Abstract—The reduction of (RS)-2-(4-methoxyphenyl)-l, 5-benzothiazepin-3,4(2H,5H)-dione[(RS)-1] to (2S,3S)-2,3-dihydro-3-hydroxy-2-(4-methoxyphenyl)-l,5-benzothiaepin- 4(5H)-one using bakers’ yeast was carried out in the laboratory scale 10L fermenter. Under optimum reaction conditions, 200g of substrate was reduced to desired chiral intermediate in 4L reaction volume with 79.33% of conversion within 89h. The optimum conditions for the effective reduction were at pH 6.5 and at 30°C temperature. The crystals of desired isomer were isolated from the reaction mixture with the total yield of 42%, having 95.42% of assay purity with 99.80% of enantiomeric excess.
Index Terms—Asymmetric reduction, bakers’ yeast,bioconversion, diltizem hydrochloride.
Pradipta Tokdar, Prafull Ranadive and Saji George is in Fermentation Technology Lab, Natural Products Department.
Abhay Upare, Sandesh Vishwasrao, Mita Roy, and Hariharan Sivaramakrishnan is in Innovations Group, Synthetic Lab. Piramal Life Sciences Ltd, 1, Nirlon Complex, Off Western Express Highway, Goregaon(East), Mumbai-400063, India.(e-mail:pradipta.tokdar@piramal.com).
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Cite: Pradipta Tokdar, Prafull Ranadive, Saji George, Abhay Upare, Sandesh Vishwasrao, Mita Roy, and Hariharan Sivaramakrishnan, "Bakers' Yeast Mediated Stereo Selective Reduction of Cis (+) Diketolactam to Cis (+)Hydroxylactam, a Key Intermediate for Diltiazem Synthesis in a Laboratory Scale Bioreactor," International Journal of Chemical Engineering and Applications vol. 2, no. 6, pp. 386-389, 2011.
