Hydrochloric Acid → (+/-)-6-Formyl-chroman-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of the compound from Example 9 (11.5 g, 64.5 mmol) in dichloromethane (60 mL) was added to a cooled (−10° C.) mixture of aluminum chloride (21.5 g, 161 mmol) in dichloromethane (30 mL). The mixture was cooled to −30° C. for 20 minutes and dichloromethyl methyl ether (11.7 mL, 129 mmol) was added dropwise over one hour. After an additional 45 minutes the mixture was poured into a mixture of ice (325 mL) and concentrated HCl (5 mL). The mixture was filtered and the filtrate removed. The collected solids were dissolved in tetrahydrofuran. The tetrahydrofuran solution was dried (MgSO4) and concentrated to give a solid. The solid was washed with dichloromethane (3×25 mL) and dried in vacuo at room temperature to give a light pink solid (4.34 g, 33%). 1H NMR (300 MHz, DMSO-d6) δ 13.17 (br s, 1H), 9.81 (s, 1H), 7.64 (m, 2H), 6.99 (d, J=9.2 Hz, 1H), 4.94 (t, J=5.0 Hz, 1H), 2.87 (m, 1H), 2.14 (m, 2H); MS (FAB) m/z 207 (MH+).

Provenance & Evidence