Reaction #1256767

Reaction equation

trifluoroacetic acid

BF3.Et2O

methanesulfonic acid

triethylsilane

Compound 28

4-(3-Ethoxycarbonyl-propyl)-5-oxo-1-(4-methylphenylsulfonyl)-2,3,4,5-tetrahydro-1H-benzo[b]azepine-4-carboxylic acid ethyl ester

→

compound 29

Yield 53.0%

4-(3-Ethoxycarbonyl-propyl)-1-(4-methylphenylsulfonyl)-2,3,4,5-tetrahydro-1H-benzo[b]azepine-4-carboxylic acid ethyl ester

Yield 53.0%

Solvents

1,2-dichloroethane

Conditions

Workup

1. 1
   Temperatureto slowly warm to room temperature over 18 hours
2. 2
   TemperatureThe reaction was cooled to 5° C.
3. 3
   Othercautiously quenched with saturated aqueous NaHCO3 (100 mL)
4. 4
   ExtractionThe reaction mixture was extracted with ethyl acetate (100 mL)
5. 5
   Extractionthe ethyl acetate extract
6. 6
   Extractionwas extracted with saturated aqueous NaHCO3, water, brine (2×)
7. 7
   Dryingdried over Na2SO4
8. 8
   Concentrationconcentrated in vacuo
9. 9
   Otherto give an oil
10. 10
    OtherThis oil was purified by column chromatography on silica gel eluting with hexane/ethyl acetate (17:3)

Procedure

Compound 28 (4.76 g, 9.48 mmol) was dissolved in 45 mL of dry 1,2-dichloroethane, cooled to 5° C., and treated with trifluoroacetic acid (1.3 mL), BF3.Et2O (1.4 mL), anhydrous methanesulfonic acid (3.2 mL) and triethylsilane (5.7 mL). The reaction was allowed to slowly warm to room temperature over 18 hours. The reaction was cooled to 5° C. and cautiously quenched with saturated aqueous NaHCO3 (100 mL). The reaction mixture was extracted with ethyl acetate (100 mL) and the ethyl acetate extract was extracted with saturated aqueous NaHCO3, water, brine (2×), dried over Na2SO4, and concentrated in vacuo to give an oil. This oil was purified by column chromatography on silica gel eluting with hexane/ethyl acetate (17:3) to give 2.43 g (53%) of compound 29 as a colorless oil.

Source