“…8−11 Over the past several years, considerable studies have been reported for the synthesis of 1,5-benzodiazepines utilizing ytterbium triflate, 12 gallium(III)triflate, 13 erbium(III)triflate, 14 scandium(III)triflate, 15 ytterbium perfluorooctanesulfonate, 16 BF 3 -etherate, 17 p-toulenesulfonic acid, 18 NaBH 4 , 19 MgO/POCl 3 , 20 polyphosphoric acid, 21 CeCl 3 -NaI/SiO 2 , 22 Al 2 O 3 /P 2 O 5 , 23 sulfated zirconia, 24 1,3-n-dibutylimidazolium bromide, 25 SbCl 3 -Al 2 O 3 , 26 iodine, 27 magnesium perchlorate, 28 sodium dodecyl sulfate, 29 Ag 3 PW 12 O 40 , 30 zinc chloride, 31 dodecyl sulfonic acid, 32 piperidine acetic acid, 33 La(NO 3 ) 3 , 34 SmI 2 , 35 sulfamic acid, 36 organic acid, 37 HClO 4 -silica, 38 YbCl 3 , 39 ceric ammonium nitrate, 40 N-bromosuccinimide, 41 acetic acid/MW, 42 (NH 4 )-H 2 PW 12 O 40 , 43 SnCl 2 , 44 K10-montmorillonite, 45 Zn-montmorillonite heterogeneous catalysts 46 borax/phosphorus oxychloride, 47 amberlyst-15, 48 InBr 3 , 49 InCl 3 , 50 NbCl 5 , 51 and RuCl 3 • xH 2 O 52 as catalysts. In addition, a solvent-free procedure has been reported for the synthesis of 1,5-benzodiazepines using iodine, 53 silver nitrate, 54 and HBF 4 -SiO 2…”