-ETHYL-4-METHYL-PYRAZOLE-3-CARBOXAMIDE DERIVATIVE HAVING ACTIVITY AS AGONIST OF TAAR

The present invention relates to a compound of formula

and to a pharmaceutically suitable acid addition salt thereof.

The compound disclosed herein and covered by Formula I above may exhibit tautomerism. It is intended that the invention encompasses any tautomeric form of this compound, or mixtures of such forms, and is not limited to any one tautomeric form depicted in the formula above.

It has now been found that the compound of formula I (5-ethyl-4-methyl-N-[4-[(2 _l S') morpholin-2-yl]phenyl]-lH-pyrazole-3-carboxamide) has a good affinity to the trace amine associated receptors (TAARs), especially for TAARl, and less side effects compared with compounds of the prior art.

Similar ligands of mouse TAARl and rat TAARl have been disclosed in

WO2011/076678 and WO2012/16826.

The compound of formula I and its pharmaceutically usable addition salts possess valuable pharmacological properties. Specifically, it has been found that the

compound of the present invention is a partial agonist of the human trace amine

associated receptor 1 (hTAARl).

The compound of the present invention has significant advantages over compounds of the prior art, which advantages are

- potent agonistic activity at the human TAARl receptor,

selectivity against the dopamine transporter (DAT),

selectivity against the hERG ion channel, a low amphiphilic vector and thereby posing a low risk of causing drug- induced phospholipidosis (DIPL) (vide infra).

The compound of formula I may therefore be used as a safe drug for the

treatment of depression, anxiety disorders, bipolar disorder, attention deficit

hyperactivity disorder (ADHD), stress-related disorders, psychotic disorders such as

schizophrenia, neurological diseases such as Parkinson' s disease, neurodegenerative

disorders such as Alzheimer' s disease, epilepsy, migraine, hypertension, addiction,

substance abuse and metabolic disorders such as eating disorders, diabetes, diabetic

complications, obesity, dyslipidemia, disorders of energy consumption and assimilation, disorders and malfunction of body temperature homeostasis, disorders of sleep and

circadian rhythm, and cardiovascular disorders.

The classical biogenic amines (serotonin, norepinephrine, epinephrine, dopamine, histamine) play important roles as neurotransmitters in the central and peripheral nervous system ^[1] . Their synthesis and storage, as well as their degradation and reuptake after release, are tightly regulated. An imbalance in the levels of biogenic amines is known to be responsible for the altered brain function under many pathological conditions ^{[2 5]} . A second class of endogenous amine compounds, the so-called trace amines (TAs), significantly overlaps with the classical biogenic amines regarding structure, metabolism and subcellular localization. The TAs include p-tyramine, β-phenylethylamine, tryptamine and octopamine, and they are present in the mammalian nervous system at generally lower levels than classical biogenic amines ^[6] .

Dysregulation of TAs has been linked to various psychiatric diseases like schizophrenia and depression ¹⁷¹ and to other conditions like attention deficit hyperactivity disorder, migraine headache, Parkinson's disease, substance abuse and eating disorders ¹⁸ ' ⁹¹ .

For a long time, TA- specific receptors had only been hypothesized based on

anatomically discrete high-affinity TA binding sites in the CNS of humans and other mammals ^{[10 11]} . Accordingly, the pharmacological effects of TAs were believed to be mediated through the well-known machinery of classical biogenic amines, by either

triggering their release, inhibiting their reuptake or by "cross-reacting" with their

Γ9 12 131

receptor systems ' ' . This view changed significantly with the identification of

several members of a novel family of GPCRs, the trace amine-associated receptors

(TAARs) ^[7 ' ^14] . There are 9 TAAR genes in human (including 3 pseudogenes) and 16

genes in mouse (including 1 pseudogene). The TAAR genes do not contain introns (with one exception, TAAR2 contains 1 intron) and are located next to each other on the same chromosomal segment. The phylogenetic relationship of the receptor genes, in

agreement with an in-depth GPCR pharmacophore similarity comparison, and

pharmacological data suggest that these receptors form three distinct subfamilies ^{[7 14]} .

TAAR1 is in the first subclass of four genes (TAAR1-4) highly conserved between

human and rodents. TAs activate TAAR1 via G _a s. Dysregulation of TAs was shown to contribute to the aetiology of various diseases like depression, anxiety disorders, bipolar disorder, attention deficit hyperactivity disorder (ADHD), stress-related disorders,

psychotic disorders such as schizophrenia, neurological diseases such as Parkinson's disease, neurodegenerative disorders such as Alzheimer's disease, epilepsy, migraine, hypertension, addiction, substance abuse and metabolic disorders such as eating

disorders, diabetes, diabetic complications, obesity, dyslipidemia, disorders of energy consumption and assimilation, disorders and malfunction of body temperature

homeostasis, disorders of sleep and circadian rhythm, and cardiovascular disorders.

Therefore, there is a broad interest to increase the knowledge about trace amine- associated receptors.

Literature references:

[1] Deutch, A.Y. and Roth, R.H.; "Neurotransmitters." In Fundamental Neuroscience (2 ^nd

Edn) (Zigmond, M.J., Bloom, F.E., Landis, S.C., Roberts, J.L, and Squire, L.R., Eds.), pp.

193-234, Academic Press (1999);

[2] Wong, M.L. and Licinio, J.; "Research and treatment approaches to depression." Nat. Rev.

Neurosci. 2001, 2, 343-351;

[3] Carlsson, A. et al. ; "Interactions between monoamines, glutamate, and GABA in

schizophrenia: new evidence." A nnu. Rev. Pharmacol. Toxicol. 2001, 41, 237-260;

[4] Tuite, P. and Riss, J.; "Recent developments in the pharmacological treatment of

Parkinson's disease." Expert Opin. Investig. Drugs 2003, 12, 1335-1352;

[5] Castellanos, F.X. and Tannock, R.; "Neuroscience of attention-deficit/hyperactivity

disorder: the search for endophenotypes." Nat. Rev. Neurosci. 2002, 3, 617-628;

[6] Usdin, Earl; Sandler, Merton; Editors; Psychopharmacology Series, Vol. 1: Trace Amines and the Brain. [Proceedings of a Study Group at the 14th Annual Meeting of the American College of Neuropsychoparmacology, San Juan, Puerto Rico] (1976);

[7] Lindemann, L. and Hoener, M.; "A renaissance in trace amines inspired by a novel GPCR family." Trends in Pharmacol. Sci. 2005, 26, 274-281; [8] Branchek, T.A. and Blackburn, T.P.; "Trace amine receptors as targets for novel therapeutics: legend, myth and fact." Curr. Opin. Pharmacol. 2003, 3, 90-97;

[9] Premont, R.T. et al ; "Following the trace of elusive amines." Proc. Natl. Acad. Sci. USA

2001, 98, 9474-9475;

[10] Mousseau, D.D. and Butterworth, R.F.; "A high-affinity [ H] tryptamine binding site in human brain." Prog. Brain Res. 1995, 106, 285-291;

[11] McCormack, J.K. et al. ; "Autoradiographic localization of tryptamine binding sites in the rat and dog central nervous system." J. Neurosci. 1986, 6, 94-101;

[12] Dyck, L.E.; "Release of some endogenous trace amines from rat striatal slices in the

presence and absence of a monoamine oxidase inhibitor." Life Sci. 1989, 44, 1149-1156;

[13] Parker, E.M. and Cubeddu, L.X.; "Comparative effects of amphetamine, phenylethylamine and related drugs on dopamine efflux, dopamine uptake and mazindol binding." J.

Pharmacol. Exp. Ther. 1988, 245, 199-210;

[14] Lindemann, L. et al ; "Trace amine associated receptors form structurally and

functionally distinct subfamilies of novel G protein-coupled receptors." Genomics 2005,

85, 372-385.

Objects of the present invention are the new compound of formula I and its

pharmaceutically acceptable salts, their use for the treatment of diseases related to the biological function of the trace amine associated receptors, their manufacture and medicaments based on the compound in accordance with the invention in the control or prevention of illnesses such as depression, anxiety disorders, bipolar disorder, attention deficit hyperactivity disorder, stress- related disorders, psychotic disorders such as schizophrenia, neurological diseases such as Parkinson's disease, neurodegenerative disorders such as Alzheimer's disease, epilepsy, migraine, substance abuse, addiction and metabolic disorders such as eating disorders, diabetes, diabetic complications, obesity, dyslipidemia, disorders of energy consumption and assimilation, disorders and malfunction of body temperature homeostasis, disorders of sleep and circadian rhythm, and cardiovascular disorders.

The present compound of formula I and its pharmaceutically acceptable salts can be prepared by methods known in the art, for example, by processes described below, which process comprises a) cleaving off the N-protecting group (PG) from compounds of formula to a compound of formula

wherein PG is a N-protecting group selected from -C(0)0-tert-butyl (BOC), and,

if desired, converting the compound obtained into pharmaceutically acceptable acid addition salts.

GENERAL PROCEDURE

Scheme 1

The starting materials 1,1' and 2 are commercially available or may be prepared by methods well known in the art. Racemic tert-butyl 2-(4-aminophenyl)morpholine-4-carboxylate (CAS RN: 1002726-96-6) is commercially available. tert-Butyl (2R)-2-(4-aminophenyl)morpholine-4- carboxylate (CAS RN: 1260220-42-5) is commercially available. tert-Butyl (25 2-(4- aminophenyl)morpholine-4-carboxylate (CAS RN: 1260220-43-6) is commercially available, or can be prepared as described in the literature, for instance as described in Trussardi, R. & Iding, H, PCT Int. Appl. WO 2015/086495 Al .

Step A: Amide bond formation can be accomplished by a coupling reaction between amine 2 and carboxylic acid compound 1 in the presence of a coupling reagent such as DCC, EDC, TBTU or HATU in the presence of an organic base such as triethylamine, N,N-diisopropylethylamine or iV-methylmorpholine in halogenated solvents such as dichloromethane or 1,2-dichloroethane or ethereal solvents such as diethyl ether, dioxane, THF, DME or TBME.

Preferred conditions are TBTU with iV-methylmorpholine in THF at 50-60 °C for 12-48 hours.

Alternatively, amide bond formation can be accomplished by a coupling reaction between amine

2 and acyl chloride compound 1' in halogenated solvents such as dichloromethane or 1,2- dichloroethane or ethereal solvents such as diethyl ether, dioxane, THF, DME or TBME, in the presence of an organic base such as triethylamine or N,N-diisopropylethylamine.

Preferred conditions are triethylamine in THF at room temperature for 18 hours.

If desired, the acyl chloride compound 1' may be prepared in situ from the corresponding carboxylic acid 1 by treatment with oxalyl chloride in halogenated solvents such as

dichloromethane or 1,2-dichloroethane or ethereal solvents such as diethyl ether, dioxane, THF,

DME or TBME in the presence of a catalyst such as DMF.

Preferred conditions are dichloroethane at room temperature for 1 hour.

Alternatively, the acyl chloride compound 1' may be prepared in situ from the corresponding carboxylic acid 1 by treatment with l-chloro-N,N,2-trimethylpropenylamine [CAS 26189-59-3] in dichoromethane, followed by removal of the solvent in vacuo, according to the method of

Ghosez and co-workers (J. Chem. Soc, Chem. Commun. 1979, 1180; Org. Synth. 1980, 59, 26-

34).

Step B: Removal of the BOC N-protecting group can be effected with mineral acids such as HCl, H ₂ S0 ₄ or H ₃ PO ₄ or organic acids such as CF ₃ COOH, CHCl ₂ COOH, HOAc or p-toluenesulfonic acid in solvents such as CH ₂ C1 _2, CHC1 ₃ , THF, MeOH, EtOH or H ₂ 0 at 0 to 80 °C.

Preferred conditions are CF ₃ COOH in aqueous acetonitrile at 80 °C for 3 hours or 4 N HCl in dioxane at room temperature for 16 hours. Where racemic starting material 2 has been used, the resulting racemic mixture of morpholine compounds I' may be separated into its constituent enantiomers by using chiral HPLC.

Alternatively, compound I may be obtained in enantiomerically pure form by starting from enantiomerically pure compound 2.

Isolation and purification of the compounds

Isolation and purification of the compounds and intermediates described herein can be effected, if desired, by any suitable separation or purification procedure such as, for example, filtration, extraction, crystallization, column chromatography, thin-layer chromatography, thick-layer chromatography, preparative low or high-pressure liquid chromatography or a combination of these procedures. Specific illustrations of suitable separation and isolation procedures can be had by reference to the preparations and examples herein below. However, other equivalent separation or isolation procedures could, of course, also be used. Racemic mixtures of chiral compounds of formula I can be separated using chiral HPLC. Racemic mixtures of chiral synthetic intermediates may also be separated using chiral HPLC.

Salts of compound of formula I

The compound of formula I is basic and may be converted to a corresponding acid addition salt. The conversion is accomplished by treatment with at least a stoichiometric amount of an appropriate acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, and organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like. Typically, the free base is dissolved in an inert organic solvent such as diethyl ether, ethyl acetate, chloroform, ethanol or methanol and the like, and the acid added in a similar solvent. The temperature is maintained between 0 °C and 50 °C. The resulting salt precipitates spontaneously or may be brought out of solution with a less polar solvent.

Example 1

5-Ethyl-4-methyl-N-[4-[(25)-morpholin-2-yl]phenyl]-lH-pyrazo le-3-carboxamide

a) tert-Butyl (2^)-2-r4-r(5-ethyl-4-methyl-lH-pyrazole-3-carbonyl)aminolph enyllmorpholine-4- carboxylate

To a stirred solution of tert-butyl (2S)-2-(4-aminophenyl)morpholine-4-carboxylate (CAS RN: 1260220-43-6, 350 mg, 1.26 mmol, 1.00 equiv.) and 5-ethyl-4-methyl-lH-pyrazole-3- carboxylic acid (CAS RN: 957129-38-3, 245 mg, 1.51 mmol, 1.20 equiv.) in THF (8 ml) were added TBTU (807 mg, 2.51 mmol, 2.00 equiv.) and N-methylmorpholine (509 mg, 553 μΐ, 5.03 mmol, 4.00 equiv.). The reaction mixture was stirred at 50 °C for 15 h. TLC at t = 15 h showed the reaction was complete. The reaction mixture was concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, eluant: 0% to 100% EtOAc in heptane) to afford tert-butyl (2S)-2-[4-[(5-ethyl-4-methyl-lH-pyrazole-3- carbonyl)amino]phenyl]morpholine-4-carboxylate as an off-white solid (501 mg, 96%). MS (ISP): 413.7 ([Μ-Η] ^" ). b) 5-Ethyl-4-methyl-N-r4-r(2 _t S')-morpholin-2-yllphenyll-lH-pyrazole-3-carboxamide

To a stirred solution of trifluoroacetic acid (1.37 g, 918 μΐ, 12.0 mmol, 10 equiv.) in water (8 ml) was added a suspension of tert-butyl (2S)-2-[4-[(5-ethyl-4-methyl-lH-pyrazole-3- carbonyl)amino]phenyl]morpholine-4-carboxylate (497 mg, 1.2 mmol, 1.00 equiv.) in acetonitrile (4 ml). The reaction mixture was stirred at 80 °C for 3 h. MS at t = 3 h showed the reaction was complete. The reaction mixture was poured into 1 M aq. NaOH and extracted twice with EtOAc. The organic layers were dried over Na ₂ S0 ₄ and concentrated in vacuo. The crude material was purified by flash column chromatography (SiliaSep™ amine cartridge, eluant: 0% to 100% EtOAc in heptane, then 0% to 10% MeOH in EtOAc) to afford 5-ethyl-4-methyl-N-[4- [(2S)-morpholin-2-yl]phenyl]-lH-pyrazole-3-carboxamide (327 mg, 87%) as an off-white solid. MS (ISP): 315.7 ([M+H] ⁺ ).

Example 2 (comparative example)

5-Ethyl-4-methyl-N-[4-[(2R)-morpholin-2-yl]phenyl]-lH-pyrazo le-3-carboxamide

The title compound was obtained in analogy to example 1 using (2R)-2-(4- aminophenyl)morpholine-4-carboxylate (CAS RN: 1260220-42-5) in place of (25 2-(4- aminophenyl)morpholine-4-carboxylate in step (a). White solid. MS (ISP): 315.6 ([M+H] ⁺ ).

Example 3 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-6-(2,2,2-trifluoroethoxy)p yridine-3-carboxamide

The title compound was obtained in analogy to example 1 using 6- (2,2,2- trifluoroethoxy)nicotinic acid (CAS RN: 159783-29-6) in place of 5-ethyl-4-methyl- lH- pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 382.1 ([M+H] ⁺ ).

Example 4 (comparative example)

6-Chloro-N-[4-[(25)-mor holin-2-yl]phenyl]pyridine-3-carboxamide

The title compound was obtained in analogy to example 1 using 6-chloro-nicotinic acid (CAS RN: 5326-23-8) in place of 5-ethyl-4-methyl- lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 320.1 ([{ ³⁷ C1}M+H] ⁺ ), 318.2 ([{ ³⁵ C1}M+H] ⁺ ).

Example 5 (comparative example)

2-Chloro-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine-4-carboxa mide

The title compound was obtained in analogy to example 1 using 2-chloro-isonicotinic acid (CAS RN: 6313-54-8) in place of 5-ethyl-4-methyl- lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 320.1 ([{ ³⁷ C1}M+H] ⁺ ), 318.1 ([{ ³⁵ C1}M+H] ⁺ ).

Example 6 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-2-phenyl-l,3-thiazole-5-ca rboxamide

The title compound was obtained in analogy to example 1 using 2-phenylthiazole-5-carboxylic acid (CAS RN: 10058-38-5) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 366.1 ([M+H] ⁺ ).

Example 7 (comparative example)

2,6-Dichloro-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine-4-car boxamide

The title compound was obtained in analogy to example 1 using 2,6-dichloro-isonicotinic acid (CAS RN: 5398-44-7) in place of 5-ethyl-4-methyl- lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 356.1 ([{ ³⁷ C1}M+H] ⁺ ), 354.1 ([{ ³⁷ C1 ³⁵ C1 }M+H] ⁺ ), 352.1 ([{ ³⁵ C1}M+H] ⁺ ).

Example 8 (comparative example)

4-Methyl-N-[4-[(25)-morpholin-2-yl]phenyl]-5-phenyl-lH-pyraz ole-3-carboxamide

The title compound was obtained in analogy to example 1 using 4-methyl-5-phenyl-lH- pyrazole-3-carboxylic acid (CAS RN: 879770-33-9) in place of 5-ethyl-4-methyl-lH-pyrazole-3- carboxylic acid in step (a). White solid. MS (ISP): 363.2 ([M+H] ⁺ ).

Example 9 (comparative example)

5,6-Dichloro-N-[4-[(25 -morpholin-2-yl]phenyl]pyridine-3-carboxamide

The title compound was obtained in analogy to example 1 using 5,6-dichloro-nicotinic acid (CAS RN: 41667-95-2) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 356.1 ([{ ³⁷ C1 ³⁵ C1 }M+H] ⁺ ), 354.1 ([{ ³⁷ C1}M+H] ⁺ ), 352.1

([{ ³⁵ C1}M+H] ⁺ ).

Example 10 (comparative example)

6-Cyano-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine-3-carboxam ide

The title compound was obtained in analogy to example 1 using 6-cyano-nicotinic acid (CAS RN: 70165-31-0) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 309.1 ([M+H] ⁺ ).

Example 11 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-6-(trifluoromethyl)pyridin e-3-carboxamide

The title compound was obtained in analogy to example 1 using 6-(trifluoromethyl)nicotinic acid (CAS RN: 158063-66-2) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 352.2 ([M+H] ⁺ ).

Example 12 (comparative example)

5- Chloro-N- [4- [(2S)-morpholin-2-yl]phenyl]pyridine-2-carboxamide

The title compound was obtained in analogy to example 1 using 5-chloro-picolinic acid (CAS RN: 86873-60-1) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 320.1 ([{ ³⁷ C1}M+H] ⁺ ), 318.2 ([{ ³⁵ C1}M+H] ⁺ ).

Example 13 (comparative example)

5- Chloro-N- [4- [(2S)-morpholin-2-yl]phenyl]pyridine-3-carboxamide

The title compound was obtained in analogy to example 1 using 5-chloro-nicotinic acid (CAS RN: 22620-27-5) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 320.1 ([{ ³⁷ C1}M+H] ⁺ ), 318.1 ([{ ³⁵ C1}M+H] ⁺ ).

Example 14 (comparative example)

2-Chloro-6-methyl-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine- 4-carboxamide

The title compound was obtained in analogy to example 1 using 2-chloro-6-methylpyridine-4- carboxylic acid (CAS RN: 25462-85-5) in place of 5-ethyl-4-methyl- lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 334.1 ([{ ³⁷ C1}M+H] ⁺ ), 332.1 ([{ ³⁵ C1}M+H] ⁺ ).

Example 15 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-2-phenyl-l,3-oxazole-4-car boxamide

The title compound was obtained in analogy to example 1 using 2-phenyloxazole-4-carboxylic acid (CAS RN: 23012- 16-0) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 350.2 ([M+H] ⁺ ).

Example 16 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-2-phenyl-l,3-thiazole-4-ca rboxamide

The title compound was obtained in analogy to example 1 using 2-phenylthiazole-4-carboxylic acid (CAS RN: 7113- 10-2) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 366.1 ([M+H] ⁺ ).

Example 17 (comparative example)

2-Methyl-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine-4-carboxa mide

The title compound was obtained in analogy to example 1 using 2-methyl-isonicotinic acid (CAS RN: 4021- 11-8) in place of 5-ethyl-4-methyl- lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 298.2 ([M+H] ⁺ ).

Example 18 (comparative example)

2,6-Dimethyl-N-[4-[(25)-morpholin-2-yl]phenyl]pyridine-4-car boxamide

The title compound was obtained in analogy to example 1 using 2,6-dimethyl-isonicotinic acid (CAS RN: 54221-93- 1) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 312.2 ([M+H] ⁺ ). Example 19 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-2-methyl-l,3-thiazole-4-ca rboxamide

The title compound was obtained in analogy to example 1 using 2-methylthiazole-4-carboxylic acid (CAS RN: 35272- 15-2) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 304.1 ([M+H] ⁺ ).

Example 20 (comparative example)

N-[4-[(25)-Morpholin-2-yl]phenyl]-l-phenylpyrazole-3-carboxa mide

The title compound was obtained in analogy to example 1 using 1 -phenyl- lH-pyrazole-3- carboxylic acid (CAS RN: 4747-46-0) in place of 5-ethyl-4-methyl-lH-pyrazole-3-carboxylic acid in step (a). White solid. MS (ISP): 349.2 ([M+H] ⁺ ).

As mentioned above, the compound of the present invention has significant advantages over compounds of the prior art, which advantages are potent agonistic

activity at the human TAAR1 receptor, selectivity against the dopamine transporter

(DAT), selectivity against the hERG ion channel, and a low amphiphilic vector and

thereby posing a low risk of causing drug-induced phospholipidosis (DIPL) (vide infra).

The following comparative data and comments may be provided to show the superiority advantages of the compound of formula I in comparison with known

compounds of the prior art.

1. Pharmacological effects and therapeutic potential of partial agonists of the human trace amine-associated receptor 1 (hTAARl) There is evidence of significant species differences in ligand-receptor interactions between rodent and human TAAR1 ^[1] . Therefore, when selecting compounds for use as human therapeutics for the treatment of TAARl -related diseases it is important to prioritize candidate compounds based on the potency of their functional activity at the human form of the TAARl receptor (hTAARl). hTAARl is a G protein-coupled transmembrane receptor (GPCR), whereby ligands may function as antagonists, agonists, partial agonists or inverse agonists of the receptor. The compound of formula I and comparative examples have been tested in vitro for functional activity at hTAARl, whereby the compound of formula I was found to be a partial agonist of hTAARl. The experimentally determined hTAARl EC ₅₀ values for the compound of formula I and a selection of comparative examples are shown in Table 1 (vide infra). The compound of example 1 has thereby been found, in particular, to be a potent partial agonist of hTAARl in vitro.

Ex vivo electrophysiology experiments in the ventral tegmental area and dorsal raphe nuclei showed that TAARl partial agonists enhanced DA and 5-HT neuron firing rates in wild-type mice ^[2 ' ^3] , whereas full agonists like /7-tyramine decreased firing rates ^[3 ' ^4] . However, both full and partial agonists have been shown to be protective against the rewarding and reinforcing effects of the psychostimulant cocaine ^[5] . Whereas full agonists like amphetamine induce negative feedback to blunt their own effect on DA and 5-HT systems ^[6 ' ^7] , partial agonists might increase their effect on neuronal signal transmission by increasing firing rates via TAARl. Because of these findings, and the reports that TAARl partial agonists have a richer in vivo pharmacology in rodents than full agonists ^[3 ' ^8] , a strong body of preclinical evidence is emerging which suggests that TAARl partial agonists show highly promising potential for use as human therapeutics for the treatment of CNS diseases including, but not limited to, schizophrenia, bipolar disorder, depression, Parkinson's disease, as well as for the treatment of alcohol and drug addiction.

For instance, TAARl partial agonists are proposed to be superior to existing atypical antipsychotic drugs by displaying antipsychotic efficacy with the benefit of improved cognition and mood as well as with a reduced side effect profile (e.g. no induction of the metabolic syndrome which is seen with current antipsychotics) ¹³ ' ⁸¹ . Other literature suggests possible indications include bipolar disorder, ^[8] drug addiction ^[5 ' ^9] , and diabetes ^[10] . Literature references:

[1] Simmler, L. D.; Buchy, D.; Chaboz, S.; Hoener, M.C.; Liechti, M. E.; "In vitro

characterization of psychoactive substances at rat, mouse and human trace amine- associated receptor 1 ". J. Pharmacol. Exp. Ther. 2016, Fast Forward article DOI:

10.1124/jpet.115.229765;

[2] Bradaia, A. et al.; "The selective antagonist EPPTB reveals TAARl -mediated regulatory mechanisms in dopaminergic neurons of the mesolimbic system". Proc. Nat. Acad. Sci. USA 2009, 106, 20081-20086;

[3] Revel, F. G. et al.; "Trace amine-associated receptor 1 partial agonism reveals novel paradigm for neuropsychiatric therapeutics". Biol. Psychiatry 2012, 72, 934-942;

[4] Revel, F. G. et al.; "TAARl activation modulates monoaminergic neurotransmission, preventing hyperdopaminergic and hypoglutamatergic activity". Proc. Nat. Acad. Sci. USA 2011, 108, 8485-8490;

[5] Pei, Y.; Mortas, P.; Hoener, M. C; Canales, J. J.; "Selective activation of the trace amine- associated receptor 1 decreases cocaine's reinforcing efficacy and prevents cocaine- induced changes in brain reward thresholds". Prog. Neuro-Psychopharmacol. & Biol. Psychiatry 2015, 63, 70-75;

[6] Lindemann, L. et al.; "Trace amine-associated receptor 1 modulates dopaminergic

activity". J. Pharmacol. Exp. Ther. 2008, 324, 948-956;

[7] Di Cara, B. et al:, "Genetic deletion of trace amine 1 receptors reveals their role in auto- inhibiting the actions of ecstasy (MDMA)". J. Neuroscience 2011, 31, 16928-16940;

[8] Revel, F. G. et al.; "A new perspective for schizophrenia: TAARl agonists reveal

antipsychotic- and antidepressant-like activity, improve cognition and control body weight". Mol. Psychiatry 2013, 18, 543-556;

[9] Pei, Y.; Lee, J.; Leo, D.; Gainetdinov, R. R.; Hoener, M. C; Canales, J. J.; "Activation of the trace amine-associated receptor 1 prevents relapse to cocaine seeking".

Neuropsychopharmacology 2014, 39, 2299-2308;

[10] Raab, S. et al.; "Incretin-like effects of small molecule trace amine-associated receptor 1 agonists". Mol. Metabolism 2016, 5, 47-56.

2. Dopamine transporter (DAT) and associated liability for drug abuse and/or

addiction potential The pharmacology of the dopamine transporter (DAT) has been implicated inter alia in the psychostimulatory effects and in the abuse liability and addiction mechanism of certain psychostimulant drugs such as cocaine and MDPV. ^{[1 3]} Therefore, for a new therapeutic intended for human use, it is desirable to avoid inhibition of, or interaction with, the dopamine transporter DAT in order to minimize the risk of abuse liability or potential for addiction.

For instance, evidence suggests that cocaine's reinforcing effects depend on its ability to rapidly block the dopamine transporter (DAT). In animal studies, dopamine reuptake inhibitors other than cocaine are also self-administered, with a relative potency that generally correlates positively with their potency in inhibiting the DAT, but not the serotonin or norepinephrine transporters (SERT, NET) ^{[4 8]} . Animals trained to self- administer cocaine will also self-administer direct dopamine agonists ^19"11] . In addition, destruction of dopamine nerve terminals can lead to extinction of cocaine self- administration behavior ^{[12 13]} , and these effects have been observed even when responding maintained by other reinforcers was preserved ^{114 15]} . In humans, cocaine- induced "high" correlates with DAT occupancy in the brain ^[16] .

To further test the hypothesis that DAT is essential to cocaine's reinforcing effects, a functional but "cocaine-insensitive" DAT was generated and expressed in mice ^{[17 18]} . This mutant DAT demonstrated an 89-fold lower affinity for cocaine relative to wild-type DAT, and cocaine failed to increase extracellular dopamine in the nucleus accumbens, or to induce increases in locomotor activity, stereotypies, or conditioned place preferences, in knock- in (DATki) mice expressing this mutant DAT ^{[18 20]} . In addition, cocaine failed to serve as a positive reinforcer in these DATki mice, whereas food, d-amphetamine, and a direct dopamine agonist reliably maintained operant behavior in these mice, at levels comparable with wild-type mice ^[21] . Reintroduction of the cocaine- sensitive wild type DAT to brain areas including inter alia the ventral tegmental area (VTA) led to restoration of cocaine reward behavior in the DATki mice ^[22] . In conclusion, cocaine's ability to block DAT is sufficient to abolish its reinforcing effects in mice providing strong evidence that DAT blockade is critical for cocaine's reinforcing effects.

Therefore, taken together, these findings suggest that for a new therapeutic intended for human use, it is highly desirable to avoid inhibition of, or interaction with, the dopamine transporter DAT in order to minimize the risk of abuse liability or

potential for addiction.

The measured in vitro DAT K _; for a series of TAAR1 compounds are shown in Table 1 (vide infra). It has surprisingly been found that Example 1 is a significantly weaker ligand at DAT than other compounds, while simultaneously being a potent

partial agonist of hTAARl, and therefore the hTAARl/DAT selectivity ratio for

Example 1 is significantly higher than for other compounds.

Literature references:

[I] Meil, W. M. and Boja, J. W.; "The dopamine transporter and addiction." Chapter 1, pp. 1- 21 in Neurochemistry of Abused Drugs (Karch, S. B., Ed.), CRC Press (2008);

[2] Simmler, L. D. et ah; "Pharmacological characterization of designer cathinones in vitro".

Brit. J. Pharmacol. 2013, 168, 458-470;

[3] Baumann, M. H.; Partilla, J. S.; Lehner, K. R.; "Psychoactive 'bath salts': not so soothing".

Eur. J. Pharmacol. 2013, 698, 1-5;

[4] Ritz., M. C; Lamb, R. J.; Goldberg, S. R.; Kuhar, M. J.; "Cocaine receptors on dopamine transporters are related to self-administration of cocaine". Science 1987, 237, 1219-1223;

[5] Bergmann., J.; Madras, B. K.; Johnson, S. E.; Spealman, R. D.; "Effects of cocaine and relared drugs in nonhuman primates. III. Self-administration by squirrel monkeys". J.

Pharmacol. Exp. Ther. 1989, 251, 150-155;

[6] Howell., L. L. & Byrd, L. D.; "Serotonergic modulation of the behavioural effects of

cocaine in the squirrel monkey". J. Pharmacol. Exp. Ther. 1995, 275, 1551-1559;

[7] Roberts, D. C. S. et ah; "Self-administration of cocaine analogs by rats".

Psychopharmacology 1999, 144, 389-397;

[8] Wee, S. et ah; "Relationship between serotonergic activity and reinforcing effects of a series of amphetamine analogs". J. Pharmacol. Exp. Ther. 2005, 313, 848-854;

[9] Woolverton, W. L.; Goldberg, L. I.; Ginos, J. Z.; "Intravenous self-administration of

dopamine receptor agonists by Rhesus monkeys". J. Pharmacol. Exp. Ther. 1984, 230,

678-683;

[10] Wise, R. A.; Murray, A.; Bozarth, M. A.; "Bromocriptine self-administration and

bromocriptine-reinstatement of cocaine-trained and heroin-trained lever pressing in rats".

Psychopharmacology 1990, 100, 355-360;

[I I] Caine, S. B. & Koob, G. F.; "Modulation of cocaine self-administration in the rat through D-3 dopamine receptors". Science 1993, 260, 1814-1816; [12] Roberts, D. C. S.; Corcoran, M. E.; Fibiger, H. C; "On the role of ascending catecholaminergic systems in intravenous self-administration of cocaine". Pharmacol.

Biochem. Behaviour 1977, 6, 615-620;

[13] Roberts, D. C. S.; Koob, G. F.; Klonoff, P.; Fibiger, H. C; "Extinction and recovery of cocaine self-administration following 6-hydroxydopamine lesions of the nucleus accumbens". Pharmacol. Biochem. Behaviour 1980, 12, 781-787;

[14] Pettit, H. O.; Ettenberg, A.; Bloom, F. E.; Koob, G. F.; "Destruction of dopamine in the nucleus accumbens selectively attenuates cocaine but not heroin self-administration in rats". Psychopharmacology 1984, 84, 167-173;

[15] Caine, S. B. & Koob, G. F.; "Effects of mesolimbic dopamine depletion on responding maintained by cocaine and food". J. Exp. Anal. Behavior 1994, 61, 213-221;

[16] Volkow, N. D. et ah; "Relationship between subjective effects of cocaine and dopamine transporter occupancy". Nature 1997, 386, 827-830;

[17] Chen, R.; Han, D. D.; Gu, H. H.; "A triple mutation in the second transmembrane domain of mouse dopamine transporter markedly decreases sensitivity to cocaine and

methylphenidate". J. Neurochem. 2005, 94, 352-359;

[18] Chen, R. et ah; "Abolished cocaine reward in mice with a cocaine-insensitive dopamine transporter". Proc. Nat. Acad. Sci. USA 2006, 103, 9333-9338;

[19] Tilley, M. R. & Gu, H. H.; "Dopamine transporter inhibition is required for cocaine- induced stereotypy". Neuroreport 2008, 19, 1137-1140;

[20] Tilley, M. R.; O'Neill, B.; Han, D.D.; Gu, H. H.; "Cocaine does not produce reward in absence of dopamine transporter inhibition". Neuroreport 2009, 20, 9-12;

[21] Thomsen, M.; Han, D.D.; Gu, H. H.; Caine, S. B.; "Lack of cocaine self-administration in mice expressing a cocaine-insensitive dopamine transporter". J. Pharmacol. Exp. Ther.

2009, 331, 204-211;

[22] Wu, H. et ah; "Restoration of cocaine stimulation and reward by reintroducing wild type dopamine transporter in adult knock-in mice with a cocaine-insensitive dopamine transporter". Neuropharmacology 2014, 86, 31-37.

3. hERG blockade and associated liability for cardiac QT interval prolongation

Minimization of the likelihood to cause drug-induced cardiac side effects is highly

desirable for a therapeutic agent intended for safe use in humans, especially for a drug intended to be used for chronic treatment regimens. In recent years, regulatory

authorities have delayed approval or imposed restrictions on the use of, and even denied approval or removed from the market, therapeutic agents prolonging the cardiac QT interval. The QT interval is the time from the beginning of the QRS complex to the end of the T wave of the electrocardiogram (ECG) and is a measure of the duration of ventricular depolarization and repolarization. Drugs prolonging the QT interval have been associated with a polymorphic ventricular tachycardia referred to as Torsades de Pointes (TdP). This arrhythmia can cause serious cardiovascular outcomes and can progress to irreversible ventricular fibrillation and death. The ICH S7B regulatory guideline ^11] recommends an overall non-clinical strategy for evaluating cardiovascular risk of new molecular entities (NMEs) which includes the in vitro IK _r assay [potassium current conducted by the human ether- a-go-go related gene (hERG)]. Inhibition of hERG was identified as the major mechanism for QT prolongation. ^[2] Therefore, the recommended minimal non-clinical QT interval de-risking strategy is to test

representative compounds from a given chemical series in the in vitro hERG assay. ^[3] The goal is to select compounds causing no more than 20% hERG inhibition at

concentrations at least 30-fold below the efficacious in vitro (or in vivo if available) concentration for therapeutic activity. In the case of TAARl agonists, the hTAARl EC ₅₀ can be considered as the relevant in vitro concentration predictive of therapeutic activity (vide supra). Therefore it is desirable to select TAARl agonists where the ratio hERG IC ₂₀ hTAARl EC ₅₀ is at least 30-fold.

The measured in vitro hERG IC ₂₀ and IC50 for a series of TAARl compounds are shown in Table 1 (vide infra).

Basic compounds in particular are known to be especially prone to causing potent inhibition of the hERG channel. ^[4] All of the TAARl compounds bear the same morpholino head group, therefore all compounds are expected to be similarly basic. The basic moiety is required for agonist activity at hTAARl. It has surprisingly been found that Example 1 is a significantly weaker hERG channel inhibitor than comparative compounds, and therefore the hERG IC ₂ o/hTAARl EC ₅₀ ratio for Example 1 is

significantly higher than the recommended 30-fold minimum.

Literature references:

[1] ICH Guideline. "The nonclinical evaluation of the potential for delayed ventricular repolarization (QT interval prolongation) by human pharmaceuticals (S7B)" issued as CPMP/ICH/423/02, adopted by CHMP in May 2005; http://www.ich.org/products/guidelines/safety/safety-single/ article/the-non-clinical- evaluation-of-the-potential-for-delayed-ventricular-repolari zation-qt-interval-pro.html

[2] Redfern, W. S.; Carlsson, L.; Davis, A. S.; Lynch, W. G.; MacKenzie, I.; Palethorpe, S.;

Siegl, P.K.; Strang, I; Sullivan, A. T.; Wallis, R.; Camm, A.J.; Hammond, T. G.;

"Relationships between preclinical cardiac electrophysiology, clinical QT interval prolongation and torsade de pointes for a broad range of drugs: evidence for a provisional safety margin in drug development". Cardiovasc. Res. 2003, 58, 32-45;

[3] Helliwell, R. M.: "Potassium Channels". Methods in Molecular Biology (Totowa, NJ, United States) 2008, 491, 279-295;

[4] Zolotoy, A. B.; Plouvier, B. P.; Beatch, G. B.; Hayes, E. S.; Wall, R. A.; Walker, M. J. A.;

"Physicochemical determinants for drug-induced blockade of hERG potassium channels: Effect of charge and charge shielding". Curr. Med. Chem. - Cardiovascular &

Hematological Agents 2003, 1, 225-241. 4. Amphiphilicity and associated liability for drug-induced phospholipidosis (DIPL)

Phospholipidosis (PLD) is a lysosomal storage disorder characterized by the excess

accumulation of phospholipids in tissues ^[1][2][3] Many cationic amphiphilic drugs,

including anti-depressants, antianginal, antimalarial, and cholesterol-lowering agents, are reported to cause drug-induced phospholipidosis (DIPL) in animals and humans. The mechanisms of DIPL involve trapping or selective uptake of DIPL drugs within the

lysosomes and acidic vesicles of affected cells. Drug-trapping is followed by a gradual accumulation of drug-phospholipid complexes within the internal lysosomal

membranes. The increase in undigested materials results in the abnormal accumulation of multi-lammellar bodies (myeloid bodies) in tissues. Although phospholipidosis is

primarily considered to be a storage disorder, with some compounds the storage disorder is known to be associated with inflammation and necrosis leading to functional

impairment of the affected tissues. It is therefore highly desirable that a therapeutic drug should not pose a risk for causing DIPL. This is especially true in the case of medicines intended for chronic use, for instance, drugs intended for the treatment of chronic

psychiatric disorders such as schizophrenia, bipolar disorder or depression, or drugs

intended for the treatment of chronic metabolic disorders such as diabetes.

DIPL is an adverse effect known to be particularly associated with cationic amphiphilic drugs (CAD). ^[4] To avoid DIPL either the basic pK _a (basic pK _a < 6.3) or the amphiphilicity (AAG _am > - 6 kJ mol ^"1 ) of a compound has to be reduced (i.e. AAG _am

needs to be increased). ^[5] A compound is classified as DIPL negative if either the basic pK _a value is below 6.3 or the amphiphilicity is above AAG _am = -6 kJ mol ^"1 . The

amphiphilicity for a given compound can be calculated in silico directly from the

molecular structural formula, ^[6] and therefore the predicted risk for DIPL for that

compound can also be calculated in silico} ⁵ ^ whereby the prediction algorithm uses a

DIPL risk classification defined according to the following criteria, which are based on parameters extracted from a computational training set comprising experimentally

determined phospholipidosis results for a large set of compounds:

AMPHIPHILIC VECTOR > -5.0 kJ/mol and BPKA 1 <= 5.60 results in

NEGATIVE DIPL prediction;

-7.0 kJ/mol < AMPHIPHILIC VECTOR < -5.0 kJ/mol and/or 7.0 >

BPKA1 > 5.60 results in BORDERLINE DIPL prediction;

AMPHIPHILIC VECTOR < -7.0 kJ/mol and BPKA1 >= 7.00 results in POSITIVE DIPL prediction.

The calculated amphiphilicities (AAG _am in kJ mol ^"1 ) as well as the in silico

DIPL risk predictions (negative/borderline/positive) for a series of TAAR1 compounds are shown in Table 1 (vide infra).

All of the TAAR1 compounds bear the same morpholino head group, therefore the basic pK _a of all compounds is very similar and clearly above 6.3. The basic moiety is required for agonist activity at hTAARl . Therefore, the only way to avoid

DIPL is to reduce the lipophilicity of the backbone of the molecules. It has surprisingly been found that for Example 1 the lipophilicity is reduced significantly more than

expected based on the results for similar compounds, and therefore the amphiphilicity of Example 1 is clearly reduced and, as a consequence, this compound is not predicted to cause DIPL.

Literature references:

[1] Anderson, N.; Borlak, J.; "Drug-induced phospholipidosis". FEBS Lett. 2006, 580, 5533- 540;

[2] Reasor, M. J.; Hastings, K. L.; Ulrich, R. G.; "Drug-induced phospholipidosis: issues and future directions". Expert Opin. Drug Safety 2006, 5, 567-83;

[3] Nonoyama, T.; Fukuda, R.; "Drug induced phospholipidosis pathological aspects and its prediction". J. Toxicol. Pathol. 2008, 21, 9-24; [4] Lullmann, H.; Lullmann-Rauch, R.; Wassermann, O.; "Lipidosis induced by amphiphilic cationic drugs." Biochem. Pharmacol. 1978, 27, 1103-8;

[5] Fischer, H.; Atzpodien, E. A.; Csato, M; Doessegger, L.; Lenz, B.; Schmitt, G.; Singer, T.;

"In silico assay for assessing phospholipidosis potential of small drug like molecules: training, validation and refinement using several datasets." J. Med. Chem. 2012, 55,

126-139;

[6] Fischer, H.; Kansy, M.; Bur, D.; "CAFCA: a novel tool for the calculation of amphiphilic properties of charged drug molecules". Chimia 2000, 54, 640-645. The compounds were investigated in accordance with the tests given hereinafter.

Materials and Methods

Human TAAR1

For the construction of expression plasmids the coding sequences of human TAAR 1 were amplified from genomic DNA essentially as described by Lindemann et al. [14]. The Expand High Fidelity PCR System (Roche Diagnostics) was used with 1.5 mM Mg ²⁺ and purified PCR products were cloned into pCR2.1-TOPO cloning vector (Invitrogen) following the instructions of the manufacturer. PCR products were subcloned into the pIRESneo2 vector (BD Clontech, Palo Alto, California), and expression vectors were sequence verified before introduction in cell lines.

HEK293 cells (ATCC # CRL-1573) were cultured essentially as described by Lindemann et al. (2005). For the generation of stably transfected cell lines HEK293 cells were transfected with the pIRESneo2 expression plasmids containing the TAAR coding sequences (described above) with Lipofectamine 2000 (Invitrogen) according to the instructions of the manufacturer, and 24 hrs post transfection the culture medium was supplemented with 1 mg/ml G418 (Sigma, Buchs, Switzerland). After a culture period of about 10 d clones were isolated, expanded and tested for responsiveness to trace amines (all compounds purchased from Sigma) with the cAMP Biotrak Enzyme immunoassay (EIA) System (Amersham) following the non-acetylation EIA procedure provided by the manufacturer. Monoclonal cell lines which displayed a stable EC ₅₀ for a culture period of 15 passages were used for all subsequent studies.

cAMP measurements were performed as described previously (Revel et al., Proc. Natl. Acad. Sci. USA 2011, 108, 8485-8490). In brief, cells that expressed human TAAR1 were plated on 96- well plates (BIOCOAT 6640; Becton Dickinson, AUschwil, Switzerland) and incubated for 20 h at 37 °C. Prior to stimulation of the cells with a broad concentration range of agonists for 30 min at 37 °C, the cells were washed with PBS and preincubated with PBS that contained 1 mM 3- isobutyl-l-methylxanthine for 10 min at 37 °C and 5% C0 ₂ . Stimulation with 0.2% DMSO was set as the basal level, and the effect of 30 μΜ β-ΡΕΑ was set as the maximal response.

Subsequently, the cells were lysed, and cAMP assays were performed according to the manufacturer's instructions (cAMP kit; Upstate/Millipore, Schaffhausen, Switzerland). Finally, the plates were read with a luminometer (1420 Multilabel counter; PerkinElmer, Schwerzenbach, Switzerland), and the amount of cAMP was calculated. The results were obtained from at least three independent experiments. Experiments were run in duplicate or triplicate. EC ₅₀ values are presented as mean + standard deviation (in μΜ). The E _max value for the functional activity data at TAAR1 describes the degree of functional activity compared with 100% for the endogenous ligand and full agonist β-ΡΕΑ. Human DAT

Binding to dopamine transporter (DAT) in vitro. Human embryonic kidney (HEK) 293 cells (Invitrogen, Zug, Switzerland) stably transfected with human DAT were cultured. The cells were collected and washed three times with phosphate-buffered saline (PBS). The pellets were frozen at -80 °C. The pellets were then resuspended in 400 ml of 20 mM HEPES-NaOH, pH 7.4, that contained 10 mM EDTA at 4 °C. After homogenization with a Polytron (Kinematica, Lucerne, Switzerland) at 10000 rotations per minute (rpm) for 15 s, the homogenates were centrifuged at 48000 x g for 30 min at 4 °C. Aliquots of the membrane stocks were frozen at -80 °C. All assays were performed at least three times. The test compounds were diluted in 20 ml of binding buffer (252 mM NaCl, 5.4 mM KC1, 20 mM Na ₂ HP0 ₄ , 3.52 mM KH ₂ P0 ₄ , pH 7.4) and 10 point dilution curves were made and transferred to 96-well white polystyrene assay plates (Sigma- Aldrich, Buchs, Switzerland). [ ³ H]-WIN35,428 (-86 Ci /mmol; Perkin-Elmer) was the radioligand for the DAT assay and had a K _d of 12 nM. Fifty microliters of [ ³ H]-WIN35,428 (-40 nM concentration) was added to each well of the hDAT assay plates, targeting a final [ H]- WTN35428 concentration of 10 nM. Twenty microliters of binding buffer alone in the assay plate defined the total binding, whereas binding in the presence of 10 μΜ indatraline defined nonspecific binding. Frozen DAT membrane stocks were thawed and resuspended to a concentration of approximately 0.04 mg protein/ml binding buffer (1: 1 diluted in H ₂ 0) using a polytron tissue homogenizer. The membrane homogenates (40 g/ml) were then lightly mixed for 5-30 min with polyvinyl toluene (PCT) wheat germ agglutinin-coated scintillation proximity assay (WGASPA; Amersham Biosciences) beads at 7.7 mg beads/ml homogenate. One hundred thirty microliters of the membrane/bead mixture were added to each well of the assay plate that contained radioligand and test compounds (final volume in each well, 200 μΐ) to start the assay, which was incubated for approximately 2 h at room temperature with agitation. The assay plates were then counted in the PVT SPA counting mode of a Packard Topcount. Fifty microliters of the [¾]-WIN35428 stocks were counted in 5 ml of ReadySafe scintillation cocktail (Beckman Industries) on a Packard 1900CA liquid scintillation counter to determine the total counts added to the respective assays. Non-linear regression was used to fit the data to sigmoid curves and determine IC ₅₀ values for binding and uptake. Kj values for binding and uptake were calculated using the following Cheng-Prusoff equation: Kj = ICso/(l+ [S]/K _m ).

Human ERG (hERG)

The whole-cell patch-clamp technique was used to investigate the effects of the test items on hERG (human-ether-a-go-go related gene) potassium channels in stably transfected CHO cells near physiological temperature (36 + 1 °C). The effects of compounds on hERG K ⁺ -current parameters were evaluated at 4 concentrations (0.3-3-30-300 μΜ) in at least 3 CHO cells stably expressing the hERG channel. For electrophysiological measurements cells were seeded onto 35 mm sterile culture dishes containing 2 ml culture medium without Hygromycin B. Cells were cultivated at a density that enabled single cells (without visible connections to neighbouring cells) to be measured. Cells were incubated at 37 °C in a humidified atmosphere with 5% C0 ₂ (rel. humidity about 95%). The cells were continuously maintained in and passaged in sterile culture flasks containing nutrient mixture F-12 (DMEM/F-12 with L-Glutamine) supplemented with 10% foetal bovine serum and 10% penicillin/streptomycin solution. Every day at least three cells were treated with a selective IK _r blocker (E-4031, reference substance) to assure accuracy of the method. The 35 mm culture dishes upon which cells were seeded at a density allowing single cells to be recorded were placed on the dish holder of the microscope and continuously perfused (at approximately 1 ml/min) with the bath solution (sodium chloride 150 mM, potassium chloride 4 mM, calcium chloride 1.2 mM, magnesium chloride 1 mM, HEPES 10 mM, pH (NaOH) 7.4) at near physiological temperature (36 + 1 °C). After formation of a Gigaohm seal between the patch electrodes and individual hERG stably transfected CHO cells (pipette resistance range: 2.0 ΜΩ - 7.0 ΜΩ; seal resistance range: > 1 GQ) the cell membrane across the pipette tip was ruptured to assure electrical access to the cell interior (whole-cell patch-configuration). In case the quality of the seal was poor, the process of seal formation was repeated with a different cell and a new pipette. As soon as a stable seal was established, hERG outward tail currents were measured upon depolarization of the cell membrane to -40 mV for 50 ms followed by 500 ms at +20 mV (activation of channels) from a holding potential of -80 mV and upon subsequent repolarization to -40 mV for 500 ms. This voltage protocol was run at least 10 times at intervals of 10 s. If current density was judged to be too low for measurement, another cell was recorded. Once control recordings have been accomplished, cells were continuously perfused with a bath solution containing the test items. During wash-in of the test item the voltage protocol indicated above was run continuously again at 10 s intervals until the steady-state level of block was reached. The four test item concentrations of the compound were applied sequentially to 3 cells in a cumulative manner. As hERG tail currents were inhibited by the test item, the concentration-response curve was generated and IC ₅₀ value calculated. Based on the IC ₅₀ value the IC ₂₀ was estimated. Each concentration of the test item was analyzed in three experiments (n=3).

Amphiphilic vector (ΔΔ G _am ) calculation and in silico DIPL prediction

Amphiphilic vector (ΔΔ G _am ) and in silico DIPL prediction were computationally determined from the molecular structural formula for the compound of formula I and comparative compounds according to the published algorithms (Fischer, H.; Kansy, M.; Bur, D.; "CAFCA: a novel tool for the calculation of amphiphilic properties of charged drug molecules". Chimia 2000, 54, 640-645; Fischer, H.; Atzpodien, E. A.; Csato, M; Doessegger, L.; Lenz, B.; Schmitt, G.; Singer, T.; "In silico assay for assessing phospholipidosis potential of small drug like molecules: training, validation and refinement using several datasets." J. Med. Chem. 2012, 55, 126-139).

The compound of formula I has partial agonist activity on hTAARl (EC ₅₀ in μΜ), binding affinity at hDAT (Kj in μΜ), and channel blocking activity at hERG (IC ₂₀ and IC ₅₀ in μΜ) as shown in Table 1. Table 1 also shows the calculated amphiphilic vector (AAG _am in kJ mol ^"1 ) and in silico phospholipidosis estimation (negative/positive/borderline prediction for in vitro DIPL and in vivo DIPL) for the compound of formula I and comparative compounds, as calculated using the procedure described above.

Table 1

4 0.0619 49 49.67 12.42 201 -5.31 NEGATIVE BORDERLINE 2.50 4

5 0.0656 40 81.71 22.16 338 -5.9 NEGATIVE BORDERLINE 1.52 23

6 ¾ 0.08 30 1.31 0.38 5 -8.46 POSITIVE POSITIVE 5.93 7

7 0.0849 57 11.39 3.67 43 -7.41 POSITIVE POSITIVE 0.79 9

8 0.1086 33 10.78 3.01 28 -4.89 NEGATIVE NEGATIVE 9.77 9

9 0.1437 32 4.46 1.14 8 -8.83 POSITIVE POSITIVE 0.48 3

10 0.1837 38 31.72 5.78 31 -3.11 NEGATIVE NEGATIVE 11.30 6

11 0.2027 46 17.42 2.59 13 -6.18 POSITIVE BORDERLINE 2.33 1

12 ο ο 0.2119 40 14.26 3.21 15 -6.59 POSITIVE BORDERLINE 1.78 8

Η

Η

13 ο ο 0.4045 37 66.04 9.14 23 -6.23 POSITIVE BORDERLINE 1.31 3

Η

CI

14 0.4467 53 73.18 21.63 48 -6.96 POSITIVE BORDERLINE 7.32 16

Η

15 0.6632 35 9.65 2.40 4 -7.4 POSITIVE POSITIVE >26.1 >3

16 0.666 35 8.98 3.35 5 -8.48 POSITIVE POSITIVE 16.22 2

17 0.6727 45 518.2 129.55 193 -4.53 NEGATIVE NEGATIVE 10.32 15

H

18 0.8271 63 711.5 146.78 177 -5.82 NEGATIVE BORDERLINE >26.1 >3

H

19 1.025 32 60.47 8.32 8 -4.59 NEGATIVE NEGATIVE 21.9 21

H

20 2.480 59 10.75 2.49 1 -5.37 NEGATIVE BORDERLINE >26.1 >1

% agonist activity for hTAARl is reported on a scale calibrated such that effect of the endogenenous ligand β-phenylethylamine = 100% agonis

It has surprisingly been found that the compound of formula I (example 1) displays an overall superior combination of properties in terms of potent agonist activity at hTAARl, high selectivity against hDAT, high selectivity against hERG, low amphiphilic vector and

consequently low phospholipidosis risk compared to other TAARl compounds of the prior art. Inspection of Table 1 reveals that example 1 has potent partial agonist activity at hTAARl (EC ₅₀ = 0.059 μΜ), is highly selective against hDAT (K _; = 27.5 μΜ; selectivity ratio = 471-fold versus hTAARl EC ₅₀ ), is highly selective against hERG (IC ₂₀ = 36.2 μΜ; selectivity ratio = 619-fold versus hTAARl EC ₅₀ ) and has a low amphiphilic vector (AAG _am = - 3.47 kJ mol ^"1 ) well below the threshold of concern for phospholipidosis (in silico DIPL risk prediction = negative).

Inspection of Table 1 reveals that close analogues of example 1 have inferior properties compared to example 1 in one or more regards.

For instance, comparative example 2, which is the R enantiomer of example 1, is less potent at hTAARl (EC ₅₀ = 0.2632 μΜ), which teaches that the S configuration of absolute stereochemistry, as in example 1, is preferred in order to obtain higher potency at hTAARl.

Comparative example 3 is significantly more potent at hERG (IC ₂₀ = 1.97 μΜ; selectivity ratio = 52-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 6.3 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 4 is significantly more potent at DAT (Kj = 2.5 μΜ; selectivity ratio = 40-fold versus hTAARl EC ₅₀ ) and also has a higher amphiphilic vector (AAG _am = - 5.3 kJ mol ^"1 ) and thus a borderline DIPL prediction.

Comparative example 5 is significantly more potent at DAT (Kj = 1.5 μΜ; selectivity ratio = 23-fold versus hTAARl EC ₅₀ ) and also has a higher amphiphilic vector (AAG _am = - 5.9 kJ mol ^"1 ) and thus a borderline DIPL prediction.

Comparative example 6 is significantly more potent at hERG (IC ₂₀ = 0.38 μΜ; selectivity ratio = 5-fold versus hTAARl EC ₅₀ ), is more potent at DAT (K _; = 5.9 μΜ; selectivity ratio = 74- fold versus hTAARl EC 50) and also has a significantly higher amphiphilic vector (AAG _am = - 8.46 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 7 is significantly more potent at hERG (IC ₂₀ = 3.57 μΜ; selectivity ratio = 43-fold versus hTAARl EC ₅₀ ), is significantly more potent at DAT (K _; = 0.79 μΜ;

selectivity ratio = 9-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 7.41 kJ mol ^"1 ) and thus a positive DIPL prediction. Comparative example 8 is significantly more potent at hERG (IC ₂₀ = 3.01 μΜ; selectivity ratio = 28-fold versus hTAARl EC ₅₀ ).

Comparative example 9 is less potent at hTAARl (EC ₅₀ = 0.144 μΜ), is significantly more potent at hERG (IC ₂₀ = 1.14 μΜ; selectivity ratio = 8-fold versus hTAARl EC ₅₀ ), is significantly more potent at DAT (K _; = 0.48 μΜ; selectivity ratio = 3-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 8.83 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 10 is less potent at hTAARl (EC ₅₀ = 0.184 μΜ) and is more potent at hERG (IC ₂₀ = 5.78 μΜ; selectivity ratio = 31-fold versus hTAARl EC ₅₀ ).

Comparative example 11 is less potent at hTAARl (EC ₅₀ = 0.203 μΜ), is significantly more potent at hERG (IC ₂₀ = 2.59 μΜ; selectivity ratio = 13-fold versus hTAARl EC ₅₀ ), is significantly more potent at DAT (Kj = 2.33 μΜ; selectivity ratio = 12-fold versus hTAARl

EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 6.18 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 12 is less potent at hTAARl (EC ₅₀ = 0.212 μΜ), is significantly more potent at hERG (IC ₂₀ = 3.21 μΜ; selectivity ratio = 15-fold versus hTAARl EC ₅₀ ), is significantly more potent at DAT (Kj = 1.78 μΜ; selectivity ratio = 8-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 6.59 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 13 is significantly less potent at hTAARl (EC ₅₀ = 0.405 μΜ), is more potent at hERG (IC ₂₀ = 9.14 μΜ; selectivity ratio = 23-fold versus hTAARl EC ₅₀ ), is significantly more potent at DAT (K _; = 1.31 μΜ; selectivity ratio = 3-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 6.23 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 14 is significantly less potent at hTAARl (EC ₅₀ = 0.447 μΜ), is significantly more potent at DAT (K _; = 7.32 μΜ; selectivity ratio = 16-fold versus hTAARl

EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 6.96 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 15 is significantly less potent at hTAARl (EC ₅₀ = 0.663 μΜ), is significantly more potent at hERG (IC ₂₀ = 2.40 μΜ; selectivity ratio = 4-fold versus hTAARl

EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 7.4 kJ mol ^"1 ) and thus a positive DIPL prediction. Comparative example 16 is significantly less potent at hTAARl (EC ₅₀ = 0.666 μΜ), is significantly more potent at hERG (IC ₂₀ = 3.35 μΜ; selectivity ratio = 5-fold versus hTAARl EC ₅₀ ) and also has a significantly higher amphiphilic vector (AAG _am = - 8.48 kJ mol ^"1 ) and thus a positive DIPL prediction.

Comparative example 17 is significantly less potent at hTAARl (EC ₅₀ = 0.673 μΜ) and is more potent at DAT (K _; = 10.32 μΜ; selectivity ratio = 15-fold versus hTAARl EC ₅₀ ).

Comparative example 18 is significantly less potent at hTAARl (EC ₅₀ = 0.827 μΜ) and also has a higher amphiphilic vector (AAG _am = - 5.82 kJ mol ^"1 ) and thus a borderline DIPL prediction.

Comparative example 19 is significantly less potent at hTAARl (EC ₅₀ = 1.025 μΜ) and is more potent at hERG (IC ₂₀ = 8.32 μΜ; selectivity ratio = 8-fold versus hTAARl EC ₅₀ ).

Finally, comparative example 20 is significantly less potent at hTAARl (EC ₅₀ = 2.48 μΜ), is significantly more potent at hERG (IC ₂₀ = 2.49 μΜ; selectivity ratio = 1-fold versus hTAARl EC ₅₀ ) and also has a higher amphiphilic vector (AAG _am = - 5.37 kJ mol ^"1 ) and thus a borderline DIPL prediction.

Therefore, taking all of the data in Table 1 into consideration, the compound of formula I (example 1) is the overall most preferred compound for the intended use as a safe and effective therapeutic agent for treatment in humans of TAARl-related disorders, especially for the treatment of chronic CNS disorders, such as depression, anxiety disorders, bipolar disorder, attention deficit hyperactivity disorder (ADHD), stress-related disorders, psychotic disorders such as schizophrenia, neurological diseases such as Parkinson's disease, neurodegenerative disorders such as Alzheimer's disease, epilepsy, migraine, hypertension, substance abuse, addiction and metabolic disorders such as eating disorders, diabetes, diabetic complications, obesity, dyslipidemia, disorders of energy consumption and assimilation, disorders and malfunction of body temperature homeostasis, disorders of sleep and circadian rhythm, and cardiovascular disorders. The most preferred disorders are schizophrenia, bipolar disorder or depression.

The compound of formula I and the pharmaceutically acceptable salts of the compound of formula I can be used as medicaments, e.g. in the form of pharmaceutical preparations. The pharmaceutical preparations can be administered orally, e.g. in the form of tablets, coated tablets, dragees, hard and soft gelatine capsules, solutions, emulsions or suspensions. The administration can, however, also be effected rectally, e.g. in the form of suppositories, or parenterally, e.g. in the form of injection solutions.

The compound of formula I can be processed with pharmaceutically inert, inorganic or organic carriers for the production of pharmaceutical preparations. Lactose, corn starch or derivatives thereof, talc, stearic acids or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragees and hard gelatine capsules. Suitable carriers for soft gelatine capsules are, for example, vegetable oils, waxes, fats, semi-solid and liquid polyols and the like. Depending on the nature of the active substance no carriers are however usually required in the case of soft gelatine capsules. Suitable carriers for the production of solutions and syrups are, for example, water, polyols, glycerol, vegetable oil and the like. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi-liquid or liquid polyols and the like.

The pharmaceutical preparations can, moreover, contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.

Medicaments containing a compound of formula I or a pharmaceutically acceptable salt thereof and a therapeutically inert carrier are also an object of the present invention, as is a process for their production, which comprises bringing the compound of formula I and/or pharmaceutically acceptable acid addition salts and, if desired, one or more other therapeutically valuable substances into a galenical administration form together with one or more

therapeutically inert carriers.

The most preferred indications in accordance with the present invention are those which include disorders of the central nervous system, for example the treatment or prevention of depression, schizophrenia and bipolar disorders.

The dosage can vary within wide limits and will, of course, have to be adjusted to the individual requirements in each particular case. In the case of oral administration the dosage for adults can vary from about 0.01 mg to about 1000 mg per day of a compound of general formula I or of the corresponding amount of a pharmaceutically acceptable salt thereof. The daily dosage may be administered as single dose or in divided doses and, in addition, the upper limit can also be exceeded when this is found to be indicated. Tablet Formulation (Wet Granulation)

Item Ingredients mg/tablet

1. Compound of formula I 5 25 100 500

2. Lactose Anhydrous DTG 125 105 30 150

3. Sta-Rx 1500 6 6 6 30

4. Microcrystalline Cellulose 30 30 30 150

5. Magnesium Stearate 1 1 1 1

Total 167 167 167 831

Manufacturing Procedure

1. Mix items 1, 2, 3 and 4 and granulate with purified water.

2. Dry the granules at 50°C.

3. Pass the granules through suitable milling equipment.

4. Add item 5 and mix for three minutes; compress on a suitable press.

Capsule Formulation

Item Ingredients mg/capsule

1. Compound of formula I 5 25 100 500

2. Hydrous Lactose 159 123 148 —

3. Corn Starch 25 35 40 70

4. Talc 10 15 10 25

5. Magnesium Stearate 1 2 2 5

Total 200 200 300 600

Manufacturing Procedure

1. Mix items 1, 2 and 3 in a suitable mixer for 30 minutes.

2. Add items 4 and 5 and mix for 3 minutes.

3. Fill into a suitable capsule.