SI9300674A - 2-(2-furyl)-5-(2-(morpholino)etylamino) (1,2,4)triazolo(1,5-a) (1,3,5)triazine-7-amin for use as an adenosinic antagonist - Google Patents

Abstract

2-(2-Furyl)-5-[2-(morpholino)ethylamino][1,2,4]triazolo[1,5-a][1,3,5]t riazine-7-amine and the pharmaceutically acceptable salts thereof, which are selective A2a adenosine antagonists. Also disclosed are pharmaceutical compositions comprising the compounds and processes for their preparation.

Description

Zeneca Limited

2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] -triazine-7-amine for use as adenosine antagonist

The present invention relates to novel azole derivatives, more particularly to the novel 2-heteroaryltriazolo [1,5-a] [1,3,5] triazine and its pharmaceutically acceptable salts, which have useful pharmacological properties (and in particular antagonize the action of adenosine, such as e.g., vasodilation). The present invention also includes pharmaceutical compositions containing novel azole derivatives for use in the treatment of certain diseases and disorders affecting the cardiac, peripheral or cerebral vascular system in mammals. Methods for the manufacture and formulation of new azole derivatives are also included.

Theophylline (1,3-dimethylxanthine) is used clinically (usually as its ethylenediamine salt, also known as aminophylline) as a respiratory stimulant, a centrally active stimulant, a bronchodilator, a cardiac stimulant and as a diuretic. This diversity of clinical uses is an indication of the range of pharmacological actions attributed to theophylline. These include phosphodiesterase inhibition, adenosine receptor antagonism, calcium mobilization in cells, and catecholamine release. Recently, theophylline has also been reported to be useful in the treatment of myocardial ischemia (Masheri et al., The Lancet, 1989, 683-686), skeletal muscle ischemia (Picano et al., Angiology, 1989, 40, 1035-1039), and cerebral ischemia (Skinhoj et al., Acta. Neurol. Scand., 1970, 46, 129-140). It is believed that the beneficial effects of theophylline in these ischemic disorders are due to the reduction or the preventing a phenomenon known as vascular steal based on the ability of a compound to antagonize adenosine action by blocking adenosine receptors that mediate metabolism-related vasodilation.

The phenomenon of a vascular site can occur if the main artery supplying a particular vascular region is partially or completely closed, resulting in ischemia. In this condition, the compromised vascular cortex expands and blood flow is maintained either because of increased flow through the constricted vessel or because of increased flow through parallel vessels. In any case, the result of increased metabolic efficiency in adjacent vascular tracts is the release of mediators, e.g. adenosine causing expansions that result in limited blood flow to the compromised vascular regions stolen by these adjacent areas. The loss of blood from compromised vascular regions to those with normal flow, due to the phenomenon of vascular locus, further reduces blood flow in the compromised vascular area.

Due to the variety of pharmacological properties that theophylline has, its use in the treatment or prevention of occlusive diseases and vascular conditions is difficult. Therefore, its additional function as a phosphodiesterase inhibitor results in stimulation of the heart, which is detrimental to patients with myocardial ischemia. Furthermore, due to the low efficacy of theophylline, dose levels that are therapeutically useful are close to those that can cause serious central side effects.

European Patent Application no. EP-A1-459702 discloses certain 2-heteroarylthriazolo [1,2,4] triazolo [1,5-a] [1,3,5] triazines and pyrazolo [2,3-a] [1,3,5] triazines, which are effective antagonists of adenosine actions, in particular its vasodilatory actions.

The compound 2-heteroaryl-triazolo [1,2,4] triazolo [1,5-a] [1,3,5] triazine has now been found to have particularly desirable pharmacological properties.

Thus, the present invention provides a compound

2- (2-furyl) -5- [2- (morpholino) -ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] -triazine-7amine and its pharmaceutically acceptable salts .

The compound of the invention may be represented by Formula I, which is hereinafter referred to, together with other formulas, which are referred to herein by Roman numerals. We then refer to the compound of the invention as the compound of formula I.

The compound of formula I was found to be a selective adenosine antagonist at the adenosine A2a receptor, a receptor that mediates the vasodilatory action of adenosine. It has also been found to be particularly well soluble in water and surprisingly effective in vivo, with oral or parenteral administration.

This combination of features is unexpected and especially desirable.

Particularly pharmaceutically acceptable salts of the compounds of formula I include e.g. salts with acids that give physiologically acceptable anions, e.g. salts with acids such as e.g. hydrochloric, hydrobromic, sulfuric, phosphoric, methanesulfonic, trifluoroacetic, oxalic, citric and maleic acids.

According to another aspect, the present invention provides a process for the preparation of a compound of formula I or a pharmaceutically acceptable salt thereof, comprising:

(a) reacting a compound of formula II in which Z is a suitable leaving group, e.g. hydrocarbylsulfonyl such as e.g. (1-6C) alkylsulfonyl (such as methylsulfonyl or ethylsulfonyl), aryloxy such as e.g. phenoxy or halogen (such as chloro or bromo), with N- (2aminoethyl) morpholine or a salt thereof.

The reaction may conveniently be carried out at a temperature in the range of 0 to 120 ° C, e.g. Suitable reaction solvents include nitriles, such as e.g. acetonitrile; alcohols, such as ethanol or propanol; ethers, such as e.g. tetrahydrofuran, 1,2 dimethoxyethane or t-butyl methyl ether; and amides, such as e.g. Ν, Ν-dimethylformamide.

Examples of N- (2-aminoethyl) morpholine salts include alkali metal salts, such as e.g. lithium, sodium and potassium salts.

The starting materials of formula II can be obtained by the procedures described in EP-A1-459702. So you can e.g. those compounds of formula II in which Z is alkylsulphonyl may be prepared by oxidation of the corresponding alkylthio derivative of formula III in which R ¹ is (l-6C) alkylthio, with the use of a conventional oxidant, such as. peracids, e.g. peracetic, perbenzoic or chloroperbenzoic acids, suitable at a temperature in the range, e.g. from 0 to 40 ° C and in a suitable solvent or diluent, such as e.g. dichloromethane or chloroform. Similarly, those compounds of formula II in which Z is chloro or bromo can be obtained e.g. by reacting an alkylthio derivative of Formula III (especially in which R ^{1 is} methylthio or ethylthio) with chlorine or bromine in the presence of hydrogen chloride, or hydrogen bromide at a temperature generally in the range of e.g. -20 to 15 ° C and generally in an inert polar solvent, such as e.g. ethanol or 2-propanol.

Initial alkylthio starting materials of formula III can be obtained e.g. by reacting a compound of formula IV with the corresponding dialkyl N-cyanodithioiminocarbonate of formula V at elevated temperature in e.g. from 60 to 200 ° C, suitable as a melt without the presence of solvent or diluent.

The starting compounds of formula IV can be obtained e.g. by reaction of the corresponding iminoether of the formula Q.C (OR) = NH in which Q is 2-furyl and R is (1-4C) alkyl, such as e.g. methyl or ethyl (formed from the corresponding nitrile of the formula Q.CN and the alcohol of the formula R.OH in the presence of anhydrous acid such as hydrogen chloride) with an aminoguanidine salt (especially nitrate) in the presence of a suitable base, such as e.g. pyridine or

2.6-lutidine, which can also be used as a reaction solvent, at a temperature in the range of e.g. 60-120 ° C.

Compounds of formula II in which the Z phenoxy group can be conveniently prepared by reaction of 5,7-diphenoxy [1,2,4] triazolo [1,5-a] [1,3,5] -triazine with ammonia. The process is conveniently carried out at a temperature in the range of e.g. from 0 to 100 ° C. Suitable solvents for the process include alcohols, such as e.g. ethanol and ethers, such as e.g. tetrahydrofuran. A solution of ammonia in alcohol, such as e.g. ethanol, at room temperature.

5.7-diphenoxy [1,2,4] triazolo [1,5-a] [1,3,5] -triazine starting materials can be obtained by dehydrating a compound of formula VI in which each Z is a phenoxy group. Suitable dehydrating agents include e.g. silyl esters of polyphosphoic acid, such as e.g. polyphosphoric acid trimethylsilylester; phosphorus pentoxide and sulfonyl chlorides such as e.g. p-toluenesulfonyl chloride. The dehydration is conveniently carried out at a temperature in the range of 60 to 180 ° C. When using polyphosphoic acid silylester or phosphorus pentoxide, suitable solvents are aromatic hydrocarbons such as e.g. xylene or toluene. When sulfonyl chloride is used, suitable solvents are tertiary amines such as e.g. pyridine.

Compounds of formula VI can be obtained by reacting a compound of formula VII in which each is

With a phenoxy group, with a compound of the formula QCOHal in which Hal is a halogen atom, such as e.g. chlorine atom. The reaction is conveniently carried out at a temperature in the range of -10 to

41 ° C. Suitable reaction solvents include halogenated hydrocarbons such as e.g. dichloromethane.

Compounds of formula VII can be obtained by reacting a compound of formula VIII in which each Z is a phenoxy group with hydrazine.

Alternatively, compounds of formula VI can be obtained by reacting a compound of formula VIII in which each Z is a phenoxy group, with a compound of formula QCONHNH ₂ .

According to another aspect of the present invention, a different process is provided for the preparation of a compound of Formula I or a pharmaceutically acceptable salt thereof, comprising (b) reacting a compound of Formula IX in which Z ^{1 is a} suitable leaving group, e.g. hydrocarbylsulfonyloxy (such as p-toluenesulfonyloxy) or halogen (such as chloro or bromo), with morpholine.

The process is conveniently carried out at a temperature in the range of e.g. from 10 to 120 ° C, more preferably in the range from 30 to 80 ° C. Suitable reaction solvents include, e.g. alcohols, such as ethanol, nitriles, such as e.g. acetonitrile, amides such as e.g. N, N-dimethylformamide and ethers such as e.g. tetrahydrofuran, 1,2-dimethoxyethane and t-butyl methyl ether.

The starting materials of formula IX can be obtained by standard procedures well known in the art from the corresponding compound of formula IX in which Z ^{1 is a} hydroxy group. This compound can be prepared by reacting a compound of formula II with 2-aminoethanol according to the procedure (a) described previously.

According to another aspect of the present invention, a different process is provided for the preparation of a compound of formula I or a pharmaceutically acceptable salt thereof, comprising (c) reacting a compound of formula X, wherein Z ^{2 is a} suitable leaving group, e.g. aryloxy (such as phenoxy), alkylthio (such as methylthio) or halogen (such as chloro or bromo), with ammonia.

The reaction is conveniently carried out at a temperature in the range, e.g. from 0 to 100 ° C. Suitable solvents for the process include water, alcohols, e.g. ethanol and ethers, such as e.g.

tetrahydrofuran.

The starting materials of formula X can be obtained by dehydrating a compound of formula XI. Suitable dehydrating agents include, e.g. phosphorus pentoxide, polyester phosphorylate silylester such as e.g. polyphosphoric acid trimethylsilylester or sulfonyl chloride, such as e.g. p-toluenesulfonyl chloride. The dehydration is conveniently carried out at a temperature in the range of 60 to 180 ° C. When phosphorus pentoxide is used, suitable solvents are aromatic hydrocarbons such as e.g. xylene or toluene. When sulfonyl chloride is used, suitable solvents are tertiary amines such as e.g. pyridine.

Compounds of formula XI can be obtained by reacting a compound of formula VI with N- (2aminoethyl) -morpholine.

According to another aspect of the present invention, a different process is provided for the preparation of a compound of formula I or a pharmaceutically acceptable salt thereof, comprising (d) dehydrating a compound of formula XII.

Suitable dehydrating agents include e.g. silyl esters of polyphosphoic acid, such as e.g. polyphosphoric acid trimethylsilylester, phosphorus pentoxide, and sulfonyl chlorides such as e.g. p-toluenesulfonyl chloride. The dehydration is conveniently carried out at a temperature in the range of 60 to 180 ° C. When polyphosphoric acid or phosphorus pentoxide silylester is used, suitable solvents include aromatic hydrocarbons such as e.g. xylene or toluene. When sulfonyl chloride is used, suitable solvents include tertiary amines such as e.g. pyridine.

The starting materials of formula XII can be prepared from the compound of formula VIII by reaction with ammonia, N- (2-aminoethyl) morpholine and 2-furoic acid hydrazide in any convenient way.

If a pharmaceutically acceptable salt is then required, it can be obtained, e.g. by reacting a compound of formula I with a suitable acid or base which gives a physiologically acceptable ion, or by another suitable process.

As stated previously, the compounds of the invention have the property of antagonizing one or more physiological actions of adenosine and are valuable in the treatment of diseases and medical conditions affecting the cardiac, peripheral and / or cerebral vascular system in mammals, such as e.g. ischemic heart disease (angina), peripheral vascular disease (claudication) and cerebral ischemia. The compounds are also useful in the treatment of migraines.

The effects of compounds of formula I as adenosine receptor antagonists can be demonstrated by one or more of the following standard in vitro and / or in vivo assays.

(a) Adenosine receptor affinity test

This test includes the ability of the test adenosine antagonist to displace the known adenosine mimetic agent [ ³ H] -N-ethylcarboxamidoadenosine (NECA) from binding sites to membrane preparations derived from rat PC12 pheochromocytoma cell line (available from Beatson Institute, Glasgow). The basic procedure is described by Williams et al. (J. Neurochemistry, 1987, 48 (2), 498-502).

The membrane preparation is obtained as follows:

The frozen PC12 cell pellets were washed twice with ice-cold buffered saline and the cells were recovered by centrifugation (1500 g) at 3 ° C. The separated cells were then suspended in hypotonic solution (distilled water), allowed to stand on ice for 30 minutes, and then carefully homogenized, using a standard high speed homogenizer, periodically cooled with ice to give a fine suspension. The homogenate was centrifuged (48,000 g) and the pellet was resuspended in 50 mM tris-HCl buffer, pH 7.4 containing adenosine deaminase (5 units / ml, type VII, from calf intestinal mucosa, available from Sigma Chemical Corporation, under reference no. A1280). The mixture was then incubated at 37 ° C. After 20 minutes, complete the reaction by dilution with ice-cold buffer and transfer to ice. The resulting cell membrane-containing substance was recovered by centrifugation and washed with resuspension in buffer and re-centrifuged. The produced pellet is then resuspended in ice-cold buffer using a manually operated homogenizer. The resulting membrane suspension was frozen and stored in liquid nitrogen for as long as necessary.

Binding studies were performed in microtiter plates, the test mixture being puffed into 50 mM tris-HCl, pH 7.4 at room temperature. The test compound was dissolved in dimethylsulfoxide (DMSO) and then diluted with test buffer to obtain the test solutions. (The final DMSO concentration should not exceed 1% vol., Since this value no longer affects the radioligand binding to the membrane receptor).

The incubations were performed at 30 ° C for 90 minutes in a total volume of 150 μ \, comprising test solution or buffer (50 μϊ), NECA treated with rubbing (50 μϊ) and membrane suspension (50 μϊ). After incubation, the samples were quickly filtered through glass fiber covers and the filter covers washed to remove nonreceptor bound radioligand. Receptor-bound radioligand trapped on filter entanglements are then determined by liquid scintillation counting. Filtration and washing are carried out with a conventional vacuum filtration cell collector.

Specific binding (defined as the difference between total binding and nonspecific binding) in the presence of a specific test compound is determined and compared with a control value. The results are conveniently expressed as the negative logarithm of the concentration required to cause a 50% displacement of control specific binding (pIC ₅₀ ).

The compound of Example 1 has a pIC of _S0 7.6. Using the same test procedure, the known 1,3-dimethylxanthine compound typically has a pIC _{50 of} about 5.

(b) Atrial bradycardic test in guinea pig

This test is also described by Collis et al. (Britisch J. Pharmacology, 1989, 97, 1274-1278) and includes the ability of the test compound to antagonize the bradycardic effect of the adenosine mimetic, 2-chloroadenosine, in the preparation of a fluttering guinea pig atrium, an effect mediated by the adenosine receptor known as A ₁ .

The atrial vapor preparation can be obtained as follows:

Atrial fumes are obtained from guinea pig (Dunkin Hartley genus, 250-400 g males) and are placed in organic baths containing oxygenated Krebs buffer solution 95% O ₂ ; 5% CO ₂ ) at 37 ° C. The spontaneously flickering atrium was then placed under a stationary load of 1 g and allowed to equilibrate for 50 minutes by continuous pouring. The overflow was then stopped and then adenosine deaminase (1 unit / ml) was added to prevent the accumulation of endogenously produced adenosine. After balancing for 15 minutes, a cumulative dose corresponding to the curve for the adenosine mimetic, 2-chloroadenosine (10 M to 10 M) was administered to produce a maximum slowing of the atrial beat. After washing for 30 minutes, the adenosine deaminase was again placed in a bath, which was allowed to equilibrate for 15 minutes. Then a 10 ' ⁵ M solution of the test compound in DMSO was added to the bath and incubated for 30 minutes. Any effect on the blink rate due to the test compound is recorded before repeating the dose response curve

2-chloroadenosine. Compounds that are adenosine antagonists reduce the 2-chloroadenosine response.

Test compounds are evaluated by comparing dose response curves for 2-chloroadenosine alone with those obtained in the presence of the compound. Competitive adenosine antagonists produce a parallel shift in the 2-chloroadenosine dose response curve. The dose ratio (DR) is calculated from the ratio of 2-chloroadenosine concentration that results in a 50% reduction in atrial beat (ED ₅₀ ) in the presence of the test compound and is divided by the ED ₅₀ concentration of 2-chloroadenosine without the test compound for each atrial pair. pA2 is then calculated using standard calculation techniques. The compound of Example 1 has a pA2 of 5.5. The known 1,3-dimethylxanthine compound typically has a pA2 of about 5.

Comparing the pA2 value obtained for the compound of Example 1 in this assay with the pIC _{5 ()} obtained for the same compound in assay (a), it can be seen that the compound is more than 100 times more selective for the receptor than for the receptor. This is particularly desirable because adenosine antagonism at the Aj receptor is combined with effects on the kidney, adipocytes, heart, and central nervous system.

(c) Anesthetized dog test

This test evaluates the effects of the test compound on antagonizing the actions of adenosine in reducing heart rate and increasing vasodilation (as measured by a decrease in perfusion pressure in the hind limb).

Beagle dogs (12 - 18 kg) were anesthetized with sodium pentobarbitone (50 mg / kg, iv). The following blood vessels are catheterized: right jugular vein (for infusion of anesthetic at about 112 mg per hour as 3 mg / ml isotonic saline), right brachial vein (for administration of drugs and test agents), right brachial artery (for measurement of systemic blood pressure and pulse rate) and left carotid artery (for administration of adenosine to the left ventricle). Both nerves, the right femoral and the ishiadic nerve are ligated and separated. A bolus injection of 1250 units of heparin is given before perfusion of the right hind limb at constant blood flow with iliac artery blood. Bind the right leg just below the ankle. Xamoterol (1 mg / kg) was then administered to the animals to stabilize the heart rate at high levels and nitrobenzylthioinosine (NBTI, 0.5 mg / kg) to inhibit adenosine uptake. The animal was sensitized to adenosine during equilibration time, according to NBTI, by performing a dose response curve (DRC). During this time, any gas imbalance or blood pH is corrected. An adenosine control DRC was performed, followed by up to 3 DRCs after cumulative administration of the test compound, which was administered in a mixture of 50% vol / vol polyethylene glycol (PGE) 400 and 0.1 M sodium hydroxide. Each DRC is performed 15 minutes after administration of the test compound and after the measured parameters of heart rate and perfusion pressure of the hind limb return to a stable state. Similarly, blood gases and pH are maintained within physiological limits throughout the evaluation.

The amount of adenosine required to cause a 50% drop in the measured parameters (ED ₅₀ ), ie heart rate and perfusion pressure of the hind limb, was calculated for each dose of test compound and a Schild diagram was drawn up. From this diagram, we determine the K _B value for the antagonism of the heart rate response and the vasodilatory response to adenosine. The compound of Example 1 was found to have a K _B in the range of 0.01 to 0.24 mg / kg for antagonism of the vasodilatory response to adenosine, without any indication of toxicity or other adverse characteristics at doses several times greater than the minimum effective dose.

(d) A conscious cat's blood pressure test

With this assay, we evaluate the ability of the test compound to antagonize the diastolic blood pressure drop induced by adenosine administration.

Male cats (2-4.5 kg) are selected and trained to sit quietly and quietly in the open front boxes. Suitable animals are then prepared for chronic catheterization. Anesthesia was performed with alfaxaxone / alfadolone (18 mg, iv) and maintained with oxygen containing halothane (1.5-3%). The dorsal and ventral regions of the neck are excised and then wiped with an alcohol / chlorhexidine / water solution (70/20/10% vol / vol). The right carotid artery (to measure systemic arterial blood pressure) and the right jugular vein (to administer adenosine or test substance) are catheterized and exposed. Sew both catheters and close the incision with a suture. Let the cats regain consciousness before moving them to the animals' individual housing areas. After surgery, allow a minimum of 1 week recovery time before using any of the animals for the test.

All surgical procedures are performed using aseptic techniques, and all instruments are steam sterilized before use. Immerse the catheters in an alcohol / chlorhexidine solution for at least 1 hour before implantation, then rinse the catheters with sterile saline to avoid alcohol / chlorhexidine-induced tissue necrosis.

The cats are housed individually, unobstructed in the front open boxes. After a short period, acclimatized] ^- a local dose of adenosine administered 0.6 mg / kg to determine the sensitivity of the cat to adenosine. Three consecutive bolus injections of 0.6, 1.0, or 1 mg / kg are administered and a drop in diastolic blood pressure is measured. The cats were then dosed with the test compound either as a solid or as a solution in polyethylene glycol (PEG) 400, after or in solution for intravenous administration.

The adenosine challenges were repeated at a time between 15 minutes and 24 hours after administration of the test compound. The activity of the test compound is expressed as a percentage inhibition of the diastolic blood pressure response. The compound of Example 1 was found to have a significant adenosine antagonist efficacy at a dose of 0.3 to 1 mg / kg, without any indication of apparent toxicity at several times the minimum effective dose.

The compounds of the invention are generally best administered to warm-blooded animals for therapeutic or prophylactic purposes in the treatment or prevention of cardiovascular diseases and conditions, in the form of a pharmaceutical composition comprising a compound of formula I or a pharmaceutically acceptable salt thereof in admixture or together with a pharmaceutically acceptable diluent or to the bearer. These compositions are provided as a further object of the present invention.

It is generally intended to administer the compound of Formula I orally, intravenously or in any other medically acceptable manner (such as by inhalation, insufflation, sublingual or transdermal), so that it is generally received in the range of 0.001 mg to 10 mg (and more particularly in the range of, for example, 0.05 to 5 mg / kg) per kg body weight. However, it should be borne in mind that the exact doses administered necessarily vary according to the nature and severity of the disease or condition being treated and the age and gender of the patient.

The composition of the present invention may be in various dosage forms. Thus, e.g. in the form of tablets, capsules, solutions or suspensions for oral administration; in the form of suppositories for rectal administration; in the form of a sterile solution or suspension for administration by intravenous or intramuscular injection; in the form of an aerosol or spray solution or suspension for administration by inhalation; in powder form, together with a pharmaceutically acceptable inert solid diluent, such as e.g. lactose, for administration by insufflation;

or in the form of a skin patch for transdermal administration. The compositions may conveniently be in a single dose containing e.g. 5-200 mg of a compound of Formula I or an equivalent amount of a pharmaceutically acceptable salt thereof.

The weight percent of the compound of formula I present in the composition of the present invention varies according to the route of administration, e.g. the composition may comprise from 0.1 to 99.5% by weight of a compound of formula I or a pharmaceutically acceptable salt thereof.

The compositions may be obtained by conventional methods, using pharmaceutically acceptable diluents and carriers well known in the art. Tablets and capsules for oral administration can be conveniently formulated with enteric coatings (such as those based on cellulose acetate phthalate) to minimize the contact of the effective Formula I ingredient with gastric acids.

The compositions of the invention may also contain one or more agents known to be useful in the treatment of cardiovascular diseases or conditions. Therefore, they may contain, in addition to the compound of formula I, e.g. known platelet aggregation inhibitors, prostanoid constrictor antagonist or synthase inhibitor (thromboxane antagonist or synthase inhibitor), cyclooxygenase inhibitor, hypolipidemic agent, inotropic agent or thrombolytic agent.

In addition to their use in therapeutic medicine, compounds of Formula I are also useful as pharmacological devices in the development and standardization of test systems for the evaluation of new cardiovascular agents in laboratory animals, such as e.g. cats, dogs, rabbits, monkeys, rats and mice.

The present invention is illustrated by the following non-limiting examples in which, unless otherwise stated:

(i) evaporation a is performed by rotary evaporation in vacuo;

(ii) the operations are carried out at room temperature in the range of 18-26 ° C;

(iii) Flash column chromatography or medium pressure liquid chromatography (MPLC) was performed on silica gel [Fluka Kieselgel 60 (catalog no. 60738), available from Fluka AG, Buchs, Switzerland or Merck Kieselgel Art. 9385, available from E Merck, Darmstadt, Germany];

(iv) the winnings are given for illustrative purposes only and are not necessarily the maximum achievable by steadily developing the process;

(v) proton NMR spectra are normally determined at 200 MHz in deuterated dimethylsulfoxide, using tetramethylsilane (TMS) as an internal standard and expressed as chemical shifts (delta values) in ppm relative to TMS, using conventional abbreviations to indicate major peaks : s, singlet; m, multiplet; t, triplet; br, broad; d, doublet; q, quartet; and (vi) all end products are characterized by microanalysis, NMR and / or mass spectroscopy.

Example 1

N- (2-aminoethyl) morpholine (2.60 g) was added to a stirred suspension of 7-amino-2- (2-furyl) -5methylsulfonyl- [1,2,4] triazolo [1,5-a] [1. 3,5] triazine (3.36 g) in acetonitrile 200 ml and stirring was continued for 2 hours. The solvent was evaporated and the residue was purified by chromatography on silica (200 g) eluting with dichloromethane containing methanol (10% vol / vol). The resulting solid (4.0 g) was crystallized from ethanol to give 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3 , 5] triazine-7-amine (3.03 g), m.p. Mp 242-244 ° C; microanalysis, found: C, 50.7; H, 5.40; N, 33.7%; C ₁₄ H _lg N _g O ₂ Calc .: C 50.9 H 5.5 N 33.9% NMR: 2.47 (br, 6H, CH? CLL,) ^, 3.43 (q, 2H, CH N, NH, 3.61 (m, 4H, C tjOCH ^, 6.68 (d from d, 1H, furyl-4H, 7.06 (d, 1H, furyl-3H), 7.27 (br, NH). 7.86 (d, 1H, furyl-5H) and 8.15 (br, 2H, NH 4; m / e 331 (M + H) ⁺ .

Prepare the required starting material as follows:

(1) Hydrogen chloride gas (20.0 g) is bubbled into an ice-cold mixture of 2-furonitrile (46.5 g) and absolute ethanol (23.0 g). After the addition of gas, the solid crystallizes from the mixture. The crystalline solid was collected by filtration and heated in pyridine (300 ml) with aminoguanidine nitrate (56.0 g) at reflux for 4 hours. The mixture was cooled, the solid was removed by filtration and the filtrate was evaporated to give crude 3-amino-5- (2-furyl) 1,2,4-triazole. This substance was purified by treatment with nitric acid (400 ml 50% vol / vol). The crystalline salt formed was collected by filtration, washed successively with water (100 ml) and ethanol (50 ml) and air-dried to give 3-amino-5- (2-furyl) -1,2,4-triazole nitrate (45.0 g), m.p. 130-133 ° C (dec.). Individual batches (184.0 g) of these salts were suspended in hot water (400 ml) and sodium carbonate (46.0 g) was added portionwise. The basic solution obtained was allowed to cool to give 3-amino-5- (2-furyl) -1,2,4triazole (82.0 g) as colorless prisms, m.p. Mp 204-206 ° C; NMR 6.05 (s, 2H, NH ₂ ), 6.6 (s, 1H, furyl-4H), 6.7 (s, 1H, furyl-3H), 7.7 (s, 1H, furyl-5H) ), 12.05 (br s, 1H NH).

(2) A homogeneous mixture of 3-amino-5- (2-furyl) -1,2,4-triazole (33.0 g) and dimethyl N-cyanodithioiminocarbonate (33.0 g) was heated at 170 ° C for 1 hour at slow during argon. After cooling, the resulting solid was purified by silica column chromatography (600 g) eluting with increasing amount of ethyl acetate in dichloromethane (5-10% vol / vol to give 7-amino-2- (2-furyl) -5-methylthio- [1,2,4] triazolo [1,5-a] [1,3,5] triazine as a colorless solid (11.1 g), substantially pure by TLC, which is used without further purification. the above solids were recrystallized from ethanol to give crystals, mp 238-240 ° C;

microanalysis, found: C 44.0; H, 3.3; N, 33.7; C ₉ H _g N ₆ SO. 0.05 C ₂ H ₅ OH calculated: C, 43.6; H, 3.3; N, 33.6; NMR 1.05 and 3.4 (t + q, ethanol from crystallization), 2.5 (s, 3H, Cl ^ S-), 6.7 (dd, 1H, furyl-4H), 7.2 (d , 1H, furyl-3H), 7.7 (d, 1H, furyl-5H), 8.7-9.0 (br d, 2H, NH ₂ ) m / e 248 (M ⁺ ).

(3) A solution of 3-chloroperoxybenzoic acid (50% conc, 45.0 g) in dichloromethane (300 ml) was added to a stirred ice-cold suspension of 7-amino-2- (2-furyl) 5-methylthio- [1,2] , 4] triazolo [1,5-a] [1,3,5] triazine (8.0 g) in dichloromethane (300 ml). Discard the remaining water layer. The resulting suspension was allowed to warm to room temperature and stirred for 16 hours. The solvent was evaporated and ethanol (150 ml) was added to the residue. Allow the resulting suspension to stand for 30 minutes and stir occasionally. The solid was then collected by filtration, washed with ethanol and dried to give 7-amino-2- (2-furyl) -5-methylsulfonyl- [1,2,4] triazolo [1,5-a] [1,3 , 5] triazine (6.6 g) as a colorless solid, NMR: 3.3 (s, 3H), CH ₃ .SO ₂ ), 6.7 (q, 1H, furyl-4H), 7.3 ( q, 1H, furyl-3H), 7.9 (q, 1H, furyl-5H), 9.4-9.8 (d, 2H, NFL ^), which was used without further purification.

Example 2

A mixture of 7-amino-2- (2-furyl) -5-phenoxy- [1,2,4] triazolo [1,5-a] [1,3,5] triazine (1.47 g) and N- ( 2-Aminoethyl-morpholine (0.78 g) in propanol (75 ml) was heated at reflux for 48 hours, until it was detected by thin layer chromatography that the reaction was substantially complete. The solvent was removed and the residue was purified by flash chromatography eluting with methylene chloride / methanol 10% vol / vol. The resulting solid (1.1 g) was crystallized from ethanol to give 2- (2-furyl) -5- [2- (morpholino) ethylamino]

- [1,2,4] triazolo [1,5-a] [1,3,5] triazine-7-amine (0.69 g), m.p. 243-246 ° C, which is identical in all respects to the product obtained in Example 1.

The necessary starting material can be prepared as follows:

Hexamethyldisiloxane (3.0 mol) was added to a phosphorus pentoxide broth (1.5 mol, measured as Ρ ₄ Ο _1θ ) in xylene. The mixture was then heated to 90 ° C for 1.5 hours and then stirred at 90 ° C for 1 hour to dissolve all the solid during that time. N-2- (4,6-diphenoxy) - [1,3,5] triazinyl] -N '- (2-furoyl) hydrazine (1.0 mol) was then added to the solution and the temperature was raised to reflux. The solids dissolve but another solid precipitates during cyclization. The cyclization is usually complete within 2.5 hours and after that time the mixture is cooled to 25 ° C and conveniently maintained at this temperature overnight. Acetonitrile was then added and the temperature lowered to 15 ° C. Add water. The mixture was then boiled back to 15 ° C and 0.91 g of ammonia solution was added while maintaining the temperature below 25 ° C. When the addition is complete, the temperature is raised to 40 ° C for 1 hour. The reaction mixture was then cooled to 25 ° C, the solid was filtered off and washed with a large amount of water. The yield is about 85%.

N-2- (4,6-diphenoxy) -1,3,5] triazinyl-N '- (2-furoyl) hydrazine required:

A solution of 2,4,6-triphenoxy-1,3,5-triazine (7.2 g) and 2-furoic acid hydrazide (2.5 g) in xylene (60 ml) was refluxed for 3 hours. The solvent was then removed by evaporation and the residue was purified by chromatography on silica gel (400 g) eluting with methylene chloride / methanol (2-3% vol / vol). A solid was crystallized from isopropanol to give N-2- (4,6-diphenoxy) - [1,3,5] triazinyl-N '- (2-furoyl) hydrazine as a colorless prism; m.p. 182-184 ° C; microanalysis; found: C, 61.4; H, 3.8; N, 17.7%; C ₂₀ H ₁₅ N ₅ O ₄ Calcd .: C, 61.7; H, 3.9; N, 18.0%; NMR 6.63 (dd, 1H, 4-furyl H), 7.05-7.5 (complex, 1H, 3-furyl H and phenyl H), 7.87 (s, 1H, 5-furyl H), 9.96 (s, 1H, NH) and 10.34 (s, 1H, NH); m / e 390 (M + H) < ⁺ >.

Example 3

2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] triazine-7-amine (14.2 g ) was dissolved in warm methanol (1400 ml) and acidified to pH 3 with 7 N hydrogen chloride in dioxane. The mixture was allowed to remain at pH 3 for 30 minutes. The solvent was evaporated and replaced with fresh methanol, which was then evaporated. We repeat this process twice more.

The residue was recrystallized from methanol (80 ml) to give, after drying at 80 ° C in vacuo for 16 hours, 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] -triazolo- [1,5-a] [1,3,5] triazine-7-amine, bis-hydrochloride (15.6 g), m.p. 313-315 ° C (dec), microanalysis;

found: C, 39.6; H, 5.4; N, 26.6; Cl, 15.9; H2O, 5.1%; C ₁₄ H _lg N _g O ₂ - 2HC1 -1.2 _Η Ό Ο 0.05 CHjOH Calc .: C, 39,57; H, 5.34; N, 26.27; Cl, 16.63; Κ, Ο, 5.06%; MS 331 (M + H) < ⁺ >. NMR: At room temperature, there are complications in the spectrum due to the presence of rotational isomers (rotamers). At 373 K δ 3.3 (m, 6H, 3 x CH ₂ N; 3.75 (t, 2H, CH ₂ NH); 3.9 (t, 4H, CH ₂ OCH ₂ ); 6.65 (m , 1H, furyl-4H); 7.09 (d, 1H, furyl-3H); 7.5 (brs, 1H, NHCH ₂ ); 7.8 (d, 1H, furyl-5H); 8.0 ( brs, 2H, NH ₂ ); also at δ 3.2 (s, methanol since crystallization.

Example 4

Examples of pharmaceutical dosage forms containing a compound of formula I or a pharmaceutically acceptable salt thereof (thereafter referred to as compound X) for therapeutic or prophylactic use in humans are illustrated:

Tablet mg / tablet Compound X 50 Lactose Ph.Eur 223,75 Croscarmellose sodium 6.0 Corn starch 15.0 Polyvinylpyrrolidone (5% w / v paste) 2.25 Magnesium stearate 3.0 Capsule mg / capsule Compound X 10 Lactose Ph. Eur 488,5 Magnesium stearate 1.5

The above formulations can be obtained by conventional methods well known in the pharmaceutical art. The tablets may be enteric coated by conventional means, e.g. the cellulose acetate phthalate coating is allowed.

Claims (7)

PATENT APPLICATIONS 1. 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo- [1,5-a] - [1,3,5] triazin-7-amine and pharmaceutically acceptable salts thereof. Salt according to claim 1, characterized in that it is selected from salts formed with hydrochloric, hydrobromic, sulfuric, phosphoric, methanesulfonic, trifluoroacetic, oxalic, citric or maleic acid. Compound according to claim 1, characterized in that it is selected from 2- (2-furyl) -5 [2- (morpholino) ethylamino] [1,2,4] triazolo- [1,5-a] [i , 3,5] triazine-7-amine and 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo- [1,5-a] [1,3,5] triazine-7amine, bischydrochloride. Compound according to claim 1, characterized in that 2- (2-furyl) -5- [2 (morpholino) ethylamino] [1,2,4] triazolo- [1,5-a] [1,3 , 5] triazine-7-amine. 5. A process for the preparation of 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo- [1,5-a] [1,3,5] triazine-7- amine or pharmaceutically acceptable salts thereof, characterized in that it comprises (a) the reaction of a compound of formula (II) IC in which Z is a suitable leaving group, with N- (2-aminoethyl) -morpholine or a salt thereof; (b) reacting a compound of formula IX IX in which Z ^{1 is a} suitable leaving group, with morpholine; (c) reacting a compound of formula X in which Z ^{2 is a} suitable leaving group with ammonia; or (d) dehydrating a compound of formula XII MHj. O wherein then, if a pharmaceutically acceptable salt is required, salt formation. Pharmaceutical composition comprising 2- (2-furyl) -5- [2 (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] triazine-7-amine or a pharmaceutically acceptable salt thereof, in admixture with or together with a pharmaceutically acceptable diluent or carrier. 2s 7. Use of 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] triazine-7-amine or its pharmaceutically acceptable salts for the manufacture of a medicament for the treatment of ischemic heart disease, peripheral vascular disease or cerebral ischemia. For Zeneca Limited: FIIEN1MA PiSASSI LJUBLJANA " / 23447-ΧΙΙ-93-ΚΑ SUMMARY 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5]-triazine-7-amine for use as adenosine antagonist 2- (2-furyl) -5- [2- (morpholino) ethylamino] [1,2,4] triazolo [1,5-a] [1,3,5] triazine-7-amine and its pharmaceutically acceptable salts , which are selective A ^ adenosine antagonists. Also disclosed are pharmaceutical compositions containing these compounds and processes for their preparation.