Toluene → tert-butyl N-[(2S)-4-methyl-1-oxopentan-2-yl]carbamate

Temperature

15 °C

Boc-leucinol (3) (12.88 g, 58.9 mmol) was flushed with toluene and then purged with argon gas. It was dissolved in dimethylsulfoxide (dehydrated, 200 ml) and, after addition of triethylamine (22 ml, 158 mmol), cooled in a 15° C. water bath. Meanwhile, in another flask, sulfur trioxide-pyridine complex (25.3 g, 159 mmol) was dissolved in dehydrated DMSO (100 ml) and stirred for 10 minutes under argon stream. Cooling at 15° C., the sulfur trioxide solution was added dropwise (4 minutes) to the solution of Boc-leucinol (3), and, after further stirring of 8 minutes, the reaction mixture was poured into 1500 ml of cold water to terminate the reaction. Following extraction with ethyl acetate, the organic layer was washed with 0.1 M hydrochloric acid, water and saturated saline solution in the order, dried with anhydrous sodium sulfate, and concentrated after removal of the drying agent. Purification using a silica gel open column (250 g, ethyl acetate/hexane=1/5) gave the aimed compound, Boc-Leu-H (aldehyde) (4). Yield: 10.9 g (85.8%).

1. custompurged with argon gas
2. dissolutionIt was dissolved in dimethylsulfoxide (dehydrated, 200 ml)
3. temperatureCooling at 15° C.
4. stirringafter further stirring of 8 minutes
5. customto terminate
6. customthe reaction
7. extractionextraction with ethyl acetate
8. washthe organic layer was washed with 0.1 M hydrochloric acid, water and saturated saline solution in the order
9. dry with materialdried with anhydrous sodium sulfate
10. concentrationconcentrated
11. customafter removal of the drying agent
12. customPurification

ORD record

ord-96363541b9cf48b4acc9285684ee44c5

Source dataset

uspto-grants-2009_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07585938B2