tert-Butanol → 1,2-dihydroxy-11-(N-methylacetamido)undecane

関与物質

反応手順

A solution of 1-(N-methylacetamido)-10-undecene (2.0 g, 8.9 mmol), N-methylmorpholine-N-oxide (4 mL of a 60% aqueous solution in water, 18 mmol) and potassium osmate dihydrate (10 mg) in acetone (50 mL), water (30 mL), and t-butanol (10 mL) was stirred at ambient temperature for 17 hours. Sodium dithionite (200 mg) was added to reduce the osmium catalyst. After 30 minutes, the mixture was added to dichloromethane (50 mL) and the layers separated. The aqueous layer was extracted with dichloromethane (3×50 mL). The combined organic layers were washed with saturated aqueous salt solution (50 mL) and dried over sodium sulfate, the solvent being subsequently evaporated under vacuum to a thick residue. The residue was purified by chromatography using silica and a dichloromethane/15% methanol eluant, resulting in 1.61 g of 1,2-dihydroxy-11-(N-methylacetamido)undecane (70% yield). This resulting diol (1.61 g, 6.2 mmol) was stirred in a 30% solution of hydrogen bromide in acetic acid (3.7 mL) for 1 hour. The solution was added to a mixture of sodium bicarbonate (7 g) in water (50 mL) and dichloromethane (25 mL). After bubbling ceased, the layers were separated and an aqueous layer extracted with dichloromethane (2×70 mL). The combined organic layers were washed with water (30 mL) and saturated aqueous salt solution (30 mL), then dried over sodium sulfate. The solvent was removed under vacuum to obtain 2.16 g of 1-(N-methylacetamido)-10-acetoxy-11-bromoundecane as a colorless oil (96% yield). Sodium methoxide (351 mg, 6.5 mmol) was added to a solution of bromoacetate (2.16 g, 5.9 mmol) in methanol (15 mL). After 1 hour of stirring, the mixture was added to water (25 mL) and extracted with dichloromethane (3×25 mL). The combined organic layers were washed with saturated aqueous salt solution (25 mL) and dried over sodium sulfate. The solvent was evaporated under vacuum and the residue purified with chromatography using silica and an ethyl acetate eluant, yielding 831 mg of 1,2-oxido-11-(N-methylacetamido)undecane (58% yield).

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