WO2005044267A1

WO2005044267A1 - Alkynes ii

Info

Publication number: WO2005044267A1
Application number: PCT/US2004/034519
Authority: WO
Inventors: Peter Bach; Udo Bauer; Karolina Nilsson; Andreas WÅLLBERG
Original assignee: Astrazeneca Ab; Nps Pharmaceuticals, Inc.
Priority date: 2003-10-31
Filing date: 2004-10-20
Publication date: 2005-05-19
Also published as: EP1677790A1; CA2549969A1; JP2007509935A

Abstract

The present invention is directed to novel compounds of formula (I), to a process for their preparation, their use and pharmaceutical compositions comprising the novel compounds. The novel compounds are useful in therapy, and in particular for the treatment of gastroesophageal reflux disease (GERD).

Description

ALKYNES II

Field of the invention

The present invention is directed to novel compounds, to a process for their preparation, their use in therapy and pharmaceutical compositions comprising said novel compounds.

Background of the invention

The metabotropic glutamate receptors (mGluR) are G-protein coupled receptors that are involved in the regulation and activity of many synapses in the central nervous system (CNS). Eight metabotropic glutamate receptor subtypes have been identified and are subdivided into three groups based on sequence similarity. Group I consists of mGluRl and mGluR.5. These receptors activate phospholipase C and increase neuronal excitability. Group II, consisting of mGluR2 and mGluR3 as well as group III, consisting of mGluR4, mGluR6, mGluR7 and mGluR.8 are capable of inhibiting adenylyl cyclase activity and reduce synaptic transmission. Several of the receptors also exist in various isoforms, occurring by alternative splicing (Chen, C-Yet al, Journal of Physiology (2002), 538.3, pp. 773-786; Pin, J-P et al, European Journal of Pharmacology (1999), 375, pp. 277-294; Brάuner-Osbome, H et al. Journal of Medicinal Chemistry (2000), 43, pp. 2609-2645; Schoepp, D.D, Jane D.E. Monn J.A. Neuropharmacology (1999), 38, pp. 1431-1476).

The lower esophageal sphincter (LES) is prone to relaxing intermittently. As a consequence, fluid from the stomach can pass into the esophagus since the mechanical barrier is temporarily lost at such times, an event hereinafter referred to as "reflux".

Gastro-esophageal reflux disease (GERD) is the most prevalent upper gastrointestinal tract disease. Current pharmacotherapy aims at reducing gastric acid secretion, or at neutralizing acid in the esophagus. The major mechanism behind reflux has been considered to depend on a hypotonic lower esophageal sphincter. However, e.g. Holloway & Dent (1990) Gastroenterol Clin. N. Amer. 19, pp. 517-535, has shown that most reflux episodes occur during transient lower esophageal sphincter relaxations (TLESRs), i.e. relaxations not triggered by swallows. It has also been shown that gastric acid secretion usually is normal in patients with GERD.

The problem underlying the present invention was to find new compounds useful in the treatment of GERD.

WO 01/16121 Al discloses a compound A-L-B, where A is a 5-, 6- or 7-membered heterocycle

L is an alkenylene, alkynylene or azo; and

B is a hydrocarbyl; cyclohydrocarbyl; heterocycle (optionally containing one or more double bonds); or aryl. These compounds have been described as being useful in inter alia cerebral ischemia, chronic neurodegeneration, psychiatric disorders, epilepsy and diseases of the pulmonary system as well as the cardiovascular system.

WO 99/02497 A2 discloses compounds of the formula

wherein X may be an alkenylene or an alkynylene bonded via vicinal unsaturated carbon atoms, or an azo group; and R⁵ may be an aromatic or heteroaromatic group. These compounds have been described as being useful in inter alia epilepsy, cerebral ischemia and Alzheimer's disease.

Outline of the invention The present invention is directed to novel compounds according to the general formula I:

wherein

R¹ is selected from hydrogen, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, aryl and heteroaryl, wherein the aryl or heteroaryl may be substituted by C₁-C₄ alkyl;

R² is selected from hydrogen and C₁-C₄ alkyl;

R³ is selected from hydrogen, C₁-C alkyl, F, CF₃, CHF₂ and CH₂F;

R⁴ is selected from hydrogen, F, CF₃, CHF₂, CH₂F and CH₃;

R⁵ is selected from hydrogen and F;

R⁶ is selected from hydrogen and F;

Q is S, NH or NCH₃, optionally substituted by C C₄ alkyl;

Y¹ is selected from hydrogen; halogen; nitrile; C1-C₄ alkoxy; C₁-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; benzyloxy; nitro in the meta or para position; and C₁-C₄ alkyl ester;

Y² is selected from hydrogen; halogen; nitrile; C₁-C₄ alkoxy; C₁-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; and

C alkyl ester;

Y³ is selected from hydrogen; halogen; nitrile; Ci-C₄ alkoxy; C₁-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; and d-C alkyl ester; or 1 9

Y and Y may form an aromatic or non-aromatic ring, optionally substituted by halogen, nitrile, Ci-C₄ alkoxy, C₁-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom, benzyloxy or C₁-C₄ alkyl ester; as well as pharmaceutically acceptable salts, hydrates, isoforms and/or optical isomers thereof.

The general terms used in the definition of formula I have the following meanings:

Halogen is chloro, fluoro, bromo or iodo.

C₁-C₄ alkyl is a straight or branched alkyl group, each independently containing 1, 2, 3 or 4 carbon atoms, for example methyl, ethyl, n-propyl, n-butyl or isopropyl. In one embodiment, the alkyl groups may contain one or more heteroatoms selected from O, N and S. Examples of such groups are methyl-ethylether, methyl-ethylamine and methyl- thiomethyl.

Cycloalkyl is a cyclic alkyl, each independently containing 3, 4, 5 or 6 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

0^0₄ alkoxy is an alkoxy group containing 1, 2, 3 or 4 carbon atoms, such as methoxy, ethoxy, n-propoxy, n-butoxy or isopropoxy.

The herein used term aryl means aromatic rings with 6-14 carbon atoms including both single rings and polycyclic compounds, such as phenyl, benzyl or naphtyl.

The term heteroaryl as used herein means aromatic rings with 5-14 carbon atoms, including both single rings and polycyclic compounds, such as imidazopyridine, in which one or several of the ring atoms is either oxygen, nitrogen or sulphur, such as furanyl or thiophenyl. Within the scope of the invention are also pharmaceutically acceptable salts of the compounds of formula I as well as isomers, hydrates and isoforms thereof.

Pharmaceutically acceptable salts of the compound of formula I are also within the scope of the present invention. Such salts are for example salts formed with mineral acids such as hydrochloric acid; alkali metal salts such as sodium or potassium salts; or alkaline earth metal salts such as calcium or magnesium salts.

The novel compounds according to the present invention are useful in therapy. In one aspect of the invention said compounds are useful for the inhibition of transient lower esophageal sphincter relaxations (TLESRs) and thus for treatment or prevention of gastro- esophageal reflux disorder (GERD). In further embodiments, the compounds according to the present invention are useful for the prevention of reflux, treatment or prevention of regurgitation, treatment or prevention of asthma, treatment or prevention of laryngitis, treatment or prevention of lung disease and for the management of failure to thrive.

A further aspect of the invention is the use of a compound according to formula I, for the manufacture of a medicament for the inhibition of transient lower esophageal sphincter relaxations, for the treatment or prevention of GERD, for the prevention of reflux, for the treatment or prevention of regurgitation, treatment or prevention of asthma, treatment or prevention of laryngitis, treatment or prevention of lung disease and for the management of failure to thrive.

A further aspect of the invention is the use of a compound according to formula I for the manufacture of a medicament for the treatment or prevention of functional gastrointestinal disorders, such as functional dyspepsia (FD). Yet another aspect of the invention is the use of a compound according to formula I for the manufacture of a medicament for the treatment or prevention of irritable bowel syndrome (IBS), such as constipation predominant IBS, diarrhea predominant IBS or alternating bowel movement predominant IBS. Still a further aspect of the invention is a method for the treatment of any one of the conditions mentioned above, whereby a pharmaceutically effective amount of a compound according to formula I above, is administered to a subject suffering from said condition(s).

In one aspect of the invention, the compounds of formula I are useful for the treatment and/or prevention of acute and chronic neurological and psychiatric disorders, anxiety and chronic and acute pain disorders. In a further aspect, said compounds are useful for the prevention and/or treatment of pain related to migraine, inflammatory pain, neuropathic pain disorders such as diabetic neuropathies, arthritis and rheumatoid diseases, low back pain, post-operative pain and pain associated with various conditions including cancer, angina, renal or billiary colic, menstruation, migraine and gout.

The term "isomers" is herein defined as compounds of formula I, which differ by the position of their functional groups and/or orientation. By "orientation" is meant stereoisomers, diastereoisomers, regioisomers and enantiomers.

The term "isoforms" as used herein is defined as compounds of formula I which differ by their crystal lattice, such as crystalline compounds and amorphous compounds.

The wording "TLESR", transient lower esophageal sphincter relaxations, is herein defined in accordance with. Mittal, R.K., Holloway, R.H., Penagini, R., Blackshaw, L.A., Dent, J, 1995; Transient lower esophageal sphincter relaxation. Gastroenterology 109, pp. 601-610.

The wording "reflux" is defined herein as fluid from the stomach being able to pass into the esophagus, since the mechanical barrier is temporarily lost at such times. The wording "GERD", gastro-esophageal reflux disease, is defined herein in accordance with van Heerwarden, M.A., SmoutA.JP.M., 2000; Diagnosis of reflux disease. Bailliere 's Clin. Gastroenterol. 14, pp. 759-774.

Methods of preparation

First, a Sonogashira coupling (Tetrahedron Letters 1975, 50, 4467, S. Thorand, N. Krause J. Org Chem., 1998, 63, 8551-8553, M. Erdelyi, A. Gogoll, J. Org. Chem., 2001, 66, 4165-4169) of the aryl bromide A and the alcohol B in the presence of a base such as triethyl amine at room temperature to 60 °C gives the alcohol C which is then converted into the mesylate D with methanesulfonyl chloride in triethyl amine at about -20 to 0°C. The mesylate of the primary alcohol is isolated and characterised, while those of the secondary alcohols are made in situ. Finally, the respective mesylate is reacted with primary or secondary amines or thiol nucleophiles to generate product (I) (Scheme 1).

SCHEME 1

In those cases where the alcohol B is not commercially available with desired R /R - groups, the product (I) is formed by an alternative route (scheme 2): first the aryl bromide A is coupled with ethynyl(trimethyl)silane F via Sonogashira coupling at 60 °C in triethyl amine to give product G. Deprotection of G at room temperature with potassium carbonate in methanol or methanol/DCM gives terminal alkyne H, which is deprotonated with lithium hexamethyldisilazide or lithium bis(trimethylsilyl)amide in THF at - 78 °C. At - 78 °C an aldehyde or ketone is added and the reaction mixture is allowed to reach room temperature and kept at that temperature for the appropriate time to form the alcohol I. Having isolated I, the mesylate J is formed in situ with methanesulfonyl chloride and triethyl amine, either at room temperature or with cooling. Subsequently an amine is added and the reaction mixture is stirred at room temperature for the appropriate time to form product (I).

SCHEME 2

In the schemes 1 and 2 above, R¹, R², R³, R⁴, R⁵, R⁶, Y¹, Y² and Y³ are defined as for the compounds of formula I above. Experimental details

DCM is dried over 3 A molecular sieves. THF was distilled from Na/benzophenone just prior to use. All reactions are run under a nitrogen atmosphere. All glassware is dried in at 150 °C for at least two hours prior to its use. Phase separators from International Sorbent Technology (1ST) are used. Purification by chromatography is done either on silica gel 60 (0.040-0.063 mm), or by reverse phase chromatography with a C8 column. All NMR spectra are measured in ^-chloroform.

2-bromo-6-methylpyridine is commercially available from Aldrich, (PPh₃)₂PdCl₂ from Avacado, Pd (OAc)₂ from Aldrich and Cul from Fluka. If not stated otherwise, the chemicals used are commercially available and are used as such without further purification.

Pharmaceutical formulations

For clinical use, the compounds of formula I are in accordance with the present invention suitably formulated into pharmaceutical formulations for oral administration. Also rectal, parenteral or any other route of administration may be contemplated to the skilled man in the art of formulations. Thus, the compounds of formula I are formulated with at least one pharmaceutically and pharmacologically acceptable carrier or adjuvant. The carrier may be in the form of a solid, semi-solid or liquid diluent.

In the preparation of oral pharmaceutical formulations in accordance with the invention, the compound of formula I to be formulated is mixed with solid, powdered ingredients such as lactose, saccharose, sorbitol, mannitol, starch, amylopectin, cellulose derivatives, gelatin, or another suitable ingredient, as well as with disintegrating agents and lubricating agents such as magnesium stearate, calcium stearate, sodium stearyl fumarate and polyethylene glycol waxes. The mixture is then processed into granules or compressed into tablets.

Soft gelatine capsules may be prepared with capsules containing a mixture of the active compound or compounds of the invention, vegetable oil, fat, or other suitable vehicle for soft gelatine capsules. Hard gelatine capsules may contain the active compound in combination with solid powdered ingredients such as lactose, saccharose, sorbitol, mannitol, potato starch, corn starch, amylopectin, cellulose derivatives or gelatine.

Dosage units for rectal administration may be prepared (i) in the form of suppositories which contain the active substance(s) mixed with a neutral fat base; (ii) in the form of a gelatine rectal capsule which contains the active substance in a mixture with a vegetable oil, paraffin oil, or other suitable vehicle for gelatine rectal capsules; (iii) in the form of a ready-made micro enema; or (iv) in the form of a dry micro enema formulation to be reconstituted in a suitable solvent just prior to administration.

Liquid preparations for oral administration may be prepared in the form of syrups or suspensions, e.g. solutions or suspensions, containing the active compound and the remainder of the formulation consisting of sugar or sugar alcohols, and a mixture of ethanol, water, glycerol, propylene glycol and polyethylene glycol. If desired, such liquid preparations may contain colouring agents, flavouring agents, saccharine and carboxymethyl cellulose or other thickening agent. Liquid preparations for oral administration may also be prepared in the form of a dry powder to be reconstituted with a suitable solvent prior to use.

Solutions for parenteral administration may be prepared as a solution of a compound of the invention in a pharmaceutically acceptable solvent. These solutions may also contain stabilizing ingredients and/or buffering ingredients and are dispensed into unit doses in the form of ampoules or vials. Solutions for parenteral administration may also be prepared as a dry preparation to be reconstituted with a suitable solvent extemporaneously before use. In one aspect of the present invention, the compounds of formula I may be administered once or twice daily, depending on the severity of the patient's condition.

A typical daily dose of the compounds of formula I is from 0.1 - 10 mg per kg body weight of the subject to be treated, but this will depend on various factors such as the route of administration, the age and weight of the patient as well as of severity of the patient's condition.

Examples Method G

Example 1

Preparation of 3-(6-methylpyridin-2-yl prop-2-yn-l-ol (compound 16):

To 2-bromo-6-methylpyridine (1.72 g, 0.01 mol) was added (PPh₃)₂PdCl₂ (0.116 g, 0.2 mmol, 0.02 eq.) and Cul (0.063 g, 0.3 mmol, 0.03 eq.) at 0 °C under nitrogen, followed by prop-2-yn-l-ol (2.24 g, 2.33 mL, 0.4 mol, 4.0 eq.) and triethylamine (1.50 mL). The reaction mixture was allowed to reach room temperature and then heated at 60 °C for 3.5 h. Then the reaction mixture was added to water (10 mL) and the pH was adjusted to 6-7 with 2 M HCl. The water phase was extracted with DCM (3 x 10 mL) and the combined organic phases were dried with sodium sulphate and evaporated. This gave 1.719 g crude product. 1.098 g hereof was subjected to flash chromatography on silica gel with pentane/EtOAc, first 1:1, then 1:2, finally 1:3, as eluent. This gave 0.578 g product. ¹³C NMR (75 MHz): 157.7, 141.1, 136.2, 123.7, 122.3, 88.4, 83.0, 49.9, 23.5. Method H

Example 2 Preparation of 3-(6-methylpyridin-2-yl)prop-2-yn-l-yl methanesulfonate (compound 17):

3-(6-methylpyridin-2-yl)prop-2-yn-l-ol (0.300 g, 2.04 mmol) was dissolved in DCM (10 mL) under nitrogen over 5-10 min. The solution was cooled to -20 °C (cooling bath: acetone + pieces of dry ice). Triethylamine (0.268 g, 0.37 mL, 0.27 mmol, 1.30 eq.) was added. Methanesulfonyl chloride (0.280 g, 0.19 mL, 0.24 mmol, 1.2 eq.) in DCM (1.5 mL) was added over 3 min. The reaction mixture was stirred at -18 to -22 °C for lh after which time LC/MS only showed product. Water (10 mL) was added. The organic phase was separated and the water phase was extracted with DCM (3 x 10 mL). The organic phases were pooled, dried with magnesium sulphate and evaporated. This gave 0.450 g (yield: 98 %) as a yellow oil.

1H NMR (300 MHz): 7.61 (t, J = 7.7 Hz, 1H), 7.31 (d, J =7.7 Hz,lH), 7.19 (d, J = 7.7 Hz, 1H), 5.10 (s, 2H), 3.18 (s, 3H), 2.58 (s, 3H). ¹³C NMR (75 MHz): 158.9, 140.2, 136.8, 124.5, 123.8, 87.8, 80.7, 57.7, 38.9, 24.2.

Method I

Example 3 Preparation of N-r3-(6-methylpyridin-2-yl)prop-2-yn-l-yl]aniline (compound 18):

3-(6-methylpyridin-2-yi)prop-2-yn-l-yl methanesulfonate (0.044 g, 0.195 mmol) was stirred with aniline (0.182 g, 0.180 mL, 1.95 mmol, 10.0 eq.) in triethylamine (0.372 g, 0.270 mL, 10.0 eq.) at room temperature for 1.5h. According to LC/MS no mesylate remained after that time.

The mixture was evaporated and purified by reverse phase column chromatography. Yield:

0.017 g (40%).

1H NMR (500 MHz): 7.50 (t, J = 7.7 Hz, IH), 7.28-7.16 (m, overlap with CDC1₃, 3H), 7.08 (d, J = 7.8 Hz, IH), 6.82-6.69 (m, 3H), 4.18 (s, 2H), 2.54 (s, 3H).

¹³C NMR (125 MHz): 158.6, 146.7, 141.9, 136.1, 129.0,124.0, 122.5, 118.3, 113.4, 86.0,

82.7, 34.4, 24.5.

Example 4 Preparation of N-benzyl-3-(6-methylpyridin-2-yl prop-2-vn-l-amine (compound 19): prepared according to method I above, with benzylamine as starting material

Yield: 23 % after reverse phase chromatography.

1H NMR (500 MHz): 7.54 (t, J = 7.8 Hz, IH), 7.38-7.32 (m, 4H), 7.29-7.23 (m, 2H), 7.09 (d, J = 7.8 Hz, IH), 3.95 (s, 2H), 3.68 (s, 2H), 2.56 (s, 3H), 1.80 (br, 2H, acetate). Method J

Example 5

Preparation of JV-methyl-iV- [3 -f6-methylpyridin-2-yl)prop-2-vn-l-yl] aniline (compound 20):

3-(6-methylpyridin-2-yl)prop-2-yn-l-yl methanesulfonate (0.042 g, 0.19 mmol) was stirred with N-methyl-aniline (0.040g, 0.040 mL, 0.37 mmol, 2.0 eq.) in triethylamine (0.20 mL) at room temperature for 21h. According to LC/MS no mesylate remained after that time.

3.5 mg (7 %).

1H NMR (500 MHz): 7.48 (t, J = 7.8 Hz, IH), 7.29-7.25 (m, 2H), 7.16 (d, J = 7.8 Hz, IH), 7.06 (d, J = 7.8 Hz, IH), 6.91 (m, 2H), 6.81 (t, J = 7.4 Hz, IH), 4.30 (s, 2H), 3.05 (s, 3H),

2.53 (s, 3H), 1.68 (br, 3H, acetate).

Example 6 Preparation of (3-Chloro-phenyl)-(^"l-methyl-3-(6-methyl-pyridin-2-yl)-prop-2-vnyl1-amine The compound was prepared according to method M using (i?S -4-(6-methylpyridin-2- yl)but-3-yn-2-ol and 3-chloro-aniline as starting materials.

1H NMR (400 MHz): 7.48 (t, 1 H), 7.18-7.04 (m, 3 H), 6.71 (m, 2 H), 6.60 (m, 1 H), 4.43 (m, 1 H), 3.93 (br s, 1 H), 2.53 (s, 3 H), 1.61 (d, 3 H).

Example 7

Preparation of (3 -methylphenyl) [3 -(6-methylpyridin-2- vDprop-2-yn- 1 -y 1] amine :

To w-toluidine (0.054 g, 0.50 mmol, 2.5 eq.) in a glass vial was added anhydrous potassium carbonate (0.033 g, 0.024 mmol, 1.2 eq.) and acetone (0.2 mL). Then, 0.5 mL of a 0.4 M solution of A (0.045 g, 0.20 mmol) in acetone was added. The vial was sealed and heated at 60°C for 5 h. The reaction material was filtered through Celite and then vacuum centrifuged. Purification was done by reverse phase column chromatography. Yield: 0.013 g (28 %).

1H NMR (500 MHz): 7.50 (t, J = 7.8 Hz, IH), 7.20 (d, J = 7.8 Hz, IH), 7.13-7.06 (m, 2H), 6.61 (d, J = 7.4 Hz, IH), 6.55-6.52 (m, 2H), 4.17 (s, 2H), 2.54 (s, 3H), 2.30 (s, 3H). MS ^m/_z: 237 (M+l)

Example 8

Preparation of (3 -methoxyphenyl) [3 -(6-methylp yridin-2-yl prop-2-yn- 1 - yll amine :

Prepared in analogy to example 6, but with 3-methoxyaniline as starting material. Yield: 0.016 g (31 %).

1H NMR (500 MHz): 7.51 (t, J = 7.8 Hz, IH), 7.20 (d, J = 7.6 Hz, IH), 7.14-7.07 (m, 2H), 6.34 (m, 2H), 6.27 (br t, J = 2.2 Hz, IH), 4.16 (s, 2H), 3.78 (s, 3H), 2.54 (s, 3H).

¹³C NMR (75 Hz): 160.5, 158.6, 148.2, 141.9, 136.1, 129.8, 124.0, 122.5, 106.3, 103.6, 99.4, 85.9, 82.8, 55.1, 34.4, 24.5. MS ^ra/_z: 253 (M+l)

Example 9

Preparation of (3-chlorophenyl)[3-(6-methylpyridin-2-yl)prop-2-yn-l-yl]amine:

Prepared in analogy to example 6, but with 3-chloroaniline as starting material. Yield: 0.011 g (21 %).

1H NMR (500 MHz): 7.51 (t, J = 7.8 Hz, IH), 7.20 (br d, J = 7.8 Hz, IH), 7.14-7.07 (m, 2H), 6.74 (br d, J = 7.4 Hz, IH), 6.69 (m, IH), 6.58 (br d, J = 8.4 Hz, IH), 4.16 (s, 2H), 2.54 (s, 3H). Example 10

Preparation of r(3-phenylprop-2-yn-l-yl)thio] benzene

The compound was prepared according to example 15 using methanesulfonic acid 3- pyridin-2-yl-prop-2-ynyl ester and thiophenol.

1H NMR: 8.55 (m, IH), 7.59 (m, IH), 7.48 (m, 2H), 7.25 (m, 5H), 3.84 (s, 2H). ¹³C NMR: 150.1, 143.3, 136.3, 135.2, 130.6, 129.2, 127.4, 127.2, 123.0, 85.9, 83.1, 23.8

Example 11

Preparation of 3 -Pyridin-2- yl-prop-2- yn- 1 -ol 3-Pyridin-2-yl-prop-2-yn-l-ol was prepared according to method G using 2-bromopyridine and ρrop-2-yn-l-ol as starting materials.

1H NMR (400 MHz, MeOH-d₄): 8.48 (m, 1 H), 7.82 (dt, 1 H), 7.53 (m, 1 H), 7.38 (dd, 1 H), 4.42 (s, 2 H).

Example 12

Preparation of Methanesulfonic acid 3-pyridin-2-yl-prop-2-ynyl ester Methanesulfonic acid 3-pyridin-2-yl-prop-2-ynyl ester was prepared according to method H using 3 -pyridin-2-yl-prop-2-yn- 1 -ol as starting material .

Example 13 Preparation of 1 -methoxy-3 - [( 3 -phenylprop-2-yn- 1 -yl)thio]benzene :

The compound was prepared according to example 15 using methanesulfonic acid 3- pyridin-2-yl-prop-2-ynyl ester and 3-methoxy-thiophenol.

1H NMR: 8.55 (m, IH), 7.61 (t, IH), 7.34 (d, IH), 7.22 (m, 2H), 7.07 (m, 2H), 6.78 (m,

IH), 3.86 (s, 2H), 3.78 (s, 3H)

¹³C NMR: 160.1, 150.1, 143.2, 136.5, 136.3, 130.0, 127.4, 123.1, 122.5, 115.6, 113.2,

85.9, 83.1, 55.5, 23.6.

Example 14

Preparation of 2-{ 3 - [Y3 -chlorophenyl)thio^"]but- 1 -yn- 1 - yl I -6-methyrpyridine :

The compound was prepared according to method M using (i? -4-(6-methylpyridin-2- yl)but-3-yn-2-ol and 3-chloro-thiophenol as starting materials.

1H MR: 7.59 (m, IH), 7.47 (m, 2H), 7.26 (m, 2H), 7.14 (d, IH), 7.06 (d, IH), 4.14 (q, IH), 2.53 (s, 3H), 1.62 (d, 3H).

¹³C NMR: 159.0, 142.4, 136.5, 136.0, 134.6, 131.2, 130.0, 128.2, 124.5, 122.9, 89.5, 83.8, 34.1, 24.7, 21.6.

Example 15

Preparation of 2-methyl-6-|^"3-(phenylthio prop-l-yn-l-yl]pyridine (compound 26):

Thiophenol (0.019 g, 0.11 mmol, 1.50 eq.) was dissolved in THF (0.5 mL) at 0 °C under nitrogen. Triethylamine (0.015 g, 2.0 eq.) was added. The mixture was stirred at room temperature for 5 min. Then, 3-(6-methylpyridin-2-yl)prop-2-yn-l-yl methanesulfonate (0.017 g, 0.075 mmol) in THF (0.5 mL) was added at 0 °C. The mixture was then stirred at room temperature for lh. Water (10 mL) was added. Subsequently, extraction with DCM (3x10 mL) was performed. The combined organic phases were dried with magnesium sulphate and evaporated. This gave 0.023g product, which was purified by reverse phase chromatography. The selected fractions were pooled. Water was added and the MeCN- water phase was extracted with DCM (3x10 mL). The combined organic phases were dried with magnesium sulphate and evaporated. This gave 0.007g (yield: 39 %). 1H NMR (300 MHz): 7.53-7.45 (m, 3H), 7.36-7.20 (m, 3H), 7.14 (d, J = 7.7 Hz, IH), 7.07 (d, J = 7.7 Hz, IH), 3.86 (s, 2H), 2.53 (s, 3H). ¹³C NMR (75 MHz): 158.6, 142.1, 136.1, 134.9,130.2, 128.8, 126.8, 124.0, 122.5, 85.0, 83.0, 24.5, 23.7.

Example 16 Preparation of 2-{3-[(3-chlorophenyl)thio]prop-l-yn-l-yll-6-methylpyridine (compound 27): prepared according to according to example 15 with 3-chlorobenzenethiol as starting material

1H NMR (500 MHz): 7.46-7.41 (m, 2H), 7.29 (d t, J_x = 7.6 Hz, J₂ = 1.4 Hz, IH), 7.18 (t, J = 7.6 Hz, IH), 7.16-7.13 (m, IH), 7.10 (d, J = 7.8 Hz, IH), 7.01 (d, J = 7.8 Hz, IH), 3.79 (s, 2H), 2.46 (s, 3H).

¹³C MR (75 MHz): 158.8, 141.9, 137.0, 136.2, 134.5, 129.9, 129.7, 128.0, 127.0, 124.2, 122.7, 84.3, 83.4, 24.4, 23.3.

Example 17

Preparation of 2-(3-r(3-methoxyphenyl)thio1prop-l-vn-l-vU-6-methylpyridine (compound 28): prepared according to according to example 15 with 3-methoxybenzenethiol as starting material.

1H NMR (500 MHz): 7.50 (t, J = 7.8 Hz, IH), 2.27-7.21 (m, IH), 7.17 (d, J = 7.8 Hz, IH), 7.09-7.05 (m, 3H), 6.79 (d d, Jj = 8.4 Hz, J₂ = 2.3 Hz, IH), 3.86 (s, 2H), 3.80 (s, 3H), 2.53 (s, 3H).

Example 18

Preparation of 2-methyl-6- { 3 - |Y3 -methylphenvDthiol prop- 1 -yn- 1 -yl > yridine (compound 29): prepared according to according to example 15 with 3-methylbenzenethiol as starting material

1H NMR (300 MHz): 7.42 (t, J = 7.8 Hz, IH), 7.28-7.04 (m, 4H), 7.02-6.95 (m, 2H), 3.77 (s, 2H), 2.46 (s, 3H), 2.26 (s, 3H). ¹³C NMR (75 MHz): 158.6, 142.1, 138.5, 136.1, 134.6, 130.9, 128.6, 127.7, 127.2, 124.0, 122.4, 85.1, 83.0, 24.5, 23.7, 21.3.

Method L Example 19 Preparation of (i?S -(6-methylpyridin-2-yl)but-3-yn-2-ol (compound 30):

2-bromo-6-methylpyridine (0.258 g, 1.5 mmol) was mixed with but-3-yn-2-ol (0.116 g, 1.65 mmol, 1.1 eq.) and (PPh₃)₂PdCl₂ (0.032 g, 0.045 mmol, 0.03 eq.). At 0 °C triethylamine (0.61 g, 0.84 mL, 6.0 mmol, 4.0 eq.) was added. The mixture was stirred at 0 °C for 10 min and Cul (0.006 g, 0.03 mmol, 0.02 eq.) was added. The mixture was allowed to reach room temperature and was finally heated at 60 °C for 4h. Phosphate buffer (10 mL, 0.2 M, pH 7) was added and the water phase was extracted with DCM (3x10 mL) by using a phase separator. The combined organic phases were dried with , sodium sulphate and evaporated. This gave 0.286 g crude product. After flash chromatography on Si with pentane/EtOAc fractions (first 1:1, then 3:2 and finally 1 :2) as eluent 0.163 g (Yield: 67 %) pure product was isolated as a yellow oil. TLC: R_f (pentane/EtOAc 1 :1) = 0.20.

1H NMR (300 MHz): 7.40 (t, J = 7.8 Hz, IH), 7.10 (d, J = 7.8 Hz, IH), 6.96 (d, J = 7.8 Hz,

IH), 4.90 (b, IH), 4.76 (q, J = 6.8 Hz, IH), 2.43 (s, 3H), 1.49 (d, J = 6.7 Hz, 3H).

¹³C NMR (75 MHz): 158.2, 141.7, 136.2, 123.9, 122.4, 91.7, 82.3, 57.6, 23.9, 23.8.

Method M

Example 20

Preparation of (RS) -2- { 3 - \{3 -methoxyphenyl)thio]but- 1 -yn- 1 - yl > -6-methylpyridine

(compound 31):

(i?S -4-(6-methylpyridin-2-yl)but-3-yn-2-ol (0.020 g, 0.12 mmol) was dissolved in DCM (2 mL) and cooled to -20 °C. Triethylamine (0.015 g, 0.021 mL, 0.15 mmol, 1.20 eq.) was added followed by methanesulfonyl chloride (0.015 g, 0.010 mL, 0.13 mmol, 1.1 eq.) in DCM (1 mL). The reaction mixture was stirred for lh at that temperature and then worked up by extraction with water (3 5 mL), followed by drying with sodium sulphate. After filtration, where DCM (3-5 mL) was used for rinsing, the solution was slightly concentrated to 3 mL volume and then re-cooled to -20 °C. NEt₃ (1 mL) and then 3- methoxybenzenethiol (0.019 g, 0.017 mL, 1.10 eq.) in DCM (0.5 mL) was added. The mixture was allowed to reach room temperature over 4h. Stirring was continued at room temperature for another 20h. At that time the reaction mixture was evaporated. Preparative chromatography on Si-plate in heptane/EtOAc 4:1 (R_f = 0.22) gave 0.006 g pure product. 1H NMR (300 MHz): 7.49 (t, J = 7.8 Hz, IH), 7.28-7.20 (m, 2H), 7.18-7.11 (m, 2H), 7.06 (d, J =7.8 Hz, IH), 6.87-6.81 (m, IH), 4.14 (q, J = 7.1 Hz, IH), 3.78 (s, 3H), 2.53 (s, 3H), 1.63 (d, J = 7.1 Hz, 3H). ¹³C NMR (75 MHz): 159.4, 158.5, 142.2, 136.0, 134.7, 129.4, 125.0, 124.1, 122.3, 117.8, 113.9, 89.7, 83.1, 55.2, 33.8, 24.5, 21.5.

Example 21 Preparation of 2-methyl-6-[(trimethylsilyl)ethvnyl1pyridine (compound 32):

6-bromo-2-methylpyridine (0.516 g, 3.0 mmol) ethynyl(trimethyl)silane was mixed with ethynyl(trimethyl)silane (0.324 g, 3.3 mmol, 1.10 eq.) and (PPh₃)₂PdCl₂ (0.063 g, 0.09 mmol, 0.03 eq.) and triethylamine (1.21g, 1.67 mL, 12.0 mmol, 4.0 eq.) was added at 0 °C.

The mixture was stirred for 0.5h at 0 °C before Cul (0.017 g, 0.09 mmol, 0.03 eq.) was added. The mixture was allowed to reach room temperature over 15 min. The mixture was stirred for 15 min. at room temperature before heating to 60 °C. Heating was maintained for 2h and finally the reaction mixture was left at room temperature for 16h. Phosphate buffer (5 mL, 0.2 M, pH 7) was added. Extracted with DCM (3 x 5 mL) by use of phase separator. The organic phases were combined and dried with sodium sulphate and evaporated. This gave 0.623g.

Flash chromatography on Si-gel by eluting with 5 %, later 10 % EtOAc in heptane was performed. 0.320 g pure material was isolated. (Yield: 56 %).

TLC: R_f (heptane/EtOAc 2:1) = 0.56.

1H NMR (300 MHz): 7.37 (t, J = 7.8 Hz, IH), 7.13 (d, J = 7.8 Hz, IH), 6.93 (d, J = 7.8 Hz,

IH), 2.40 (s, 3H), 0.14 (s, 9H).

¹³C NMR (75 MHz): 158.2, 141.8, 135.7, 124.0, 122.3, 103.5, 93.6, 24.2, -0.51.

Example 22

Preparation of 2-ethynyl-6-methylpyridine (compound 33):

2-methyl-6-[(trimethylsilyl)ethynyl]pyridine (1.67 g, 8.82 mmol) was dissolved in MeOH (10 mL) and DCM (20 mL) and anhydrous potassium carbonate (3.66 g, 26.5 mmol, 3.0 eq.) was added at room temperature. The mixture was stirred at room temperature for 2h and then concentrated in vacuo. Then the material was passed through a Si plug, 10 g, while rinsing with DCM. This gave 1.0 g (yield: 97 %) pure product. 1H NMR (400 MHz): 7.55 (t, J = 7.8 Hz, IH), 7.31 (d, J = 7.8 Hz, IH), 7.14 (d, J = 7.8 Hz, IH), 3.13 (s, lH), 2.56 (s, 3H).

Example 23

Preparation of 4-methyl- 1 -(6-methylpyridin-2-yl)pent- 1 -yn-3 -ol :

2-ethynyl-6-methylpyridine (0.040 g, 0.34 mmol) was dissolved in THF (2.5 mL) and the solution was cooled to -78 °C. Lithium bis(trimethylsilyl)amide (0.69 mL of a 1.0 M solution in THF, 2.0 eq.) was added and the solution was stirred for 0.5h at that temperature before 2-methylprόpanal (0.050 g, 0.063 mL, 0.69 mmol, 2.0 eq.) was added. After that time the temperature of the reaction mixture was allowed to reach room temperature and after stirring for 0.5h at that temperature, the mixture was passed through a SCX column, 5 g, while eluting with THF and MeOH, respectively. To elute the compound, the column was finally eluted with a saturated solution of ammonia in MeOH. This gave 0.080 g crude product that was used for the preparation of compound 35 (see below) without further purification. 1H NMR (400 MHz): 7.48 (t, J = 7.8 Hz, IH), 7.19 (d, J = 7.8 Hz, IH), 7.04 (d, J = 7.8 Hz,

IH), 4.38 (d, J = 5.9 Hz, IH), 2.50 (s, 3H), 1.96 (m, IH), 1.05 (d, J = 6.8 Hz, 3H), 1.02 (d,

J = 6.8 Hz, 3H).

¹³C NMR (100 MHz): 158.5, 142.0, 136.3, 124.1, 122.5, 89.6, 84.3, 67.5, 34.3, 24.1, 18.1,

17.7.

Example 24

Preparation of 2- [3 -(3 -chlorophenyl)-4-methylpent- 1 -yn- 1 - yl] -6-methylpyridine :

4-methyl- l-(6-methylpyridin-2-yl)pent-l -yn-3 -ol (0.080 g crude product, 0.34 mmol) was dissolved in DCM (2.5 mL) and triethylamine (0.73 g, 0.099 mL, 0.72 mmol, 2.1 eq.) was added. Methanesulfonyl chloride (0.63 g, 0.43 mL, 0.55 mmol, 1.6 eq.) was added dropwise at room temperature. Stirring at room termerature was continued for 3h. The reaction mixture was evaporated. The crude product was dissolved in DCM (2.5 mL) and

NEt₃ (0.70 g, 0.095 mL, 0.69 mmol, 2.0 eq.) and then 3-chlorobenzenethiol (0.10 g, 0.69 mmol, 2.0 eq.) was added at room temperature.

The reaction mixture was stirred at room temperature for 16h. A 1 M aqueous solution of potassium carbonate (25 mL) was added and the water phase was extracted with DCM (3 x

25 mL). The combined organic phases were dried with sodium sulphate and evaporated.

Flash chromatography on Si-gel (eluent: heptane/ AcOEt 100:0 to 80:20 with gradient) gave 0.005 g product, (yield: 4 %).

1H NMR (400 MHz): 7.56 (m, IH), 7.50 (t, J = 7.8, IH), 7.46-7.40 (m, IH), 7.26-7.22 (m, 2H), 7.16 (d, J = 7.8, IH), 7.08 (d, J = 7.8, IH), 3.97 (d, J = 5.4 Hz, IH), 2.54 (s, 3H), 2.13

(m, IH), 1.21 (d, J = 6.6 Hz, 3H), 1.19 (d, J = 6.6 Hz, 3H). Example 24

Preparation of 2- { 3 - 1Y3 ,4-dimethylphenyl)thio1prop- 1 - vn- 1 -yl ) -6-methylpyridine :

To 3,4-dimethylbenzenethiol (0.041 g, 0.30 mmol) in a glass vial was added 0.5 mL of a 0.6 M solution of 3-(6-methylpyridin-2-yl)prop-2-yn-l-yl methanesulfonate (0.068 g, 0.30 mmol, 1.0 eq.) in dichloromethane, followed by triethylamine (0.304 g, 0.418 mL, 3.0 mmol, 10.0 eq.). The vial was sealed and the reaction mixture was heated at 60 °C for 5h and then stirred at room temperature for 14h. The material was filtered through Celite and vacuum centrifuged. Purification was done by reverse phase column chromatography. Yield: 0.024 g (30 %).

MS ^m/_z: 268 (M+l)

Example 25

Preparation of 2-13 - [^"(3 , 5 -dimethylphenyDthio] rop- 1 -yn- 1 - yl -6-methylpyridine :

Prepared in analogy to example 24, but with 3,5-dimethylbenzenethiol as starting material. Yield: 0.034 g (42 %).

MS ^ra/_z: 268 (M+l)

Example 26 Preparation of methyl 2- { [3 -(6-methylpyridin-2-yl)prop-2-yn- 1 -yl]thio ) benzoate :

Prepared in analogy to example 24, but with methyl 2-mercaptobenzoate as starting material. Yield: 0.006 g (7 %).

MS ^m/_z: 298 (M+l)

Example 27

Preparation of 2-methyl-6-[3-(l-naphthylthio)prop-l-yn-l-yl1pyridine:

Prepared in analogy to example 24, but with naphthalene- 1 -thiol as starting material. Yield: 0.015 g (17 %).

MS ^m/_z: 290 (M+l)

Example 28 Preparation of 2-{3- (3-ethoxyphenyl)thio]prop-l-yn-l-yl>-6-methylpyridine:

Prepared in analogy to example 24, but with 3-ethoxybenzenethiol as starting material. Yield: 0.023 g (0.027 g).

MS ^m/_z: 284 (M+l)

Example 29

Preparation of 2- {3-[f4-fert-butylphenyl)thio]prop- 1 -yn- 1 -yl) -6-methylpyridine:

Prepared in analogy to example 24, but with 4-tert-butylbenzenethiol as starting material. Yield: 0.024 g (27 %).

MS ^m/_z: 296 (M+l)

Example 30 Preparation of l-(6-Methyl-pyridin-2-yl)-pent-l-yn-3-ol

l-(6-Methyl-pyridin-2-yl)-pent-l-yn-3-ol was prepared according to the method in example 23 using 2-ethynyl-6-methylpyridine and propionaldehyde as starting materials.

1H NMR (400 MHz): 7.47 (t, 1 H), 7.19 (d, 1 H), 7.03 (d, 1 H), 4.55 (t, 1 H), 4.13 (br s, 1 H), 2.49 (s, 3 H), 1.81 (m, 2 H), 1.03 (t, 3 H).

Example 31 Preparation of 2- {3-r(3-chlorophenyl)thio pent- 1 -yn- 1 -yl} -6-methylpyridine: The alcohol l-(6-Methyl-pyridin-2-yl)-pent-l-yn-3-ol (74.7 mg, 0.43 mmol) and triethylamine (173 mg, 1.70 mmol) were dissolved in DCM (5.0 mL) and added mesyl chloride (73.3 mg, 0.64 mmol) dropwise. After 1 h w-chlorothiophenol (123 mg, 0.85 mmol) added the solution. The mixture was stirred overnight at room temperature. Hereafter K₂CO₃ (1.0 M, 25 mL) was added and the solution was extracted with DCM. The organic phases were pooled, dried (Na₂SO₄), filtrated and evaporated. The resulting crude product was subjected to flash chromatography on silica gel with gradient (heptane/EtOAc 1 :0 to 3:2) and preparative HPLC (Cs kromasil), which afforded the pure product 12.1 mg (9.4 %).

1H-NMR (400 MHz): 7.57 (m, IH), 7.49 (m, IH), 7.42 (m, IH), 7.24 (m, 2H), 7.14 (d, IH), 7.06 (d, IH), 3.98 (t, IH), 2.53 (s, 3H), 1.91 (m, 2H), 1.17 (t, 3H). ¹³C-NMR (400 MHz): 159.0, 142.5, 136.5, 136.2, 134.6, 132.7, 131.1, 130.0, 128.0, 124.6, 122.8, 88.5, 84.8, 41.1, 28.5, 24.8, 12.1.

Biological evaluation

Functional assessment of mGluR5 antagonism in cell lines expressing mGluR5d

The properties of the compounds of the invention can be analyzed using standard assays for pharmacological activity. Examples of glutamate receptor assays are well known in the art as described in for example Aramori et al, Neuron 8:757 (1992), Tanabe et al, Neuron 8:169 (1992), Miller et al, J. Neuroscience 15: 6103 (1995), Balazs, et al, J.

Neurochemistry 69:151 (1997). The methodology described in these publications is incorporated herein by reference. Conveniently, the compounds of the invention can be studied by means of an assay (FLIPR) that measures the mobilization of intracellular calcium, [Ca²⁺]i in cells expressing mGluR5 or another assay (IP3) that measures inositol phosphate turnover. FLIPR Assay

Cells expressing human mGluR5d as described in WO97/05252 are seeded at a density of 100,000 cells per well on collagen coated clear bottom 96-well plates with black sides and experiments are done 24 h following seeding. All assays are done in a buffer containing 127 mM NaCl, 5 mM KCl, 2 mM MgCl₂, 0.7 mM NaH₂PO₄, 2 mM CaCl₂, 0.422 mg/ml NaHCO₃, 2.4 mg/ml HEPES, 1.8 mg/ml glucose and 1 mg/ml BSA Fraction IV (pH 7.4). Cell cultures in the 96-well plates are loaded for 60 minutes in the above mentioned buffer containing 4 μM of the acetoxymethyl ester form of the fluorescent calcium indicator fluo- 3 (Molecular Probes, Eugene, Oregon) in 0.01%> pluronic acid (a proprietary, non-ionic surfactant polyol - CAS Number 9003-11-6). Following the loading period the fluo-3 buffer is removed and replaced with fresh assay buffer. FLIPR experiments are done using a laser setting of 0.800 W and a 0.4 second CCD camera shutter speed with excitation and emission wavelengths of 488 nm and 562 nm, respectively. Each experiment is initiated with 160 μl of buffer present in each well of the cell plate. A 40 μl addition from the antagonist plate was followed by a 50 μL addition from the agonist plate. A 90 second interval separates the antagonist and agonist additions. The fluorescence signal is sampled 50 times at 1 second intervals followed by 3 samples at 5 second intervals immediately after each of the two additions. Responses are measured as the difference between the peak height of the response to agonist, less the background fluorescence within the sample period. IC₅₀ determinations are made using a linear least squares fitting program.

IP 3 Assay

An additional functional assay for mGluR5d is described in WO97/05252 and is based on phosphatidylinositol turnover. Receptor activation stimulates phospholipase C activity and leads to increased formation of inositol l,4,5,triphosphate (IP₃).

GHEK stably expressing the human mGluR5d are seeded onto 24 well poly-L-lysine coated plates at 40 x 10⁴ cells /well in media containing 1 μCi/well [3H] myo-inositol. Cells were incubated overnight (16 h), then washed three times and incubated for 1 h at 37°C in HEPES buffered saline (146 mM NaCl, 4.2 mM KCl, 0.5 mM MgCl₂, 0.1% glucose, 20 mM HEPES, pH 7.4) supplemented with 1 unit/ml glutamate pyruvate transaminase and 2 mM pyruvate. Cells are washed once in HEPES buffered saline and pre-incubated for 10 min in HEPES buffered saline containing 10 mM LiCl. Compounds are incubated in duplicate at 37°C for 15 min, then either glutamate (80 μM) or DHPG (30 μM) is added and incubated for an additional 30 min. The reaction is terminated by the addition of 0.5 ml perchloric acid (5%) on ice, with incubation at 4°C for at least 30 min. Samples are collected in 15 ml polyproplylene tubes and inositol phosphates are separated using ion-exchange resin (Dowex AG1-X8 formate form, 200-400 mesh, BIORAD) columns. Inositol phosphate separation was done by first eluting glycero phosphatidyl inositol with 8 ml 30 mM ammonium formate. Next, total inositol phosphates is eluted with 8 ml 700 mM ammonium formate / 100 mM formic acid and collected in scintillation vials. This eluate is then mixed with 8 ml of scintillant and [3H] inositol incorporation is determined by scintillation counting. The dpm counts from the duplicate samples are plotted and IC₅₀ determinations are generated using a linear least squares fitting program.

Abbreviations

BSA Bovine Serum Albumin

CCD Charge Coupled Device

CRC Concentration Response Curve

DHPG 3,5-dihydroxyphenylglycine DPM Disintegrations per Minute

EDTA Ethylene Diamine Tetraacetic Acid

FLIPR Fluorometric Imaging Plate reader

GHEK GLAST-containing Human Embrionic Kidney

GLAST glutamate/aspartate transporter HEPES 4-(2-hydroxyethyl)-l~piperazineethanesulfonic acid (buffer)

IP₃ inositol triphosphate

Generally, the compounds are active in the assay above with IC₅₀ values less than 10 000 nM. In one aspect of the invention, the IC₅₀ value is less than 1 μM. In a further aspect of the invention, the IC₅₀ value is less than 100 nM. Examples of IC₅₀ values for individual compounds is given below:

Screening for compounds active against TLESR

Adult Labrador retrievers of both genders, trained to stand in a Pavlov sling, are used. Mucosa-to-skin esophagostomies are formed and the dogs are allowed to recover completely before any experiments are done.

Motility measurement

In brief, after fasting for approximately 17 h with free supply of water, a multilumen sleeve/sidehole assembly (Dentsleeve, Adelaide, South Australia) is introduced through the esophagostomy to measure gastric, lower esophageal sphincter (LES) and esophageal pressures. The assembly is perfused with water using a low-compliance manometric perfusion pump (Dentsleeve, Adelaide, South Australia). An air-perfused tube is passed in the oral direction to measure swallows, and an antimony electrode monitored pH, 3 cm above the LES. All signals are amplified and acquired on a personal computer at 10 Hz.

When a baseline measurement free from fasting gastric/LES phase III motor activity has been obtained, placebo (0.9% NaCl) or test compound is administered intravenously (i.v., 0.5 ml/kg) in a foreleg vein. Ten min after i.v. administration, a nutrient meal (10% peptone, 5% D-glucose, 5% Intralipid, pH 3.0) is infused into the stomach through the central lumen of the assembly at 100 ml/min to a final volume of 30 ml/kg. The infusion of the nutrient meal is followed by air infusion at a rate of 500 ml/min until an intragastric pressure of lO±l mmHg is obtained. The pressure is then maintained at this level throughout the experiment using the infusion pump for further air infusion or for venting air from the stomach. The experimental time from start of nutrient infusion to end of air insufflation is 45 min. The procedure has been validated as a reliable means of triggering TLESRs.

TLESRs is defined as a decrease in lower esophageal sphincter pressure (with reference to intragastric pressure) at a rate of >1 mmHg/s. The relaxation should not be preceded by a pharyngeal signal <2s before its onset in which case the relaxation is classified as swallow- induced. The pressure difference between the LES and the stomach should be less than 2 mmHg, and the duration of the complete relaxation longer than 1 s.

Claims

1. A compound of formula I

wherein R¹ is selected from hydrogen, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, aryl and heteroaryl, wherein the aryl or heteroaryl may be substituted by C₁-C₄ alkyl; R² is selected from hydrogen and C_!-C₄ alkyl; R³ is selected from hydrogen, C₁-C₄ alkyl, F, CF₃, CHF₂ and CH₂F; R⁴ is selected from hydrogen, F, CF₃, CHF , CH₂F and CH₃; R⁵ is selected from hydrogen and F; R⁵ is selected from hydrogen and F; Q is S, NH or NCH₃, optionally substituted by C₁-C₄ alkyl; Y¹ is selected from hydrogen; halogen; nitrile; C₁-C₄ alkoxy; C₁-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; benzyloxy; nitro in the meta or para position; and C1-C₄ alkyl ester; Y² is selected from hydrogen; halogen; nitrile; C₁-C₄ alkoxy; Ci-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; and -Q. alkyl ester; Y³ is selected from hydrogen; halogen; nitrile; C₁-C₄ alkoxy; C1-C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom; and -C₄ alkyl ester; or 1 9 Y and Y may form an aromatic or non-aromatic ring, optionally substituted by halogen, nitrile, C₁-C₄ alkoxy, -C₄ alkyl wherein one or more of the hydrogen atoms of the alkyl group may be substituted for a fluorine atom, benzyloxy or C₁-C₄ alkyl ester; as well as pharmaceutically acceptable salts, hydrates, isoforms and/or optical isomers thereof.

2. A compound of formula I

wherein R¹ is selected from hydrogen, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, aryl and heteroaryl, wherein the aryl or heteroaryl may be substituted by C₁-C₄ alkyl; R² is selected from hydrogen and C₁-C₄ alkyl; R³ is selected from hydrogen, C₁-C₄ alkyl, F, CF₃, CHF₂ and CH₂F; R⁴ is selected from hydrogen, F, CF₃, CHF₂, CH₂F and CH₃; R⁵ is selected from hydrogen and F; R⁵ is selected from hydrogen and F; Q is S, NH or NCH₃, optionally substituted by C₁-C₄ alkyl; Y¹ is selected from hydrogen, halogen, nitrile, C₁-C₄ alkoxy, and C₁-C₄ alkyl Y² is selected from hydrogen, halogen, nitrile, C_Ϊ-C₄ alkoxy, and Ci-C₄ alkyl Y is selected from hydrogen, halogen, nitrile, C₁-C₄ alkoxy, and C₁-C₄ alkyl as well as pharmaceutically acceptable salts, hydrates, isoforms and/or optical isomers thereof.

3. A compound according to formula I of claim 1 or 2, wherein R¹ is hydrogen or Ci-C₃ alkyl; R is hydrogen; R³ is selected from hydrogen and methyl; R⁴ is hydrogen; R⁵ is hydrogen; R⁶ is hydrogen; Q is S, NH orNCH₃, optionally substituted by C₁-C₄ alkyl; Y¹ is selected from hydrogen, chloro, 0^₂ alkoxy, and -C₂ alkyl; and Y² is selected from hydrogen, chloro, - alkoxy, and C_!-C₂ alkyl; and Y³ is hydrogen.

4. A compound according to claim 1 selected from N-[3-(6-methylpyridin-2-yl)prop- 2-yn-l-yl] aniline; N-benzyl-3-(6-methylpyridin-2-yl)prop-2-yn- 1 -amine; N-methyl-N-[3-(6-methylpyridin-2-yl)prop-2-yn-l-yl]aniline; (3 -methylphenyl) [3 -(6-methylpyridin-2-yl)prop-2-yn- 1 -yl] amine; (3-methoxyphenyl)[3-(6-methylpyridin-2-yl)prop-2-yn-l-yl]amine; (3 -chlorophenyl) [3 -(6-methylpyridin-2-yl)prop-2-yn- 1 -yl] amine; [(3-phenylprop-2-yn- 1 -yl)thio]benzene; 1 -methoxy-3-[(3-phenylprop-2-yn- 1 -yl)thio]benzene; 2- { 3 - [(3 -chlorophenyl)thio]but- 1 -yn- 1 -yl } -6-methylpyridine; 2-methyl-6- [3 -(phenylthio)prop- 1 -yn- 1 -yl]pyridine ; 2- { 3 - [(3 -chlorophenyl)thio] prop- 1 -yn- 1 -yl } -6-methylpyridine ; 2-{3-[(3-methoxyphenyl)thio]prop-l-yn-l-yl}-6-methylpyridine; 2-methyl-6-{3-[(3-methylphenyl)thio]prop-l-yn-l-yl}pyridine; (i?ιS⁾-2-{3-[(3-methoxyphenyl)thio]but-l-yn-l-yl}-6-methylpyridine; 2- [3 -(3-chlorophenyl)-4-methylpent- 1 -yn- 1 -yl] -6-methylpyridine; 2-{3-[(3,4-dimethylphenyl)thio]prop-l-yn-l-yl}-6-methylpyridine; 2- {3-[(3,5-dimethylphenyl)thio]prop- 1 -yn- 1 -yl} -6-methylpyridine; 2- { 3 - [(3 -ethoxyphenyl)thio]prop- 1 -yn- 1 -yl } -6-methylpyridine; 2- { 3 - [(4-tert-butylphenyl)thio]prop- 1 -yn- 1 -yl } -6-methylpyridine ; and 2- { 3 - [(3 -chlorophenyl)thio] pent- 1 -yn- 1 -yl } -6-methylpyridine .

5. A compound according to any one of claims 1-4 for use in therapy.

6. A compound according to claim 5, wherein the therapy is treatment or prevention of gastroesophageal reflux disease.

7. Use of a compound of formula I of claim 1 or 2, or a pharmaceutically acceptable salt or an optical isomer thereof, for the manufacture of a medicament for the inhibition of transient lower esophageal sphincter relaxations.

8. Use of a compound of formula I of claim 1 or 2, or a pharmaceutically acceptable salt or an optical isomer thereof, for the manufacture of a medicament for treatment or prevention of gastroesophageal reflux disease.

9. A pharmaceutical composition comprising a compound of formula I of claim 1 or 2 as an active ingredient, together with a pharmacologically and pharmaceutically acceptable carrier.

10. A process for the preparation of a compound of formula I, whereby a coupling reaction of the aryl bromide A

A and the alcohol B

B is performed in the presence of a base such as triethyl amine, giving the alcohol C

which is then converted into the mesylate D

and reacted with primary or secondary amines or a thiol nucleophile, and wherein

R² is selected from hydrogen and C1-C4 alkyl;

R³ is selected from hydrogen, C₁-C₄ alkyl, F, CF₃, CHF₂ and CH₂F;

R⁴ is selected from hydrogen, F, CF₃, CHF₂, CH F and CH₃;

R⁵ is selected from hydrogen and F;

R⁶ is selected from hydrogen and F.

11. A compound selected from (.ft -4-(6-methylpyridin-2-yl)but-3-yn-2-ol; 4-methyl- l-(6-methylpyridin-2-yl)pent-l-yn-3-ol; Methanesulfonic acid 3-pyridin-2-yl-prop- 2-ynyl ester; and l-(6-Methyl-pyridin-2-yl)-pent-l-yn-3-ol.

12. A method for the inhibition of transient lower esophageal sphincter relaxations whereby an effective amount of a compound of formula I of claim 1 or 2 is administered to a subject in need of such inhibition.

13. A method for the treatment or prevention of gastroesophageal reflux disease, whereby an effective amount of a compound of formula I of claim 1 or 2 is administered to a subject in need of such treatment or prevention.