The synthesis of novel GABA uptake inhibitors. Part 2. Synthesis of 5-hydroxytiagabine, a human metabolite of the GABA reuptake inhibitor tiagabine
作者:Knud E. Andersen、Mikael Begtrup、Mukund S. Chorghade、Elaine C. Lee、Jesper Lau、Behrend F. Lundt、Hans Petersen、Per O. Sørensen、Henning Thøgersen
DOI:10.1016/s0040-4020(01)85345-x
日期:1994.1
(R)-1-(4-(2,5-Dihydro-3-methyl-5-oxothien-2-ylidene)-4-(3-methyl-2-thienyl)butyl)-3- piperidinecarboxylic acid (5-hydroxytiagabine) 13, has been prepared in 8 steps from 2-bromo-3-methylthiophene 3. Key steps are Grignard reactions, displacement of heteroaromatic chlorine with methoxy, and simultaneously demethylation and opening of a hydroxymethylcyclopropane with bromotrimethylsilane. An alternative approach involving acylation of 2-lithio-3-methylthiophene 17a was found less satisfying. A metalloporphyrin assisted hydroxylation of tiagabine 1 also yielded the target metabolite. The structure of 5-hydroxytiagabine was confirmed by NMR-data including COSY, ROESY, HMQC and HMBC experiments.