Highly efficient one-pot, three-component synthesis of 1,5-benzodiazepine derivatives

Article abstract of DOI:10.1016/j.cclet.2013.11.035

A general, mild and efficient protocol for the synthesis of ethyl 4-methyl-2-(thiophen)-2,5-dihydro-1,5-benzodiazepine-3-carboxylate is achieved for first time using H₃PMo₁₂O₄₀ in ethanol at 0 C by a one-pot, three-component condensation of various thiophene aldehydes, substituted o-phenylenediamines and ethyl acetoacetate. Compared with the conventional synthesis method, this procedure has the advantages of convenient operation, excellent yields, and environmentally benign. A plausible formation mechanism has been proposed. The structure of the products is characterized by ¹H NMR, IR, MS and elemental analysis.