Carbon Dioxide → Benzo(b)thiophene-3-carboxylic acid

A solution of 3-bromobenzothiophene (0.40 mole, (D15)) and methyl iodide (25 ml, 0.40 mole) in dry ether (400 ml) was added to a stirred mixture of magnesium turnings (24 g, 1.0 mole) and dry ether (100 ml) under nitrogen, at such a rate as to maintain a steady reflux. After the addition was complete, the reaction mixture was heated under reflux for 30 minutes and then allowed to cool to room temperature. The solution was diluted with dry toluene (500 ml) and stirred vigorously as dry carbon dioxide was bubbled through over 3 hours. The thick precipitate which formed was dissolved by the addition of dilute hydrochloric acid and the organic layer was then separated. The aqueous solution was extracted with ethyl acetate (2×300 ml) and all the organic solutions were then combined and extracted with 10% sodium carbonate solution (4×300 ml). The aqueous extracts were combined, washed with ether (2×200 ml) and then acidified with dilute hydrochloric acid. The precipitate was filtered off, washed with water and then dried under vacuum to give the title compound as a white solid (31.2 g, 44%) m.p. 171°-173°.

1. temperatureat such a rate as to maintain a steady reflux
2. additionAfter the addition
3. temperaturethe reaction mixture was heated
4. temperatureunder reflux for 30 minutes
5. customwas bubbled through over 3 hours
6. customThe thick precipitate which formed
7. customthe organic layer was then separated
8. extractionThe aqueous solution was extracted with ethyl acetate (2×300 ml) and all the organic solutions
9. extractionextracted with 10% sodium carbonate solution (4×300 ml)
10. washwashed with ether (2×200 ml)
11. filtrationThe precipitate was filtered off
12. washwashed with water
13. customdried under vacuum

ORDレコード

ord-61428b7594504909ae8ab63384ed4ea3

出典データセット

uspto-grants-1985_10

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US04548948