Asymmetric synthesis of duloxetine intermediate (S)-(-)-3-N-methylamino-1-(2-thienyl)-1-propanol using immobilized Saccharomyces cerevisiae in liquid-core sodium alginate/chitosan/sodium alginate microcapsules.

Duloxetine intermediate (S)-(-)-3-N-methylamino-1-(2-thienyl)-1-propanol was synthesized using ACA liquid-core immobilized Saccharomyces cerevisiae CGMCC No. 2230. The optimum culture time for ACA liquid-core immobilized cells was found to be 28 h. The optimum ACA liquid-core capsule formation conditions were found to be 90% chitosan deacetylation, 30,000-50,000 chitosan molecular weight, 5.0 g/L chitosan, and pH 6.0 citrate buffer solution. The highest activity was found when reduction conditions were pH 6.0, 30 °C and 180 rpm. The ACA-immobilized cells can be reused nine times and only 40% of the activity is retained after nine cycles. Product inhibition of reduction was observed in batch reduction. Continuous reduction in the membrane reactor was found to remove the product inhibition on reduction and improve production capacity. Conversion reached 100% and enantiometric excess of (S)-(-)-3-N-methylamino-1-(2-thienyl)-1-propanol exceeded 99.0% in continuous reduction of 5 g/L 3-N-methylamino-1-(2-thienyl)-1-propanone in the membrane reactor.

Synthesis of duloxetine intermediate (S)-3-Chloro-1-(2-thienyl)-1-propanol with liquid-core immobilized Candida pseudotropicalis 104.

(S) -3-Chloro-1-(2-thienyl)-1-propanol was synthesized by the asymmetric reduction of 3-chloro-1-(2-thienyl)propanone with liquid-core immobilized Candida pseudotropicalis 104. The optimum time was 28 h for the re-cultivation of immobilized cells. The optimum film solvent for the liquid-core capsule was 0.3 % chitosan (M (w) 1.0 × 10(5)). Conversion decreased with the increase of the liquid-core capsule diameter and with the addition of more substrates at the same reduction time. The immobilized cells show good reduction ability in a potassium phosphate buffer (pH 6.6~7.2). The material outside the spread speed of immobilized cells was not restricted when the shaking speed was higher than 160 r/min. Liquid-core immobilized cells can be reused 11 times. Compared with the batch reduction, the continuous reduction of 3-chloro-1-(2-thienyl)propanone in the membrane reactor with liquid-core immobilized cells as catalyst can relieve the inhibition from a high-concentration substrate. Conversion and enantiometric excess of (S)-3-chloro-1-(2-thienyl)-1-propanol reached 100 % and >99 % in a continuous reduction of 12 g/L 3-chloro-1-(2-thienyl)propanone for 10 days.

Enzymological Characteristics of Catalytic Antibody-catalyzed enantioselective Hydrolysis of Ibuprofen Ester in Water-in-oil microemulsion / 生物化学与生物物理进展

The asymmetric hydrolyzation of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. A catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was successfully elicited against an immunogen consisting of tetrahedral sulfate hapten attached to bovine serum albumin (BSA). The rate constant enhancement factor Kcat/Kuncat was about 1.6x104. The catalytic activity of the catalytic antibody in a reverse micelle reaction system based on sodium b/s (2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane was studied. Kinetic analysis of the catalytic antibody-catalyzed reaction was found to be possible in this system. Kinetic studies showed that hydrolysis in the microemulsion system follow Michaelis-Menten kinetics. The catalytic antibody can also accelerate catalysis of S-ibuprofen methyl ester in the microemulsion system. Temperature effects, the pH profile, Km,app and Kcat were determined. The dependence of the catalytic antibody hydrolytic activity on the Wo (molar ratio of water to surfactant) showed a bell-shaped curve, presenting a maximum at about wo = 21.