Co-reporter:Xin Ye, Chunsong Xie, Yuanyuan Pan, Laihong Han, and Tian Xie
Organic Letters 2010 Volume 12(Issue 19) pp:4240-4243
Publication Date(Web):September 9, 2010
DOI:10.1021/ol101576q
α-Amino imides can be accessed straightforwardly from tertiary amines through copper-catalyzed three-component reactions involving the direct functionalization of sp3 C−Hs adjacent to nitrogen atoms. This reaction has demonstrated a tolerance to a wide range of functionalizations and can be performed under very mild conditions. A plausible mechanism has been proposed in which an Ugi-type cascade assembly has been included.
Co-reporter:Chunsong Xie, Deyu Han, Yue Hu, Jinhua Liu, Tian Xie
Tetrahedron Letters 2010 Volume 51(Issue 40) pp:5238-5241
Publication Date(Web):6 October 2010
DOI:10.1016/j.tetlet.2010.07.108
A novel and efficient synthesis of pyrrolidin-2-ones through the tandem reactions of vinyl sulfonium salts with malonyl amides under very mild conditions is reported. The reaction demonstrates a wide tolerance toward various aryls, acyl, sulfonyl, and benzyl while aliphatic groups delivering the tetrahydro-2-oxofuran product.
Co-reporter:Xiaolin Pei;Qiuyan Wang;Xiaofeng Qiu
Applied Biochemistry and Biotechnology 2010 Volume 162( Issue 5) pp:1423-1434
Publication Date(Web):2010 November
DOI:10.1007/s12010-010-8924-1
2-Deoxyribose-5-phosphate aldolase (DERA) catalyzes a sequential aldol reaction useful in synthetic chemistry. In this work, the effect of a feeding strategy on the production of a thermophilic DERA was investigated in fed-batch cultures of recombinant Escherichia coli BL21 (pET303-DERA008). The predetermined specific growth rate (µset) was evaluated at 0.20, 0.15, and 0.10 h−1, respectively. The DERA concentration and volumetric productivity were associated with µset. The cells synthesized the enzyme most efficiently at µset = 0.15 h−1. The maximum enzyme concentration (5.12 g/L) and total volumetric productivity (0.256 g L−1 h−1) obtained were over 10 and five times higher than that from traditional batch cultures. Furthermore, the acetate concentration remained at a relatively low level, less than 0.4 g/L, under this condition which would not inhibit cell growth and target protein expression. Thus, a specific growth rate control strategy has been successfully applied to induce fed-batch cultures for the maximal production of the thermophilic 2-deoxyribose-5-phosphate aldolase.