Ligand‐ and solvent‐free synthesis of 2‐aminobenzothiazoles by copper‐catalyzed tandem reaction of 2‐haloanilines with isothiocyanates

We report an environmentally friendly, efficient and practical method for the synthesis of 2‐aminobenzothiazoles by a copper(II)‐catalyzed tandem reaction of 2‐haloanilines with isothiocyanates under ligand‐ and solvent‐free conditions in air. The developed methodology conforms to the principles of 'green chemistry' and addresses the shortage of such methods for the synthesis of 2‐aminobenzothiazoles. The reaction is quite general and generates a variety of 2‐aminobenzothiazoles in good to excellent yields. Copyright © 2012 John Wiley & Sons, Ltd.     

A Convenient and Efficient Conversion of 4‐Aminobenzophenone into Some New 1,2,3‐Triazole and Benzothiazole Derivatives

Several heterocyclic systems such as 1,2,3‐triazoles ( 5–9 ), pyrimidotriazoles ( 10–13 ), benzothiazole ( 16 ), thiazolo ( 17 ), and pyrimidinone derivative ( 18 ) was obtained from 4‐aminobenzophenone ( 1 ) and the appropriate reagents.     

Functionalized graphene oxide supported copper (I) complex as effective and recyclable nanocatalyst for one‐pot three component synthesis of 1,2,3‐triazoles

Efficient, one pot three‐component reaction of alkyl halides, sodium azide with terminal alkynes can be catalyzed by functionalized graphene oxide with copper(I) under thermal conditions. A series of 1,4‐disubstituted 1,2,3‐triazoles were obtained by this one‐pot strategy. The catalyst was prepared and characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), emission scanning electron microscopy (FE‐SEM) and energy dispersive X‐ray (EDX). The catalyst can be reused at least five times without significant deactivation.     

Synthesis and Antifungal Activities of ω‐[4‐Aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenones

New 4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thiones 3 have been synthesized by the intramolecular cyclization of 4‐aryl‐1‐(1‐phenyl‐5‐methyl‐1,2,4‐triazol‐4‐formyl)thiosemicarbazides 2 with an 8% NaOH solution, and then 3 reacted with ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone to afford ω‐[4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)‐acetophenones 4 . The preliminary biological test showed that the representative compounds possess some anti fungal activities.     

Design and Synthesis of New Bile AcidSterol Conjugates Linked via 1,2,3‐Triazole Ring

A new steroid conjugates have been obtained from bile acids and sterol derivatives using ‘click chemistry’. Intermolecular 1,3‐dipolar cycloaddition of the propargyl ester of bile acids (lithocholic, deoxycholic, and cholic acid) and azide derivatives of sterols (ergosterol and cholesterol) gave a new bile acid? sterol conjugates linked with a 1,2,3‐triazole ring. The structures of all products were confirmed by spectroscopic (¹H‐ and ¹³C‐NMR, and FT‐IR) analyses, mass spectrometry (ESI‐MS), and in silico biological activity evaluation methods (PASS), as well as PM5 semiempirical methods.     

Triton B catalyzed three‐component,one‐pot synthesis of 2‐amino‐2‐chromenes at ambient temperature

A one‐pot, three‐component synthesis of 2‐amino‐2‐chromenes is described at ambient temperature by the reaction of an aldehyde and malononitrile or ethyl cyanoacetate with α‐naphthol or β‐naphthol in ethanol in presence of a catalytic amount of Triton B. J. Heterocyclic Chem., (2011).     

A three‐component,one‐pot synthesis of oxazinoquinolin‐3‐one derivatives

Oxazino[5,6‐f]quinolin‐3‐one derivatives have been synthesized in a one‐pot, and efficient process by condensation of 6‐quinolinol, aromatic aldehydes and urea under microwave‐assisted and thermal solvent‐free conditions.     

Polyethylene glycol mediated one‐pot three‐component synthesis of new 4‐thiazolidinones

An efficient one‐pot three‐component cyclocondensation of 4‐(p‐toulyl sulfonoxy) benzaldehyde, aryl amines, and mercaptoacetic acid in polyethylene glycol 400 (PEG‐400) was conducted to obtain new 2,3‐disubstituted‐4‐thiazolidinones. This route is economical and ecofriendly. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:166–170, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20766     

Synthesis and Antibacterial Activities of 2‐(1‐Aryl‐5‐Methyl‐1,2,3‐triazol‐4‐yl)‐1,3,4‐Oxadiazole Derivatives

Eighteen novel 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazole derivatives and two acylhydrazone intermediate compounds were synthesized by various pathways starting from 1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐formhydrazide ( 1 ). All products were identified by spectroscopic analysis, and 2‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐5‐benzalthio‐1,3,4‐oxadiazole was further validated by X‐ray crystallography. Results from primary antibacterial activity tests indicated that most of the compounds were effective against E. coli, P. aeruginosa, B. subtilis and S. aureus.     

Design,synthesis, characterization and catalytic performance of a new cellulose‐based magnetic nanocomposite in the one‐pot three‐component synthesis of α‐aminonitriles

A sulfonated magnetic cellulose‐based nanocomposite was prepared and characterized using scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction and Fourier transform infrared spectroscopy. Then, it was used as a green nanocatalyst for the synthesis of α‐aminonitriles by a one‐pot three‐component condensation reaction of aldehydes or ketones, amines and trimethylsilylcyanide in ethanol at room temperature. The reaction procedure is simple, yields are very high, reaction time is very short and the catalyst can be easily separated from the reaction mixture and reused in subsequent reactions without significant loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

Design,Synthesis, and Antifungal Evaluation of Novel Benzoxazole Derivatives Containing a 1,2,3‐Triazole Moiety

For finding novel bioactive compounds with significant antifungal activities, 17 novel benzoxazole derivatives containing a 1,2,3‐triazole moiety were synthesized by the copper(II) acetylacetonate‐catalyzed cyclization reaction between 2‐aminophenol derivatives and 1H‐1,2,3‐triazole‐4‐carbaldehyde derivatives ( 4a ), which were prepared through three steps using aromatic amine as the starting material. Antifungal activities of the prepared compounds were evaluated against Botrytis cinerea (BC) and Fusarium Verticillium (FV). The test results indicated that compounds 5b , 5c , 5h, and 5n show good inhibitory effects on fungi. The preliminary structure–activity relationship is also discussed.     

Facile synthesis of tetrahydrobenzoxanthenones via a one‐pot three‐component reaction using an eco‐friendly and magnetized biopolymer chitosan‐based heterogeneous nanocatalyst

A chitosan‐based magnetic nanocomposite was synthesized by an eco‐friendly and simple procedure, and was characterized using scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction and Fourier transform infrared spectroscopy. It was then used for the efficient synthesis of tetrahydrobenzoxanthen‐11‐one derivatives via a one‐pot three‐component condensation of 2‐naphthol, various aldehydes and dimedone in ethanol. The catalyst was recovered easily and reused several times without significant loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

An efficient one‐pot three‐component reaction for synthesis of spirooxindole derivatives in water media under catalyst‐free condition

An efficient, clean, and environmentally benign synthesis of spirooxindole derivatives by one‐pot three‐component reaction of isatins, malononitrile, and carbonyl compound in the absence of catalysis in water was described. A variety of spirooxindole derivatives were obtained with excellent yields within short reaction time. This novel protocol has the advantages of convenient operation, low cost, and environmental benign. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:673–677, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20723     

(Bromodimethylsulfonium) bromide–catalyzed one‐pot three‐component synthesis of imidazo[1,2‐a]pyridines

(Bromodimethylsulfonium) bromide–catalyzed one‐pot multicomponent reaction of 2‐aminopyridine with aromatic aldehyde(s) and TMSCN yielding N‐benzylidene‐2‐phenylimidazo[1,2‐a]pyridines exclusively has been described. The reaction is solvent free, versatile, and takes significantly short time. J. Heterocyclic Chem., (2011).     

Synthesis and properties of novel polytriazoleimides derived from 1,2,3‐triazole‐containing diamines and aromatic dianhydrides

A new kind of 1,2,3‐triazole‐containing aromatic diamines were synthesized by the Cu(I)‐catalyzed 1,3‐dipolar cycloaddition reaction. These diamines were employed to synthesize a series of novel polytriazoleimides (PTAIs) by polycondensation with various aromatic dianhydrides in N,N‐dimethylacetamide (DMAc) via the conventional two‐step method. The obtained polyimides were characterized by Fourier transform infrared, hydrogen‐1 nuclear magnetic resonance, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis techniques. The results show that the PTAIs are soluble in most of strong polar solvents and have inherent viscosity values of 0.47–0.68 dl/g (DMAc). PTAI films have tensile strengths of 60.6–102.6 MPa and elongations at breakage of 3.0–4.1%, glass transition temperatures (T_g) of 208–262°C, and decomposition temperatures (at 5% weight loss) of 368–401°C in N₂ atmosphere, which depend on the structure of the polymers. The PTAIs also exhibit good adhesion to copper and gas separation properties. Copyright © 2011 John Wiley & Sons, Ltd.     

Selenium‐Containing Heterocycles from Isoselenocyanates: Synthesis of 5‐Amino‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐selones

The reaction of S‐methylisothiosemicarbazide hydroiodide (=S‐methyl hydrazinecarboximidothioate hydroiodide; 1 ), prepared from thiosemicarbazide by treatment with MeI in EtOH, and aryl isoselenocyanates 5 in CH₂Cl₂ affords 3H‐1,2,4‐triazole‐3‐selone derivatives 7 in good yield (Scheme 2, Table 1). During attempted crystallization, these products undergo an oxidative dimerization to give the corresponding bis(4H‐1,2,4‐triazol‐3‐yl) diselenides 11 (Scheme 3). The structure of 11a was established by X‐ray crystallography.     

Synthesis of 3‐[5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐yl]‐6‐substituted‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles

Several 3‐[5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐yl]‐6‐substituted‐1,3,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles have been synthesized and the structures of these compounds were established by elemental analysis, MS, IR and ¹H NMR spectral data.