Diphosgene → HCID 59864978, compound

Participants

Reaction Steps

To a magnetically stirred solution of 3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydropyrazole (Intermediate (IV-1) (0.47 gram, 1.43 mmol) in dichloromethane (10 ml) was successively added DIPEA (0.35 ml, 2.07 mmol) and trichloromethyl chloroformate (0.25 ml, 2.07 mmol, dissolved in 10 ml dichloromethane) at 0° C. and the resulting solution was allowed to attain room temperature and subsequently reacted at room temperature for 1 hour in a nitrogen atmosphere. Subsequent Sepacore column chromatographic purification (eluant: petroleum ether/diethyl ether=93/7 (v/v)) gave pure 3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-(1H)-pyrazole-1-carbonyl chloride (Intermediate VIII-1) (0.20 g, 43% yield). (Intermediate VIII-1). 1H-NMR (400 MHz, CDCl3) δ 0.87 (t, J=7, 3H), 1.11 (s, 3H), 1.27-1.39 (m, 2H), 1.45-1.59 (m, 5H), 2.10-2.20 (m, 1H), 2.36-2.46 (m, 1H), 3.91 (s, 1H), 7.01 (br d, J˜8 Hz, 2H), 7.30-7.40 (m, 3H).

Provenance & Evidence