9-Fluorenylmethyl chloroformate → HCID 10689544, compound

0.759 g (5.70 mmol) of (2R, 3S)-3-amino-2-hydroxypentanoic acid were admixed with a solution of 1.199 g (14.28 mmol) of sodium hydrogen carbonate in 20 ml of water, and with 20 ml of dioxane. The resulting mixture was cooled with ice. To this solution was dropwise added a solution of 1.623 g (6.27 mmol) of 9-fluorenylmethyl chloroformate in 10 ml of dioxane under cooling with ice for 30 minutes. After the completion of the addition, the reaction mixture was stirred at room temperature for 2 hours, diluted with 100 ml of water, and successively washed with 150 ml of ether and 75 ml of ether. To the aqueous layer were added 2.8 ml of 6N hydrochloric acid to adjust to pH 1.5. Then the aqueous layer was extracted three times with 50 ml of ethyl acetate. The oil layer was washed with 50 ml of a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and distilled to remove the solvent therefrom, so that 1.622 g of crude (2R, 3S)-3-(9-fluorenylmethoxycarbonyl)amino-2-hydroxypentanoic acid were obtained.

1. temperatureThe resulting mixture was cooled with ice
2. temperatureunder cooling with ice for 30 minutes
3. additionAfter the completion of the addition
4. washsuccessively washed with 150 ml of ether and 75 ml of ether
5. additionTo the aqueous layer were added 2.8 ml of 6N hydrochloric acid
6. extractionThen the aqueous layer was extracted three times with 50 ml of ethyl acetate
7. washThe oil layer was washed with 50 ml of a saturated aqueous sodium chloride solution
8. dry with materialdried over anhydrous sodium sulfate
9. distillationdistilled
10. customto remove the solvent

ORD record

ord-2460d08c9ce5447cbd86e5b74e1d6e11

Source dataset

uspto-grants-1992_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05162500