Methylglyoxal bis-(N,N-dimethylhydrazone): Synthesis and some reactions
Methods were proposed for the synthesis of the methylglyoxal 1,2-bis-(N,N-dimethylhydrazone). A possibility was shown for the first time of its participation in the Diels-Alder reaction with maleic anhydride as an electron-rich diene. The second reaction of these reagents, which is observed in a wet media, is the formation of the hydrazinium salt of the initial diene with maleic acid. The most probable structure of the protonated diene among the four possible forms was revealed by the quantum-chemical calculations of the energy of the molecules and by the analysis of the 13C NMR chemical shifts.
Configurational assignment and conformational study of methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor
A configurational assignment of the isomeric methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor has been performed based on experimental measurements and high-level ab initio calculations of 1J(C,C) and 1J(C,H) couplings. The results reveal the marked stereochemical dependence upon the orientation of the lone pairs of both nitrogen atoms in different isomers. Methylglyoxal bisdimethylhydrazone is shown to exist in a mixture of the EE and ZE isomers (ca. 75:25), both of which adopt predominant s-trans conformations with minor (up to 8°) out-of-plane deviations. CSIRO 2006.
Krivdin, Leonid B.,Larina, Lyudmila I.,Chernyshev, Kirill A.,Keiko, Natalia A.
Synthesis of 2-ethoxyprop-2-enal dimethylhydrazone and its Diels-Alder reactions
Conditions were found for the preparation of 2-ethoxyprop-2-enal dimethylhydrazone by reaction of 2-ethoxypropenal with N,N-dimethylhydrazine. 2-Ethoxyprop-2-enal dimethylhydrazone reacted with methyl vinyl ketone and methyl acrylate according to the [4 + 2]-cycloaddition pattern with regioselective formation of substituted tetrahydropyridines. The major product in the reaction of 2-ethoxyprop-2-enal dimethylhydrazone with 1,4-benzoquinone was 5-hydroxy-1-benzofuran-2-carbaldehyde dimethylhydrazone formed as a result of [3 + 2]-cycloaddition; a small amount of the corresponding [4 + 2]-cycloaddition product was also obtained. Some spontaneous transformations of the primary cycloaddition products were revealed.
(2-Alkoxyvinyl)diazenium salts 9 and 14 are obtained by O-alkylation of glyoxal- (4) and methylglyoxal monodimethylhydrazone (13), resp., with alkyl trifluoromethanesulfonates.Bromination of N-(trimethylsilyl)enehydrazines 16 and 18 in pentane leads to th
Lerche, Holger,Fischer, Hans,Severin, Theodor
p. 3011 - 3019
(2007/10/02)
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