An approach to trapping .gamma.-glutamyl radical intermediates proposed for vitamin K dependent carboxylase: .alpha.,.beta.-methyleneglutamic acid
作者:James T. Slama、Rajiv K. Satsangi、Anne Simmons、Vincent Lynch、Randall E. Bolger、John Suttie
DOI:10.1021/jm00164a056
日期:1990.2
beta-methyleneglutamate diethyl ester. Saponification of a N-protected methyleneglutamic acid dialkyl ester using limiting alkali was shown to selectively yield the alpha-alkyl ester gamma-acid. The reaction was used to produce alpha,beta-cyclopropane-containing analogues of the carboxylase substrates N-t-Boc-L-glutamic acid alpha-benzyl ester and N-benzoyl-L-glutamic acid alpha-ethyl ester. The cyclpropane-containing
维生素K依赖性羧化酶通过产生γ-谷氨酰基自由基,γ-谷氨酰基碳负离子或通过协同的羧化作用激活底物肽的谷氨酰胺γ-CH进行羧化。我们建议通过包含谷氨酸的α,β-环丙烷类似物的底物的分子内重排来拦截推定的γ-谷氨酰胺基自由基。环丙基羰基自由基重排成2-丁烯基自由基是快速,放热的,并被认为可诊断自由基的形成。谷氨酸的β-环丙烷类似物1-氨基-2-(羧甲基)环丙烷-1-甲酸酯是从α-酮戊二酸二乙酯开始合成的。首先用苄腈在硫酸中处理α-酮酯,得到α,α-二苯甲酰胺基戊二酸二乙酯。字母 在对苯磺酸在热苯中处理后,将α-二苯甲酰胺酸裂解生成α,β-脱氢氨基酸和苯甲酰胺。将重氮甲烷加到脱氢氨基酸中导致重氮甲烷的环加成和吡唑啉的生成,其在辐射下损失了N 2,得到了被保护的含环丙烷的氨基酸类似物。N-苯甲酰基-α,β-亚甲基谷氨酸二乙酯的酸性水解导致高产率地产生未保护的氨基酸,α,β-亚甲基谷氨酸。在该合成中