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本文报道N-甲基取代邻羟基芳香基苯并咪唑的合成,并研究了此类螯合剂的分子内氢键的性质。在合成N-甲基芳香基苯并咪唑或芳香基苯并咪唑过程中进行的N-甲基化时,随着(?)NH基N上的电荷密度增加和取代基空间位阻的增大,产率急剧下降。羟基的化学位移,离解常数和HMO计算均表明2-(邻羟基芳香基)-苯并咪唑、(口恶)唑、噻唑等化合物均具有较弱的分子内氢键。由于五员共轭环的生成,内氢键强度与结构之间的规律性很差。这与前文~[7]关于邻苯基偶氮芳香酚和2(-邻羟基苯基)喹啉的结果不同。
This paper reports the synthesis of N-methyl-substituted o-hydroxybenzimidazoles and studies the intramolecular hydrogen bonding properties of these chelators. As N-methylation proceeds during the synthesis of N-methylarylbenzimidazole or arylbenzimidazole, as the charge density on the (?) NH group N increases and the steric hindrance of the substituents increases , The yield dropped sharply. The chemical shifts of hydroxyl groups, dissociation constants and HMO calculations show that both 2- (orthohydroxyaromatic) -benzimidazoles, (oxazoles) and thiazoles have weak intramolecular hydrogen bonds. Due to the formation of five-member conjugate rings, the regularity between the strength and structure of hydrogen bonds is poor. This is in contrast to the previous results [7] on o-phenyl-azo-ol and 2-o-hydroxyphenyl-quinoline.