Novel Synthesis of (3R,4R)‐4‐Acetoxy‐3‐[1′(R)‐tert‐butyldimethylsilyloxyethyl] Azetidin‐2‐one: A Key Intermediate for Penem and Carbapenem Synthesis

HDAC and NF-κB mediated cytotoxicity induced by novel N-Chloro β-lactams and benzisoxazole derivatives

Novel N-chloro â-Lactam and benzisoxazole derivatives were successfully synthesized with excellent yields (92-96%) under simple and mild reaction conditions. The β-lactams as a class acquired importance since the discovery of penicillin which contains β-lactam unit as an essential structural feature of its molecule, this interest continued unabated because of the therapeutic importance of β-lactam antibiotics. In silico studies of the compounds with cancer drug target enzymes showed the inhibition of HDAC (Histone Deacetylase) and NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) significantly. The compounds were then investigated for the inhibitory potential against the same enzymes in vitro. NF-κB inhibition was investigated by trans activation assay using HEK293/NF-κB-luc cells. Overall, the synthesized compounds induce the cancer cell toxicity by restraining the NF-κB transcription factor mediated by HDAC inhibition and thus the compounds act as dual inhibitors.

Asymmetric synthesis of optically active methyl-2-benzamido-methyl-3-hydroxy-butyrate by robust short-chain alcohol dehydrogenases from Burkholderia gladioli

Specific short-chain alcohol dehydrogenases were discovered and used in the dynamic kinetic asymmetric transformation of methyl 2-benzamido-methyl-3-oxobutanoate with excellent stereo-selectivity.

Stereoselective determination of 2-benzamidomethyl-3-oxobutanoate and methyl-2-benzoylamide-3-hydroxybutanoate by chiral high-performance liquid chromatography in biotransformation

(2S, 3R)-methyl-2-benzamidomethyl-3-hydroxybutyrate (MBHB) is a key intermediate in the synthesis of 4-aceoxyazetidinone, a building block for the production of penems and carbapenems. More attentions have been paid to screen biocatalysts achieving asymmetric preparation of (2S, 3R)-MBHB. In this study, an improved chiral high-performance liquid chromatographic (HPLC) method was developed for the stereoselective determination of 2-benzamidomethyl-3-oxobutanoate (BMOB) and MBHB, and further employed into the biotransformation of BMOB. Chiral separation was achieved within 12 min on Chiralpak AY-H column, which was faster and more suitable for screening biocatalysts exhibited reduction activity and (2S, 3R)-stereospecificity toward BMOB than on other columns. Ultimately, a new strain, Burkholderia gladioli ZJB-12126 capable of reducing BMOB to (2S, 3R)-MBHB was successfully isolated based on this newly constructed HPLC method. Samples were prepared by liquid-liquid extraction system using ethyl acetate as the extractor solvent. The extraction recoveries of BMOB and MBHB isomers ranged from 91.6 to 94.1% with relative standard deviation (RSD) below 10%. Linear calibration curves were obtained in the concentration range of 50-5000 μg/mL for both BMOB and MBHB isomers, respectively. Intra-day and inter-day precisions and accuracy were below 15% for all isomers evaluated by RSDs and relative errors (REs), respectively. This novel method was demonstrated to be suitable for assessing the biotransformation process of BMOB.