Synthesis of DL-threo-3-(1-fluoro-1-methylethyl)- and DL-threo-3-(1,1-difluoroethyl)malic acids. Mechanistic studies of 3-isopropylmalate dehydrogenase
摘要:
For both mechanistic studies and the development of novel inhibitors of 3-isopropylmalate dehydrogenase enzyme (IPMDH), which is involved in the rate-determining step in the biosynthetic pathway of the essential amino acid L-leucine, (2R*,3S*)-3-(1-fluoro-1-methylethyl)- and (2R*,3S*)-3-(1,1-difluoroethyl)malic acids (F-IPM and F-2-EM) were designed based on the concept of mechanism-based inhibition, and the reaction kinetics with these fluorinated substrates were analysed, The reaction of F-IPM with IPMDH was studied by NMR spectroscopy and product isolation. F-IPM underwent, after the normal enzyme reaction, the expected additional elimination reaction to afford an alpha,beta-unsaturated carbonyl product, which turned out not to participate in any covalent-bond-forming reaction. The conformation of the reaction intermediate during the IPMDH reaction and the functional-group arrangement in the active site of IPMDH are discussed.
作者:Mikhail D. Kosobokov、Vitalij V. Levin、Marina I. Struchkova、Alexander D. Dilman
DOI:10.1021/acs.orglett.5b00097
日期:2015.2.6
CF2 fragment is described. The reaction involves silylation, room-temperature difluorocyclopropanation of silyl enol ethers, and selective ringopening of cyclopropanes under acidic conditions. The whole three-step sequence is conveniently performed in a one-pot mode.
the synthesis of fluorinatedcompounds have been intensively studied, recently. Development of practical fluorinating reagents is indispensable for this purpose. Herein, bench-stable electrophilic fluorinating reagents were synthesized as N-fluorobenzenesulfonimide (NFSI) substitutes. Reagents obtained by replacing one of the NFSI sulfonyl groups with an acyl group led to the highly selective monofluorination
Remarkable reversal of stereoselectivity in Wittig-type olefinations of α-fluorinated alkyl aryl ketones
作者:Tadashi Eguchi、Tetsuya Aoyama、Katsumi Kakinuma
DOI:10.1016/s0040-4039(00)61141-3
日期:1992.9
reversal of stereoselectivity in the Wittig-type olefinations of α-fluorinated alkyl aryl ketones were described. Stabilized Wittig and Horner-Emmons reagents with these ketones selectively afforded the olefinic products in the stereochemically oppposite fashion to the non-flourinated ketone cases. The Still's reagent further reversed the stereochemical outcome with the fluorinated ketones.