Patent ID: 8071767

Claim:
A process for preparation of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of formula I: or its hydrochloride salt thereof comprising: a) reacting 2-amino-3-hydroxypyridine of formula II: with 2-acetylbutyrolactone of formula III: in the presence of phosphorous oxychloride to form a reaction mass; b) quenching the reaction mass obtained in step-(a) in a mixture of ice and water to form a quenched reaction mass; c) adjusting the pH of the quenched reaction mass to 4 - 6 with a base to produce a separated substantially pure compound of formula I; d) collecting the separated substantially pure compound of formula I; and e) optionally converting the separated substantially pure compound of formula I into its substantially pure hydrochloride salt by reacting the separated substantially pure compound of formula I with alcoholic or gaseous hydrogen chloride in a solvent selected from an alcoholic solvent and an aromatic solvent.