Sodium Hydroxide → 2,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 2.0 (50 mmol) of NaOH in 10 ml of water was treated with 50 ml of 10% aqueous sodium hypochlorite solution and then with a solution of 1.04 g (4.31 mmol) of 2,2,4,4-tetramethyl-6-acetylchroman (Compound 46) in 15 ml of dioxane. The mixture was heated at 65° C. for 40 hours under a nitrogen atmosphere. The mixture was cooled to room temperature and then diluted with water. The mixture was then washed with ether and the aqueous layer was treated with sodium metabisulphite until it was negative to the potassium iodide - starch test. The aqueous layer was then acidified with 10% H2SO4 and then extracted with ether. This ether extract was washed with water and saturated NaCl solution and then dried (MgSO4). Solvent was removed in-vacuo and the residue recrystallized from ethyl acetate to give the title compound as a white solid. PMR (CDCl3): & 1.39 (6H, s), 1.40 (6H, s), 1.88 (2H, s), 6.85 (1H, d, J~8.7 Hz), 7.85 (1H, dd, J~8.7 Hz, 2.1 Hz), 8.09 (1H, d, J~2.1 Hz). MS exact mass, m/e 234.1256 (calcd. for C14H18O3, 234.1256).

Provenance & Evidence