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p-Anisaldehyde(p-CH3OC6H4CHO, MW: 136.15, CAS No. 123-11-5), is a kind of analog of benzaldehyde found from natural resources. It can be biotransformed to achiral product p-MeO-Benzyl Alcohol (p-MeO-BA) and chiral product (1R)-1-hydroxy- 1-(4-methoxyphenyl)propan-2-one(L-p-MeO-Phenyl Acetyl Carbinol, L-p-MeO-PAC) by the Alcohol Dehydrogenase (ADH) and the Pyruvate Decarboxylase (PDC) existed in the yeast, respectively. And the L-p-MeO-PAC can be further transformed to (-)-(1R,2S)-1-(4- Methoxyphenyl)Propane-1,2-Diol (p-MeO-PPDA), the key chiral intermediate for the synthesis of (R)-Tamsulosin, a drug used for the symptomatic treatment of benign prostatic hyperplasia.In order to regulate the relative activity of ADH and PDC coexisted in the whole cell of yeast-mediated biotransformation system towards the substrate of p-anisaldehyde, and improve the chiral pharmaceutical intermediate production, especially the product of p-MeO-PPDA, the bitransformation system was optimized, from the aspects of yeast species, temperature, biotransformation time, concentration of sucrose, concentration of p- anisaldehyde, cell activation time, initial pH, rotary speed, acetaldehyde, auxiliary solvents, cell immobilization, with the help of TLC, colorimetry and GC/MS analysis. And finally, the chiral product of p-MeO-PPDA was separated, purified and crystallized. The purity of the crystals was checked and the structure identification was carried out consequently. The optimized reaction conditions were as follows: baker’s yeast was the ideal yeast to transform p-anisaldehyde into chiral products, for its lower temperature requirements (29℃), shorter activation time(1 h), higher conversion rate, lower demand of sucrose(80 g/L) and higher chiral production, compared with Saccharomyces cerevisiae and brewer’s yeast. Further more, the appropriate condition for the chiral intermediate preparation by baker’s yeast was at the temperature of 29℃, sucrose 80 g/L, initial pH of 4.0, agitation of 80 r/min, after 40 min for cell activation, adding ethanol 3%(V/V) and p-anisaldehyde 0.08 mol/L, fermenting for 14 hrs, the composition of products was good, by-product of p-MeO-BA with the content of 63.70 percent, while p-MeO-PPDA reaching the content of 27.76 percent, and the ratio between the two descended to 2.295.The chiral product, p-MeO-PPDA, is colorless needle crystals, yield 10.12%, which were confirmed to be p-MeO-PPDA by MS, IR, UV, Nuclear Magnetic Resonance (1H NMR) and other tests.High purity up to 95%, [α]D24= -52°(c 0.005, CHCl3), melting point of 98℃, it does not dissolve in water, neither in hexane and methanol, but it can be dissolved in acetoacetate and chloroform.
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