Iodine → 3-Iodo-4-methoxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

To a mechanically stirred suspension of p-anisic acid (59.90 g, 394 mmol) and iodine (100.0 g, 394 mmol) in a mixture of 325 mL glacial acetic acid and 60 g conc H2SO4, heated to 45° C. with a water bath, was added dropwise a solution of 40 g conc HNO3 in 60 mL HOAc at such a rate that the temperature was maintained between 40-50° C. (ca. 90 min). After addition, the mixture was stirred for 30 min at 50° C., then diluted with 400 mL H2O, which produced a pink solid. The material was collected on a Büchner funnel, rinsed with 1 L 10% Na2S2O4 and 1 L H2O, then air dried. Recrystallization from 700 mL pyridine/MeOH (1:1) provided colorless plates. The crystals were collected on a Büchner funnel, rinsed with 500 mL MeOH, then allowed to air dry. After drying under high vacuum overnight, 71.4 g (65.2%) of the desired product was obtained; mp 243-244° C. (lit.10 mp 238° C.); 1H NMR (DMSO-d6) δ 3.91 (s, 3 H), 7.00 (d, 1 H, J=8.7 Hz), 7.95 (dd, 1 H, J=8.7, 1.8 Hz), 8.27 (d, 1 H, J=1.8 Hz), 12.89 (br s, 1 H).

Provenance & Evidence