PROCESS FOR PREPARING N-/2-///5-(DIMETHYLAMINO)-METHYL-2-FURANYL/-METHYL/THIO/-ETHYL/-N'-METHYL-2-NITRO-1,1-ETHENE-DIAMINE

摘要

A new process for the preparation of N-¢2-¢¢¢5-(dimethyl-amino)-methyl-2-furanyl!methyl!thio!ethyl!-N'-methyl-2-nitro-1,1-ethenediamine (ranitidine) of the formula an its phsiologically acceptable acid addition salts is described, wherein 2-¢¢¢5-(dimethylamino)methyl-2-furanyl!-methyl!thio!ethane-amine of the formula is reacted with 1-nitro-3-methyl-keteneimine of the formula CH3N=C=CHNO2 to give the desired compound. 1-nitro-3-methyl-keteneimine is formed in situ by reacting 1-methylthio-1-methylamino-2-nitroethane of the formula in a polar organic solvent, such as methanol or acetonitrile, with a salt of a heavy metal, such as AgNO3, CuCl, dissolved in the same solvent, in the presence of a proton acceptor, such as triethylamine, at room temperature. Ranitidine is a valuable medicine in the treatment of ulcer diseases. Owing to a very simple course of the reaction and an extrodinary short reaction time, the process is excellently suitable for the industrial scale production.