Ranitidine is prepared by reacting a compound of formula (II)with aziridine. The reaction may be carried out in the absence of a solvent or preferably in the presence of a solvent such as water or an alkanol at elevated temperature.

Ranitidine is prepared by treating an aldehyde of formula (II)with dimethylamine and a reducing agent which is capable of effecting reductive alkylation to introduce the group Me2NCH2 - but which does not reduce the nitroethene group. The reaction is carried out in a suitable solvent preferably in the presence of an acid or followed by treatment with an acid. Suitable reducing agents include diborane aluminium hydride and alkali or alkaline earth metal borohydrides.The aldehyde (II) may be gener...

Compounds are disclosed which are phenoxyalkoxyphenyl derivatives of general formula (I) wherein Y represents the group -A -ZA or OZA where A represents a carboxylic acid group a 5-1H-tetrazolyl ring or a N-5-1H-tetrazolylcarboxamide group; Z represents a C1-4 alkylene C2-4 alkenylene or C2-4 alkynylene chain optionally substituted by one or more C1-3 alkyl groups and Z represents a C1-4 alkylene chain optionally substituted by one or more C1-3 alkyl groups; X represents a C1-10 carbon chain w...