合成路线1

By condensation of 4-(4-fluorobenzoyl)piperidine (IX) with 6-(2-bromo ethyl)-7-methyl-2,3-dihydro-5H-thiazolo[2,3-a]pyrimidin-5-one (IV) by means of Na2CO3 in refluxing 4-methyl-2-pentanone. The starting products are obtained as follows: The cyclization of 4-hydroxy-5-(2-hydroxyethyl)-6-methyl-2-mercaptopyrimidine (I) with 1,2-dibromo ethane (II) by means of K2CO3 in hot dimethylacetamide gives 2,3-dihydro-6-(2-hydroxyethyl)-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one (II), which by reaction with HBr in refluxing acetic acid is converted to the corresponding 6-(2-bromoethyl) derivative (IV). The Grignard reaction of 4-bromofluorobenzene (V) with N benzyl-4 cyanopiperidine (VI) by means of Mg in dimethoxyethane gives 4-(4-fluorobenzoyl)-N-benzylpiperidine (VII), which is treated with ethyl chlorocarbo-nate in refluxing toluene to afford ethyl 4-(4-fluorobenzoyl)piperidine-1-carboxylate (VIII). Finally, this compound is treated with HBr in refluxing 48% HBr to give (IX).