Collect. Czech. Chem. Commun. 1984, 49, 621-636

Potential hypnotics and anxiolytics: Synthesis of 2-bromo-4-(2-chlorophenyl)-9-[4-(2-methoxyethyl)piperazino]-6H-thieno[3,2,4-triazolo[4,3-a]-1,4-diazepine and of some related compounds

Zdeněk Polívka, Jiří Holubek, Emil Svátek, Jan Metyš and Miroslav Protiva

Research Institute for Pharmacy and Biochemistry, 130 00 Prague 3


The synthesis of 2,9-dibromo-4-(2-chlorophenyl)-6H-thieno[3,2-f]-1,2,4-triazolo[4,3-a]-1,4,diazepine (XX) has been carried out. The substitution reactions of XX with 1-(2-methoxyethyl) piperazine, 1-(3-methoxypropyl)piperazine, 1-(2-ethoxyethyl)piperazine and 1-(2-methylthiothyl)-piperazine afforded the title compound XXIV and its analogues XXV-XXVII. N-Alkylations of 2-bromo-4-(2-chlorophenyl)-9-piperazino-6H-thieno[3,2-f]-1,2,4-triazolo[4,3-a]-1,4-diazepine (XXIII) with 2-phenoxyethyl bromide and 2-phenylthioethyl bromide gave compounds XXVIII and XXIX. Cyclization of 5-(2-chlorophenyl)-2-hydrazino-3H-thieno[2,3-e]-1,4-diazepine(XVIIIa) by treatment with triethyl orthoformate resulted in 4-(2-chlorophenyl)-6H-thieno[3,2-f]-1,2,4-triazolo[4,3-a]-1,4-diazepine (XIX) which could be brominated only to the 9-bromo derivative XXI; attempts at further bromination to position 2 were unsuccessful. Some contribution to the syntheses of etizolam (I) and its dechloro analogue V in the stage of intermediates are being described. Compounds XXIV-XXIX were pharmacologically tested from the point of view of discoordinating and anticonvulsant activities; they proved less active than the analogous 8-chloro-6-(2-chlorophenyl)-1-piperazino-4H-striazolo[4,3-a]-1,4-benzodiazepines.