Diisopropylethylamine → [3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-(1H)-pyrazol-1-yl]-3,5,5-trimethylhexan-1-one

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Reaction Conditions

Reaction Steps

To a magnetically stirred solution of 3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-(1H)-pyrazole (1 ml: 0.25 M in anhydrous tetrahydrofuran, 0.25 mmol) was successively added 3,5,5-trimethylhexanoyl chloride (1.1 ml: 0.25 M in anhydrous tetrahydrofuran; 0.275 mmol) and DIPEA (1.1 ml: 0.285 M in anhydrous tetrahydrofuran; 0.313 mmol) and the resulting mixture was stirred for 21 hours at 30° C. An aqueous 5% NaHCO3 solution and dichloromethane were added to the mixture. The organic layer was separated, successively washed with brine and water, dried over MgSO4, filtered and concentrated in vacuo to give [3-(n-butyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-(1H)-pyrazol-1-yl]-3,5,5-trimethylhexan-1-one as a mixture of diastereomers (55 mg, 57% yield). 1H-NMR (400 MHz, CDCl3) δ 0.88 (t, J=7, 3H), 0.94 (s, 9H), 1.00 and 1.01 (2×d, J=7, 3H), 1.12-1.20 (m, 4H), 1.25-1.39 (m, 3H), 1.47-1.58 (m, 5H), 2.07-2.34 (m, 3H), 2.46-2.55 (m, 1H), 2.63-2.73 (m, 1H), 3.72 and 3.74 (2×s, 1H), 6.98 (br d, J=8 Hz, 2H), 7.28-7.37 (m, 3H).

Provenance & Evidence