MXPA99005488A - PREPARATION OF [1S-[1a,2b,3b,4a(S*)]]-4-[7-[[1-(3-CHLORO-2-THIENYL) METHYL]PROPYL]AMINO]-3H-IMIDAZO[4,5-b]PYRIDIN-3-yl]-N-ETHYL-2,3-DIHYDROXYCYCLOPENTANECARBOXAMIDE - Google Patents

Abstract

This invention is directed to methods for the preparation of [1S-[1a,2b,3b,4a(S*)]]-4-[7-[[1-(3-chloro-2-thienyl)methyl]propyl]amino]-3H-imidazo[4,5-b]pyridin-3-yl]-N-ethyl-2, 3-dihydroxycyclopentanecarboxamide, methods for the preparation of intermediates thereto, and to said intermediates themselves.

Description

PREPARATION OF RUSSIA, 2b.3b.4a (S *) n-4-r7-rri- (3-CHLORO-2-THIENYL) METlUPROPlL1AMINO1-3H-IMIDAZQr4,5-b1PIRIDIN-3-IU-N-ETlL- 2.3- DIHYDROXICICLOPENTANOCARBOXAMIDE 1. FIELD OF THE INVENTION This invention is directed to methods for the preparation of [1S- [1a, 2b, 3b, 4a (S *)]] - 4- [7 - [[1- (3-chloro-2-thienyl) methyl] propii] amino] -3H-imidazo [4,5-b] -pyridin-3-yl] -N-etl-2,3-dihydroxycyclopentanecarboxamide, that is, compound I, (l) methods for the preparation of intermediaries thereof, and said intermediaries by themselves. Compound I is useful as a cardiovascular agent, more particularly as an antihypertensive and anti-ischemic agent, as a cardioprotective agent that reduces ischemic damage or the magnitude of myocardial infarction consequent to myocardial ischemia, and as an antilipolytic agent It reduces plasma lipid levels, serum triglyceride levels, and plasma cholesterol levels. For example, U.S. Patent No. 5,364,862 describes compound I and related compounds as being useful as antihypertensive and anti-ischemic agents, and U.S. Patent No. 5,561, 134 describes their utility as cardioprotective and antilipolytic agents. 2. REPORTED DEVELOPMENTS The methods of preparation of compound I, related compounds and intermediates thereof, have been described by Spada et al. In U.S. Patent No. 5,364,862, issued November 15, 1994, and in the United States patent. No. 5,561, 134. The preparation methods of the present invention offer improved yields, purity and ease of preparation and / or isolation of intermediates and final product, and industrially more useful reaction and workability conditions over other preparation methods described above.

BRIEF DESCRIPTION OF THE INVENTION This invention is directed to the methods for the preparation of [1 S- [1 a, 2b, 3b, 4a (S *)]] - 4- [7 - [[1- (3-chloro-2-thienyl) methyl] ] propyl] amino] -3H-imidazo [4,5- b] pyridin-3-yl] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide, that is compound I, methods for the preparation of intermediates thereof, and said intermediates by themselves.

DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments according to the invention are illustrated in Schemes I, II, III, and IV.

Scheme Scheme II Scheme lll An embodiment according to the invention is directed to a method for preparing compound I, which comprises reacting [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4- [[1- [3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound IX) with formamidine acetate, or with an orthoformate ester or dimethylacetal of dimethylformamide, optionally in the presence of a catalytic amount of an inorganic or organic acid. The reaction preferably takes place in an organic solvent, or mixture of organic solvents, water or a mixture of an organic solvent or solvents and water. In a special mode of methods according to the invention, the reaction preferably takes place with formamidine acetate in n-butyl acetate. In another special embodiment of methods according to the invention, the reaction preferably takes place with triethyl orthoformate, in the presence of a catalytic amount of an inorganic or organic acid, preferably hydrochloric acid or camphorsulfonic acid. A preferred embodiment according to the invention is directed to a method for preparing compound I, preferably in crystalline form, comprising the steps of forming the free base of compound IX from a hydrochloride salt thereof, followed by the reaction of said free base with formamidine acetate, said steps being carried out in a concatenated manner without the need for intermediate isolation and purification of the free base of compound IX. A preferred embodiment according to the invention is directed to a method for preparing compound I in a crystalline form, which comprises reacting the dihydrochlorhydrate salt of compound IX with formamidine acetate, without the initial formation of the free base of compound IX. Another embodiment of the invention is directed to a method for preparing said compound IX, which comprises hydrolyzing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -2- pyridinyl] amino] -N-etltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide (Compound VIII), preferably in the presence of an organic solvent or a mixture of organic solvents, and an aqueous or organic mineral acid. Examples of suitable organic solvents include methanol, ethanol, sodium propane, ethyl acetate, toluene, tetrahydrofuran, tetrahydropyran and dioxane. In a special embodiment of the methods according to the invention, the preferred solvent is methanol or a mixture of toluene and isopropanol. In special embodiments of the methods according to the invention, a preferred mixture for carrying out the hydrolysis of compound VIII to compound IX is tetrahydrofuran and aqueous hydrochloric acid, methanol, ethanol or isopropanol, and aqueous hydrochloric acid, or ethyl acetate or ethyl acetate. ethyl and isopropanol, and aqueous hydrochloric acid. Another embodiment of the invention is directed to a method for preparing said compound VIII, which comprises reducing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3 -chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide (compound VII), preferably in the presence of an organic solvent or a mixture of an organic solvent and water. Examples of suitable organic solvents include methanol, ethanol, isopropanol, ethyl acetate, tetrahydrofuran, tetrahydropyran and dioxane. In a special embodiment of the methods according to the invention, the preferred solvent is methanol. The reduction preferably takes place at a temperature range from about 20 ° C to about 90 ° C; preferably to reflux of the system in which the reduction takes place. In a special embodiment of the methods according to the invention, the preferred temperature is about 65 ° C, or that of the reflux of the reduction system taking place in methanol. The reduction of compound VII to compound VIII takes place in the presence of reducing agents known in the art or as described herein. Reducing agents that are suitable for reduction include potassium borohydride in the presence of copper (I) chloride, iron and aqueous hydrochloric acid, zinc and calcium chloride, platinum on carbon or palladium on carbon in the presence of hydrogen, platinum on carbon in presence of ammonium formate, zinc dust in the presence of ammonium acetate, and platinum on carbon sulphide in the presence of ammonium formate. In special embodiments of the methods according to the invention, a preferred reducing agent is platinum on carbon wet with water, or zinc powder in the presence of a species capable of transferring hydrogen to the nitro group to be reduced, preferably ammonium acetate, or platinum on carbon in the presence of hydrogen. Another embodiment of the invention is directed to a method for preparing said compound VII, which comprises reacting (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3- Nitro-4-pyridineamine (compound V) with 2R.3S-isopropylidenedioxy-4R-amino-1 S-ethylaminocarbonylcyclopentane (compound VI), preferably in the presence of an aprotic organic solvent. Aprotic organic solvents that are suitable for the reaction include ethers aprotic organic, aromatic hydrocarbons, heteroaromatic hydrocarbons, aliphatic hydrocarbons and aprotic organic amides. In a special embodiment of the methods according to the invention, a preferred organic solvent is toluene. According to the invention, the reaction of compound V with compound VI takes place in the presence of a base. Bases that are suitable for the reaction include aqueous alkali metal hydroxides, aqueous alkali metal carbonates, aqueous alkali metal bicarbonates and aprotic organic amines. In a special embodiment of the methods according to the invention, a preferred base is potassium carbonate. Another embodiment of the invention is directed to a method for preparing said compound V, which comprises replacing the hydroxyl portion of (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridinamine (compound IV) with a group chlorine, preferably in the presence of an aprotic organic solvent. The aprotic organic solvents which are suitable for the reaction include aprotic organic ethers, aromatic hydrocarbons, heteroaromatic hydrocarbons, aliphatic hydrocarbons and aprotic organic amides. In a special embodiment of the methods according to the invention, a preferred organic solvent is toluene. Agents that are suitable for carrying out the replacement include oxalyl chloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride and phosphorus oxychloride. In a special embodiment of the methods according to the invention, the preferred agent is phosphorus oxychloride.

Another embodiment of the invention is directed to a method for preparing said compound IV, which comprises reacting 4-chloro-3-nitropyridin-2 (1 H) -one (compound II) with (R) -3-chloro-a- ethyl-2-thiopheneethenamine (compound III), preferably in the presence of an organic solvent or mixture of organic solvents, water, or a mixture of solvent or organic solvents and water. Examples of suitable organic solvents include methanol, ethanol, isopropanol, ethyl acetate, tetrahydrofuran, tetrahydropyran, and dioxane. Examples of preferred solvents include methanol, ethanol, sodium propane, and a mixture of methanol, ethanol or isopropanol and water. According to the invention, the reaction of compound II with compound III takes place in the presence of a base. Bases that are suitable for the reaction include aqueous alkali metal hydroxides, aqueous alkali metal carbonates, aqueous alkali metal bicarbonates and aprotic organic amines. In a special embodiment of the methods according to the invention, a preferred base is N, N-diisopropylethylamine. Another embodiment of the invention is directed to a method for preparing said compound II, which comprises reacting 4-hydroxy-3-nitro-2 (1 H) -pyridone (Compound XII) with phosphorus oxychloride or thionyl chloride, preferably oxychloride of phosphorus in the presence of an organic solvent, and in the presence of a base. Organic solvents that are suitable for the reaction include aprotic organic ethers, aromatic hydrocarbons, heteroaromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons and aprotic organic amides. The examples of organic solvents Suitable include toluene, methyl t-butyl ether, dimethylformamide, ethyl acetate, butyl acetate, 1-methyl-2-pyrrolidinone, chloroform and dichloromethane. In a special embodiment of the methods according to the invention, a preferred organic solvent is toluene. In a special embodiment of the methods according to the invention, a preferred base is N, N-diisopropylethylamine. Another embodiment of the invention is directed to a method for preparing compound XII, which comprises hydrolyzing and decarboxylating 2-hydroxy-3-cyano-4-methoxypyridine to give 2,4-dihydroxypyridine, followed by nitration of said 2,4-dihydroxypyridine. . In a special embodiment of the methods according to the invention, said hydrolyzation, decarboxylation and nitration are carried out in a concatenated manner, without the need for intermediate isolation and purification of said 2,4-dihydroxypyridine, preferably by sequential heating of 2-hydroxyl. 3-cyano-4-methoxypyridine with concentrated phosphoric acid, then glacial acetic acid, then nitric acid. A preferred embodiment of the invention is directed to a method for preparing the dihydrochloride salt of compound IX, comprising the steps of reacting compound II with compound III to form compound IV, followed by replacement of the hydroxyl portion of compound IV with a chloro group to form compound V, followed by reaction of compound V with compound VI to form compound VII, followed by reduction of compound VII to compound VIII, followed by hydrolysis of compound VIII in the presence of hydrochloric acid; These steps are carried out in a concatenated without the need for intermediate isolation and purification of intermediate compounds VIII, VII, V or IV. It will be apparent to the person skilled in the art that hydroxypyridines can exist as tautomeric pyridinones, and that pyridinones can exist as tautomeric hydroxypyridines. Therefore, compounds II, III, X, XI, and XII can exist in the form of the corresponding hydroxypyridine or pyridone, or as a mixture of the two forms. The present invention is further explained by means of the following examples, but is by no means limited thereto.

EXAMPLE 1 Preparation of pS-ria, 2b, 3b, 4a (S *) n-4-f7-rn - (3-chloro-2-thienyl) metipropylamino-3 H -amidazof 4,5-b1-pyridin-3-in -N-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound I) [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4- [1- [3-chloro-2-thienyl] methyl] propyl] amino] dihydrochloride was suspended] -2-pyridinyl] amino] -N-ethyl-2,3-dihydroxy-cyclopentanecarboxamide (Compound IX) monohydrate (20 g) in water (120 ml), and the mixture was heated to 65 ° C to give a solution. Butylium acetate (84.7 g) was added, followed by sodium carbonate (15.2 g) in water (54 g). The mixture was stirred at 55 ± 5 ° C for about 10 minutes, then the layers were separated and the organic layer was washed with brine. Formamidine acetate (10.3 g) was added to the organic layer and the mixture was stirred at 85 ± 5 ° C for about 2 hours. The mixture was cooled to 55 ± C, washed with aqueous sodium bicarbonate solution, and then water. Water (1.2 g) was added to the organic layer at 55 ± 5 ° C, then the mixture was cooled to 21 ± 2 ° C for a period of about 2 hours. The mixture was stirred for 12 to 24 hours, filtered, the solid was washed with butyl acetate and dried under vacuum with a nitrogen purge at 52 ° C for about 24 hours to give [1S- [1a, 2b, 3b , 4a (S *)]] - 4- [7 - [[1- (3-chloro-2-thienyl) methyl] propyl] amino] -3H-imydazo [4,5-b] pyridin- 3-yl] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound I), as a hydrate with about 1.7% water (w / w). 1 HNMR (200 Mhz, DMSO) d 0.915 (3h, T); 1.4 (3h, T), 3.2-3.0 (4h, m), 4.91 (1H, d); 6.3 (1 H, d); 6.6 (1 H, bd); 6.9 (1H, d); 7.4 (1H, d); 7.8 (1H, d); 8.05 (1 H, bt); 8.2 (1H, s).

EXAMPLE 2 Preparation of riS-ria, 2b, 3b.4a (S *) p-4-r7-rri- (3-chloro-2-thienyl) metinproplinaminol-3H-imidazor4,5-blpiridin-3-yN-ethyl -2,3- dihydroxycyclopentanecarboxamide (Compound I) N-butyl acetate (54.3 g) and formamidine acetate (4.5 g, 43 mmol) were combined at room temperature. The mixture was heated to 100 ° C and [1S- [1a, 1b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1- [[1- [[1-]] dihydrochloride was added thereto for 21 minutes. 3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-etl-2,3-dihydroxy-cyclopentanecarboxamide (Compound IX), monohydrate (8.4 g, mmoles). The mixture was stirred at 100 ° C for 1 hour, then it was cooled to 80 ° C and 8% aqueous sodium bicarbonate, w / w (90 ml) was added. The mixture was stirred for 5 minutes and then separated to the layers. The organic layer (which was maintained above 60 ° C) was washed with water (45 g). The organic layer was then treated with activated carbon (0.42 g) and stirred at 75 ° C for 45 minutes. The reaction was filtered and the filtrate was cooled to 22 ° C over a period of 1 hour. The mixture was stirred for 2 hours at 22 ° C and the resulting solid was filtered and washed with n-butyl acetate (6 ml). The collected white solid was dried under vacuum overnight at 60 ° C with a nitrogen purge to give compound 1.

EXAMPLE 3 Preparation of nS-ria.2b, 3b, 4a (S *) n-4-r7rri- (3-chloro-2-thienyl) methitropipaminol-3H-imidazor4,5-b1pyridin-3-in- N-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound I) N-butyl acetate and formamidine acetate (2.81 g, 27 mmol) were combined at room temperature. The mixture was heated to 100 ° C and 94-100 ° C, and a suspension of dihydrochloride of compound IX monohydrate (8.4 g, 15 mmol) in n-butyl acetate (30.6 g) was added at room temperature for 11 minutes. , rinsing with n-butyl acetate (9.0 g) to complete the transfer of the suspension. The mixture was stirred at 100 ° C for 30 minutes. The reaction mixture was cooled to 80 ° C and 8% w / w aqueous sodium bicarbonate (90 ml) was added. The mixture was stirred for 5 minutes and then It separated to the layers. The organic layer (which was maintained above 60 ° C) was washed with water (45 g). The organic layer was then treated with activated carbon (0.42 g) and stirred at 75 ° C for 45 minutes. The reaction was filtered, then cooled to 22 ° C for 1 hour. The mixture was stirred for 2 hours at 22 ° C and the resulting solid collected by filtration was washed with n-butyl acetate (5 ml) to give compound I.

EXAMPLE 4 Preparation of r3aR-r3aa, 4a.6a (R *). 6aap-6-rr3-amino-4-rM -r (3-chloro-2-thienyl) metinpropipamino-2-pyridin-amino-1-N-ethyletrahydro- 2.2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide (Compound VIII) Mix [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxarrtide (compound VII) (12.4 g), methane (32.4 g) and platinum on carbon at 5% (water humidity test 62.4%) (9.6 g). The mixture was degassed with nitrogen, and ammonium formate (10.0 g) was added. The mixture was heated to about 65 ° C for 4 hours, cooled to 23 ° C, filtered through a filter aid (SulkaFloc 300), rinsed with ethyl acetate (180.4 g). The filtrate was washed with aqueous 5% sodium bicarbonate solution (50 ml), then semi-saturated aqueous sodium chloride solution. The organic layer was evaporated in vacuo at 50 ° C to give compound VIII, as a foam that was used without additional treatment for the next reaction.

EXAMPLE 5 Preparation of M SM a, 2b, 3b, 4a (S *) p-4-rr 3 -amino-4-rri-r 3 -chloro-2-thienyl) metinpropinamino-2-pyridinipamino-1-N-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound IX) Compound VIII (11.2 g) was combined with tetrahydrofuran (160 g) and concentrated hydrochloric acid (7.8 ml) was added over a period of 2 minutes. The mixture was stirred for 15 hours, then cooled to 0 to 3 ° C and stirred for an additional hour. The mixture was filtered and the solid was washed with cold methyl-t-butyl ether (0-3 ° C); it was then dried under vacuum at 55 ± 5 ° C with a nitrogen purge for 48 hours to give compound IX as the dihydrochloride monohydrate salt, m.p. 135 ° C; MS (El), m / z 467 (50%), 1 HNMR (500 Mhz, DMSO) d 0.91 (1H, t); 1.05 (1H, t); 1.55 (2H, m); 2.39 (1H); 3.11 (1H); 4.01 (2H); 6.24 (1H); 6.36 (1H); 6.98 (1H); 7.37 (1H); 7.48 (1H); 12.47 (1H).

EXAMPLE 6 Preparation of (R) -N-H -r (3-chloro-2-thienyl) met.pprop.p-2-hydroxy-3-nitro-4-pyridinamine (Compound IV) To a three-liter round bottom flask, equipped with a mechanical stirrer, thermocouple, nitrogen inlet and condenser, were sequentially introduced: 14.5 g of (R) -3-chloro-a-ethyl-2- thiopheneteneteamine (Compound III), 10.9 g of 4-chloro-3-nitropyridin-2 (1H) -one (Compound II), 35 g of 2-propanol (IPA) and 25 ml of N, N-dusopropylethylamine (DIPEA). The mixture was stirred at 70 ° C ± 20 ° C for 7 hours before allowing the reaction to cool overnight to room temperature (22 ° C + 3 ° C). The mixture was concentrated to 41.4 g of a syrup which was subsequently dissolved in 425 ml of ethyl acetate. This solution was washed with 125 ml of water, twice with 50 ml of 5N ammonium chloride solution and 2 times with 50 ml of saturated sodium chloride solution before drying over sodium sulfate. The solution was filtered, concentrated, and the resulting solid was collected by filtration to give compound IV, m.p. 150-152 ° C. EM. (El), m / z 328 (6%), 1 HNRM (500 Mhz, DMSO) d 0.91 (3H, t); 1.8-1.6 (2H, m), 3.1 (1H, m); 3.95 (1H, m); 5.9 (1H, d); 7.0 (1H, d); 7.3 (1H, dd), 7.5 (1H, d); 8.8 81 H, d); 11.1 (1H).

EXAMPLE 7 Preparation of (R) -2-chloro-N-H -r (3-chloro-2-thienyl) methynpropin-3-nitro-4-pyridinamine (Compound V) A toluene solution of (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridinamine (Compound IV) was heated (0.1 mol 100 ml of toluene) containing 2 equivalents of DIPEA hydrochloride, at 60 ° C, and 20.6 g of phosphorus oxychloride were added during 10 minutes with stirring. The reaction was filtered at 60 ° C until complete (3 hours). After cooling to 0 ° C, 245 g of 2N sodium chloride was added at a sufficient rate to maintain the reaction temperature below 10 ° C. The biphasic mixture was stirred 1 to 2 hours at 0 ° C before allowing it to reach room temperature overnight. The lower aqueous layer was separated from the organic layer. The organic layer was concentrated in vacuo and the residue was purified by flash chromatography eluting with 25:75 ethyl acetate: heptane to give compound V. MS (El), m / z 345 (10%). 1 H NMR (500 Mhz, CDCl 3 / CD 3 OD) d 1.0 (3 H, t); 1.5-1.8 (2H, m); 2.9-3.2 (2H, m); 3.8 (1 H, m); 6.5 (1H, bd); 6.6 (1 H, d); 7.15 (1 H, d); 7.9 (1 H, d).

EXAMPLE 8 Preparation of r3aR-r3aa.4a, 6a (R *), 6aan-6-4-pr (3-chloro-2-thienyl) metinpropinamino-3-nitro-2-pyridinipaminol-N-ethylhetrahydro- 2,2-dimethyl-4H-cyclopenta-1,3-dioxoi-4-carboxamide (Compound VID To a toluene solution of (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro-4-pyridinamine (Compound V) (0.1 moles in 100 ml of toluene), 28.5 g of 325 mesh potassium carbonate was successively added, followed by 33.7 g of 2R, 3S-isopropylidenedioxy-4R-amino-1S-ethylaminocarbonylcyclopentane (Compound VI) in individual portions. The suspension was heated at 98 ° C ± 2 ° C for 6 hours. When the reaction was complete, the suspension was cooled to room temperature and 230 g of water was added with stirring. The aqueous layer was removed and a solution of 14.5% w / w ammonium chloride solution was charged to the organic layer with stirring, before removing the lower aqueous layer again. 100 g of water were added and the layers were separated again. The toluene solution was concentrated in vacuo and the residue was purified by flash chromatography, eluting with ethyl acetate: heptane: triethylamine, 60: 40: 5, to give compound VII. E.M. (FAB-LRP), (M + H) + 538 (100%), 1 HNRM (500 Mhz, CDCl 3) d 1.0 (3 H, t); 1.15 (3H, t); 1.6 (1 H, m); 1.75 (1 H, m); 2.6 (1 H, m), 2.8 (1 H, m); 3.1, (2H, m); 3.35 (2H, m) 5.95 (1 H, d); 6.85 (1 H, d); 7.1 (1 H, d); 7.8 (1 H, d), 9.25 (1 H, d); 9.55 (2H, d).

EXAMPLE 9 Preparation of r3aR-r3aa, 4a.6a (R *), 6aaTI-ß-IT3-amino-4-rrri (3-chloro-2-thienyl) metinpropinamino1-2-pyridininamino-1-N-ethyltetrahydro- 2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide (Compound HIV).

To a toluene solution of compound VII (0.09 mole in 85 ml of toluene), 24 g of methanol, 18 g of IPEA and 54 g of ammonium acetate were charged with stirring (15 minutes). Then 35 g of powdered zinc metal were added in small portions (until no exotherms were observed) while maintaining the temperature of the reaction below 40 ° C. After the addition of zinc had been completed, the reaction mixture was stirred at 40 ° C for 30 minutes before cooling the heterogeneous mixture to 0 ° C. The gray salts were filtered at 0 ° C and washed with toluene. The filtrate was concentrated in vacuo and the residue was purified by flash chromatography, eluting with ethyl acetate: heptane: triethylamine, 90: 10: 5, to give compound VIII. MS (M + H) + 508 (100%), 1 HNMR (500 Mhz, DMSO) d 0.9 (3H, t); 1.0 (3H, t); 1.7-1.4 (3H, m); 2.35 (1H, m); 2.95 (2H, m); 3.1, (2H, m); 5.75 (1H, d) 6.0 (1H, d), 7.0 (1H, d); 7.25 (1H, d); 8.15 (1 H, m).

EXAMPLE 10 Concatenated preparation of riS-ria, 2b, 3b, 4a (S *) n-4-rr3-amino-4-rn-f3-chloro-2-thieniphenyltininamin1-2-pyridn! 1,11-N-1-N-etl-2,3-dihydroxycyclopentanecarboxamide (Compound IX) To a 1-liter 3-necked round bottom flask, equipped with a mechanical stirrer, thermocouple, nitrogen inlet and condenser, were sequentially introduced: 23.3 g of (R) -3-chloro-a-ethyl- hydrochloride. 2-thiophenaneteamine (Compound III), 18.0 g of 4-chloro-3-nitropyridin-2 (1 H) -one (Compound II), 35 g of 2-propanol (IPA) and 33.3 g of N, N-diisopropylethylamine ( DIPEA). The mixture was stirred while heating the batch at 70 ° C ± 2 ° C for 5 to 7 hours. The reaction was allowed to cool overnight at room temperature (22 ° C ± 3 ° C). In the morning 240 g of toluene was added to the reaction vessel, and IPA / toluene was azeotropically removed by distillation at 80-90 ° C and reduced pressure. The residual IPA was monitored by means of gas chromatography. When the IPA level was below 0.1%, the resulting liquid / liquid biphasic mixture containing (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3 -nitro-4-pyridinamine (Compound IV), was cooled to 60 ° C and 20.6 g of phosphorus oxychloride were added during 10 minutes with stirring. The reaction was stirred at 60 ° C to complete the reaction (2-3 hours) before cooling to 0 ° C; and 245 g of a 2N aqueous sodium hydroxide solution was added at a sufficient rate to maintain the temperature of reaction below 10 ° C. The biphasic mixture was stirred 1 to 2 hours at 0 ° C before allowing it to reach room temperature overnight. In the morning, it was separated to the lower aqueous layer of the organic layer containing (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro-4 pyridinamine (Compound V), and 28.5 g of 325 mesh potassium carbonate were added to the organic layer, in individual portions, followed by 33.7 g of 2R, 3S-isopropylidenedioxy-4R-amino-1S-ethylaminocarbonyl-cyclopentane ( Compound VI). The suspension was heated to 98 ° C ± 2 ° C for 2 to 6 hours. Upon completion of the reaction, 230 g of deionized water were added with stirring. The aqueous layer was removed and 14.5% w / w aqueous ammonium chloride solution was charged to the organic layer with stirring, before again stirring the lower aqueous layer. 100 g of deionized water were added and again separated to the layers. To the toluene solution of [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide (Compound VII) was charged with 24 g of methanol , 18 g of IPA and 54 g of ammonium acetate with stirring (15 minutes). Then, 35 g of powdered zinc metal were added in small portions (until no exotherms were observed) while maintaining the temperature of the reaction below 40 ° C. After the addition of Zn was complete, the reaction mixture was stirred at 40 ° C for 30 minutes before cooling the heterogeneous mixture to 0 ° C. The gray salts were filtered and washed with toluene. The filtrate (a toluene solution of [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3- amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1, 3- dioxol-4-carboxamide (Compound VIII), was used directly in the next reaction. To the toluene solution of compound VIII was added 100 g of IPA and the mixture was stirred while heating at 50 ± 3 ° C. 31 g of concentrated hydrochloric acid were added slowly over several minutes. Upon completion of the consumption of compound VIII, the reaction temperature was reduced to 22 ° C ± 3 ° C, and stirred overnight. In the morning, the suspension was cooled to 0 ° C and 45 g of ethyl acetate were added thereto. After stirring at this temperature for 1 hour, the solids were filtered and washed sequentially with cold IPA (0 ° C) and ethyl acetate at room temperature. The whitish filter cake was dried at 40 ° C ± 3 ° C under vacuum for 10 minutes to produce [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino- 4 - [[1- [3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide as the dihydrochloride monohydrate. Melting point: 135 ° C.

EXAMPLE 11 Preparation of 4-chloro-3-nitropyridin-2 (1H) -one (Compound II) A 150 ml flask was charged with 2,4-dihydroxy-3-nitropyridine (Compound XII) (10.0 g, 0.064 mol), and toluene (30 ml). The mixture was stirred at moderate speed and heated to 47 ° C. Phosphorus oxychloride was added (POCI3) (4.4 g, 0.0289 moles) for 10 minutes by means of a syringe pump, giving an exotherm at 49 ° C. N, N-diisopropylethylamine (DIPEA) (2.22 g, 0.017 mol) was added over 10 minutes giving an exotherm at 51 ° C. Another portion of POCI3 (4.4 g, 0.0289 moles) was added for 10 minutes. A third portion of IPEA (2.22 g, 0.017 mole) was added for 10 minutes, followed by a third portion of POCI3 (4.4 g, 0.289 mole) for 10 minutes, followed by a final portion of DIPEA (2.22 g, 0.017). moles) for 10 minutes (total POCI3 added is 17.7 g), then for a final portion of POCI3 (4.4 g, 0.0289 moles) for 10 minutes (total DIPEA added is 8.9 g). The reaction was then stirred at 50 ° C for 5 hours until IPC indicated complete consumption of compound XII. The reaction was allowed to cool to 20 ° C for 30 minutes and 50 ml of water were added for 1.5 hours, allowing the temperature to rise to 47 ° C. This mixture was stirred for 4 hours while cooling to 25 ° C. The batch was filtered by washing twice with 15 ml of water, then twice with 15 ml of toluene. The product was dried to give compound II.

EXAMPLE 12 Preparation of 2,4-dihydroxy-3-nitropyridine (compound XII) Combine 86% phosphoric acid (90 ml, 151.3 g) and 3-cyano-4-methoxy-2- (1H) -pyridinone (compound X) (30.0 g, 0.20 mole) under argon in a 500 ml beaker equipped with a mechanical agitator, reflux condenser. The mixture was heated in an oil bath at 175-180 ° C for 23 hours. The The reaction mixture was cooled to 71 ° C and glacial acetic acid (90 ml, 94.5 g) was added thereto and the mixture was heated at 90 ° C for about 90 minutes. Fuming nitric acid (density = 1.52) (12.6 g, 8.3 ml) was then carefully added over a period of 15 minutes (giving a slight exotherm) and the mixture was heated at 90-95 ° C for 2 hours. Water (90 ml) was then added to the mixture and heating to 90 ° C was continued for 1 hour. The mixture was then cooled slowly with stirring at room temperature, filtered through a concreted glass funnel and the residue was washed with water to give compound XII, m.p. 268 ° C; NMR (DMSO) d 7.44 (1 H, d); 6.0 (1 H, d); 3.5 (2H).

EXAMPLE 13 Preparation of M S-T1 a.2b.3b, 4a (S *) n-4-rr3-amin-4-rp -r3-chloro-2-thienyl) methyropynaminol-2-pyridinamino-1-N-ethyl -2,3-dihydroxy-cyclopentanecarboxamide (compound IX) A 3-neck round bottom flask covered under nitrogen blanket was charged sequentially with 5% Pt C (RA / W type F101 Degussa, 21.6 grams, 2.71 mmol), ammonium formate (34 grams, 543 mmol), ethyl acetate solution of compound VII (110 ml containing 29 grams of compound VII, 54.3 mmol), and methanol (66 grams) with mechanical stirring. The black suspension was heated at 60 ° C for 6 hours, cooled to room temperature and filtered through Celite to remove the insoluble species. The filter cake was washed twice with 50 ml of ethyl acetate. To the Combined filtrates were added concentrated hydrochloric acid (40 ml) for several minutes with stirring and the mixture was stirred for 3 minutes at room temperature. Filtration followed by drying at 50 ° C in a vacuum oven yielded compound IX as the dihydrochloride monohydrate as an off-white solid.

EXAMPLE 14 Preparation of f 1 SM a, 2 b, 3 b, 4 a (S *) p-4-rr 3 -amino-4-rri-r 3 -chloro-2-thienyl) methitropynaminol-2-pyridininamino-1-N-ethyl- 2,3-dihydroxy-cyclopentanecarboxamide (compound IX) To a bottle of Paar of 500 ml was charged 1.8 g of Pt on carbon at 5% (Aldrich, wet, Degussa F101 RA / W) and a solution in toluene of the compound Vil (8.9 grams, 16.6 mmoles, in 50 grams of toluene). The mixture was stirred under a hydrogen pressure of 3.6 kg / cm2 for 15 hours at room temperature. The black suspension was filtered through Celite to give a solution of compound VIII. To this solution was added at 20 ° C, 2-propanol (20 grams), toluene (57 grams) and concentrated hydrochloric acid (7.4 grams) in succession, and the solution was heated to 45 ° C with mechanical stirring. After 2 hours at this temperature, the tan precipitate was filtered and washed with 20 ml of 2-propanol. The filter cake was dried for 6 hours at 45 ° C to give compound IX as the dihydrohydrate monohydrate.

EXAMPLE 15 Preparation of H SM a, 2b, 3b, 4a (S *) p-4-r7-rp - (3-chloro-2-thieniD-metinpropinaminol-3H-imidazof4,5-b1pyridin-3-in-N- ethyl-2,3- dihydroxycyclopentanecarboximate (compound I) In a three-necked round bottom flask equipped with a condenser and a magnetic stir bar, compound IX was added sequentially as the dihydrochloride monohydrate (2.2 g, 3.9 mmol), and deionized water (12 grams) the suspension was heated at 65 ° C and an aqueous solution of sodium carbonate (1.7 g of Na 2 CO 3 in 5 grams of deionized water, heated to 65 ° C) was added. The organic phase is separated as a light tan oil. Triethyl orthoformate (6.8 ml, 41 mmol) was then added to the diphasic mixture and the lower aqueous layer was removed. After the addition of concentrated hydrochloric acid (90 μl), the solution was heated for 5 hours at 80 ° C. The solution was cooled to 70 ° C, n-butyl acetate (10 ml) was added and the organic layer was washed with saturated sodium carbonate followed by water and brine. The organic layer was cooled to room temperature and stirred for 16 hours. Filtration followed by drying at 50 ° C in an oven yielded compound I.

EXAMPLE 16 Preparation of H SM a, 2b, 3b, 4a (S *) 11-4-r7-rri - (3-chloro-2-thieniD-metinpropinamno1-3H-imidazor4,5-b1pyridin-3-yNN -ethyl-2.3- dihydroxycyclopentanecarboxamide (compound I) In a 3-neck round bottom flask equipped with a condenser and a magnetic stir bar, compound IX was added sequentially as the dihydrochloride monohydrate (2.0 g, 3.6 mmol) and deionized water (12 grams). The suspension was heated to 65 ° C and an aqueous solution of sodium carbonate was added at 65 ° C (1.6 g of Na2CO3 in 5 grams of deionized water, heated to 65 ° C). Triethyl orthoformate (9.0 ml, 54.3 mmol) was then added to the biphasic mixture and the lower aqueous layer was removed. The organic layer was washed with deionized water (5 ml) and the lower layer was removed again. After the addition of (1 R) (-) 10-camphor-sulfonic acid (42 mg, 0.18 mmol), the solution was heated for 2 hours at 80 ° C and hours at 25 ° C. The reaction mixture was heated again to 70 ° C, n-butyl acetate (10 ml) was added and the organic layer was washed with saturated sodium carbonate followed by water and brine. The organic layer was cooled to room temperature and stirred for 16 hours. Filtration followed by drying at 50 ° C in a vacuum oven yielded compound I.

EXAMPLE 17 Preparation of n S-ria, 2b, 3b, 4a (S *) n-4-r7-rp- (3-chloro-2-thienl) -methin-propinamino-3H-imidazor4,5-b1-pyridin-3 NN-ethyl-2,3-dihydroxycyclopentanecarboxamide (Compound I) To a 250 ml 3-necked round bottom flask equipped with a magnetic stirrer, thermocouple, nitrogen inlet and a condenser, it was charged sequentially at 22 ° C: 8.4 g of compound IX as dihydrochloride monohydrate, 54.3 g of acetate of n-butyl and 4.5 g of formamidine acetate. The suspension was stirred while heating at 90 ° C for 2 to 4 hours. Upon completion of the reaction (disappearance of compound IX) the reaction mixture was cooled to 60 ° C and washed with a dilute solution of warm sodium bicarbonate followed by 45 grams of warm water. After removing the aqueous layers, the organic solution was treated with 400 mg of activated carbon and 0.5 g of water and heated to 70 ° C with stirring for 45 minutes. The hot suspension was filtered and the filtrate was cooled to room temperature and stirred for a further 2 hours at 22 ° C. The resulting solid was collected by filtration, washed with butyl acetate and dried in a vacuum oven at 50 ° C. The person skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects of the invention, and obtain the purposes and advantages mentioned, as well as those inherent thereto.

The compounds and methods described in this specification are presented as representative of the preferred embodiments, or are intended to be exemplary and not limitations of the scope of the present invention.

Claims (27)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A method for preparing [1S- [1 a, 2b, 3b, 4a (S *)]] - 4- [7 - [[1 - (3-chloro-2-thienyl) methyl] propyl] amino] - 3H-midazo [4,5-b] pyridin-3-yl] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide, which comprises reacting [1S- [1a, 2b, 3b, 4a (S *)] ] -4 - [[3-amino-4 - [[1- [3-chloro-2-thienyl) methy1] propyl] amino] -2-pyridinyl] amino] -N-ethyl-2,3 -dihydroxycyclopentanecarboxamide with an orthoformate ester, formamidine acetate, or dimethylformamide dimethylacetal.
2. 2. The method according to claim 1, characterized in that said reaction is with formamidine acetate.
3. 3. The method according to claim 1, further characterized in that it comprises hydrolyzing [3aR- [3aa, 4a, 6a (R *). 6aa]] - 6 - [[3-amino-4 - [[1 - [ (3-Chloro-2-thienyl) -methyl] propyl] amino] -2-pyridinyl] amino-N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide to form said [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1- [3-chloro-2-thienyl) methyl] propyl] amino-2 -pyridinyl] -amino] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide.
4. 4. The method according to claim 3, characterized in that said hydrolysis takes place in the presence of aqueous hydrochloric acid. 5.- A method to prepare [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1- [3-chloro-2-thienl)] methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyl-2,3-d-hydroxycyclopentanecarboxamide, which comprises hydrolyzing [3aR- [3aa, 4a, 6a (R *). 6aa ]] - 6 - [[3- amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyl-tetrahydro-2,2-dimethyl-4H-c Clopenta-1,3-dioxol-4-carboxamide. 6. The method according to claim 3, further characterized by comprising reducing [3aR- [3aa, 4a, 6a (R) .6aa]] - 6 - [[4 - [[1 - [(3-chloro- 2-thienyl) methyl] propyl] amino] -3-ntr-2-pyridinyl] amino] -N-ethyl-tetrahydro-2,2-dimethyl-4H-cyclopenta-1, 3- dioxol-4-carboxamide to form said [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl)] methyl] propyl] amino-2-pyridinyl] amino] -N-etltetrahydro-2,2-d-methyl-4H-cyclopenta-1,3-d-oxo-4-carboxamide. 7. The method according to claim 6, further characterized in that said reduction takes place in the presence of platinum on wet carbon of water and ammonium format, or in the presence of zinc and ammonium acetate, or in the presence of platinum on carbon in the presence of hydrogen. 8.- A method to prepare [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] ] propyl] amino] -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, which comprises reducing [3aR- [3aa, 4a, 6a ( R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino-N -ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-d-oxo-4-carboxamide in the presence of platinum on water-wet carbon and ammonium formate. 9.- A method for preparing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) met L] propyl] amino] -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, which comprises reducing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2- pyridinyl] amino-N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide in the presence of zinc and ammonium acetate. 10. A method for preparing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] ] propyl] amino] -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-d-oxo-4-carboxamide, which comprises reducing [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino -N-Ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide in the presence of platinum on carbon and hydrogen. 11. The method according to claim 6, further characterized in that it comprises reacting (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro- 4-pyridinamine with 2R, 3S-isopropyldenedioxy-4R-amino-1S-ethylaminocarbonylcyclopentane to form said [3R- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4- [1 - [(3 -chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino] -N-ethylhetrahydro-2, 2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide. 12. The method according to claim 11, characterized in that said reaction takes place in the presence of toluene and an alkali metal carbonate. 13.- A method to prepare [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) meth]] propii ] amino] -3-nitro-2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, which comprises reacting (R) -2-chloro -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro-4-pyridinamine with 2R, 3S-isopropyldenedioxy-4R-amino-1S-ethylaminocarbonylcyclopentane in the presence of an alkali metal carbonate. 14. The method according to claim 11, further characterized in that it comprises replacing the hydroxy portion of (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2 -hydroxy-3-nitro-4-pyridinamine with a chloro group to form said (R) -2-chloro-N- [1 - [(3-chloro-2-methyl] propyl] -3-nitro-4-pyridinamine 15. The method according to claim 14, characterized in that said replacement takes place in the presence of phosphorus oxychloride 16.- A method for preparing (R) -2-chloro-N- [1 - [(3- chloro-2-thienyl) methyl] propyl] -3-nitro-4-pyridineamine, which comprises replacing the hydroxyl portion of (R) -N- [1 - [(3-chloro-2-thienyl) methyl] ] propyl] -2-hydroxy-3-nitro-4-pyridinamine 17. The method according to claim 14, further characterized in that it comprises reacting 4-chloro-3-nitropyridin-2 (1H) -one with (R) -3-chloro-a-ethyl-2-thiopheneethanamine to form said (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro -4-pyridinamine 18.- The method d according to claim 17, characterized in that said reaction takes place in the presence of isopropanol and N-N-diisopropylethylamine. 19. A method for preparing (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridineamine, which comprises reacting 4-chloro-3- > nitropyridin-2 (1 H) -one with (R) -3-chloro-a-ethyl-2-thiopheneethanamine. 20. The method according to claim 17, characterized in that it comprises reacting 4-hydroxy-3-nitro-2 (1 H) -pyridone with phosphorus oxychloride to form said 4-chloro-3-nitropyridin-2 (1 H) -one 21. A method for preparing 4-hydroxy-3-nitro-2 (1 H) -pyridone, which comprises hydrolyzing and decarboxylating 2-hydroxy-3-cyano-4-methoxypyridine to give 2,4-dihydroxypyridine, followed by nitration. of said 2,4-dihydroxypyridine. 22. A method according to claim 21, characterized in that said hydroidization, decarboxylation and nitration, are carried out in a concatenated manner without the need for intermediate isolation or purification of said 2,4-dihydroxypyridine. 23.- A method for preparing the dihydrochloride salt of [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1- [3-chloro-2-] tienii) methyl] propyl] aminoJ2-pyridinyl] amino] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide, comprising the steps of reacting 4-chloro-3-nitropyridin-2 (1 H) -one with (R) - 3-chloro-a-ethyl-2-thiopheneethanamine, to form (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridinamine , followed by replacement of the hydroxyl portion of (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridinamine with a chloro group to form (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro-4-pyridinamine, followed by the reaction of (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methy1] propyl] -3-nitro-4-pyridinamine with 2R, 3S-isopropylidenedioxy-4R-amino-1S-ethylaminocarbonylcyclopentane , to form [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thyl) methyl] propyl] amino] - 3-nitro-2-pyridinyl] amine, followed by reduction from [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro-2- pyridinium] amine a [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, followed by hydrolyzation of [3aR- [3aa, 4a, 6a (R * ), 6aa]] - 6 - [[3-amino-4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N- ethyltetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, in the presence of hydrochloric acid; said steps are carried out in a concatenated manner, without the need for intermediate isolation or purification of the intermediate compounds [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[3-amino-4 - [[ 1 - [(3-Chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] -N-ethyl-tetrahydro-2,2-dimethyl-4H-cyclopenta-1, 3- dioxol-4-carboxamide, [3aR- [3aa, 4a, 6a (R *), 6aa]] - 6 - [[4 - [[1 - [(3-chloro-2-thienyl) methyl] propyl] amino] -3-nitro-2-pyridinyl] amino] -N-ethyltetrahydro-2, 2-dimethyl-4H-cyclopenta-1,3-dioxol-4-carboxamide, (R) -2-chloro-N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -3-nitro -4-pyridinamine or (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridineamine. 24.- A method to prepare [1S- [1a, 2b, 3b, 4a (S *)]] - 4- [7 - [[1- (3-chloro-2-thienyl) methyl] propyl] am No] -3H-imidazo [4,5-b] pyridin-3-yl] -N-ethyl-2,3-dihydroxy-cyclopentanecarboxamide in crystalline form, comprising the steps of forming the free base of [1S- [1a, 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1- [3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino ] -N-ethyl-2,3-dihydroxycyclopentanecarboxamide from a dihydrochloride salt thereof, followed by the reaction of said free base with formamidine acetate, said steps being performed in a concatenated manner without the need for intermediate isolation or purification of said free base. 25.- A method to prepare [1S- [1a, 2b, 3b, 4a (S *)]] - 4- [7 - [[1- (3-chloro-2-thienyl) methyl] propyl] amino ] -3H-α-dazo [4,5-b3pyridin-3-yl] -N-etii-2,3-dihydroxy-cyclopentanecarboxamide in crystalline form, which comprises reacting [1 S- [1 a] dihydrochloride , 2b, 3b, 4a (S *)]] - 4 - [[3-amino-4 - [[1 - [3-chloro-2-thienyl) methyl] propyl] amino] -2-pyridinyl] amino] - N-ethyl-2,3-dihydroxycyclopentanecarboxamide with formamidine acetate. 26.- (R) -N- [1 - [(3-chloro-2-thienyl) methyl] propyl] -2-hydroxy-3-nitro-4-pyridinamine. 27.- [1 S [1 a, 2b, 3b, 4aS *)]] - 4 - [[3-amino-4 - [[1 - [3-chloro-2-thienyl) methyl] propyl] amino] - 2-pyridinyl] amino] -N-ethyl-2,3-dihydroxycyclopentane-carboxamide.