Reduction of a series of N,N＇-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N,...Reduction of a series of N,N＇-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N,N＇-diaryl adipyl dihydrazine. The results show that hydrazine hydrate can selectively reduce azo bonds with other potential reducible bonds intact in the N,N＇-diaryl adipyl bis-azo compounds. The yields are high up to 92% under mild reaction conditions. According to the previous reports, this reduction process was attributed to an indirect reduction mechanism through an intermediate diimide.展开更多
Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylfor...Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylformamide in dry benzene. The effects of reaction temperature, time, catalyst and solvent amount on the yield of 2a and 2b were investigated. The results show that chlorination of 1a and 1b under optimal conditions gives 2a and 2b in 95.5% and 99.2% yield respectively. The given method is facile and suitable for large-scale synthesis.展开更多
Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides f...Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.展开更多
A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chlor...A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chloride under very mild conditions. Their solubility, crystallinity, thermostability, UV-vis absorption properties and photoisomerization behaviors were carefully examined. When the number of azobenzene unit grew, the solubility of the synthesized compounds basically decreased, the crystallinity of the synthesized compounds firstly rose then dropped, while the thermostability and UV-vis absorption ability of the synthesized compounds greatly im- proved. All the aromatic azo compounds exhibited typical reversible photoisomerization behaviors and were expected to be applied in photosensitive material areas.展开更多
Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tet...Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tetrafluoroborate salts with nucleophiles under mild conditions. This protocol features wide substrate scope and good functional group compatibility.Azaarene-containing chiral azo compounds were stable enough in Japp-Klingemann reaction condition. The key to success of the reaction was the employment of metal salt/N,N′-dioxide ligand and the dual-task roles of the base. Moreover, the X-ray crystal structure of Ni(II)/N,N′-dioxide/substrate complex confirmed that the substrate was activated by bidentate coordination, which shed light on the origin of chiral control of the reaction.展开更多
A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium di...A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.展开更多
In this short review, excerpts from the literature of azo-bridged triazoles(mainly 1,2,4-triazoles), some of their derivatives(chloromethyl,dinitro and trinitro pyrazole substituted ones, etc.) and some of their salts...In this short review, excerpts from the literature of azo-bridged triazoles(mainly 1,2,4-triazoles), some of their derivatives(chloromethyl,dinitro and trinitro pyrazole substituted ones, etc.) and some of their salts, have been presented focusing on the most recent investigations. These classes of compounds, known as high nitrogen compounds, are generally high energy density materials. Therefore, if available some of their ballistic properties were included.展开更多
A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(a...A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(acyl-DHP)reagents that besides being as radical reservoirs,they also enabled the conversion of radical adducts to anion intermediates via reduction.Under“catalyst-oxidant-additive free”conditions,a wide range of structurally different acyl hydrazide products were readily obtained in 56%—99%yields.The utility of this transformation was further demonstrated by the scale-up synthesis and downstream derivatization.展开更多
基金Supported by the Science Foundation of Education Department of Heilongjiang Province(12511142)
文摘Reduction of a series of N,N＇-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N,N＇-diaryl adipyl dihydrazine. The results show that hydrazine hydrate can selectively reduce azo bonds with other potential reducible bonds intact in the N,N＇-diaryl adipyl bis-azo compounds. The yields are high up to 92% under mild reaction conditions. According to the previous reports, this reduction process was attributed to an indirect reduction mechanism through an intermediate diimide.
文摘Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylformamide in dry benzene. The effects of reaction temperature, time, catalyst and solvent amount on the yield of 2a and 2b were investigated. The results show that chlorination of 1a and 1b under optimal conditions gives 2a and 2b in 95.5% and 99.2% yield respectively. The given method is facile and suitable for large-scale synthesis.
基金Project (No. 20072033) supported by the National Natural ScienceFoundation of China and Specialized Research Fund for the DoctoralProgram of Higher Education of China
文摘Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.
文摘A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chloride under very mild conditions. Their solubility, crystallinity, thermostability, UV-vis absorption properties and photoisomerization behaviors were carefully examined. When the number of azobenzene unit grew, the solubility of the synthesized compounds basically decreased, the crystallinity of the synthesized compounds firstly rose then dropped, while the thermostability and UV-vis absorption ability of the synthesized compounds greatly im- proved. All the aromatic azo compounds exhibited typical reversible photoisomerization behaviors and were expected to be applied in photosensitive material areas.
基金supported by the National Natural Science Foundation of China(21890723,21921002)。
文摘Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tetrafluoroborate salts with nucleophiles under mild conditions. This protocol features wide substrate scope and good functional group compatibility.Azaarene-containing chiral azo compounds were stable enough in Japp-Klingemann reaction condition. The key to success of the reaction was the employment of metal salt/N,N′-dioxide ligand and the dual-task roles of the base. Moreover, the X-ray crystal structure of Ni(II)/N,N′-dioxide/substrate complex confirmed that the substrate was activated by bidentate coordination, which shed light on the origin of chiral control of the reaction.
基金This project was supported by the Natural Science Foundation of Henan province, China.
文摘A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.
文摘In this short review, excerpts from the literature of azo-bridged triazoles(mainly 1,2,4-triazoles), some of their derivatives(chloromethyl,dinitro and trinitro pyrazole substituted ones, etc.) and some of their salts, have been presented focusing on the most recent investigations. These classes of compounds, known as high nitrogen compounds, are generally high energy density materials. Therefore, if available some of their ballistic properties were included.
基金support from the National Natural Science Foundation of China(21702013 and 22271010)the Fundamental Research Funds for the Central Universities(XK1802-6)at the BUCT.
文摘A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(acyl-DHP)reagents that besides being as radical reservoirs,they also enabled the conversion of radical adducts to anion intermediates via reduction.Under“catalyst-oxidant-additive free”conditions,a wide range of structurally different acyl hydrazide products were readily obtained in 56%—99%yields.The utility of this transformation was further demonstrated by the scale-up synthesis and downstream derivatization.
