名称:
Simple and Efficient Preparation of [10,20-13C2]- and [10-CH3,13-13C2]-10-Methylretinal: Introduction of Substituents at the 2-Position of 2,3-Unsaturated Nitriles
摘要:
In this paper, we present the synthesis of [10,20-C-13(2)] -10-methylretinal and [10-CH3,13-C-13(2)] -10-methylretinal, two doubly C-13-labeled chemically modified retinals that have been recently used to study the structural and functional details behind the photocascade of bovine rhodopsin (Verdegem et al. Biochemistry 1999, 38, 11316; de Lange et al. Biochemistry 1998, 37, 1411). To obtain both doubly C-13-labeled compounds, we developed a novel synthetic method to directly and regiospecifically introduce a methyl substituent on the 2-position of 3-methyl-5-(2',6',6'-trimethyl-1'cyclohexen-1'-yl)-2,4-pentadienenitrile. Encouraged by these results, we investigated the scope of this novel reaction by developing a general method for the introduction of a variety of substituents to the 2-position of 3-methyl-2,3-unsaturated nitriles, paving the way for simple and efficient synthesis of a wide variety of 10-, 14-, and 10,14-substituted chemically modified retinals, and other biologically important compounds.