摘要:
The present invention provides a process for the preparation of a 4H-pyrrido[1,2-a]-pyrimidin-4-one derivative, wherein the 4H-pyrrido[1,2-a]-pyrimidin-4-one derivative is Paliperidone or 3-(2-chloroethyl)-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrrido[1,2-a]-pyrimidin-4-one (‘CMHTP’), said process comprising enzymatically hydroxylating Risperidone or 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrrido[1,2-a]-pyrimidin-4-one (‘ClMTTP’), respectively, with at least one oxidoreductase enzyme; and optionally isolating or purifying the Paliperidone or CMHTP, wherein the at least one oxidoreductase enzyme is selected from the group of peroxidases, dioxygenases, monooxygenases and any combination thereof.