Aza-analogs of Stilbene with a Dipolar Character. (E)-1-Alkyl-[2-(azolyl-2-idene)etylidene]dihydropyridines and (E)-2-[2-(1-Alkyl-3-pyridinium)vinyl]azolate Inner Salts
Aza-analogs of Stilbene with a Dipolar Character. (E)-1-Alkyl-[2-(azolyl-2-idene)etylidene]dihydropyridines and (E)-2-[2-(1-Alkyl-3-pyridinium)vinyl]azolate Inner Salts
A convenient synthesis and characterization of several examples of (E)-2- [2-(1-alkyl-3-pyridinio): vinyl] benzimidazolate inner salts and (E)-1-alkyl-2(or 4)-[2- (benzimidazol-2-ylidene)ethylidene]-dihydropyridines with a betaine character is reported. Their structural aspects are discussed mainly on the basis of the H-1 NMR data and experimental dipole moment values (11.6-13.0 D). The experimental information available for (E)-1-alkyl-2(or 4)- [2- (benzimidazol-2-ylidene)ethylidene] dihydrepyridines (A <-> B) is consistent with a betaine character, and the dipolar form (B) has been shown to make an important contribution to the ground state.
Alcalde Ermitas, Dinares Immaculada, Pons Josep-Maria, Roca Tomas, J. Org. Chem, 59 (1994) N 3, S 639- 643
作者:Alcalde Ermitas, Dinares Immaculada, Pons Josep-Maria, Roca Tomas