Microwave assisted synthesis of 2,3-dihydro-4H-benzo[4,5]thiazolo[3,2-a]furo[2,3-d]pyrimidin-4-ones and 6,7-dihydro-5H-furo[2,3-d]thiazolo[3,2-a]pyrimidin-5-ones using Mn(OAc)3

Abstract 2-Hydroxy-4 H -benzo[4,5]thiazolo[3,2- a ]pyrimidin-4-one 2a and 7-hydroxy-5 H -thiazolo[3,2- a ]pyrimidin-5-one 2b , were obtained in high yields under mild conditions from the cyclization reactions of bis-(2,4,6-trichlorophenyl) malonate and 2-aminobenzothiazole or 2-aminothiazole, respectively. A new class of compounds, 2,3-dihydro-4 H -benzo[4,5]thiazolo[3,2- a ]furo[2,3- d ]pyrimidin-4-ones and 6,7-dihydro-5 H -furo[2,3- d ]thiazolo[3,2- a ]pyrimidin-5-ones, were synthesized via the microwave assisted radical addition of compounds 2a and 2b to various alkenes using manganese(III) acetate. A preliminary acetylcholine esterase (AchE) inhibition test of compound 4e showed excellent (92%) inhibitory potential, comparable with the standard drug Donapezil®.