Sodium Hydroxide → 3-Chlorobenzoic Acid

関与物質

反応条件

反応手順

4-Bromotetrahydropyran (Frontier Scientific #B10197, 25.8 g, 156 mmol) was added to the solution of sodium hydroxide (16.0 g, 400 mmol) in 40 mL water. The biphase mixture was stirred in 90° C. with a condenser for 1 day. The mixture was cooled to RT and transferred to a small separatory funnel. The organic phase was carefully separated. It was a mixture of alkene J79 (major) and leftover 4-bromotetrahydropyran. This mixture was dissolved in 100 mL chloroform. To it was added MCPBA (77%, 26.8 g, 120 mmol) in small portions. The mixture was vigorously stirred at RT for overnight. The thick suspension was chilled in ice bath and filtered through celite. The solid cake was washed with ice-chilled chloroform 500 mL×3. All the filtrate and wash solutions were transferred into a big separatory funnel. It was washed with saturated NaHCO3 solution twice. The organic phase was then dried over anhydrous Na2SO3 (30 g). The mixture was filtered and the filtrate was concentrated on a rotary instrument in ice-bath bath (<5° C.) to remove chloroform. A light liquid (J80) with some remaining meta-chlorobenzoic acid solid was obtained. This mixture was dissolved in 100 mL isopropanol. To it was added (S)-(−)-α-methylbenzylamine (15.2 mL, 120 mmol). A gel-like mixture was got initially. The mixture was slowly heated to 70° C. and stirred. A clean solution was then got. The clear solution was stirred for 2 days at 70° C. It was then concentrated in vacuo. The residue was taken into 500 mL EtAOc and washed with saturated Na2CO3 solution three times. The organic phase was dried, concentrated and subjected to flash column (0-40% EtOAc in DCM) to isolate desired product J81 (3.52 g) as a cream-colored solid. UV: 259 nm. M+H found for C13H19NO2: 222.2. NMR (DMSO-d6): 7.32-7.25 (4H, m), 7.18 (1H, t), 4.89 (1H, d), 3.86 (1H, m), 3.63 (1H, m), 3.45-3.37 (2H, m, partially obscured by water), 3.19 (1H, m), 2.66 (1H, m), 2.22 (1H, m), 1.92 (1H, m), 1.74 (1H, d), 1.35 (1H, m), 1.22 (3H, d, J=6.4 Hz) ppm.

情報源と証拠