30313-07-6Relevant articles and documents
The Knoevenagel condensation of O,S- and S,S-diethyl malonates and ethyl pyruvate
Wilk, Bogdan K.
, p. 7097 - 7100 (1997)
The Knoevenagel condensation of O,O-, O,S- and S,S-diethyl malonates with ethyl pyruvate is described. The elimination sequence in 2 and 6 is suppressed by the presence of ZnCl2.
Artificial Glutamate Mutase Composed of Hydrophobic Vitamin B12 and Synthetic Bilayer Membrane
Murakami, Yukito,Hisaeda, Yoshio,Ohno, Teruhisa
, p. 1357 - 1360 (1987)
The alkylated hydrophobic vitamin B12, prepared by the reaction between heptapropyl cobyrinate and diethyl bromomethylasparate, afforded diethyl glutamate, the rearrangement product, in single-compartment vesicles under anaerobic photolysis conditions.
Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with the Michael acceptor, diethyl ethoxycarbonylbutendienoate
Okuro, Kazumi,Alper, Howard
experimental part, p. 4420 - 4424 (2012/06/18)
Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with diethyl ethoxycarbonylbutendienoate produces 2,3,3-triethoxycarbonyl-2,3- dihydro-4(1H)-quinolinone derivatives in moderate to good yields. This protocol involves Michael additio
Rotation of the exo-methylene group of (R)-3-methylitaconate catalyzed by coenzyme B12-dependent 2-methyleneglutarate mutase from Eubacterium barkeri
Pierik, Antonio J.,Ciceri, Daniele,Broeker, Gerd,Edwards, Christopher H.,McFarlane, William,Winter, Joachim,Buckel, Wolfgang,Golding, Bernard T.
, p. 14039 - 14048 (2007/10/03)
2-Methyleneglutarate mutase from the anaerobe Eubacterium (Clostridium) barkeri is an adenosylcobalamin (coenzyme B12)-dependent enzyme that catalyzes the equilibration of 2-methylene-glutarate with (R)-3-methylitaconate. Two possibilities for the mechanism of the carbon skeleton rearrangement of the substrate-derived radical to the product-related radical are considered. In both mechanisms an acrylate group migrates from C-3 of 2-methyleneglutarate to C-4. In the "addition-elimination" mechanism this 1,2-shift occurs via an intermediate, a 1-methylenecyclopropane-1,2-dicarboxylate radical, in which the migrating acrylate is simultaneously attached to both C-3 and C-4. In the "fragmentation-recombination" mechanism the migrating group, a 2-acrylyl radical, becomes detached from C-3 before it starts bonding to C-4. In an attempt to distinguish between these two possibilities we have investigated the action of 2-methyleneglutarate mutase on the stereospecifically deuterated substrates (Z)-3-methyl[2′-2H1]itaconate and (Z)-3-[2′-2H1,methyl-2H3] methylitaconate. The enzyme catalyzes the equilibration of both compounds with their corresponding E-isomers and with a 1:1 mixture of the corresponding (E)- and (Z)-2-methylene-[2′-2H1]glutarates, as shown by monitoring of the reactions with 1H and 2H NMR. In the initial phase of the enzyme-catalyzed equilibration a significant excess (8-11%) of (E)-3-methyl[2′-2H1]itaconate over its equilibrium value was observed ("E-overshoot"). The E-overshoot was only 3-4% with (Z)-3-[2′-2H1methyl-2 H3]methylitaconate because the presence of the deuterated methyl group raises the energy barrier from 3-methylitaconate to the corresponding radical. The overshoot is explained by postulating that the migrating acrylate group has to overcome an additional energy barrier from the state leading back to the substrate-derived radical to the state leading forward to the product-related radical. It is concluded that the fragmentation-recombination mechanism can provide an explanation for the results in terms of an additional energy barrier, despite the higher calculated activation energy for this pathway.
