Isopropanol → 4-(Trifluoromethyl)benzaldehyde

Participants

Reaction Steps

Under cooling in an ice-bath, a 8N Jones' reagent (50 ml) was added dropwise to a solution of the crude product of silyl ether 8a obtained above in 170 ml of acetone over 15 minutes. After completion of the addition, the mixture was stirred for 35 minutes and then 11.4 ml (150 mmoles) of 2-propanol was added. The mixture was allowed to warm to room temperature while being stirring for 1 hour. The reaction mixture was filtered and the residual chromium sulfate was washed with acetone. The washing was combined with the reaction mixture, and the mixture was concentrated in vacuo. The residue was dissolved in 40 ml of ethyl acetate, 150 ml of water and 120 ml of n-hexane were added to the solution, and then the solution was extracted. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. n-Hexane (80 ml) was added to the residue, the insoluble materials were filtered off, the filtrate was concentrated in vacuo and the residue was dried in vacuo at 40° C. for 30 minutes with stirring to give 21.6 g (84.6% from compound 7a) of the crude product of the desired compound III-a as an oil. When this was stored in a refrigerator overnight, it gave crystals with low melting point. However, this was used in the next reaction without further purification. Melting point: 28°-29° C. (methanol).

Provenance & Evidence