3-methyl-2,4-dihydro-1,5-benzodioxepin-3-ol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture (23.7 g) of 2-hydroxymethyl-2-methyl-1,4-benzodioxan and 3-hydroxy-3-methyl-2H-1,5-benzodioxepine (~3:1 ratio; prepared according to the method of A. Salimbeni, E. Manghisi, J. Heterocyclic Chem., 17, 489, 1980) was stirred with 1 N aqueous sodium hydroxide solution (135 ml) and cooled to 0°-10°. A solution of potassium permanganate (42 g) in water (165 ml) was added slowly so that the temperature was maintained below 10°. After 48 hours at room temperature the mixture was filtered and the filtrate acidified with 1 M aqueous sulphuric acid and extracted with methylene chloride. The extracts were washed with aqueous sodium bicarbonate solution and the aqueous layer was acidified with sulphuric acid. Extraction with methylene chloride followed by washing, drying and evaporation of the extracts gave the carboxylic acid (11.5 g); m.p. 125°-129.5°. prepared cooled to 0°-10° was maintained below 10° After 48 hours at room temperature the mixture was filtered extracted with methylene chloride The extracts were washed with aqueous sodium bicarbonate solution Extraction with methylene chloride by washing drying evaporation of the extracts

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture (23.7 g) of 2-hydroxymethyl-2-methyl-1,4-benzodioxan and 3-hydroxy-3-methyl-2H-1,5-benzodioxepine (~3:1 ratio; prepared according to the method of A. Salimbeni, E. Manghisi, J. Heterocyclic Chem., 17, 489, 1980) was stirred with 1 N aqueous sodium hydroxide solution (135 ml) and cooled to 0°-10°. A solution of potassium permanganate (42 g) in water (165 ml) was added slowly so that the temperature was maintained below 10°. After 48 hours at room temperature the mixture was filtered and the filtrate acidified with 1 M aqueous sulphuric acid and extracted with methylene chloride. The extracts were washed with aqueous sodium bicarbonate solution and the aqueous layer was acidified with sulphuric acid. Extraction with methylene chloride followed by washing, drying and evaporation of the extracts gave the carboxylic acid (11.5 g); m.p. 125°-129.5°. prepared cooled to 0°-10° was maintained below 10° After 48 hours at room temperature the mixture was filtered extracted with methylene chloride The extracts were washed with aqueous sodium bicarbonate solution Extraction with methylene chloride by washing drying evaporation of the extracts