Regioselective synthesis of stable 2-(trifluoromethyl)-2,3-dihydro-1H-pyrrol-2-ols and derived fluorinated heterocycles

1,2-Diaza-1,3-butadienes react regioselectively with trifluoromethylated be ta -dicarbonyl compounds to give stable 2-(trifluoromethyl)-2,3-dihydro-1H- pyrrol-2-ol derivatives, which upon treatment with trifluoromethanesulphoni c anhydride. or with heterogeneous catalysts give rise to fluorinated 1-ami nopyrrole derivatives in good to excellent yields. The reaction of 2-(trifl uoromethyl)-2,3-dihydro-IH-pyrrol-2-ol derivative with 2-haloketone affords fluorinated furo[2,3-b]pyrroline derivative, while that of diethyl 1-[(ani linocarbonyl)amino]-2-methyl-5-(trifluoromethyl)- 1H-pyrrole-3,4-dicarboxyl ate with hydrazine hydrate affords fluorinated pyrrolo[3,4-d]pyridazindione derivative.