TY - JOUR
T1 - Synthesis of 4-unsubstituted dihydropyrimidines. Nucleophilic substitution at position-2 of dihydropyrimidines
AU - Cho, Hidetsura
AU - Nishimura, Yoshio
AU - Yasui, Yoshizumi
AU - Kobayashi, Satoshi
AU - Yoshida, Shin Ichiro
AU - Kwona, Eunsang
AU - Yamaguchi, Masahiko
PY - 2011/4/8
Y1 - 2011/4/8
N2 - Synthesis of novel 4-unsubstituted dihydropyrimidines (DPs) was performed. Subsequently, a variety of 4-unsubstituted 1,4(3,4)-DPs with amino moieties at position-2 were obtained in excellent yields by activation of position-2 owing to regioselective alkoxycarbonylation at position-3 of the DP skeleton. 3-Oxo-2-phenyl-2,3,5,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrimidine was obtained using phenylhydrazine instead of amines. Individual tautomers of 1,4(3,4)-DP were observed in the 1H NMR spectra of one derivative depending on temperature and concentration. On the other hand, only 1,4-DP was found in the solid state by single-crystal X-ray crystallography.
AB - Synthesis of novel 4-unsubstituted dihydropyrimidines (DPs) was performed. Subsequently, a variety of 4-unsubstituted 1,4(3,4)-DPs with amino moieties at position-2 were obtained in excellent yields by activation of position-2 owing to regioselective alkoxycarbonylation at position-3 of the DP skeleton. 3-Oxo-2-phenyl-2,3,5,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrimidine was obtained using phenylhydrazine instead of amines. Individual tautomers of 1,4(3,4)-DP were observed in the 1H NMR spectra of one derivative depending on temperature and concentration. On the other hand, only 1,4-DP was found in the solid state by single-crystal X-ray crystallography.
KW - 2,3,5,8-Tetrahydro[1,2,4]triazolo[4,3-a]
KW - Dihydropyrimidine
KW - Individual tautomer
KW - Nucleophilic substitution
KW - Pyrimidine
KW - Tautomerism
KW - X-ray diffraction
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U2 - 10.1016/j.tet.2011.01.092
DO - 10.1016/j.tet.2011.01.092
M3 - Article
AN - SCOPUS:79952575157
VL - 67
SP - 2661
EP - 2669
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 14
ER -