反应详情

47 g of 1B was added to a mixture of 100 ml of glacial acetic acid and 100 ml of 48% aqueous hydrobromic acid and the mixture was heated at 114°-115° C. for 2.5 hours. The resulting mixture was stripped to dryness, the residue was taken up in 500 ml of ether, and filtered. The filtrate was concentrated to 100 ml, 300 ml of hexane was added, the mixture was chilled and filtered to give 2,3-dihydro-2,4-dimethyl-7-nitrobenzofuran (1C), as a tan solid, m.p.: 69°-71° C.

1. temperaturethe mixture was heated at 114°-115° C. for 2.5 hours
2. filtrationfiltered
3. concentrationThe filtrate was concentrated to 100 ml, 300 ml of hexane
4. additionwas added
5. temperaturethe mixture was chilled
6. filtrationfiltered