CONFORMATIONAL STUDIES BY DYNAMIC NMR .51. GEAR EFFECT IN SUBSTITUTED PYRIDONES

被引：7

作者：

BARTOLI, G ^{[1
]}

BOSCO, M ^{[1
]}

LUNAZZI, L ^{[1
]}

MACCIANTELLI, D ^{[1
]}

机构：

[1] UNIV BOLOGNA, DIPARTIMENTO CHIM ORGAN A MANGINI, I-40136 BOLOGNA, ITALY

来源：

TETRAHEDRON | 1994年 / 50卷 / 08期

关键词：

D O I：

10.1016/S0040-4020(01)86972-6

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Two conformational isomers have been MMR detected at -30 degrees in 2-substituted pyridones having an isopropyl group bonded to the Nitrogen atom. Their existence is due to the restricted rotation of the N-isopropyl group influenced by the ''gear effect'' of the flanking 2-alkyl groups (Me, Et, Pr-i). The interconversion barrier for this process (similar to 15 kcal/mol) was measured by total line shape analysis and is independent of the size of the flanking alkyl groups. Molecular Mechanics calculations and NOE difference experiments at -70 degrees allow the unambigous identification of the structures corresponding to the gear conformers.

引用

页码：2561 / 2570

页数：10

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