Process for preparing azetidine derivatives and intermediates therein.

摘要

The invention provides a process for preparing azetidine-3-carboxylic acid
<Chemistry id="chema01" num="0001"><Image id="ia01" he="9" wi="63" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>or salts thereof, useful as chemical hybridising agents, which comprises treating a compound of formula
<Chemistry id="chema02" num="0002"><Image id="ia02" he="17" wi="45" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>

wherein R represents a hydrogen atom or a group of formula R<Sup>1</Sup>R<Sup>2</Sup>CH- wherein R' and R<Sup>2</Sup> are independently selected from hydrogen, alkyl or optionally substituted aryl moieties, with nitric acid and subjecting the resulting product to acid conditions to produce an acid-addition salt of formula I, and thereafter, if desired, converting the acid-addition salt to the free acid or another salt of the acid of formula I; and 1-nitrosoazetidine-3,3-dicarboxylic acid, 1-nitrosoazetidine-3-carboxylic acid and salts thereof being intermediates in the process.