共查询到20条相似文献,搜索用时 15 毫秒
1.
Solvent-free preparation of arylaminotetrazole derivatives using aluminum(Ⅲ) hydrogensulfate as an effective catalyst 总被引:1,自引:1,他引:0
<正>An efficient and simple method for the preparation of 5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazole derivatives is reported using aluminum(Ⅲ) hydrogensulfate(Al(HSO_4)_3) as an effective heterogeneous catalyst from secondary arylcyanamides. Generally,when the substitution in arylcyanamide is strongly electron-withdrawing the position of equilibrium would shift toward the isomer of 1-aryl-5-amino-1H-tetrazole(B) and as the electron-donating of substituent increased,the position of equilibrium is shifted toward the isomer of 5-arylamino-1H-tetrazole(A).The present methodology offers several advantages,such as excellent yields,short reaction times,easy work-up and greener conditions. 相似文献
2.
A simple and convenient method for the aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved via combination of aluminum or ferric nitrates and silica sulfuric acid as environmentally friendly and novel oxidizing media. This oxidation was carried out in dichloromethane under heterogeneous conditions with good to excellent yields. 相似文献
3.
V(HSO_4)_3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu(NO_3)_2·3H_2O in the absence of solvent. 相似文献
4.
The thermal decomposition of Co(NO3)2·6H2O (1) as well as that one of NO[Co(NO3)3] (Co(NO3)2·N2O4) (2) was followed by thermogravimetric (TG) measurements, X-ray recording and Raman and IR spectra. The stepwise decomposition reactions of 1 and 2 leading to anhydrous cobalt(II)nitrate (3) were established. In N2 atmosphere, cobalt oxides are finally formed whereas in H2/N2 (10% H2) cobalt metal is produced. Rapid heating of cobalt(II)nitrate hexahydrate causes melting (formation of a hydrate melt) and therefore side reactions in the hydrate melt by incoupled reactions and evolution/evaporation of different species as, e.g., HNO3, NO2, etc. In case of larger amounts in dense packing in the sample container, the formation of oxo(hydoxo)nitrates is possible at higher temperature. For 2, its thermal decomposition to 3 was followed and its decomposition mechanism is proposed. 相似文献
5.
<正>An efficient route for the synthesis of 5-substituted 1H-tetrazole via[2+3]cycloaddition of nitriles and sodium azide is reported usingγ-Fe_2O_3 nanoparticles as a magnetic separable catalyst.Under optimized conditions,the moderate to good yields(71-95%) can be obtained.The catalyst can be easily separated by a magnet and reused for several circles. 相似文献
6.
Abdullah Yusulf 《中国化学快报》2010,21(8):922-926
<正>Sulfuric acid immobilized on silica gel is designed as a very useful catalyst for synthesis of 2,3-unsaturated glycopyranosides. This handy,metal-free,environment friendly transformation provides high yields andα-stereoselectivities in a very few amount (0.02 eq.) of catalyst and in short reaction times(10 min). 相似文献
7.
Arsalan Mirjafari Niloufar Mobarrez James H. Davis Jr Jalil Noei 《Comptes Rendus Chimie》2011,14(12):1065-1070
A wide variety of oximes were prepared from different types of alcohols with hydroxylamine hydrochloride using 1-methylimidaziloum nitrate, [Hmim][NO3], ionic liquid as a reaction medium and promoter under microwave irradiation. This protocol provides a one-pot oxime synthesis with high yields that is facile, eco-friendly and the ionic liquid can be recovered and reused. 相似文献
8.
Nanoparticle Fe304 encapsulated CuO, as a heterogeneous catalyst, is a facile system for the synthesis of diaryl ethers by the cross-coupling reaction of various substituted aryl halides with various substituted phenols, which avoids using any type of expensive ligand and can be recovered from the reaction mixture by using a simple magnet. Moreover, this catalyst can be reused three times with high catalytic activity. 相似文献
9.
A simple and efficient catalytic system including TEMPO/acetaldoxime/InCl3 for aerobic oxidation of primary amines to corresponding oximes by using toluene as the solvent is described. This practical method can use O2 as the economic and green oxidant, tolerate a wide range of substrates, which can afford the target oximes in moderate to excellent yields. 相似文献
10.
A simple and efficient protocol is developed for the synthesis of 5-substituted 1H-tetrazoles from various oximes and sodium azide (NaN3) by using copper acetate as a catalyst. 相似文献
11.
Suryakant B. Sapkal Kiran F. Shelke Bapurao B. Shingate Murlidhar S. Shingare 《中国化学快报》2010,21(12):1439-1442
<正>l-Methyl-3-ethyl imidazolium bromide[meim]Br/basic alumina(Al_2O_3) has been found to promote the cyclocondensation of chloroacetone/chloroethyl acetate with salicylaldehydes under conventional as well as microwave irradiation to yield benzofuran derivatives. 相似文献
12.
Mihir K. Chaudhurp Shiv K. Chettri Gagan C. Mandal Pradip C. Paul Satya B. Paul Pendyala Srinivas 《Journal of Chemical Sciences》1995,107(4):305-316
An interpretative account of the results of reactions in aqueous medium of a highly peroxygenated vanadium(V) complex, K [V(O2
3]·3H2O, with different organic and inorganic substrates is presented. The reactions were monitored by solution EPR spectroscopy
and isolation of products at different stages of the reactions. Redox reactions between diperoxide, K[VO(O2)2(H2O)] and VOSO4 were conducted. The results of the investigation suggest that secondary oxygen exchange-reaction occurs which not only depends
on but also utilises the intermediates in the primary reaction during diperoxovanadate-dependent oxidation of VOSO4.
In an interesting reactiontris(acetylacetonato)-manganese(III), Mn(acac)3, on being reacted with a hydrogen peroxide adduct, KF·H2O2, and bpy and phen afforded crystalline [Mn(acac)2(bpy)] and [Mn(acac)2(phen)], respectively. The X-ray structural analysis of [Mn(acac)2(phen)] showed that the compound crystallised in orthorhombic space groupPbcn. The structure consists of a pseudooctahedral Mn(II) ion being bound to two acac−(C5H5O
2
−
) and a phen ligand with the molecule lying on two-fold axis.
Reactivity profiles of two new chromium(VI) reagents viz., pyridinium fluorochromate, C5H5NH[CrO3F] (PFC), and quinolinium fluorochromate C9H7NH [CrO3F] (QFC), have been presented. The compounds are capable of acting as both electron-transfer and oxygen-atom-transfer agents.
The X-ray analysis of PFC crystals reveals that the compound crystallises in the orthorhombic space group CmcZ1. The structure consists of discrete pyridinium cations and CrO3 F anions with no significant hydrogen bonding. This results in total disorder of the pyridinium cation. The tetrahedral [CrO3 F]− ion lies on a crystallographic mirror plane. 相似文献
13.
A simple synthesis of novel and known calix[4]resorcinarenes derivatives has been achieved by the condensation of resorcinol and different aromatic aldehydes in the presence of catalytic amounts of Fe3O4 nanoparticles under solvent-free conditions.The experimental conditions have been thoroughly optimized and established,allowing significant rate enhancements and good to excellent yields.The reactions can be run safely without using any toxic organic solvents under mild reaction conditions.The Fe3O4 nanoparticles were characterized by powdered X-ray diffraction(XRD),transmission electron microscopy(TEM) and FT-IR spectroscopy. 相似文献
14.
Varughese M. Alexander 《Tetrahedron letters》2005,46(40):6957-6959
Bismuth(III) nitrate pentahydrate is found to be an efficient catalyst for the Pechmann condensation reaction of phenols and β-ketoesters under solvent-free conditions. The reaction protocol is simple and is followed by aqueous work-up leading to the formation of the corresponding coumarin derivatives in good yield and high purity. 相似文献
15.
Malhari D. Bhor 《Tetrahedron letters》2008,49(45):6475-6479
Aldehydes and ketones were hydrogenated to the corresponding alcohols, which were then transformed in situ into their respective iodides and nitriles in good yields. A structurally well-defined O-containing transition metal complex, Ru (TMHD)3, was found to be the active catalyst for hydrogenation, iodination and cyanation reactions. It has high affinity for the transformation of benzylic alcohols to iodides and nitriles. 相似文献
16.
Ying-Xiao Zong Jun-Ke Wang Yu-Ying Niu Zheng-Liang Li Zheng-En Song Zheng-Jun Quan Xi-Cun Wang Guo-Ren Yue Yi Pan 《中国化学快报》2013,24(2):140-142
An efficient and convenient procedure of the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature,in the presence of PEG-SO3H is reported.PEG-SO3H acts as a catalyst and can be recovered and reused eight times without apparent loss of its catalytic activity. 相似文献
17.
Biswanath Das Maddeboina Krishnaiah Boyapati Veeranjaneyulu Bommena Ravikanth 《Tetrahedron letters》2007,48(36):6286-6289
Ketones were efficiently converted into the corresponding gem-dihydroperoxides in high yields within a short period of time on treatment with aqueous H2O2 (50%) in the presence of a catalytic amount of CAN in acetonitrile at room temperature. 相似文献
18.
Jalil Noei 《Tetrahedron letters》2008,49(49):6969-6971
The combination of TiCl3OTf with 1-butyl-3-methylimidazolium bromide is found to be an efficient and novel catalytic system for chemoselective one-pot transformation of arylaldoximes to their corresponding thioamides in high to excellent yields. 相似文献
19.
An efficient and straightforward procedure has been developed for the synthesis of highly substituted mono- and bis-N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates via a one-pot, four-component domino reaction of amines, dialkyl acetylenedicarboxylates and formaldehyde in the presence of InCl3 (20 mol%) in MeOH at ambient temperature. The salient advantages of this method are mild reaction conditions, environmentally benign, high to excellent yields, shorter reaction times, easy operation and no column chromatographic separation. 相似文献
20.
Biswanath Das Katta Venkateswarlu Gurram Mahender Ibram Mahender 《Tetrahedron letters》2005,46(17):3041-3044
α-Bromination of carbonyl compounds (cyclic and acyclic ketones, amides and β-ketoesters) has been achieved efficiently by treatment with N-bromosuccinimide (NBS) and catalyzed by silica-supported sodium hydrogen sulfate (NaHSO4·SiO2). The products were formed in high yields under mild reaction conditions and in short reaction times. 相似文献