Synthesis of heterocyclic systems with a carbohydrate fragment
作者:A. V. Samet、A. L. Laichter、D. N. Reznikov、A. N. Yamskov、B. I. Ugrak、N. B. Chernyshova、V. V. Yolkin、V. V. Semenov
DOI:10.1007/bf01558084
日期:1994.6
Levoglucosenone, the alpha,beta-unsaturated ketone obtained by the pyrolysis of cellulose, reacts with NH-azoles in the presence of bases. In this process not only normal Michael adducts are formed, but in some cases their hydrates (gem-diols) are also formed. In all cases the addition proceeds stereospecifically and with good yields. 3-Nitro-s-triazole, 3-nitro-and 4-nitropyrazoles, 3-methyl-4-nitropyrazole, 5-nitrotetrazole, 4,5-dicarbomethoxy-nu-triazole, 3,4-dinitropyrazole, 3(5)-methylpyrazole, pyrazole, and imidazole have been studied in this reaction. All of the adducts are characterized by NMR- and IR-spectroscopy.
Comparative Studies of Cathodically-Promoted and Base-Catalyzed Michael Addition Reactions of Levoglucosenone
作者:Alexander V. Samet、Murat E. Niyazymbetov、Victor V. Semenov、Andrei L. Laikhter、Dennis H. Evans
DOI:10.1021/jo961019g
日期:1996.1.1
Regioselective Michael addition of nitro and heterocyclic compounds to levoglucosenone, 1, is effectively catalyzed by amines and also by cathodic electrolysis. In comparison to the base-catalyzed reaction, it was found that under electrochemical conditions the reaction proceeds under milder conditions and with higher yields. Cathodically-initiated Michael addition of thiols to levoglucosenone using small currents