Studies with 2‐arylhydrazononitriles: A novel simple,efficient route to 5‐acyl‐2‐substituted‐1,2,3‐triazol‐4‐amines

Efficient route to 5‐acyl‐2‐substituted‐1,2,3‐triazol‐4‐amines via reaction of 3‐oxo‐2‐(arylhydrazono)‐pentanenitrile with hydroxylamine hydrochloride is reported. X‐ray crystal structure has been made to confirm the structure of reaction products.     

Synthesis and herbicidal activity of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives

A series of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives were designed and synthesized. The structures of all the title compounds were confirmed by ¹H NMR and elementary analysis. These compounds were screened for herbicidal activity against rape and barnyard grass. Compound B13 exhibited moderate herbicidal activity.     

Synthesis of an 4‐oxo‐1,4‐dihydropyridinomethylidene substituted 2‐indolinone

The (Z)‐3‐substituted 2‐indolinone 6 was prepared using the aldehydes 4 and 8 unknown up to now and 2‐indolinone.     

Retro‐ene reactions in heterocyclic synthesis. v. a novel synthetic method for 1,3,5‐triazine‐2,4(1H,3H)‐diones

N‐t‐Butylamidines 1 on heating with diphenyl carbonate ( 2 ) at 150‐180° gave the 1,3,5‐triazine‐2,4(1H,3H)‐dione derivatives 5 . Acylation of amidines 1 and cyclocondensation of the resulting carbamates 3 gave [1,3,5,7]tetrazocine‐2,6‐dione derivatives 4 , and subsequent retro‐ene reaction and ring contraction afforded triazine derivatives 5 .     

Highly efficient intramolecular cyclizations of 2′‐hydroxychalcones to 4‐chloro‐2H‐chromenes under vilsmeier conditions

Highly efficient intramolecular cyclization and of 2′‐hydroxychalcones to 4‐chloro‐2H‐chromenes under Vilsmeier conditions have been developed. In comparison with the reported methods, studies carried out indicate that Vilsmeier reagent generated in situ from DMF and bis(trichloromethyl) carbonate (BTC) provides excellent chemselectivity, higher yields and avoids the formation of inorganic phosphorus salts.     

An interesting cyclization of N‐methyl‐3‐phenyl‐N‐(2‐(Z)‐phenylethenyl)‐cis‐oxiranecarboxamide

Under Lewis acid condition, N‐methyl‐3‐phenyl‐N‐(2‐(Z)‐phenylethenyl)‐cis‐oxiranecarboxamide undergoes elegant double cyclizations to give interesting products.     

Synthesis of 2‐substituted benzimidazoles by iodine‐mediated condensation of orthoesters with 1,2‐phenylenediamines

Iodine was found to be an efficient catalyst for the synthesis of 2‐substituted benzimidazoles by the condensation of orthoesters and 1,2‐phenylenediamines in good to excellent yields under mild reaction conditions.     

A new convenient synthesis of 2,4‐disubstituted‐1,2,4‐triazolo[1,5‐a] quinazolin‐5(4H)‐ones

A novel series of 2,4‐disubstituted‐1,2,4‐triazolo[1,5‐a]quinazolin‐5(4H)‐ones were prepared by Dimroth rearrangement of their respective isomers namely 1,4‐disubstituted‐[1,2,4]triazolo[4,3‐a]‐quinazolin‐5(4H)‐ones. The latter were prepared via new synthetic strategy based on 1,5‐elecrocyclization of the respective N‐(4‐oxo‐3‐phenylquinazolin‐2‐yl)nitrilimines.     

Synthesis of 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinolin‐5‐ol derivatives

This paper describes the synthesis of 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinolin‐5‐ol derivatives ( 3a‐h ) and 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinoline ( 8a ) in good yield by three‐step procedures starting from 2‐aminothiophene‐3‐carbonitrile and 5‐substituted cyclohexane‐1,3‐dione.     

An efficient and greener approach to the synthesis of 3,5‐dicyanopyridin‐2(1H)‐one derivatives in aqueous media under microwave irradiation conditions

A facile and greener synthesis of a series of 3,5‐dicyanopyridin‐2(1H)‐one derivatives was accomplished via the one‐pot reaction of aldehyde, malononitrile and sodium hydroxide in aqueous media under microwave irradiation. This method had several advantages such as shorter route and time, lower cost, reduced environmental impact.     

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.     

Green chemistry approach to the synthesis of 2‐amino‐4‐aryl‐6‐ferrocenyl‐pyridine derivatives by a one‐pot reaction in aqueous medium

A clean and facile green chemistry method for the synthesis of a series of 2‐amino‐4‐aryl‐6‐ferrocenylpyridine derivatives was afforded. The products were synthesized via the one‐pot reaction of aromatic aldehyde, malononitrile or ethyl cyanoacetate, acetylferrocene and ammonium acetate in aqueous medium under microwave irradiation and conventional heating conditions without catalyst. This method had several advantages such as higher yield, lower cost, reduced environmental impact, and convenient procedure.