反应详情

To 49 ml of absolute ethanol is added with vigorous stirring, 81 g of phosphorus pentoxide. After addition, the mixture is allowed to stir at 95°-100° C for 1 hour, 400 ml of tetramethylene sufone are added and the temperature is adjusted to 86°-90° C. Then, 38.5 g of 4-(2-carboxybenzyloxy)phenylacetic acid, Example 1, are added, the mixture is stirred for 4 hours and poured onto ice water. The aqueous mixture is made basic with sodium hydroxide and extracted with toluene. Cooling of the aqueous layer followed by acidification with concentrated hydrochloric acid gives light brown crystals. Recrystallization from acetic acid-water or from dimethoxyethane provides colorless crystals, mp 126°-128° C of 6,11-dihydro-11-oxodibenz[b,e]oxepin-2-acetic acid.

1. additionAfter addition
2. customis adjusted to 86°-90° C
3. stirringthe mixture is stirred for 4 hours
4. additionpoured onto ice water
5. extractionextracted with toluene
6. temperatureCooling of the aqueous layer
7. customgives light brown crystals
8. customRecrystallization from acetic acid-water