1-Methyl-1-phenyl-ethylisocyanate → 3-butyl-5,5-dimethyl-4-phenyl-N-(2-phenylpropan-2-yl)-4,5-dihydro-1H-pyrazole-1-carboxamide

Participants

Reaction Steps

Crude 3-(n-Butyl)-5,5-dimethyl-4-phenyl-4,5-dihydropyrazole (Intermediate IV-1) (1.03 gram, 4.48 mmol maximally) was dissolved in toluene (10 ml) and treated with 1-methyl-1-phenyl-ethylisocyanate (Intermediate VII-2) (0.72 g, 4.48 mmol) and 2 drops of triethylamine and the resulting solution was stirred at room temperature for 16 hours. The solution was concentrated and purified using Sepacore equipment: (petroleum ether/diethyl ether=85/15 (v/v)) to give N-(1-methyl-1-phenyl-ethyl)-3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-(1H)-pyrazole-1-carbox-amide as a colorless oil (0.97 gram, 55% yield). Rf (petroleum ether/diethyl ether=4/1 (v/v))˜0.3. 1H-NMR (400 MHz, CDCl3) δ 0.88 (t, J=7, 3H), 1.08 (s, 3H), 1.26-1.39 (m, 2H), 1.44 (s, 3H), 1.45-1.56 (m, 2H), 1.70 (s, 3H), 1.76 (s, 3H), 2.09-2.18 (m, 1H), 2.25-2.35 (m, 1H), 3.70 (s, 1H), 6.59 (br s, 1H), 7.03 (br d, J˜8 Hz, 2H), 7.20 (br t, J˜8 Hz, 1H), 7.26-7.36 (m, 5H), 7.44 (br d, J˜8 Hz, 2H).

Provenance & Evidence