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

Participants

Reaction Conditions

Reaction Steps

A mixture of 1.0 g (4.9 mmol) of 4,4-dimethyl-6-acetyl chroman (Compound 38), 2.0 g (50 mmol) of NaOH, 60 ml of 10% aqueous sodium hypochlorite solution and 18 ml of dioxane was heated at 60° C. with stirring for 3 hours. The reaction mixture was cooled to room temperature and then treated with sodium metabisulphite until the mixture was negative to the potassium iodide/starch test. The reaction mixture was then acidified with conc. HC1 and the resultant precipitate was collected by filtration. The residue was washed with water and dried under vacuum to give the title compound as a white solid. PMR (CDCl3): & 1.25 (6H, s), 1.81-1.90 (2H, m), 4.22-4.30 (2H, m), 6.83 (1H, d, J~8.1 Hz), 7.84 (1H, dd, J~8.1 Hz, 1.8 Hz), 8.07 (1H, d, J~1.8 Hz). MS exact mass, m/e 206.0939 (calcd. for C12H14O3, 206.0943).

Provenance & Evidence