The following article describes a concise synthesis of a collection of 4,5-dihydro-1H-benzo[e][1,4]diazepines fused to a hydantoin ring. Molecular complexity and biological relevance are high and structures are generated in a mere three steps, employing the Ugi reaction to assemble diversity reagents. The protocol represents a novel UDC (Ugi-deprotect-cyclize) strategy employed in the Ugi-5-component CO2-mediated condensation, followed by further cyclization under basic conditions, to afford the fused hydantoin. Mechanistic caveats, dependent on the aldehydes of choice will be revealed and a facile oxidation of the final products to imidazolidenetriones is briefly discussed.The article describes a concise synthesis of a collection of 4,5-dihydro-1H-benzo[e][1,4]diazepines fused to a hydantoin ring, generated in a mere three steps. The protocol employs the Ugi-5-component CO2-mediated condensation, benzodiazepine formation promoted by acidic conditions and basic treatment to afford the fused hydantoin. Mechanistic caveats, dependent on the aldehydes of choice will be revealed and a facile oxidation of the final products to imidazolidenetriones is briefly discussed.

A straightforward procedure for the preparation of N-quinoxaline-indoles is presented. A base-catalyzed one-pot addition of indoles to a preformed α-iminoketone proceeds on the N-1 indole and the subsequent adduct undergoes an acid-mediated deprotection of an internal amino nucleophile, intramolecular cyclization, and final oxidation generating N-1-quinoxaline-indoles in good yield.A novel route to N-1-quinoxaline-indoles is presented. Base-catalyzed addition of indole to preformed α-iminoketones proceeds at the N-1 indole position and the subsequent adduct undergoes an acid-mediated Boc-deprotection, cyclization, and oxidation generating N-1-quinoxaline-indoles in good yield in a succinct three steps.