Patent GB-1324849-A (GB)
Title: Thieno 3,4-d pyrimidines
IPC: A61P29/00
Filed: 1970-07-14
Abstract: 1324849 Thieno[3,4-d]pyrimidines UCB SA 13 July 1971 [14 July 1970] 34144/70 Heading C2C  Novel thieno[3,4-d]pyrimidines of the general formula wherein R 1  is a hydrogen or halogen atom or an alkyl, alkoxy, amino, alkylamino, allylamino, hydroxyalkylamino, cycloalkylamino, phenylamino, dialkylamino, di-(hydroxyalkyl)-amino, N - alkyl - N - hydroxyalkyl - amino, pyrrolidino, piperidino, alkylpyrrolidino, alkylpiperidino, morpholino, 2- or 3-alkyl-morpholino, 3,5- dialkylmorpholino or N-methylpiperazino group, all alkyl, alkoxy and cycloalkyl groups containing 1-7, 1-5 and 3-6 carbon atoms, respectively; R 2  is as R 1  (all alkyl groups containing 1-8 carbon atoms) except a hydrogen or halogen atom or an alkyl or alkoxy group or it may be a C 1-5  alkoxy group when R 1  is a hydrogen or halogen atom or an alkyl or alkoxy group; and R 3  is a hydrogen atom or a C 1-7  alkyl group; and pharmaceutically acceptable acid addition salts thereof are prepared (a) when R 1  is a halogen atom and R 2  is as defined above with the exception of a hydrogen or halogen atom, by reaction of the corresponding compound wherein R 2  is a halogen atom with a compound of the general formula R 2 M, wherein R 2  is a nitrogencontaining group as defined above when M is a hydrogen atom and R 2  is a C 1-5  alkoxy group when M is an alkali or alkaline earth metal atom; (b) when R 1  is a hydrogen atom, by hydrogenolysis of the corresponding compound in which R 1  is a halogen atom; (c) when R 1  is as defined above with the exception of a hydrogen or halogen atom or an alkyl group by reaction of the corresponding compound wherein R 1  is a halogen atom with a compound of the general formula R 1 M, wherein M is a hydrogen atom when R 1  is a nitrogen-containing group as defined above or an alkali or alkaline earth metal atom when R 1  is an alkoxy group; (d) when R 1  and R 2  are identical and are each a nitrogencontaining group as defined above, by reaction of the corresponding compound wherein R 1  and R 2  are each a halogen atom with an excess of a compound of the general formula R 1 H; (e) when R 1  and R 2  are identical and are each an alkoxy group, by reaction of the corresponding compound wherein R 1  and R 2  are each a halogen atom with an excess of an alkali or alkaline earth metal C 1-5  alkoxide; (f) when R 1  is an alkoxy group and R 2  is a nitrogencontaining group as defined above, by reaction of the corresponding compound wherein R 2  is an alkoxy group with a compound of the general formula R 2 H; and (g) when R 1  is an alkyl group and R 2  is as defined above with the exception of a hydrogen or halogen atom, by reaction of the corresponding compound wherein R 2  is a halogen atom with a compound of the general formula R 2 H; followed optionally by salification of the product. 2,4 - Dichloro - thieno[3,4-d]pyrimidine is pre pared by reaction of 3-amino-4-carbomethoxythiophene hydrochloride with potassium cyanate in the presence of hydrochloric acid, treatment of the resulting 3-meido-4-carbomethoxy-thiophene with concentrated HCl in ethanol with heating, and chlorination of the resulting 2,4- dihydroxy-thieno[3,4-d]pyrimidine. 2,4-Dichloro- 5-methyl-thieno[3,4-d]pyrimidine is prepared analogously from 4-amino-3-carbethoxy-2-methylthiophene hydrochloride, which is prepared by treatment of 3-carbethoxy-4-isonitroso-2-methyl-tetrahydrothiophene with ethanolic HCl. 4 - Chloro - 2 - n - propyl - thieno[3,4 - d]pyrimidine is prepared by reaction of butyric anhydride with 3 - amino - 4 - carbomethoxythiophene hydrochloride, hydrolysis of the resulting 3 - butanoylamino - 4 - carbomethoxythiophene with a mixture of NaOH, water and methanol, treatment of the resulting 3-butanoylamino-4-thienoic acid with acetic anhydride, reaction of the resulting 2-n-propyl-4-oxothieno[3,4-d]-4H-1,3-oxazine with concentrated ammonia and chlorination of the resulting 4- hydroxy - 2 - n - propyl - thieno[3,4 - d]pyrimidine. Pharmaceutical compositions having cardiovascular, respiratory and analeptic effects, stimulating or depressing effects on the central nervous system and analgesic, anti-inflammatory, diuretic, cytostatic, bacteriostatic and fungistatic effects comprise, as active ingredient, at least one thieno[3,4-d]pyrimidine of the first general formula above or a pharmaceutically acceptable acid addition salt thereof, in admixture with a solid or liquid pharmaceutical diluent or carrier, and may be administered orally, parenterally or rectally.