NEW PROCESS FOR PREPARING 3-METHYL-4-PHENYLISOXAZOLO[3,4-D]PYRIDAZIN-7(6H)-ONE

摘要

Disclosed is a process for preparing 3-methyl-4-phenylisoxazolo[3,4-d]pyridazin-7(6H)-one which process comprises the steps of: a) reacting 1-phenylbutane-1 ,3-dione with ethyl 2-chloro-2-(hydroxyimino)acetate b) subsequently reacting the product from step (a) with hydrazine or an hydrate thereof to yield 3-methyl-4-phenylisoxazolo[3,4-d]pyridazin-7(6H)-one wherein the process is characterised by the fact that step (b) is carried out on the mixture resulting from step (a) without isolating ethyI 4-benzoyl-5-methylisoxazole 3-carboxylate there from.