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1558952 
Journal Article 
Regiospecific synthesis of 5-trichloromethyl-1H-pyrazole and 1H-pyrazole-5-carboxylic ester derivatives 
Moura, S; Flores, AFC; Paula, FR; Pinto, E; Machado, P; Martins, MAP 
2008 
1 
Letters in Organic Chemistry
ISSN: 1570-1786 
5 
2 
91-97 
WOS:000254079000005 
Reaction of 1,1,1-trichloro-4-methoxy-3-penten-2-one (1)
with hydrazines (2a-h) (NH2NHR, R = H, Me, t-Bu, Ph, 4-NO2-C6H4, C6F5, CO2Me, CONH2) under
differing conditions regiospecifically affords different pyrazole derivatives, 3-methyl-5-
trichloromethyl-5-hydroxy-4,5-dihydropyrazoles (3a, d-h), 3-methyl-5-trichloromethyl-1H-pyrazoles
(4a,b,d-g) and 5-carboxyethyl-3-methyl-1H-pyrazoles (5a-e). The structural assignments were based
on the analysis of their H-1/C-13 NMR and ESI-MS data. 
pyrazoles; trichloromethyl-1H-pyrazoles; 1,1,1-trichloro-4-alkoxy-3-alken-2-ones; cyclocondensation [CCC plus NN]