Process for the preparation of robenidine and salts thereof

摘要

The invention relates to a novel method for producing robenidine and salts thereof of the general formula wherein X denotes a halogen atom. The method uses hydrazine hydrate and a cyano compound as the starting materials, and the starting materials are first reacted in a C1-4 alcohol or a C1-4 alcohoVwater mixture as solvent or in an aprotic organic solvent, to produce a diaminoguanidine of the general formula wherein Y denotes a halogen atom or tosyl. This diaminoguanidine is then converted directly, without isolation, by reacting with a p-halobenzaldehyde of the general formula in a C1-4 alcohol or a C1-4 alcohol/water mixture as solvent or in a mixture of water and an aprotic polar organic solvent to produce the robenidine and salts thereof of general formula I.