Síntese de BIS-1H-pirazóis trialometil substituídos

Abstract

The present research describes the use of b-alcoxyvinyl trihalomethyl ketones (1,2) [CX3C(O)CHCRR1, where X: Cl, F; R: H, Me, Ph, 4-MePh, 4-MeOPh, 4-FPh, 4- ClPh, 4-BrPh, 4-NO2Ph, 4,4 -Biphenyl, 1-Naphtyl, 2-Furyl, 2- Thienyl; R1: OMe, OEt] in the regioselective synthesis of Oxalyl-1,1 -Bis-5-trihalomethyl-5-hydroxy-4,5-dihydro- 1H-pyrazoles (6,8), Succinyl-1,1 -Bis-5-trihalomethyl-5-hydroxy-4,5-dihydro-1Hpyrazoles (10,14), Succinyl-1-(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H)-pyrazole- 1 -(5-trichloromethyl-5-hydroxy-4,5-dihydro-1H)-pyrazole (13) e Carbonyl-1,1 -Bis-5- trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazole (16), obtained from the cyclocondensation reaction of 1,1,1-trihalo-4-alkoxy-3-alken-2-ones (1,2) and dihydrazide oxallyc, di-hydrazide succinic and carbohydrazide, respectively. For the synthesis of these compounds, ethanol was used as solvent, at temperature of 50-80 oC, in reaction time of 2-16 hours, with yields of 51-91%. The Bis-5-hydroxy-4,5-dihydro-1H-pyrazolines (6,8,10,14,16) were submitted the dehydration reactions carried out in thionyl choride, pyridine, benzene, at temperature of 0-80 oC, giving the aromatic compounds Oxalyl-1,1 -Bis-3-aryl-5-trihalomethyl-1Hpyrazoles (7,9) and Succinil-1,1 -Bis-5-trihalomethyl-1H-pyrazoles (11,15), with yields of 53-78%. Also, were obtained a series of Carbonyl-1,1 -Bis-5-trihalomethyl-1Hpyrazoles (3,5), in direct synthesis, thus, in one pot method, from the vinyl trihalomethyl ketones (1,2) and 1,3-diaminoguanidine hydrochloride, carried out in ethanol/water, reaction time of 4-5 hours, with yields of 62-86%. Finally, 5-trifluoromethyl-5-hydroxy-4,5-dihydro-1-succinilhydrazino-1Hpyrazole (12) and 5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazole-1- carbohydrazide (18), were chemoselectively synthesized, in mild conditions reactions and using ethanol as solvent , in reaction time of 4 hours, with yields of 44-86%, respectively. The cyclocondensation reaction of the compounds (12,18) using vinyl trihalomethyl ketones (1) with di-hydrazide succinic or carbohydrazide, and in molar ratio of 1:1. The compounds were characterized by spectral and analytical experiments of 1H s and 13C s NMR, X-Ray Difraction, and the purity were demonstrated by elemental analyzes.