O Formylphenoxyacetic acid

ETHYL BENZOATE VIA THE NITRO-SOAMIDE DECOMPOSITION, 47, 44 Decachlorobi-2,4-cyclopentadienyl, dechlorination by triisopropyl phosphite, 46, 93 a-Decalones, 46, 82 Decanoyl fluoride, 46, 6 Decarboxylation, in formation of couma-rone from o-formylphenoxyacetic acid, 46, 28... 

A. o-Formylphenoxyacetic acid. A solution of 80.0 g. (2 moles) of sodium hydroxide pellets in 200 ml. of distilled water is added to a mixture of 106 ml. (122 g., 1 mole) of salicylaldehyde (Note 1), 94.5 g. (1 mole) of chloroacetic acid (Notes 1 and 2), and 800 ml. of water. The mixture is stirred slowly and heated to boiling. The resulting black solution (Note 3) is heated under reflux for 3 hours (Note 4). The solution is acidified with 190 ml. of concentrated hydrochloric acid (sp. gr. 1.19) and is steam-distilled to remove unchanged salicylaldehyde (40.0-40.5 g.) (Note 5). The residual acidic mixture is cooled to 20°, and the precipitated product is collected on a Buchner funnel and rinsed with water. The light tan solid when dry weighs 99-100 g. (82-83% based on recovered salicylaldehyde), m.p. 130.5-133.0° (Note 6). 

Benzofuran. Heat under reflux for 8 hours a mixture of 20 g (0.11 mol) of o-formylphenoxyacetic acid, 40 g of anhydrous sodium acetate, 100 ml of acetic anhydride and 100 ml glacial acetic acid. Pour the light brown solution into 600 ml of iced water, and allow to stand for a few hours with occasional stirring to aid the hydrolysis of acetic anhydride. Extract the solution with three 150 ml portions of ether and wash the combined ether extracts with 5 per cent aqueous sodium hydroxide until the aqueous layer is basic the final basic washing phase acquires a yellow colour. Wash the ether layer with water until the washings are neutral, dry the ethereal solution over anhydrous calcium chloride and remove the ether on a rotary evaporator. Distil the residue and collect the benzofuran as a fraction of b.p. 170-172°C. The yield of colourless product is 9.5 g (91%). 

A procedure by Burgstahler and Worden2 for the preparation of benzofurane (6) from o-formylphenoxyacetic acid (5) calls for refluxing for 8 hrs. a mixture of 0.5 mole of (5), 2.2 moles of sodium acetate. 450 ml. of acetic anhydride, and 450 ml. of acetic acid benzofurane (6), the product of cyclodehydration and decarboxyla-... 

Use of purified o-formylphenoxyacetic acid increases the yield in this step by only 11%. 

---