The dynamic kinetic resolution of 3-oxo-4-phenyl-β-lactam by recombinant E. coli overexpressing yeast reductase Ara1p
摘要:
Using a recombinant E coli strain overexpressing yeast reductase Ara 1 p, we reduced racemic 3-oxo-4-phenyl-beta-lactam to cis-(3S,4R)-3-hydroxy-4-phenyl-beta-lactam as a single enantiopure product. The dynamic kinetic resolution occurred over the course of fermentation at pH 7. Under the same conditions, 3-oxo-4-(2-thiophenyl)-beta-lactam 4 and 3-oxo-4-(2-furyl)-beta-lactam 5 were not resolved. (c) 2005 Elsevier Ltd. All rights reserved.
Preparation of .alpha.-Methylene and .alpha.-Ethylidene .beta.-Lactams via the Ester Enolate-Imine Condensation Using .beta.-(Dialkylamino) Esters as Starting Materials: Scope and Synthetic Applications
A new, simple procedure for the preparation of appropriately substituted alpha-methylene and alpha-ethylidene beta-lactams via the ester enolate-imine condensation is described. The method is based on the use of lithium 3-(dialkylamino) ester enolates as synthetic equivalents of the corresponding acrylate alpha-anions. Thus, the reaction of lithium enolates of 3-(dialkylamino) esters with imines produced alpha-[(dialkylamino)alkyl] beta-lactams stereoselectively and in high yield. Upon dehydroamination the latter furnished a variety of alpha-alkylidene beta-lactams. The synthesis of 3-alkylidene-4-formyl-2-azetidinones is a particularly significant feature of this work. Preparation of functionalized alpha-keto beta-lactams and beta-lactam-furan hybrids through a dihydroxylation-oxidation process starting from different alpha-alkylidene derivatives is also described. In addition, reduction of various 4-functionalized (Z)- and (E)-3-ethylidene-2-azetidinones yielded the corresponding 3-ethylideneazetidines as advanced precursors of polyoximic acids.
Mihovilovic, Marko D.; Feicht, Anton; Kayser, Margaret M., Journal fur Praktische Chemie (Weinheim), 2000, vol. 342, # 6, p. 585 - 590
作者:Mihovilovic, Marko D.、Feicht, Anton、Kayser, Margaret M.