An Unequivocal Synthesis of 4-Amino-1,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-2,7-diones and 2-Amino-3,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-4,7-diones
An Unequivocal Synthesis of 4-Amino-1,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-2,7-diones and 2-Amino-3,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-4,7-diones
Selective Hydrolysis of 2,4-Diaminopyrimidine Systems: A Theoretical and Experimental Insight into an Old Rule
作者:J. Teixidó、J. I. Borrell、C. Colominas、X. Deupí、J. L. Matallana、J. L. Falcó、B. Martinez-Teipel
DOI:10.1021/jo0056390
日期:2001.1.1
unexpectedly afforded exclusively the 4-amino-2-oxopyrimidine isomer (3). In this paper, we present the experimental work and ab initio calculations carried out to understand this discrepancy. As a part of such study, eight compounds containing a 2,4-diaminopyrimidine moiety were calculated in gas phase and in aqueous solution, and some acid hydrolyses were reexamined. Results showed that the presence of an
Cyclization of 5-Cyano-6-cyanoimino-3,4-dihydropyridin-2(1H)-ones with Amines
作者:José I. Borrell、Núria Mont、Francisco Carrión、Jordi Teixidó
DOI:10.3987/com-09-11860
日期:——
The cyclization of 5-cyano-6-cyanoimino-3,4-dihydropyridin-2(1h)-ones with amines, leading to pyrido[2,3-d]pyrimidines, is studied. Four play all important role oil the direction of cyclization: (1) the planarity of the reaction area; (2) the cyclization proceeds by the nucleophilic attack of all amidine onto ail electrophilic group which call be either a cyano group or all alkylamidine; (3) the basicity of the amine plays all important role, the ionization Of the Substrate making more difficult the formation of the aforementioned amidine which is needed for the cyclization; and (4) the nucleophilic attack and the tautomerization of the cyclization product are processes which call occur practically Simultaneously, so that the electronic movement involved in the tautomerization process coincides with the one which happens In the nucleophilic attack, both processes promoting each other.
VICTORY, PEDRO;CRESPO, ANA;NOMEN, ROSA;BORRELL, JOSE I., AFINIDAD, 46,(1989) N20, C. 107-113
作者:VICTORY, PEDRO、CRESPO, ANA、NOMEN, ROSA、BORRELL, JOSE I.
DOI:——
日期:——
VICTORY, P.;GARRIGA, M., HETEROCYCLES, 24,(1986) N 11, 3053-3058