Реакция #159097

Уравнение реакции

HBr HOAc

trimethylsilyldiazomethane

3-Bromo-6H-benzo[c]chromene-8-carboxylic acid

oxalyl chloride

sodium bicarbonate

→

2-Bromo-1-(3-bromo-6H-benzo[c]chromen-8-yl)-ethanone

Растворители

DCM

EtOAc

DCM

Условия реакции

Обработка

1. 1
   Температураcooled to 25° C
2. 2
   ДругоеExcess reagents and solvent were removed under reduced pressure and co-evaporated with toluene
3. 3
   Концентрированиеwas concentrated
4. 4
   workup.DISSOLUTIONThe residue was dissolved in EtOAc
5. 5
   Температураwas cooled to 0° C
6. 6
   workup.STIRRINGThe mixture was stirred at 25° C. for 1 hour
7. 7
   workup.STIRRINGthe mixture was stirred for 30 minutes
8. 8
   Промывкаwas washed with water and brine
9. 9
   Сушкаwas dried with Na2SO4
10. 10
    КонцентрированиеConcentration

Методика

To 3-Bromo-6H-benzo[c]chromene-8-carboxylic acid (0.5 mmol) was added a solution of oxalyl chloride in DCM (2.0 N, 5 ml, 10 mmol). The mixture was heated at 45° C. for 2 hours and cooled to 25° C. Excess reagents and solvent were removed under reduced pressure and co-evaporated with toluene. To the solution of above residue in DCM (5 ml) at 0° C. trimethylsilyldiazomethane (2.0 N, 0.75 ml, 1.5 mmol) was added dropwise. The mixture was stirred at 25° C. for 12 hours and was concentrated. The residue was dissolved in EtOAc and was cooled to 0° C. To above solution HBr/HOAc (0.28 ml, 1.5 mmol) was added dropwise. The mixture was stirred at 25° C. for 1 hour. Solid sodium bicarbonate was added and the mixture was stirred for 30 minutes. The mixture was diluted with EtOAc, and was washed with water and brine and was dried with Na2SO4. Concentration gave 2-Bromo-1-(3-bromo-6H-benzo[c]chromen-8-yl)-ethanone, which was used for next step without purification.

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