Solid-phase synthesis of tetrahydro-1,4-benzodiazepin-2-one derivatives

An efficient method for solid-phase construction of tetrahydro-1,4-benzodiazepin-2-one scaffold is described. Polymer-bound 4-(bromomethyl)-3-nitrobenzoic acid was reacted with alpha-amino acid methyl esters, followed by nitro group reduction and hydrolysis. Subsequent intramolecular cyclization and alkylation at N(4) afforded the structurally diverse products in high yields and excellent purities.