| 摘要 |
A process for the preparation of 3-substituted ethyl-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2,-a]pyrimidin-4-one of the formula IIB: where X may be halo, acyloxy, or sulfonyloxy such as tosyloxy or mesyloxy, an intermediate in the synthesis of the anti-psychotic risperidone. The process comprises hydrogenation of 3-substituted ethyl-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one in aqueous inorganic acid medium at atmospheric to 60 psi at 0-100° C. in the presence of a metal catalyst and the product is isolated. A process for the preparation of risperidone of the formula I: comprising condensation of 3-substituted ethyl-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2,-a]pyrimidin-4-one with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole in water in the presence of an inorganic base at 25-100° C. and the product is isolated.
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