A catalyst-free four-component domino reaction for the synthesis of functionalized 3-acyl-1,5-benzodiazepines?

Organic & Biomolecular Chemistry Pub Date: 2019-01-04 DOI: 10.1039/C8OB02903B

Abstract

Various functional 3-acyl-1,5-benzodiazepines containing carboxyl, ester and acyl groups at the 2-position were synthesized via an efficient, sustainable and catalyst-free domino reaction. During the synthesis process, one new cycle and four new bonds (one C–C, two C–N and one C[double bond, length as m-dash]C) were constructed by the nucleophilic substitution, nucleophilic addition, dehydration and cyclization reaction by the H+ shift. Furthermore, a total of 26 examples were examined by reacting inexpensive starting materials of N,N-dimethylformamide dimethyl acetal, aromatic ketones, 1,2-phenylenediamine compounds and aldehyde derivatives. Therefore, it displayed a broad substrate scope, good functional group tolerance, high yields (77–97%) and the ease of obtaining target compounds without the involvement of toxic solvents and column chromatography, which provided a novel method for the synthesis of a wide variety of biologically relevant 1,5-benzodiazepines.

Graphical abstract: A catalyst-free four-component domino reaction for the synthesis of functionalized 3-acyl-1,5-benzodiazepines
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