formula III b) converting the compound of Formula III to the compound of Formula IV c) converting the compound of Formula IV to the compound of Formula V

wherein R 2 0 is the same as R1O as defined above, or is a protected form of R1O, d) converting the compound of Formula V to the compound of Formula VI wherein R1O is as defined above, e) subjecting the compound of Formula VI to enzymatic hydrolysis with b-glucosidase to give the compound of Formula (I).

The group R1O in the compound of Formula I can be any alcohol moiety. Preferably, Ri is substituted or unsubstituted alkyl or alkene, or a substituted or unsubstituted aryl. According to a preferred embodiment, Ri is a C1-C15 alkyl or alkene, optionally substituted with aryl, alkoxy, acyl, hydroxyl, amino, halogen, thiol, nitrile, carboxyl. According to another preferred embodiment Ri is aryl, optionally substituted with alkyl, alkoxy, halogen, amino, hydroxyl, thiol, nitrile, carboxyl.

More preferably, Ri is wherein R 3 , R4, Rs, R 6 and R 7 are the same or different and are selected from hydrogen, hydroxyl, halogen, alkyl, alkoxy.

According to another preferred embodiment, Ri is selected from

In cases where R1 does not contain any functional groups which can interfere with the esterification reaction of step c), i.e. the reaction of the compound of formula IV with an alcohol of formula R 2 OH, R 2 in R 2 OH (and in the compound of Formula V) is the same as Ri. In cases where Ri contains one or more functional groups which can interfere with the esterification reaction, for example a hydroxyl group, this group is preferably in a protected form, for example, as acetyl, benzoyl, benzyl or ether. In such a case R 2 moiety is a protected form of Ri. The protection of functional groups is well known to a person skilled in the art. Thus, for example, in the process for the production of oleocanthal or oleacein, RiO is a tyrosol or hydrotyrosol moiety respectively as shown below

In such a case the mixed anhydride of Formula IV reacts with R 2 OH in which the hydroxyl group(s) on the phenyl ring are already protected, for example by an acetyl group. In such a case, R 2 is a protected form of the respective Ri as shown below The compound of Formula II is oleuropein, an abundantly available product. Namely, thousands of tons of olive tree leaves are gathered each year in olive oil producing countries, which are burned in the fields, however, they represent a tremendous source of oleuropein, which is the major metabolite that could be found within [N. Xynos, G. Papaefstathiou, M. Psychis, A. Argyropoulou, N. Aligiannis, A.-L. Skaltsounis, J. Supercrit. Fluids 2012, 67, 89-93] The isolation of oleuropein from olive tree leaves can be carried out using processes well known in the art, such as the one disclosed in V.-l. Boka, A. Argyropoulou, E. Gikas, A. Angelis, N. Aligiannis, A.-L. Skaltsounis, Planta Med. 2015, 81, 1628-1635. Step a) in the process of the present invention is a saponification, i.e. ester hydrolysis of oleuropein, which can be carried out by processes well know in the art. For example, the reaction can be carried out with NaOH at room temperature.

Alternatively, the saponification of oleuropein can be conducted in an acetonic olive leaf extract, prior the purification, and the compound of Formula III can then be purified for example, by fast centrifugal partition chromatography (FCPC) by using, for example, the system of solvents EtOAc/2-Propanol/EtOH/H 2 0/Acetic acid 8/2/1/10/0.5 This sequence provides a simple and powerful approach to obtain high amounts of the compound of Formula III in high optical purity. By following this approach, and depending on the olive leafs used [C. Savournin, B. Baghdikian, R. Elias, F. Dargouth- Kesraoui, K. Boukef, G. Balansard, J. Agile. Food Chem. 2001, 49, 618-621 ; T. Michel, I. Khlif, P. Kanakis, A. Termentzi, N. Allouche, M. Halabalaki, A.-L. Skaltsounis, Phytochem. Lett. 2015, 11, 424-439.], from 380 g of olive leaves, approximately 4 g of oleoside can be obtained.

One key element in the synthetic procedure of the present invention is the stereo selective mono-esterification of the dicarboxylic acid of Formula III. Attempts to prepare the compound of Formula VI through Yamaguchi esterification conditions gave only small quantities of the desired product, with laborious purifications. The use of many other different conditions did not improve the reaction. Unexpectedly, the present inventors have found that the synthesis of the compound of Formula VI can be achieved through the mixed anhydride of Formula IV. This approach provides, selectively, the desired ester due to steric hindrance around the anhydride moiety. Additionally, the protection of the sugar’s hydroxyl groups can be incorporated in one step, during the synthesis of the mixed anhydride.

Step b) involves the synthesis of the mixed anhydride of formula IV. This reaction can be carried out, for example, by treatment of the compound of Formula III with acetic anhydride in the presence of pyridine.

Step c) involves the treatment of the mixed anhydride of Formula IV with a suitable alcohol of formula R 2 OH. In cases where Ri does not contain any functional groups which can interfere with the esterification reaction, R 2 in R 2 OH (and in the compound of Formula V) is the same as Ri. In cases where Ri contains one or more functional groups which can interfere with the esterification reaction, for example a hydroxyl group, this group is preferably in a protected form, for example, as acetyl, benzoyl, benzyl or ether. In such a case, the R 2 moiety is a protected form of Ri. The esterification reaction can be carried out following processes well known in the art, for example, in the presence of triethylamine and 4-dimethylaminopyriding (DMAP) in a suitable solvent, such as chloroform.

Step d) involves the deprotection of the hydroxyl groups of the sugar moiety. This reaction can be carried out, for example, with excess hydrazine or diethylamine in methanol. When R 2 contains protected functional groups the deprotection of these functional groups is preferably carried out simultaneously with the deprotection of the hydroxyl groups of the sugar moiety. Alternatively, the deprotection of these functional groups is carried out separately from the deprotection of the hydroxyl groups of the sugar moiety.

Step e) involves the enzymatic hydrolysis of the compound of Formula VI with b- glucosidase. The reaction can be carried out by following processes well known in the art, such as the one described in S. Hanessian, E. Mainetti, F. Lecomte, Org. Lett. 2006, 8, 4047-4049.

According to a preferred embodiment, steps b) and c) are carried out in one pot, i.e. without isolating the compounds of Formula IV and Formula V respectively. In such a case, the five-step process can be carried out in three pots, providing additional simplicity and advantages.

The process of the present invention provides significant advantages over the processes of the prior art. Thus, it is shorter than the processes of the prior art and provides the final products in good yields without compromising their optical purity. It utilizes oleuropein, an abuntantly available natural product as starting material, it is simple and versatile and it can be carried out on a large scale. Furthermore, it can be easily used for the production of a large number of structurally diverse products by varying the structure of the alcohol moiety.

Examples

Example 1

Oleoside or (4S,5E,6S)-4-(carboxymethyl)-5-ethylidene-6-r(2S,3R,4S,5S,6R )-3,4,5- trihvdroxy-6-(hvdroxymethyl ' )oxan-2-yl1oxy-4/-/-pyran-3-carboxylic acid (compound of Formula Illy

A solution of olive leaves acetonic extract (55% oleuropein) (20 g, 20.35 mmol, 1 equiv.) and NaOH (3.25 g, 81.4 mmol, 4 equiv.) in H 2 0 (150 ml.) was stirred for 20 hours at room temperature. The mixture was acidified with 2 N HCI until pH value 4-5 and concentrated under reduced pressure. The purification step took place by using Centrifugal Partition Chromatography (CPC). The biphasic solvent system was composed of ethyl acetate, 2-propanol, ethanol, water and acetic acid in proportion 8/2/1/10/0.5. In a single run of 4 hours on a column with a capacity of 1 L, 5.55 g of oleoside, were successfully recovered. Example 2

(2R.4S.EV3-ethylidene-4-(2-methoxy-2-oxoethylV2-(((2R.3S. 4R.5S.6SV3.4.5- triacetoxy-6-(acetoxymethyl)tetrahvdro-2H-pyran-2-yl)oxy)-3, 4-dihydro-2/-/-pyran-5- carboxylic acid.

To a solution of the compound of Formula III (400.0 mg, 1.025 mmol, 1 equiv.) in pyridine (805.51 ml_, 10.25 mmol, 10 equiv.) at 0 °C was added Ac 2 0 (1.69 ml_, 17.94 mmol, 17.5 equiv.) and stirred at room temperature for 2 h, under argon. The mixture was concentrated under reduced pressure and diluted in dry toluene for azeotropic distillation of pyridine and Ac 2 0. Crude compound of Formula IV was diluted in dry ACN, under argon at 0 °C and a mixture of MeOH (45.6 pl_, 0.845 mmol, 1.1 equiv.), triethylamine (285.73 mI_, 2.05 mmol, 2 equiv.) and DMAP (375.7 mg, 3.07 mmol, 3 equiv.) in dry ACN was added dropwise. After 3 h the reaction mixture was acidified with 2 N HCI until a pH value of 4-5 and concentrated under reduced pressure. Water was added in the crude mixture and washed three times with CH 2 CI 2 . The combined organic phases were dried over Na 2 S04 and concentrated under reduced pressure to afford the title compound which was used for the next step without any further purification. Example 3

(2R.4S.E1-3-ethylidene-4-(2-methoxy-2-oxoethvn-2-(((2R.3S .4R.5R.6S1-3.4.5- trihvdroxy-6-(hvdroxymethyl)tetrahvdro-2H-pyran-2-yl)oxy)-3, 4-dihvdro-2H-pyran-5- carboxylic acid.

To a stirred solution of crude (2R,4S,E)-3-ethylidene-4-(2-methoxy-2-oxoethyl)-2- (((2R,3S,4R,5S,6S)-3,4,5-triacetoxy-6-(acetoxymethyl)tetrahy dro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid in methanol (2 mL), diethylamine (67.78 pL, 0.875 mmol, 5 equiv.) was added and room temperature for 20 h, under argon. The reaction mixture was acidified with HCI until pH value 4-5 and washed three times with EtOAc, dried over Na 2 S0 4 , and removed by rotary evaporation. The crude product was purified by silica gel chromatography (CH 2 CI 2 /MeOH, 100 95:5 v/v) to yield 45 % of the title compound (overall yield from oleoside).

Example 4

(S, EVmethyl 4-formyl-3-(2-oxoethyl ' )hex-4-enoate To a solution of (2R,4S,E)-3-ethylidene-4-(2-methoxy-2-oxoethyl)-2- (((2R,3S,4R,5R,6S)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahy dro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid (50 g, 0.123 mmol, 1 equiv.) in CH 3 COOH/CH 3 COONa 0.05M pH=5 (5 mL) b-glucosidase was added (7.09 mg, 17.46 units/mg, 1 equiv.) and stirred at 37 °C for 3 h. The reaction mixture was washed three times with dichloromethane (DCM). The organic layer was dried over Na 2 S0 4 , and removed by rotary evaporation. The purification was accomplished by silica gel chromatography (DCM/MeOH, 100 95:5 v/v) to obtain the title compound (18.2 mg, 75%).

Example 5

(2R,4S,E)-4-(2-(4-acetoxyphenethoxy)-2-oxoethyl)-3-ethyli dene-2-(((2R,3S,4R,5S,6S)- 3,4,5-triacetoxy-6-(acetoxymethyl)tetrahvdro-2H-pyran-2-yl)o xy)-3,4-dihvdro-2H-pyran- 5-carboxylic acid.

To a solution of the compound of Formula III (300.0 mg, 0.768 mmol, 1 equiv.) in pyridine (1.27 ml_, 15.78 mmol, 20 equiv.) at 0 °C was added Ac 2 0 (2.54 ml_, 26.89 mmol, 35 equiv.) and stirred at room temperature for 20 h. The mixture was concentrated under reduced pressure and diluted in dry toluene for azeotropic distillation of pyridine and AC 2 0. The crude compound of Formula IV was diluted in dry CH 2 CI 2 , under argon at 0 °C and a mixture of 4-(2-hydroxyethyl)phenyl acetate (152.31 mg, 0.845 mmol, 1.1 equiv.), triethylamine (321.50 pl_, 2.305 mmol, 3 equiv.) and DMAP (28.17 mg, 0.230 mmol, 0.3 equiv.) in dry CH 2 CI 2 was added dropwise. After 20 h the reaction mixture was acidified with HCI 9% until a pH value of 4-5 and washed with H 2 0 at 0 °C. The water layer was washed three times with EtOAc. The combined organic phases were dried over Na 2 S0 4 and concentrated under reduced pressure to afford the title compound which was used for the next step without any further purification.

Example 6

(2R,4S,E)-3-ethylidene-4-(2-(4-hvdroxyphenethoxy)-2-oxoet hvD-2- (((2R,3S,4R,5R,6S)-3,4,5-trihvdroxy-6-(hvdroxymethyl)tetrahv dro-2H-pyran-2-vDoxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid.

To a stirred solution of crude (2R,4S,E)-4-(2-(4-acetoxyphenethoxy)-2-oxoethyl)-3- ethylidene-2-(((2R,3S,4R,5S,6S)-3,4,5-triacetoxy-6-(acetoxym ethyl)tetrahydro-2H- pyran-2-yl)oxy)-3,4-dihydro-2H-pyran-5-carboxylic acid in ethanol (85 % aqueous) (5 ml_), hydrazine monohydrate (447.28 pl_, 9.22 mmol, 12 equiv.) was added and stirred at 44 °C for 6 h. The reaction mixture was acidified with HCI 9% until pH value 4-5 and washed with EtOAc, dried over Na2S04, and removed by rotary evaporation. The crude product was purified by silica gel chromatography (CH 2 CI 2 /MeOH, 100 85:10 v/v) to yield 40 % of the title compound (overall yield from oleoside). Example 7 Oleocantal or (S,E)-4-hydroxyphenethyl 4-formyl-3-(2-oxoethyl)hex-4-enoate

To a solution of (2R,4S,E)-3-ethylidene-4-(2-(4-hydroxyphenethoxy)-2-oxoethyl )-2- (((2R,3S,4R,5R,6S)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahy dro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid (50 g, 0.095 mmol, 1 equiv.) in CH 3 COOH/CH 3 COONa 0.05M pH=5 (5 ml.) b-glucosidase was added (7.09 mg, 17.46 units/mg, 1 equiv.) and stirred at 37 °C for 3 h. The reaction mixture was washed with DCM. The organic layer was dried over Na2S04, and removed by rotary evaporation. The purification was accomplished by silica gel chromatography (DCM/MeOH, 100 95:5 v/v) to obtain oleocanthal (21.9 mg, 76%). Example 8

(2R,4S,E)-4-(2-(3,4-diacetoxyphenethoxy)-2-oxoethyl)-3-et hylidene-2-

(((2R,3S,4R,5S,6S)-3,4,5-triacetoxy-6-(acetoxymethyl)tetr ahydro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid.

To a solution of the compound of Formula III (300.0 mg, 0.768 mmol, 1 equiv.) in pyridine (1.27 ml_, 15.78 mmol, 20 equiv.) at 0 °C was added Ac 2 0 (2.54 ml_, 26.89 mmol, 35 equiv.) and stirred at room temperature for 20 h. The mixture was concentrated under reduced pressure and diluted in dry toluene for azeotropic distillation of pyridine and AC 2 0. The crude compound of Formula IV was diluted in dry CH 2 CI 2 , under argon at 0

°C and a mixture of 4-(2-hydroxyethyl)-1 ,2-phenylene diacetate (201.38 mg, 0.845 mmol, 1.1 equiv.), triethylamine (321.50 pl_, 2.305 mmol, 3 equiv.) and DMAP (28.17 mg, 0.230 mmol, 0.3 equiv.) in dry CH 2 CI 2 was added dropwise. After 20 h the reaction mixture was acidified with HCI 9% until a pH value of 4-5 and washed with H 2 0 at 0 °C. The water layer was washed three times with EtOAc. The combined organic phases were dried over Na 2 S04 and concentrated under reduced pressure to afford the title compound which was used for the next step without any further purification. Example 9

(2R,4S,E)-4-(2-(3,4-dihvdroxyphenethoxy)-2-oxoethyl)-3-et hylidene-2- (((2R,3S,4R,5R,6S)-3,4,5-trihvdroxy-6-(hvdroxymethyl)tetrahy dro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid.

To a stirred solution of crude (2R,4S,E)-4-(2-(3,4-diacetoxyphenethoxy)-2-oxoethyl)-3- ethylidene-2-(((2R,3S,4R,5S,6S)-3,4,5-triacetoxy-6-(acetoxym ethyl)tetrahydro-2H- pyran-2-yl)oxy)-3,4-dihydro-2H-pyran-5-carboxylic acid in ethanol (85 % aqueous) (5 ml_), hydrazine monohydrate (447.28 pl_, 9.22 mmol, 12 equiv.) was added and stirred at 44 °C for 6 h. The reaction mixture was acidified with HCI 9 % until pH value 4-5 and washed with EtOAc, dried over Na 2 S04, and removed by rotary evaporation. The crude product was purified by silica gel chromatography (CH 2 CI 2 /MeOH, 100 85:10 v/v) to yield 46 % of the title compound (overall yield from oleoside).

Example 10

Oleacein or 2-(3,4-dihydroxyphenyl)ethyl (Z)-4-formyl-3-(2-oxoethyl)hex-4-enoate To a solution of (2R,4S,E)-4-(2-(3,4-dihydroxyphenethoxy)-2-oxoethyl)-3-ethyl idene-2- (((2R,3S,4R,5R,6S)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahy dro-2H-pyran-2-yl)oxy)- 3,4-dihydro-2H-pyran-5-carboxylic acid (50 mg, 0.095 mmol, 1 equiv.) in CH 3 COOH/CH 3 COONa 0.05M pH=5 (5 ml.) b-glucosidase was added (7.09 mg, 17.46 units/mg, 1 equiv.) and stirred at 37 °C for 3 h. The reaction mixture was washed with DCM. The organic layer was dried over Na 2 S0 4 , and removed by rotary evaporation. The purification was accomplished by silica gel chromatography (DCM/MeOH, 100 95:5 v/v) to obtain oleacein (22.8 mg, 75%).