Richter Gedeon Vegyeszeti Gyar Rt

Eva Gai Nee Csongor

Kalman Harsanyi

Bela Hegedus

Ferenc Trischler

Erik Bogsch

Gyorgy Domany

Peter Bod

Eva Fekecs

Istvan Szabadkai

The invention relates to a new process for the preparation of N-sulfamyl-3-(2-guanidinothiazol-4-yl-methylthio)-propionitrile (famotidine) of the formula (I) ##STR1## by S-alkylation of 2-guanidino-thiazol-4-yl-methanethiol obtained from S-(2-guanidino-thiazol-4-yl-methyl)-isothiourea dihydrochloride of the formula (III) ##STR2## by in situ treatment with a base, which comprises carrying out S-alkylation with a N-sulfamyl-3-halopropionamidine of the formula (II) ##STR3## wherein X stands for halogen.

Process for the preparation of

The invention relates to new propionamidine derivatives of formula (I) ##STR1## wherein X is halogen, and to a process for their preparation. According to the invention compounds of the formula (I) are prepared by reacting a 3-halopropionitrile of the formula (III) ##STR2## wherein X is as defined above, with sulfamide of the formula (II) ##STR3## in the presence of a hydrogen halide. Compounds of the formula (I) are useful intermediates in the preparation of famotidine.

N-sulfamyl-3-halopropionamidines

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Budapest, Hungary

Eva Gai Nee Csongor