Synthesis and spectroscopic properties of Schiff bases derived from 3-hydroxy-4-pyridinecarboxaldehyde

被引：38

作者：

Sanz, D

Perona, A

Claramunt, RM

Elguero, J

机构：

[1] Univ Nacl Educ Distancia, Fac Ciencias, Dept Quim Organ & Bioorgan, E-28040 Madrid, Spain

[2] CSIC, Inst Quim Med, Ctr Quim Organ Manuel Lora Tamayo, E-28006 Madrid, Spain

来源：

TETRAHEDRON | 2005年 / 61卷 / 01期

关键词：

Schiff bases; hydrogen bonds; tautomerism; multinuclear NMR; DFT calculations;

D O I：

10.1016/j.tet.2004.10.036

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

A series of six new Schiff bases has been prepared by reacting aniline and 4-R-substituted anilines (R = CH3, OCH3, Br, Cl, NO2) with 3-hydroxy-4-pyridinecarboxaldehyde. The H-1, C-13, N-15 and O-17 NMR data of these compounds are used to discuss the tautomerism. N-15 NMR and O-17 NMR chemical shifts established the tautomer existing in solution as the hydroxy/imino. C-13 CPMAS NMR confirms that the same tautomer is found in the solid state. The stabilities of the tautomeric forms have been approached using density functional calculations (B3LYP/6-3IG**) in the gas phase. In all cases the neutral hydroxy/imino with E configuration is more stable than the oxo/enamino form (by similar to22 kJ mol(-1)) and significantly more stable than the betaine (by similar to75 kJ mol(-1)). (C) 2004 Elsevier Ltd. All rights reserved.

引用

页码：145 / 154

页数：10

共 29 条

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