ABSTRACT
A green and efficient process for the synthesis of cenobamate has been accomplished in 70% yield and >99% ee through the bio-reduction of ß-ketotetrazole using Daucus carota whole plant cells. The corresponding ß-hydroxytetrazole was isolated in 60% yield and >98% ee. This is the first report on the biocatalytic reduction of ß-ketotetrazole using plant enzymes derived from D. carota root cells with excellent enantioselectivity.
Subject(s)
Anticonvulsants , Carbamates , Chlorophenols , Ketones , Tetrazoles , Stereoisomerism , BiocatalysisABSTRACT
The ß-adrenergic receptor blocking agents are an important class of drug molecules. The present study reports a new chemo and chemo-enzymatic synthetic process for (RS)-, (R)-, and (S)-bunolol, one of the potent ß-adrenergic receptor blocker. In chemo-enzymatic process, CAL L4777 lipase was employed for enantioselective kinetic resolution to synthesize the enantiopure (R)-alcohol and (S)-ester from the corresponding racemic alcohol. Thereafter, the corresponding (R)-alcohol and deacylated (S)-ester were treated with tert-butylamine to produce (S)- and (R)-bunolol, respectively. In chemical approach, epichlorohydrin (RS-, R-, and S-) was used as a starting material via respective (RS)-, (S)-, and (R)-glycidyl ether as intermediates for synthesis of enantiomeric (RS)-, (R)-, and (S)-bunolol. In comparison between two approaches, it was found that the chemo-enzymatic process was more effective and resulted in enantiomeric excess of 98% with 35% yield.