IMPROVED PROCESS FOR THE PREPARATION OF 3-{2-`4-(6-FLUORO-1,2-BENZISOXAZOL-3-YL)-1-PIPERIDINYL!ETHYL}-6,7,8,9-TETRAHYDRO-2-METHYL-4H-PYRIDO`1,2-A!PYRIMIDIN-4-ONE

摘要

The invention relates to a process for the preparation of 3-{2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl] ethyl}-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyri midin-4-one of the Formula (I), and pharmaceutically acceptable acid addition salts thereof by subjecting the oxime of the Formula (II), to ring-closure in the presence of an alkali hydroxide, alkali carbonate or alkali-C1-4 alkoxide in an inert organic solvent, converting the base of the Formula I thus obtained into an acid addition salt or setting free the base of the Formula I from an acid addition salt thereof which comprises reacting a halogen derivative of the general Formula (XIV), (wherein Hal is halogen) with piperidine oxime derivative of the Formula (V), or an acid addition salt thereof in the presence of a base, and using by the ring-closure of the oxime of the Formula II formed a C1-4-alkanol as inert solvent. The process of the present invention enables the economical preparation of a product having a purity suitable for phamaceutical purposes.