tert-Butanol → tert-Butyl (5-chlorothiophen-2-yl)carbamate

Temperature

80 °C

Triethylamine (1.25 ml) and diphenylphosphoryl azide (1.55 ml) were added to a suspension of 5-chlorothiophene-2-carboxylic acid (0.99 g) in toluene (20 ml), and the mixture was stirred at 80° C. for 1 hour. After the reaction mixture was cooled to room temperature, tert-butanol (2 ml) was added, and the mixture was heated under reflux for 19 hours. The reaction mixture was concentrated under reduced pressure, and methylene chloride (200 ml) was added to the resultant residue. The resultant mixture was successively washed with distilled water, a 10% aqueous solution of citric acid, distilled water, a saturated aqueous solution of sodium hydrogencarbonate and saturated aqueous solution of sodium chloride and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was subjected to column chromatography on silica gel (hexane:ethyl acetate=4:1) to obtain tert-butyl 5-chloro-2-thienylcarbamate (1.05 g).

1. temperatureAfter the reaction mixture was cooled to room temperature
2. temperaturethe mixture was heated
3. temperatureunder reflux for 19 hours
4. concentrationThe reaction mixture was concentrated under reduced pressure, and methylene chloride (200 ml)
5. additionwas added to the resultant residue
6. washThe resultant mixture was successively washed with distilled water
7. distillationa 10% aqueous solution of citric acid, distilled water
8. dry with materiala saturated aqueous solution of sodium hydrogencarbonate and saturated aqueous solution of sodium chloride and then dried over anhydrous sodium sulfate
9. distillationThe solvent was distilled off under reduced pressure

ORD record

ord-d7c9994080594aba87b7b11c14cbab99

Source dataset

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07342014B2