J. Borrell, J. Teixidó, B. Martínez-Teipel
1996
Citations
0
Influential Citations
12
Citations
Journal
Collection of Czechoslovak Chemical Communications
Abstract
An unequivocal set of procedures for the synthesis of 4-amino-1,5,6,8-tetrahydropyrido[2,3- d ]pyrimidine-2,7-diones ( 7 ) and 2-amino-3,5,6,8-tetrahydropyrido[2,3- d ]pyrimidine-4,7-diones ( 8 ), in a maximum of four steps from an α,β-unsaturated ester 1 , is reported. Thus, the acid hydrolysis of the 2,4-diaminopyrido[2,3- d ]pyrimidines 3 yields the 4-amino-2-oxopyrido[2,3- d ]pyrimidines 7 while the cyclization of the Michael adducts 9 (formed by reaction of 1 and methyl cyanoacetate) with guanidine affords the corresponding 2-amino-4-oxopyrido[2,3- d ]pyrimidines 8 . Both isomers were also obtained by hydrolysis of the 4-amino-2-bromo- and 2-amino-4-bromo-5,6-dihydropyrido[2,3- d ]pyrimidin-7(8 H )-ones 5 and 6 , respectively.