R. Toplak, J. Svete, S. Grdadolnik
1999
Citations
0
Influential Citations
20
Citations
Journal
Collection of Czechoslovak Chemical Communications
Abstract
Methyl ( Z )-2-[(benzyloxycarbonyl)amino]-3-dimethylaminopropenoate ( 1 ) was used as a reagent for preparation of 3-[(benzyloxycarbonyl)amino] substituted 4 H -pyrido[1,2- a ]pyrimidin-4-ones 17 - 21 , 4 H -pyrimido[1,2- b ]pyridazin-4-ones 22 and 23 , 5 H -[1,2,4]triazolo[2,3- a ]- pyrimidin-5-one 24 , 5 H -thiazolo[3,2- a ]pyrimidin-5-one 25 , and 4 H -pyrazino[1,2- a ]pyrimidin-4-one 26 . Removal of the benzyloxycarbonyl group by catalytical transfer hydrogenation with Pd/C in the presence of cyclohexene is selective to give 3-amino-4 H -pyrido[1,2- a ]- pyrimidin-4-ones 27 - 30 in 85-92% yields, or with hydrogen bromide in acetic acid to give 3-amino-4 H -pyrimido[1,2- b ]pyridazin-4-one ( 31 ) and 6-amino-5 H -thiazolo[3,2- a ]pyrimidin-5-one ( 32 ) in 80% yields.