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.     

1‐Arylsulfonyl‐2‐styrylsulfonylthenes — source for a new class of bis heterocycles

New and novel sulfone linked bis heterocycles_ bis pyrroles and pyrrolyl pyrazolines are prepared from 1‐arylsulfonyl‐2‐styrylsulfonylethenes by 1,3‐dipolar cycloaddition methodology.     

Convenient preparations of 2‐alkyl‐5‐oxopyrrolidine‐3‐carboxylic acids

Reduction of the Michael addition products of anions of nitro compounds to dimethyl maleate led to the spontaneous formation of the respective 2‐alkyl‐5‐oxopyrrolidine‐3‐carboxylic acid methyl esters. Conventional hydrolysis of the later gave the desired compounds.     

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.     

Convenient way to 5‐substituted 4‐amino‐2,3‐dihydro‐4H‐1,2,4‐triazole‐3‐thiones

Various 4‐amino‐2,3‐dihydro‐4H‐triazoles with aromatic, aliphatic and heterocyclic substituents at the C(5) position were synthesized from corresponding esters and thiocarbohydrazide. This method allows the synthesis these heterocycles in a short time and at reduced expenses.     

1,3‐Dibromo‐5,5‐dimethylhydantoin (DBH) as an efficient promoter for acetylation of 3‐arylsydnones in the presence of acetic anhydride under neutral conditions

1,3‐Dibromo‐5,5‐dimethylhydantoin (DBH) has been found to efficiently promote the conversion of various 3‐arylsydnones to their 4‐acetyl congeners in the presence of acetic anhydride under neutral conditions in satisfactory 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.     

A novel synthesis of some 2‐imino‐4‐thiazolidinone derivatives

An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α‐Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate.     

An improved synthesis of 1‐acetyl‐1H‐indol‐3‐yl acetates

An efficient two steps procedure for the synthesis of 1‐acetyl‐1H‐indol‐3‐yl acetates, starting from 2‐chlorobenzoic acids, was developed and in general, moderate to good yields were obtained     

An efficient and clean one‐pot synthesis of 3,4‐dihydropyrimidine‐2(1H)‐ones catalyzed by tungstate sulfuric acid in solvent‐free conditions

Tungstate sulfuric acid catalyzes the three component condensation reaction of an aromatic aldehyde, urea and a β‐ketoester under solvent‐free conditions to afford the corresponding dihydropyrimidinones in high to excellent yields at room temperature.