38335-24-9Relevant articles and documents
β-Lactone formation during product release from a nonribosomal peptide synthetase
Schaffer, Jason E,Reck, Margaret R,Prasad, Neha K,Wencewicz, Timothy A
, p. 737 - 744 (2017/06/27)
Nonribosomal peptide synthetases (NRPSs) are multidomain modular biosynthetic assembly lines that polymerize amino acids into a myriad of biologically active nonribosomal peptides (NRPs). NRPS thioesterase (TE) domains employ diverse release strategies for off-loading thioester-tethered polymeric peptides from termination modules typically via hydrolysis, aminolysis, or cyclization to provide mature antibiotics as carboxylic acids/esters, amides, and lactams/lactones, respectively. Here we report the enzyme-catalyzed formation of a highly strained β-lactone ring during TE-mediated cyclization of a β-hydroxythioester to release the antibiotic obafluorin (Obi) from an NRPS assembly line. The Obi NRPS (ObiF) contains a type I TE domain with a rare catalytic cysteine residue that plays a direct role in β-lactone ring formation. We present a detailed genetic and biochemical characterization of the entire Obi biosynthetic gene cluster in plant-associated Pseudomonas fluorescens ATCC 39502 that establishes a general strategy for β-lactone biogenesis.
Bio-inspired enantioselective full transamination using readily available cyclodextrin
Zhang, Shiqi,Li, Guangxun,Liu, Hongxin,Wang, Yingwei,Cao, Yuan,Zhao, Gang,Tang, Zhuo
, p. 4203 - 4208 (2017/02/05)
The mimics of vitamin B6-dependent enzymes that catalyzed an enantioselective full transamination in the pure aqueous phase have been realized for the first time through the establishment of a new “pyridoxal 5′-phosphate (PLP) catalyzed non-covalent cyclodextrin (CD)-keto acid inclusion complexes” system, and various optically active amino acids have been obtained.
Reactions of Trialkylsilyl Trifluoromethanesulfonates XI. - Synthesis of α-Oxocarboxylic Acid Derivatives from 2-O-Functionalized Trimethylsilyl Ketene Acetals
Simchen, Gerhard,Siegl, Gerald
, p. 607 - 614 (2007/10/02)
The cyclic ketene acetals 3, 5 are prepared from the dioxolanone 2 resp. the oxazolidinediones 4 by silylation with trimethylsilyl triflate (1)/triethylamine.In an aldol addition/Peterson olefination reaction catalysed by 1 the ketene acetals 3, 5 yield the (E/Z)-benzylidene derivatives 7, 12, 13 in reaction with aromatic aldehydes 6.In a side reaction the α-(trimethylsilyl)benzylidene derivatives 8 are formed from 3 and 6.Compounds 7 can be hydrolysed to yield α-ketocarboxylic acids 14.The latter are also obtained via β-elimination of trimethylsilanol from 2,3-bis(trimethylsiloxy)carboxylic acid anhydride/DMAP/pyridine. Key Words: 1,3-Dioxolanes / 1,3-Oxazolidines / α-Oxocarboxylic acids