Phosphorus oxide (P4O10) → HCID 22152299, compound

Participants

Reaction Steps

To a solution of 50 g (0.352 mol) of phosphorous pentoxide in 500 ml of methanesulfonic acid was added dropwise 20 g (0.101 mol) of 1-(3-methoxyphenoxy)-2-methyl-2-propanol over a 30 min period. The reaction mixture was stirred for 3 h at ambient temperature. The reaction mixture was poured into 1.5 l of ice water and extracted with ether. The combined extracts were dried and evaporated. The residue was filtered through silica gel (500 g) using a gradient from hexane to 10:90 (v/v) of ether:hexane as eluent, There was obtained 13.2 g (74.06 mmol, 72%) of 2,3-dihydro-6-methoxy-3,3-dimethylbenzofuran. This material was dissolved in 75 ml of toluene an 8.12 g (0.11 mol) of dimethylformamide was added. The mixture was cooled in an ice water bath and 14.23 g (92.8 mmol) of phosphorous oxytrichloride was added dropwise. The reaction mixture was heated at reflux for 3 h. The reaction mixture was cooled to ambient temperature and poured into 300 ml of 2N sodium hydroxide solution. The organic phase was washed with 1N hydrochloric acid, water, saturated sodium chloride solution, dried and evaporated. The residue was chromatographed on silica gel (150 g) using a gradient of from hexane to 25:75 (v/v) ether:hexane as eluent. There was obtained 10.3 g (49.9 mmol, 68%) of 2,3-dihydro-6-methoxy-3,3-dimethyl-5-benzofurancarboxaldehyde as white crystals; mp 75°-76° C.

Provenance & Evidence