Synthesis of 3,4,7,8-Tetrahydro-6H-pyrido[1,2,3-ef]-1,5-benzodiazepin-2(1H)-ones via Benzotriazole Methodology - Katritzky, Alan R; Abonia, Rodrigo; Yang, Baozhen; Qi, Ming; Insuasty, Braulio (Synthesis, 1998)