Citric Acid → P-Toluenesulfonamide

Benzyl ester (100 mg, 0.0842 mmol) and Pd/C (en) (10 mg) were suspended in methanol (1 ml), and the obtained suspension was stirred in a hydrogen atmosphere at room temperature for 8 hours. Thereafter, the catalyst was filtrated with a filter, and was then washed with methanol. The filtrate was distilled away under reduced pressure. The residue was purified by silica gel column chromatography (chloroform:methanol=9:1−7:3), so as to obtain carboxylic acid (91.2 mg) in a quantitative manner. The thus obtained carboxylic acid (75.9 mg, 0.070 mg) was dissolved in THF (0.5 ml). Thereafter, diisopropylethylamine (32 μl, 0.184 mmol) and p-toluenesulfonyl isocyanate (39 μl, 0.256 mmol) were added thereto in an argon atmosphere, and the obtained mixture was stirred for 1 hour. Thereafter, N,N′-dimethyl-1,3-propanediamine (0.1 ml) was added dropwise to the reaction solution, and a 10% citric acid aqueous solution was then added thereto. An aqueous layer was extracted with chloroform. An organic layer was washed with a saline solution, and it was then dried over sodium sulfate. The solvent was distilled away under reduced pressure. The residue was purified by silica gel column chromatography (chloroform:methanol=9:1), so as to obtain 77.5 mg (87%) of tosylamide.

1. extractionAn aqueous layer was extracted with chloroform
2. washAn organic layer was washed with a saline solution, and it
3. dry with materialwas then dried over sodium sulfate
4. distillationThe solvent was distilled away under reduced pressure
5. customThe residue was purified by silica gel column chromatography (chloroform:methanol=9:1)

ORD record

ord-907d8cd9c7104406a48fb462eafe0fd6

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08076299B2