Stepwise oxidation of ketene dithioacetal is found and the different oxidation products changed with the amount of oxidant, temperature and reaction time.
Substituted pyrazolylpyrazoles were synthesized through the reaction of hydrazine hydrate and α-oxo-(3, 5-dimethyl-1 H-pyrazole-1-ly)ketene S, S- and N,S-Acetals which were obtained from α-oxo-(3,5-dimethyl-1 H-pyra...Substituted pyrazolylpyrazoles were synthesized through the reaction of hydrazine hydrate and α-oxo-(3, 5-dimethyl-1 H-pyrazole-1-ly)ketene S, S- and N,S-Acetals which were obtained from α-oxo-(3,5-dimethyl-1 H-pyrazole-1-yl) acetophenone. Pyrazolylpyrazole was also prepared via α-oxo ketene N,O-acetal by way of ring chain transformation.展开更多
A new method for the synthesis of substituted thiophenes was through intramolecular aldol condensation ofα-oxo ketene dibenzylthioacetals.All products were confirmed with IR, 1 H NMR and elemental analysis.
The oxidant iodosobenzene diacetate was combined with the cheap,environment-friendly FeCl3 as a chloride source to produce an efficient chlorinating agent for α-chlorination of ketene dithioacetals through direct C(s...The oxidant iodosobenzene diacetate was combined with the cheap,environment-friendly FeCl3 as a chloride source to produce an efficient chlorinating agent for α-chlorination of ketene dithioacetals through direct C(sp2)-H chlorination.Furthermore,the synthetic utility of α-chlorinated ketene dithioacetals was verified by the intermolecular cyclization with hydrazine hydrate,leading to the synthesis of pyrazoles,in which a 1,2-sulfur migration was involved.展开更多
A facile route to 2-benzylthio-5-phenyl-3,4-disubstituted thiophenes was described. Catalyzed by sodium hydroxide, the title compounds were synthesized in moderate to good yields simply from the intramolecular aldol t...A facile route to 2-benzylthio-5-phenyl-3,4-disubstituted thiophenes was described. Catalyzed by sodium hydroxide, the title compounds were synthesized in moderate to good yields simply from the intramolecular aldol type condensation of α-oxo ketene dibenzylthioacetals. The chemical selectivity for this annulation reaction was studied and discussed.展开更多
Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso ...Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso electrophilic addition-deacetylation mechanism.展开更多
The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via t...The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via the deacetylation reaction of the corresponding α,α-diacetyl ketene dithioacetals 1 in the presence of concentrated sulfuric acid. This reaction involves an %in-situ% electrophilic addition-deacetylation mechanism and shows the nucleophilicity of the α-carbon atom in α-oxo ketenedithioacetals. Meanwhile, when the reaction time was prolonged to 22—25 h, the β-keto thiolesters 3a and 3c were produced in good yields.展开更多
基金Supported by the National Natural Science Foundation of China(No. 29862004) Scientific and Technological DevelopmentProgram Foundation of Jilin Province(No. 20040565).
基金This work is supported by the National Natural Science Foundation of China (No. 29972030) and the Research Fund for the Doctoral Program of Higher Education.
文摘Stepwise oxidation of ketene dithioacetal is found and the different oxidation products changed with the amount of oxidant, temperature and reaction time.
文摘Substituted pyrazolylpyrazoles were synthesized through the reaction of hydrazine hydrate and α-oxo-(3, 5-dimethyl-1 H-pyrazole-1-ly)ketene S, S- and N,S-Acetals which were obtained from α-oxo-(3,5-dimethyl-1 H-pyrazole-1-yl) acetophenone. Pyrazolylpyrazole was also prepared via α-oxo ketene N,O-acetal by way of ring chain transformation.
文摘A new method for the synthesis of substituted thiophenes was through intramolecular aldol condensation ofα-oxo ketene dibenzylthioacetals.All products were confirmed with IR, 1 H NMR and elemental analysis.
基金Supported by the National Natural Science Foundation of China（No,20902010）, the Foundation of Liaoning Provincial Education Administration, China（No.L2015003） and the Science Foundation of Anshan City, China（Nos.2012KJ02, 2014KJ05）.
基金Project supported by the National Natural Science Foundation of China （No. 20272008） and the Key Grant Project of Chinese Mimstry of Eucation （No. 10412）.
基金supported by the National Natural Science Foundation of China (20902010 and 21172029)the Fundamental Research Funds for the Central Universities (10JCXK005)
文摘The oxidant iodosobenzene diacetate was combined with the cheap,environment-friendly FeCl3 as a chloride source to produce an efficient chlorinating agent for α-chlorination of ketene dithioacetals through direct C(sp2)-H chlorination.Furthermore,the synthetic utility of α-chlorinated ketene dithioacetals was verified by the intermolecular cyclization with hydrazine hydrate,leading to the synthesis of pyrazoles,in which a 1,2-sulfur migration was involved.
基金Supported by the Fundamental Research Funds for the Jilin Province Key Laboratory of Organic Functional Molecular Design ＆ Synthesis, China（No.130028652）, the Natural Science Foundation of Liaoning Province, China（No.201602002）, the Foundation of Liaoning Province Education Administration, China（No.L2015003） and the National Natural Science Foundation of China（No.20902010）.
文摘A facile route to 2-benzylthio-5-phenyl-3,4-disubstituted thiophenes was described. Catalyzed by sodium hydroxide, the title compounds were synthesized in moderate to good yields simply from the intramolecular aldol type condensation of α-oxo ketene dibenzylthioacetals. The chemical selectivity for this annulation reaction was studied and discussed.
文摘Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso electrophilic addition-deacetylation mechanism.
文摘The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via the deacetylation reaction of the corresponding α,α-diacetyl ketene dithioacetals 1 in the presence of concentrated sulfuric acid. This reaction involves an %in-situ% electrophilic addition-deacetylation mechanism and shows the nucleophilicity of the α-carbon atom in α-oxo ketenedithioacetals. Meanwhile, when the reaction time was prolonged to 22—25 h, the β-keto thiolesters 3a and 3c were produced in good yields.
