Synthesis,structures of some unsymmetrical 3,6‐disubstituted‐1,2,4,5‐tetrazines

A series of new unsymmetrical 3‐phenyl‐6‐benzyl‐1,2,4,5‐tetrazine derivatives 10a‐i were synthesized and characterized by IR, NMR, MS, and element analysis. The structures of 4a, 10c, 10d and 10h were analyzed by X‐ray crystallography, which had intermolecular C‐H‐N, C‐H‐Cl, C‐H‐II and II‐II interactions.     

An efficient and green synthesis of 3,3′‐benzylidenebis (4‐hydroxy‐6‐methylpyridin‐2(1H)‐one) derivatives through multi‐component reaction in ionic liquid

A series of new 3,3′‐benzylidenebis(4‐hydroxy‐6‐methylpyridin‐2(1H)‐one) derivatives were synthesized via a three‐component reaction of an aldehyde, an aniline or ammonium acetate and 6‐methyl‐4‐hydroxypyran‐2‐one in ionic liquid. These heterocyclic compounds produced could be conveniently separated from the reaction mixture without any volatile organic solvents, and the ionic liquid could be readily reused without efficiency loss after simple treatment.     

An efficient synthesis of new pyrido[4′,3′:4,5]thieno[2,3‐d]‐pyrimidin‐4(3H)‐one derivatives

The carbodiimides 5 , obtained from reactions of iminophosphorane 4 with aromatic isocyanates, reacted with amines, phenols or ROH to give 2‐substituted 5,6,7,8‐tetrahydropyrido[4′,3′:4,5]thieno[2,3‐d]‐pyrimidin‐4(3H)‐one 7 in the presence of catalytic amount of sodium alkoxide or solid potassium carbonate in satisfactory yields.     

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 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.     

Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas

Substituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.     

Synthesis of a novel class of 3‐(2′‐benzothiazolyl)‐2,3‐dihydroquinazolin‐4(1H)‐ones under solvent‐free and catalyst‐free conditions

A solvent‐ and catalyst‐free one‐pot three‐component condensation reaction approach was developed for the synthesis of a new class of 3‐(2′‐benzothiazolyl)‐2,3‐dihydroquinazolin‐4(1H)‐ones in relatively good yields.     

Biginelli‐like three component reaction: Synthesis of some new ethyl 6‐ethoxycarbonylmethyl‐4‐aryl‐2‐oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylate derivatives

In the context of our high‐throughput organic synthesis program, we have studied the reactivity of special β‐keto esters toward the Biginelli reaction. We have found that a diethyl‐3‐oxoglutarate reacts with one molecule of urea and one molecule of aldehyde under solvent‐free conditions to give a new family of 3,4‐dihydropyrimidin‐2(1H)‐ones in good yields.     

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.