Petrova M, Muhamadejev R, Vigante B, Duburs G, Liepinsh Edvards
Latvian Institute of Organic Synthesis, Aizkraukles 21 Street, Riga 1006, Latvia.
R Soc Open Sci. 2018 Jun 13;5(6):180088. doi: 10.1098/rsos.180088. eCollection 2018 Jun.
1,4-Dihydropyridine (1,4-DHP) derivatives have been synthesized and characterized by H, C, N nuclear magnetic resonance (NMR) spectroscopy, secondary proton/deuterium C isotope shifts, variable temperature H NMR experiments and quantum-chemical calculation. The intramolecular hydrogen bonds NH⋯O=C and CH⋯O=C in these compounds were established by NMR and quantum-chemical studies The downfield shift of the NH proton accompanied by the upfield shift of the N nuclear magnetic resonance signals, the shift to the higher wavenumbers of the NH stretching vibration in the infrared spectra and the increase of the J(N,H) values may indicate the shortening of the N-H bond length upon intramolecular NH⋯O=C hydrogen bond formation.
已经合成了1,4 - 二氢吡啶（1,4 - DHP）衍生物，并通过氢、碳、氮核磁共振（NMR）光谱、二级质子/氘碳同位素位移、变温氢核磁共振实验和量子化学计算对其进行了表征。通过核磁共振和量子化学研究确定了这些化合物中的分子内氢键NH⋯O = C和CH⋯O = C。NH质子的低场位移伴随着N核磁共振信号的高场位移、红外光谱中NH伸缩振动向更高波数的位移以及J(N,H)值的增加，这可能表明分子内形成NH⋯O = C氢键时N - H键长度缩短。
