First example of the solvent effect on absolute conformation of chiral 3,3-disubstituted 1,4-benzodiazepin-2-ones

被引：11

作者：

Avdagic, A ^{[1
]}

Lesac, A ^{[1
]}

Sunjic, V ^{[1
]}

机构：

[1] Rudjer Boskovic Inst, HR-10000 Zagreb, Croatia

来源：

TETRAHEDRON | 1999年 / 55卷 / 05期

关键词：

benzodiazepines; conformation; circular dichroism; NMR;

D O I：

10.1016/S0040-4020(98)01113-2

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Chiral 3,3-disubstituted 1,4-benzodiazepin-2-ones (3S)-7 and (3S)-8 reveal solvent dependent conformational equilibria. The conformer with absolute P-conformation, with CH2X (X = p-tosyl, CI) group in a pseudoaxial (psi a) position and CH2OAc group in a pseudoequatorial (psi e) position, prevails in nonpolar solvents, as shown by LH-NMR and CD spectra. For (3S)-7 only a small shift of the conformational equilibrium in a polar solvent (DMSO) is observed, whereas compound (3S)-8 inverts to a prevailing M-conformer. The inversion barrier for MIP equilibrium is estimated on the bases of TDNMR data. For compounds (3R)-5 and (3S)-7, 8 the relative stability of the MIP conformers in the ground state is calculated by the MM2 method; comparison of these results with CD and H-1-NMR data reveal that nonpolar solvents invert the relative stability calculated for the two conformers. (C) 1999 Elsevier Science Ltd. All rights reserved.

引用

页码：1407 / 1416

页数：10

共 12 条

[1] Lipase-catalyzed acetylation of 3-substituted 2,3-dihydro-1H-1,4-benzodiazepin-2-ones:: Effect of temperature and conformation on enantioselectivity and configuration [J].