HETEROSTRUCTURED ARGENTINEAN CLAYS AS EFFICIENT AND SELECTIVE CATALYSTS IN THE SYNTHESIS OF 1,5-BENZODIAZEPINES

MERCEDES MUÑOZ; GABRIEL SATHICQ; GUSTAVO ROMANELLI; CARMEN I. CABELLO; IRMA L. BOTTO; DELIA GAZZOLI; GIOVANNI FERRARIS

Cancun

Congreso; XX International Materials Research Congress; 2011

Soc. Mexicana de Materiales y Materials Research Society

Natural and modified Argentinean bentonite as catalysts in the synthesis of 1,5benzodiazepine through a condensation reaction between o-phenylenediamine (OPDA)and excess of acetone as reactive and solvent at room temperature were studied. Themodified clays were prepared by conventional methods and characterized by texturalanalysis (BET), electronic microscopy (ESEM-EDS), X ray diffraction technique (XRD),infrared (FTIR) and nuclear magnetic resonance (Al27-MAS NMR) spectroscopies. Theoriginal and modified materials found to be highly active and selective afford a high yieldof the corresponding benzodiazepine. The effects of the modification of naturalbentonite and reaction conditions such as temperature, time and catalyst amount wereinvestigated. Catalysts were also successfully employed for the preparation of otherderivatives of 1,5-benzodiazepine using substituted o-PDAs and ketones. In every casereactions were highly selective and were completed within 1–3 h. In all cases, thecatalytic activity was excellent, showing 86%–90% isolated yields of the correspondingderivatives of 1,5-benzodiazepine. The easy work-up procedure and the recyclablecatalyst make this methodology attractive for large-scale operations.