| abstract |
The invention provides a process for preparing azetidine-3-carboxylic acid or salts thereof; useful as chemical hybridizing agents, which comprises treating a compound of the formula ##STR1## wherein R represents a hydrogen atom or a group of formula R 1 R 2 CH-- wherein R 1 and R 2 are independently selected from hydrogen, alkyl or optionally substituted phenyl moieties, with nitric acid and subjecting the resulting initial product to acid conditions to produce an acid-addition salt of azetidine-3-carboxylic acid, and thereafter, if desired, converting the acid-addition salt to the free acid or another salt of the acid, 1-nitrosoazetidine-3,3-dicarboxylic acid, 1-nitrosoazetidine-3-carboxylic acid and salts thereof being intermediates in the process. |