Methanol → Ethyl 1,3,5-triphenyl-4,5-dihydropyrazole-4-carboxylate

Participants

Reaction Steps

A mixture of ethyl cinnamate (7, 2.55 g), benzaldehyde phenylhydrazone (2, 4.21 g), chloramine-T trihydrate (6.45 g), and methanol (45 mL) were heated under refluxing for 22 hours. The reaction mixture was diluted with 50% ethyl acetate in n-hexanes (400 mL), filtered, and evaporated. The residue was purified by column chromatography (silica gel 200 g, eluent: 0 to 10% ethyl acetate gradient in hexanes) and evaporated to give FN1-1 (8, 1.25 g) as colorless crystal. 1H NMR (CDCl3, 400 MHz) δ 7.66-7.64 (m, 1H), 7.46-7.22 (m, 13H), 6.88 (t, J=7.2 Hz, 1H), 4.81 (d, J=4.0 Hz, 1H), 4.70 (d, J=4.0 Hz, 1H), 4.07 (quartet, J=7.2 Hz, 2H), 0.97 (t, J=7.2 Hz, 3H). MS: 371.9 (M+H), 325.5, 297.5.

Provenance & Evidence