반응 #2138140

반응 방정식

rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol

3-bromobenzo[b]thiophene

triphenylphosphine

triethylamine

→

colorless crystals

수율 66.7%

rac-[2-(Benzo[b ]thiophen-3-yl)ethynyl]-3.4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran 2H-1-benzopyran-6-ol

수율 66.7%

용매

acetonitrile

반응 조건

후처리

1. 1
   기타was degassed with argon for 15 minutes
2. 2
   workup.ADDITIONPalladium acetate, 110 mg, was then added
3. 3
   기타The solvent was evaporated under reduced pressure
4. 4
   기타the residue was partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution
5. 5
   기타The organic layer was separated
6. 6
   건조dried over sodium sulfate
7. 7
   기타evaporated
8. 8
   기타The residue was chromatographed over 200 g of silica gel
9. 9
   세척for elution
10. 10
    기타Crystallization of the combined clean fractions from ether/hexane

실험 절차

A mixture of 4.6 g (20 mmol) of rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol, 6.4 g (30 mmol) of 3-bromobenzo[b]thiophene 0.4 g of triphenylphosphine, 95 mg of cuprous iodide, 6 ml of triethylamine and 150 ml of acetonitrile was degassed with argon for 15 minutes. Palladium acetate, 110 mg, was then added and stirring at room-temperature was continued for 4 days. The solvent was evaporated under reduced pressure and the residue was partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution. The organic layer was separated, dried over sodium sulfate and evaporated. The residue was chromatographed over 200 g of silica gel using methylene chloride/hexane 1:1(v/v) for elution. Crystallization of the combined clean fractions from ether/hexane yielded 3.3 g (45.5%) of colorless crystals with m.p. 123°-124° C. A lower melting modification with m.p. 88°-91° C. was also observed.

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