Methyl iodide → 2-Iodo-5-methoxy-1,3-dimethylbenzene

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Reaction Steps

O-Methyl-3,5-dimethyl-4-iodophenol was prepared by etherifying 3,5-dimethyl-4-iodophenol as follows: In a 1 l three-necked flask equipped with an overhead stirrer were placed 63.7 g (257 mmol) of 3,5-dimethyl-4-iodophenol, 70.9 g (513 mmol) potassium carbonate, 400 ml acetone and 47.5 ml (108 g, 760 mmol) methyl iodide. The reaction mixture was refluxed for 15 hours, cooled, the precipitate filtered and washed with acetone. The combined acetone washes were concentrated under reduced pressure, dissolved in methylene chloride, washed successively with 5% sodium hydroxide, saturated sodium bisulfite and water. After drying over magnesium sulfate and filtering, the solvent was removed under reduced pressure to afford a tan oil. Recrystallization from hot methanol with cooling to room temperature and then -78° C. afforded 58.2 g (86% yield) of white needles, mp 33°-34° C., which were identified as O-methyl-3,5-dimethy-4-iodophenol. 1H NMR analysis indicated: (δ, CDCl3) 6.56 (s, 2H), 3.67 (s, 3H) and 2.37 (s, 6H). Mass spectrum analysis indicated: (m/e) 262 (m+, 100%), 247, 219, 135 and 91.

Provenance & Evidence