A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)...A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)-3-[(1R)-tert-butyldimethylsilyloxyethyl]-4-acetoxy-2-azetidi-none(4AA)upon thionocarboxlic acid.The intermediates and the target product were characterized by 1HNMR,IR,elementary analysis and MS.展开更多
The thermal decomposition of 2-(4-methoxycarbonylphenyl)-5-nitryl-6-hydroxybenzoxazole(MNB) in N2 atmosphere was studied by thermogravimetry(TG) and differential thermogravimetry(DTG).It is a sequential process.The mo...The thermal decomposition of 2-(4-methoxycarbonylphenyl)-5-nitryl-6-hydroxybenzoxazole(MNB) in N2 atmosphere was studied by thermogravimetry(TG) and differential thermogravimetry(DTG).It is a sequential process.The molecular bond orders were calculated by GAMESS method and the IR spectra of MNB and its intermediates in thermal decomposition at various temperatures were determined.The mechanism of the thermal decomposition has been discussed,the C-N bond breakdown and the nitro group elimination occurred in the initial step of the decomposition.The thermal decomposition kinetic parameters such as apparent activation energy E=115.5kJ·mol-1,pre-exponential factor A = 1.698×1010 min-1 and apparent reaction order n = 0 were obtained according to test data.展开更多
文摘A compound ethyl(5S,6R)-2-(4-methylphenyl)-6-[(1R)-tert-butyldimethylsilyloxyethy]-penem-3-carboxylate was synthesized through displacement,acylation and Wittig cyclization reaction of optically active material(3R,4R)-3-[(1R)-tert-butyldimethylsilyloxyethyl]-4-acetoxy-2-azetidi-none(4AA)upon thionocarboxlic acid.The intermediates and the target product were characterized by 1HNMR,IR,elementary analysis and MS.
文摘The thermal decomposition of 2-(4-methoxycarbonylphenyl)-5-nitryl-6-hydroxybenzoxazole(MNB) in N2 atmosphere was studied by thermogravimetry(TG) and differential thermogravimetry(DTG).It is a sequential process.The molecular bond orders were calculated by GAMESS method and the IR spectra of MNB and its intermediates in thermal decomposition at various temperatures were determined.The mechanism of the thermal decomposition has been discussed,the C-N bond breakdown and the nitro group elimination occurred in the initial step of the decomposition.The thermal decomposition kinetic parameters such as apparent activation energy E=115.5kJ·mol-1,pre-exponential factor A = 1.698×1010 min-1 and apparent reaction order n = 0 were obtained according to test data.
