Ethanol → 6,11-Dihydro-11-oxodibenz[b,e]oxepin-2-propanoic acid

Participants

Reaction Conditions

Reaction Steps

Phosphorus pentoxide (10.4 g, 0.073 mole) was cautiously added to 7.4 ml of absolute ethanol under a nitrogen atmosphere and stirred at 110° C. for 1 hour; 53.1 ml of sulfolane was added and the temperature adjusted to 85° C. After adding 4-(2-carboxybenzyloxy)phenylpropanoic acid of Example 6a (5.0 g, 0.017 mole), the reaction was stirred at 85° C. for 3.5 hours. The mixture was poured into 1 liter of ice water, made basic by addition of NaOH pellets, extracted with toluene and the aqueous phase was then acidified with concentrated HCl. The resulting precipitate was filtered, triturated with isopropanol and dried giving 3.22 g of 6,11-dihydro-11-oxodibenz[b,e]oxepin-2-propanoic acid (68% yield), m.p. 128°-130° C.

Provenance & Evidence