Convergent synthesis and cytotoxicity of novel trifluoromethyl-substituted (1H-pyrazol-1-yl)(quinolin-4-yl)methanones

A convergent synthesis of a series of 16 new polysubstituted (5-hydroxy-5-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-1-yl)(quinolin-4-yl)methanones, starting from isatin and alky(aryl/heteroaryl) ketones, is described. The diheteroaryl methanones were achieved at yields of up to 95% by a [3 + 2] cyclocondensation reaction involving 4-alkyl(aryl/heteroaryl)-4-methoxy-1,1,1-trifluorobut-3-en-2-ones (by two-step reaction) and 2-alkyl(aryl/heteroaryl)-4-carbohydrazides (by three-step reaction). Subsequently, representative dehydrated heterocyclic derivatives were obtained from the respective 5-hydroxy-2-pyrazoline moieties by classical dehydration reactions, which resulted in the corresponding (5-(trifluoromethyl)-1H-pyrazol-1-yl)(quinolin-4-yl)methanones (three examples) at yields of 69-82%. The subsequent cytotoxicity evaluation showed that compounds with aromatic groups at the 2-position of the quinoline and a methyl moiety at the 3-position of the pyrazole have significant cytotoxicity in human leukocytes at high concentrations (200 mu M). 2016 Elsevier B.V. All rights reserved.