Síntese de 3H-pirido[2,3-b][1,4]diazepinos trifluormetil substituídos e diazepinonas análogas

Abstract

The present research describes new synthetic methodologies for the synthesis of new series of 2-aryl(heteroaryl)-4-trifluoro-4,5-dihydro-3Hpyrido[2,3-b][1,4]diazepin-4-ols and 2-aryl(heteroaryl)-3H-pyrido[2,3-b][1,4]diazepin-4(5H)-one analogs, in a single one-pot procedure or through on intermolecular cyclization reactions of the enaminoketones intermediates, where aryl = Ph, 4-MeC6H4, 4-OMeC6H4, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 4,4 -biphenyl, 1-naphtyl and heteroaryl = 2-furyl, 2-thienyl. The pyridodiazepinols were obtained from intramolecular cyclocondensation reactions of enaminoketones N3-[1-aryl(heteroaryl)-3-oxo-4,4,4-trifluorobut-1-en-1-yl]-2,3-diaminopyridines in methanol at temperature of 50 °C for 16 hours. In a one-pot reaction, these pyridodiazepinols can be obtained through reactions of 4-methoxy-1,1,1-trifluorobut-3-en-2-ones with 2,3-diaminopyridine, using methanol as solvent and a temperature of 55 to 60 ºC for 24 hours with yields of 56-68%. The attainment of the 2-aryl(heteroaryl)-3H-pyrido[2,3-b][1,4]diazepin-4(5H)-one analogs were obtained through the haloform intramolecular reactions, with the elimination of the trichloromethyl group, from the synthetic intermediate N3-[1-aryl(heteroaryl)-3-oxo-4,4,4-trichlorobut-1-en-yl]-2,3-diaminopyridines in methanol and a temperature of 65 °C for 20 hours with yield of 48-70%. Therefore, the respective pyridodiazepinones were obatined, in a one-pot reaction, reacting 4-aryl(heteroaryl)-4-methoxy-1,1,1-trichlorobut-3-en-2-ones with 2,3-diaminopyridine in more drastic conditions (methanol, 65 ºC and 24 hours) with yields of 48-70%. Under moderated conditions (methanol, 0 °C and 20 hours), regioselective synthesis between the 4-alkyl(aryl/heteroaryl)-4-methoxy-1,1,1-trihalobut-3-en-2-ones and 2,3-diaminopyridine, leads to the isolation of the respective N3-[1-aryl(heteroaryl)-3-oxo-4,4,4-trihalobut-1-en-1-yl]-2,3-diaminopyridines, through of addition - elimination reactions, in good yields. The N3-[1-aryl-3-oxo-4,4,4-trichlorobut-1-en-1-yl]-N2-[sulphonyl methano]-2,3-diaminopyridines were obtained by sulphonation reaction between the N3-[1-aryl-3-oxo-4,4,4-trichlorobut-1-en-1-yl]-2,3-diaminopyridines and methanesulfonyl chloride, at room temperature for 4 hours with yields of 53-66%. Finally, it was obtained a serie of N 3-[trifluoroacetyl-cycloalken-1-yl]-2,3-diaminopyridines through N-acilation reactions, involving cycloalkanones trifluoromethylated of 5, 7 or 8 members with 2,3-diaminopyridine in methanol at 0 ºC for 20 hours with yields of 65-69%. Subsequent reactions showed that, only under more drastic conditions (methanol, 50 °C e 24 hours), these cyclic enaminones underwent intramolecular cyclization, resulting the pyrido-imidazol as only product, independently of the cycloalkanone precursor. The compounds obtained in this research were identified by 1H and 13C NMR and analyzed by elemental analysis, being the N3-[1-aryl(heteroaryl)-3-oxo-4,4,4-trihalobut-1-en-1-yl]-2,3-diaminopyridines, also identified by X-ray diffraction.