A novel synthesis of 5‐aryl‐3‐phenylpyrazole from 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile and hydrazine

A new process for synthesis of 5‐aryl‐3‐phenylpyrazole is achieved. The regioselective ring‐opening reaction of 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile with hydrazine plays a crucial role in the described process.     

Convenient synthesis of N‐substituted 1‐alkyl and 1‐aryl‐3‐aminoisoquinolines

Cyclocondensation of 2‐acylphenylacetonitriles 1 with amines affords 1‐substituted 3‐aminoisoquinolines 2 in good yields.     

Synthesis and further studies of chemical transformation of the 2‐aryl‐3‐halogenoquinolin‐4(1H)‐one derivatives

The C‐3 brominated and iodinated derivatives were prepared from the corresponding 2‐arylquinolin‐4(1H)‐ones and their NMe‐4‐oxo derivatives using pyridinium tribromide in acetic acid or iodine‐Na₂CO₃ mixture in THF. The results of further studies of chemical transformation of the prepared α‐haloenones and preliminary antitumour activity of the 3‐bromo NH‐4‐oxo and NMe‐4‐oxo derivatives are also described.     

Synthesis and antimicrobial activity of new benzofuranyl‐1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones

New benzofuranyl‐1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones are synthesized in which benzofuran is coupled with 1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones through ‐CONH‐ and ‐COCH₂‐ bridges, respectively. The antimicrobial activity of these compounds is reported.     

Cyclocondensation reactions of heterocyclic carbonyl compounds XII. The double course of cyclization of 3‐(2‐aminobenzyl)‐1,2‐dihydro‐quinoxaline‐2‐one

The cyclocondensation reaction of compound 1 in boiling hydrochloric acid had an unexpected course. Instead of supposed 5,11‐dihydro‐quinoxalino[2,3‐b]quinoline 6a , 2‐(indol‐2‐yl)‐benzimidazole 4 was isolated as the major product.     

Synthesis of 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐4H‐5,6,7,8‐tetrahydrobenzo[b]pyran derivatives in ionic liquid medium

In this paper, preparation of 2‐Amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐4H‐5,6,7,8‐tetrahydrobenzo[b]pyran derivatives from aromatic aldehyde, malononitrile or cyanoacetate and 5,5‐dimethyl‐1,3‐cyclohexanedione in ionic liquid [bmim⁺][BF₄^?] was described. Compared with other methods, this new method has the advantages of easier work‐up, milder reaction conditions, high yields and environmentally benign procedure.     

One‐pot synthesis of 2‐acylimino‐3‐aryl‐1,3‐thiazoline derivatives in aqueous media

The one‐pot two‐step synthesis for acyliminothiazolines by treatment of N,N'‐substituted thioureas with α‐bromocarbonyl compounds under aqueous media was described. Compared to classical reaction in organic solvents, this method consistently has the advantages of short reaction time and being environmentally friendly.     

Synthesis of 2‐phenylquinolin‐4‐amines substituted with diverse amino and aminoalkyl groups

Facile synthetic approaches to 2‐phenylquinolin‐4‐amines containing an aminoalkyl group at N⁴ of the quinolin‐4‐amine and amino or aminoalkyl groups at the phenyl moiety are presented.     

The reaction of aryl and heteroarylhydrazines with aryl‐trifluoromethyl β‐diketones

We report the results obtained when five aromatic or heteroaromatic hydrazines react with six β‐diketones bearing trifluoromethyl and aryl substituents. Forty‐two compounds have been isolated corresponding to two isomeric trifluoromethyl pyrazoles and the intermediate 5‐CF₃, 5‐OH pyrazolines. The results have provided useful information for establishing the mechanism of the synthesis of pyrazoles.     

Synthesis of 1‐substituted 5‐aryl‐3‐styryl‐2‐pyrazolines and 3‐aryl‐5‐styryl‐2‐pyrazolines by the reaction of dibenzylideneacetones and E,E‐cinnamylideneacetophenones with hydrazines

The reaction of dibenzylideneacetones or E,E‐cinnamylidene‐ acetophenones and hydrazine hydrate provided 1‐propionyl derivatives of 5‐aryl‐3‐styryl‐2‐pyrazolines and 3‐aryl‐5‐styryl‐2‐pyrazolines. These unsaturated ketones afforded 1‐(2‐carboxyphenyl) or 1‐(4‐carboxyphenyl) 5‐aryl‐3‐styryl‐2‐pyrazolines and 1‐(4‐carboxyphenyl) derivatives of 3‐aryl‐5‐styryl‐2‐pyrazolines on treatment with (2‐carboxyphenyl)‐hydrazine or (4‐carboxyphenyl)hydrazine in hot acetic acid. Structures of all new 2‐pyrazolines have been elucidated by microanalyses and a combined utilization of various spectroscopic methods.     

Preparation of 6‐azaoxindole (6‐azaindol‐2(3H)‐one) and substituted derivatives

A general synthesis of 6‐azaoxindoles, substituted in the 3‐ and 5‐position, has been developed starting from 4‐methoxycarbomethyl‐3‐nitropyridine, via hydrogenation of the nitro group and cyclisation of the resulting 3‐amino‐4‐methoxycarbomethyl‐pyridine.     

Synthesis,crystal structure of some new 2‐(4‐methylbenzoylimino)‐3‐aryl‐4‐methyl‐1,3‐thiazolines

An efficient, straightforward synthesis of some new 2‐(4‐methylbenzoylimino)‐3‐aryl‐4‐methyl‐1,3‐thiazolines ( 2a‐i ) is described. The methodology involves the cyclization of 1‐(4‐methylbenzoyl)‐3‐arylthioureas with acetone in the presence of bromine and triethylamine. The structures were confirmed by spectroscopic data, elemental analyses and in one case ( 2i ) by the single crystal X‐ray diffraction data.     

Synthesis of some 3‐aryl‐1H‐isochromene‐1‐thiones

A rapid microwave‐accelerated thionation of some 3‐substitued isocoumarins to corresponding 1‐thio‐isocoumarins was achieved employing Lawesson's reagent under solventless conditions.     

A facile synthesis of pyrazolo[3,4‐D]pyridazines Via the 1,3‐dipolar cycloaddition of 3‐arylsydnones. Synthesis and computational studies of 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐D]pyridazine‐3,6‐diones and their 3,6‐dichloro derivatives.

The synthetic utility of 1,3‐dipolar cycloaddition of DMAD to sydnones has been exploited in the preparation of new 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐d]pyridazine‐3,6‐diones 7a‐j and their aromatic 3,6‐dichloro analogues 8a‐j . The lactam‐lactim tautomerism of compound 7a has been studied by the semi emperical (PM3) and ab initio methods.     

Palladium‐catalyzed cyclization of 3‐bromopyridine‐4‐carbaldehyde with carbon monoxide and carboxylic acids

3‐Bromopyridine‐4‐carbaldehyde is cyclized with carboxylic acids in acetonitrile at 100° under carbon monoxide pressure in the presence of a catalytic amount of a palladium catalyst along with a base to afford the corresponding 3‐oxo‐1,3‐dihydrofuro[3,4‐c]pyridine‐1‐yl alkanoates in moderate to good yields.     

Regioselective one pot synthesis of 2‐alkyl/aryl‐4h‐benzo[1,4] thiazine‐3‐one via microwave irradiation

A series of 2‐alkyl/aryl‐4H‐benzo[1,4]thiazine‐3‐ones have been synthesized by microwave irradiation of ethyl‐2‐bromo‐2‐alkyl/aryl acetate and 2‐amino thiophenol in the presence of 1,8‐diazabicyclo‐[5.4.0] undec‐7‐ene and N‐methylpiperidine. All compounds were characterized by ¹H NMR, ¹³C NMR and elemental analyses, and by X‐ray crystallography in the case of 2‐methyl‐4H‐benzo[1,4]thiazin‐3‐one.     

A series of 1‐[2‐aryl‐1‐diazenyl]‐3‐({3‐[2‐aryl‐1‐diazenyl]perhydrobenzo[d]imidazol‐1‐yl}methyl)perhydrobenzo[d]imidazoles. Synthesis and characterization

Reaction of diazonium salts with solutions of 1,2‐diaminocyclohexane mixed with formaldehyde affords the 1‐[2‐aryl‐1‐diazenyl]‐3‐({3‐[2‐aryl‐1‐diazenyl]perhydrobenzo[d]imidazol‐1‐yl}methyl)perhydrobenzo‐[d]imidazoles ( 6 ), a new series of bis‐triazenes with different connectivity than any previous type of bis‐triazene reported. The products have been characterized principally by NMR and IR spectroscopy, elemental analysis and unequivocally by X‐ray crystallography. The methylene protons of the perhydroimidazole rings are diastereotopic giving rise to a doublet of doublets pattern in the ¹H NMR spectra. However, detailed analysis of the NMR spectra shows that there is more than one set of doublet‐of‐doublet signals, suggesting the presence of different rotameric forms of the products. The ¹³C NMR spectral assignments were assisted by COSY and DEPT experiments with selected compounds.     

Solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters catalyzed by sulfamic acid

The solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters was performed and effectively catalyzed by sulfamic acid. Compared with conventional methods, this protocol features mild reaction conditions and high yields. Furthermore, it is solvent‐free and thus eco‐friendly.     

Facile preparation of 7,11‐di(4‐nitrobenzenesulfonyl)‐diaza‐1,4‐dioxa‐7,11‐spiro[4,7]dodecan‐9‐one

Compound 1 as a key intermediate for the synthesis of 3,3,7,7‐tetrakis‐(difluoroamino)octahydro‐1,5‐dinitro‐1,5‐diazocine (HNFX) and 3,3‐bis(difluoroamino)octahydro‐1,5,7,7‐tetranitro‐1,5‐diazocine (TNFX) is described. Cycloalkylation of 3 with 1,3‐dibromopropan‐2‐ol ( 4 ) afforded 1,5‐protected‐1,5‐diazocine 2 , followed by chromic acid oxidation to ketone 1 in good yield.     

One‐pot three‐component synthesis of 2‐substituted 4‐aminoquinazolines

A facile and rapid synthesis of the title compounds via one‐pot reaction of 2‐aminobenzonitrile, orthoesters and ammonium acetate under solvent‐free and microwave condition is described.