反应详情

温度

190 °C

A mixture of 93.4 g of 2B, 750 ml of DMSO, 48 g of 50% aqueous sodium hydroxide and 45.9 g of 3-chloropropene was stirred for 8 hours at 75°-80° C., then for 16 hours at room temperature, The resulting mixture was added to 3 liters of ice water and the resulting mixture was extracted with methylene chloride. The extract was washed with water, dried (MgSO4) and evaporated to dryness. The residue, in a nitrogen atmosphere, was heated slowly to 190° C. (one hour) and held at 185°-195° C. for two hours, cooled to room temperature, and dissolved in 250 ml of acetic acid. 150 ml of 48% aqueous hydrogen bromide solution was added. The mixture was stirred at reflux for three hours, then mixed with 2 liters of ice water, and the resulting mixture was extracted with a 1:1 v:v mixture of hexane and ether. The extract was washed with water, 5 % aqueous sodium bicarbonate solution, dried (MgSO4), charcoaled and concentrated to dryness. The residue was crystallized from 500 ml of 9:1 v:v hexane/ether mixture, giving 2,3-dihydro-2,5-dimethyl-4-chloro-7-nitrobenzofuran (2C), m.p.: 114°-116° C.

1. waitfor 16 hours at room temperature
2. extractionthe resulting mixture was extracted with methylene chloride
3. washThe extract was washed with water
4. dry with materialdried (MgSO4)
5. customevaporated to dryness
6. waitheld at 185°-195° C. for two hours
7. temperaturecooled to room temperature
8. dissolutiondissolved in 250 ml of acetic acid
9. addition150 ml of 48% aqueous hydrogen bromide solution was added
10. stirringThe mixture was stirred
11. temperatureat reflux for three hours
12. additionmixed with 2 liters of ice water
13. extractionthe resulting mixture was extracted with a 1:1 v
14. additionv mixture of hexane and ether
15. washThe extract was washed with water, 5 % aqueous sodium bicarbonate solution
16. dry with materialdried (MgSO4)
17. concentrationconcentrated to dryness
18. customThe residue was crystallized from 500 ml of 9:1 v