An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advanta...An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.展开更多
The title complex {[Ni(TCB)2/2(Him)2(H2O)2]· 6H2O}n(where TCB = 1,2,4,5 benzentetracarboxylic anion, Him=imidazole) has been synthesized in aqueous solution. The <IMG SRC="IMAGE/12180050.JPG" HEIGHT=...The title complex {[Ni(TCB)2/2(Him)2(H2O)2]· 6H2O}n(where TCB = 1,2,4,5 benzentetracarboxylic anion, Him=imidazole) has been synthesized in aqueous solution. The <IMG SRC="IMAGE/12180050.JPG" HEIGHT=11 WIDTH=12>crystal structure has been determined by single crystal X ray diffraction method. It crystallizes in the triclinic system, space group (# 2) with a=1.0661(4)nm,b=1.1175(3)nm,c=1.0062(4)nm,α =94.03(3)° ,β = 110.81(3)° ,γ =114.71(2)° ,V=0.9837(7)nm3,Z=1,F(000)=478,DC=1.553g· cm- 3,F.W.=920.11,u=10.41cm- 1,R=0.040,RW=0.051.In this compound, one of the nickel atom is coordinated by two oxygen atoms from TCB, two oxygen atoms from two water molecules and two nitrogen atoms from two imidazole molecules in a trans fashion to complete an octahedron; whereas the other is ligated by four nitrogen atoms from four imidazole molecules to form a planar square geometry.展开更多
The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazol...The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazoles by the one‐pot, four‐component thermal reaction of benzil with aromatic aldehydes, primary amines, and ammonium acetate under solvent‐free conditions. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials, and subsequently characterized by FT‐IR, UV and X‐ray diffraction spectroscopy, as well as microanalysis. The results showed that {Mo132} exhibited high catalytic activity towards the synthesis of 1,2,4,5‐tetrasubstituted imidazoles, with the desired products being formed in good to high yields. Furthermore, the catalyst was recyclable and could be reused at least three times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of 1,2,4,5‐tetrasubstituted imidazoles provides rapid access to the desired compounds following a simple work‐up procedure, and avoids the use of harmful organic solvents. This method therefore represents a significant improvement over the methods currently available for the synthesis of tetrasubstituted imidazoles.展开更多
Phosphorus pentoxide supported on silica gel （P2O5/SiO2） has been used as an efficient and reusable catalyst for the one-pot pseudo four-component synthesis of 2,4,5-trisubstituted imidazoles from benzil or benzoin,...Phosphorus pentoxide supported on silica gel （P2O5/SiO2） has been used as an efficient and reusable catalyst for the one-pot pseudo four-component synthesis of 2,4,5-trisubstituted imidazoles from benzil or benzoin, aldehydes, and ammonium acetate. It was also used for four-component preparation of 1,2,4,5-tetrasubstituted imidazoles from benzil or benzoin, aldehydes, primary amine, and ammonium acetate under thermal solvent-free conditions. The remarkable features of this new procedure are high conversions, cleaner reaction, simple experimental and work-up procedures and also the catalyst can be easily separated from the reaction mixture and reused several times without any loss of its activity.展开更多
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061-A25-019)the Scientific Research Fund of Gansu Provincial Education Department(No.0601-25).
文摘An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.
文摘The title complex {[Ni(TCB)2/2(Him)2(H2O)2]· 6H2O}n(where TCB = 1,2,4,5 benzentetracarboxylic anion, Him=imidazole) has been synthesized in aqueous solution. The <IMG SRC="IMAGE/12180050.JPG" HEIGHT=11 WIDTH=12>crystal structure has been determined by single crystal X ray diffraction method. It crystallizes in the triclinic system, space group (# 2) with a=1.0661(4)nm,b=1.1175(3)nm,c=1.0062(4)nm,α =94.03(3)° ,β = 110.81(3)° ,γ =114.71(2)° ,V=0.9837(7)nm3,Z=1,F(000)=478,DC=1.553g· cm- 3,F.W.=920.11,u=10.41cm- 1,R=0.040,RW=0.051.In this compound, one of the nickel atom is coordinated by two oxygen atoms from TCB, two oxygen atoms from two water molecules and two nitrogen atoms from two imidazole molecules in a trans fashion to complete an octahedron; whereas the other is ligated by four nitrogen atoms from four imidazole molecules to form a planar square geometry.
基金the Islamic Azad University, Mashhad Branch for its financial support
文摘The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazoles by the one‐pot, four‐component thermal reaction of benzil with aromatic aldehydes, primary amines, and ammonium acetate under solvent‐free conditions. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials, and subsequently characterized by FT‐IR, UV and X‐ray diffraction spectroscopy, as well as microanalysis. The results showed that {Mo132} exhibited high catalytic activity towards the synthesis of 1,2,4,5‐tetrasubstituted imidazoles, with the desired products being formed in good to high yields. Furthermore, the catalyst was recyclable and could be reused at least three times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of 1,2,4,5‐tetrasubstituted imidazoles provides rapid access to the desired compounds following a simple work‐up procedure, and avoids the use of harmful organic solvents. This method therefore represents a significant improvement over the methods currently available for the synthesis of tetrasubstituted imidazoles.
文摘Phosphorus pentoxide supported on silica gel （P2O5/SiO2） has been used as an efficient and reusable catalyst for the one-pot pseudo four-component synthesis of 2,4,5-trisubstituted imidazoles from benzil or benzoin, aldehydes, and ammonium acetate. It was also used for four-component preparation of 1,2,4,5-tetrasubstituted imidazoles from benzil or benzoin, aldehydes, primary amine, and ammonium acetate under thermal solvent-free conditions. The remarkable features of this new procedure are high conversions, cleaner reaction, simple experimental and work-up procedures and also the catalyst can be easily separated from the reaction mixture and reused several times without any loss of its activity.
