Reaction #48409

Reaction equation

Trifluoroacetic acid

benzyl (3R)-6-(2,3-difluorophenyl)-1-(2,4-dimethoxybenzyl)-2-oxo-2,3,4,7-tetrahydro-1H-azepin-3-ylcarbamate

→

title compound

Yield 66.4%

Benzyl (3R)-6-(2,3-difluorophenyl)-2-oxo-2,3,4,7-tetrahydro-1H-azepin-3-ylcarbamate

Yield 66.4%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Concentrationthe mixture was concentrated at 25° C.
2. 2
   workup.ADDITIONmethanol (150 mL) was added
3. 3
   Filtrationthe precipitate filtered
4. 4
   ConcentrationThe filtrate was concentrated
5. 5
   workup.ADDITIONdiluted with dichloromethane (100 mL)
6. 6
   Washwashed with water (2×), saturated aqueous sodium bicarbonate (2×), saturated brine
7. 7
   Dryingdried over magnesium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated
10. 10
    OtherPurification by silica gel chromatography (5% ethyl acetate/hexanes→65% ethyl acetate/hexanes)

Procedure

Trifluoroacetic acid (60 mL) was added to a solution of benzyl (3R)-6-(2,3-difluorophenyl)-1-(2,4-dimethoxybenzyl)-2-oxo-2,3,4,7-tetrahydro-1H-azepin-3-ylcarbamate (3.70 g, 7.08 mmol) in dichloromethane (40 mL). After 18 h, the mixture was concentrated at 25° C., methanol (150 mL) was added, and the precipitate filtered. The filtrate was concentrated, diluted with dichloromethane (100 mL), washed with water (2×), saturated aqueous sodium bicarbonate (2×), saturated brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel chromatography (5% ethyl acetate/hexanes→65% ethyl acetate/hexanes) gave the title compound (1.75 g). MS 373.1 (M+1).

Source