Patent ID: 6316624
Filing Date: 2001-11-13
Classification: C07D

Abstract:
A process for preparing a compound of formula (IV): ##STR3##(wherein R.sup.1 is C.sub.1-4 alkyl, C.sub.1-4 haloalkyl benzyl, C.sub.3-6 alkenyl or C.sub.3-6 alkynyl (provided that the .alpha.-carbon atom of R.sup.1 is neither substrate nor substituted with halogen), which comprises:i. ring opening a compound of formula (II): ##STR4##under acidic conditions in the presence of an organic acid or an ion exchange resin, in a suitable solvent and at a temperature between 50.degree. C. and the boiling point of the solvent used, to give a compound of formula (III): ##STR5##and,ii. reacting the compound of formula (III) with a source of hydroxylamine in the presence of an acid.