Trapping of metabolically generated electrophilic species with cyanide ion: metabolism of 1-benzylpyrrolidine
作者:Bert Ho、Neal Castagnoli
DOI:10.1021/jm00176a006
日期:1980.2
analogues of 4 with rabbit liver microsomal preparations in the presence of cyanide ion have led to the characterization of 1-benzyl-2-cyanopyrrolidine (13), cis- and trans-1-benzyl-2,5-dicyanopyrrolidine (14a and 14b, respectively), and 1-benzyl-5-cyano-2-pyrrolidinone (15). The cyano adducts of the amine are thought to result from nucleophilic attack by cyanide ion on metabolically generated iminium species
Substitution reactions of 2-phenylsulphonyl-piperidines and -pyrrolidines with carbon nucleophiles: Synthesis of the pyrrolidine alkaloids norruspoline and ruspolinone
作者:Dearg S. Brown、Philippe Charreau、Thomas Hansson、Steven V. Ley
DOI:10.1016/s0040-4020(01)86388-2
日期:1991.1
treatment with benzenesulphinic acid. On reaction with various carbon nucleophiles these sulphones gave good yields of substitution products. Typical nucleophiles used in these studies were organometallic reagents derived from Grignard reagents and zinc halide together with silyl enol ethers, silyl ketene acetals, allylsilanes and trimethylsilyl cyanide in the presence of a Lewis acid. These methods
Various bacterial and fungal strains were screened for their ability to catalyse the regioselective hydrolysis of 1-benzylpyrrolidine-2,5-dicarbonitrile (1). Among the examined strains, Rhodococcus opacus sp-lma whole cells transformed both isomers of 1 into 1-benzyl-5-cyano-2-pyrrolidinone (2) and N-benzylacetamide (3). These reactions are difficult to achieve chemically and the synthesis of compound 2 did not compete with microbiological catalysis in terms of efficiency and respect for the guidelines of green chemistry. To distinguish between an oxidative or hydrolytic based-mechanism, the origin of the oxygen atom in 2 was investigated by using O-18(2) and (OH2)-O-18 coupled with GC-MS analysis. These experiments confirmed that the oxygen atom in 2 came from water and not from molecular oxygen. The reaction is probably initiated by the dehydrogenation of 1 to generate the iminium ion, which could be trapped by a water molecule to form the cyanohydrin. The cyanohydrin intermediate would spontaneously break down to the gamma-lactam product 2. Conversion of 1 to 2 by induced rat liver microsomes suggests the involvement of a Cyt P-450-type enzyme. A mechanism that accounts for the formation of 3 is also proposed. (c) 2010 Elsevier B.V. All rights reserved.