反应详情

A methylene chloride solution (5.0 ml) of N-acetylglycine ethyl ester (72.5 mg, 0.50 mmol) and N-methylimidazole (50.4 mg, 0.61 mmol) was cooled to −45° C., and a methylene chloride solution (0.5 ml) of palmitoyl chloride (142.6 mg, 0.50 mmol) was added thereto in nitrogen atmosphere. After the mixture was stirred for 20 minutes at the same temperature, a methylene chloride solution (0.5 ml) of titanium tetrachloride (340.4 mg, 1.78 mmol) and a methylene chloride solution (0.5 ml) of tributylamine (372.4 mg, 2.01 mmol) were added thereto. The resulting mixture was stirred for 2 hours at −45° C. Water was added thereto, and the mixture was heated to room temperature, and the organic layer was separated. Further, the water layer was extracted twice with methylene chloride, and the organic layers were combined and dried with magnesium sulfate. After the solvent was removed in reduced pressure, the obtained crude product was purified by silica gel chromatography (Kieselgel 60 manufactured by Merck, hexane:ethyl acetate=3:2) to obtain the title compound (148.8 mg, yield: 88%).

1. stirringThe resulting mixture was stirred for 2 hours at −45° C
2. customthe organic layer was separated
3. extractionFurther, the water layer was extracted twice with methylene chloride
4. dry with materialdried with magnesium sulfate
5. customAfter the solvent was removed in reduced pressure
6. customthe obtained crude product
7. customwas purified by silica gel chromatography (Kieselgel 60 manufactured by Merck, hexane:ethyl acetate=3:2)