Abstract The steric and electronic effects of acyl substituents COR (R = Me, i-Pr, Ph and t-Bu) upon conformational and keto—enol equilibria in 3-acyl-3,4-dihydrocoumarins have been studied by 1 H and 13 C NMR spectroscopy. With the increase of the effective size of R, preference for the equatorial position and the keto-form population increases considerably. The 13 C substituent-induced chemical shifts
摘要 1 H 和 13 研究了酰基取代基 COR(R = Me、i-Pr、Ph 和 t-Bu)对 3-酰基-3,4-二氢香豆素的构象和酮-烯醇平衡的空间和电子效应。 C 核磁共振光谱。随着 R 的有效大小的增加,对赤道位置和酮型人口的偏好显着增加。还讨论了 13 C 取代基引起的化学位移。
Efficient Chemoselective Reduction of 3-Substituted Coumarins Utilizing ortho-Phenylenediamine and Benzaldehyde
2-Phenylbenzimidazoline, generated in situ from ortho-phenylenediamine and benzaldehyde, is an effective reagent to achieve the chemoselective reduction of the styrenic double bond in 3-substituted coumarins, which takes place in high yield.
BOJILOVA, A.;IVANOV, CH., SYNTHESIS, BRD, 1984, N 6, 489-491
作者:BOJILOVA, A.、IVANOV, CH.
DOI:——
日期:——
HUTCHINS R. O.; ROTSTEIN D.; NATALE N.; FANELLI J., J. ORG. CHEM. <JOCE-AH>, 1976, 41, NO 20, 3328-3329
作者:HUTCHINS R. O.、 ROTSTEIN D.、 NATALE N.、 FANELLI J.