Synthesis of Dipolar Ethyleneimidazolium Benzimidazolate Inner Salts and Their Transformation to 2-Vinylbenzimidazoles through a Type of b-Elimination Reaction
摘要:
The synthesis and spectroscopic properties of the fairly stable title inner salts (5) are reported. For several of the betaines (5), both the highly dipolar character due to the terminal rings and the nature of the spacer promoted a type of beta-elimination reaction. Thus, formation of 2-vinylbenzimidazoles (7) from the corresponding betaines (5) proceeds in high yield under neutral and mild conditions. Following similar treatment, the 1-(2-benzimidazol-2-ylethyl)imidazolium salt (8b) undergo nucleophilic substitution reactions.
An efficient synthesis of 2-vinylbenzimidazoles from 1-(2-(benzimidazol-2-ylethyl)pyridinium salts using an anion-exchange resin
摘要:
Transformation of several 1-(2-benzimidazol-2-ylethyl)pyridinium salts, obtained by two different procedures, into their corresponding 2-vinylbenzimidazoles either using an anion-exchange resin (OH- form) or in the solid state is described. This approach now allows a facile entry into the almost unknown 2-vinylbenzimidazole monomers.