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5-Alkylated barbituric acids are an important class of compounds that constitute the basic moiety of several clinically used hypnotic drugs. Here we report a catalyst-free domino Knoevenagel-Michael addition involving barbituric acid, aldehyde, and N,N-disubstituted aniline in solvent acetonitrile to synthesize 5-alkylated barbituric acid derivatives (72–94% yield) without using any chromatographic separation techniques. The C-4 position of aniline acts as the Michael donor. All the reactions are successfully performed without catalysts, providing an environment-friendly and economical route for the synthesis. Moreover, catalyst-free reactions are less sensitive to air and moisture unlike many metal catalysts, with easy separation of products, and simple operating procedures as there is no need for catalyst weighing, recovery, and removal. A plausible mechanism is also proposed based on control experiments. [ABSTRACT FROM AUTHOR]

A catalyst‐free approach for the synthesis of oxazolidine derivatives is developed here. Though the synthesized oxazolidines contain three stereogenic centers, single diastereomer of the product is obtained. Single crystal X‐ray analysis of the product confirmed the stereochemistry. The reaction is performed by taking tetrahydroisoquinoline/cyclic benzylic amine (1 equivalent) and aromatic aldehyde (2 equivalent) in water under refluxing condition which produces excellent yield (87–96 %). With pyrrolidine as amine substrate, the reaction gives α,β‐unsaturated cyclic imines which is an example of β‐C−H functionalization of secondary amine. The proposed mechanism shows that the reaction proceeds through the formation of azomethine ylide which undergoes [3+2]‐cycloaddition reaction providing the oxazolidine product. [ABSTRACT FROM AUTHOR]

Synthesis of a novel class of tetrazolo[4′,5′:1,6]pyrido[2,3-d]quinolines from simple acetanilides and via intra�molecular 1,3-dipolar cycloaddition of azides to nitriles using a three-component one-pot protocol is reported. [ABSTRACT FROM AUTHOR]