Acetyl chloride → 3-Acetyl-2-hydroxy-5-methylbenzoic acid

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Reaction Steps

Acetyl chloride (14.7 ml, 5 eq.) is added slowly to an ice cooled suspension of AlCl3 (27.7 g, 5 eq.) in dry CH2Cl2 (125 ml). The reaction is stirred until most of the solid is dissolved, then 5-methyl salicylic acid 236 (6.31 g, 41 mmol) is added. The reaction is stirred at 0° C. for 1.5 hr, then at room temperature for 1.5 hr. The reaction is poured onto ice, diluted with Et2O, and washed with water, brine, dried (MgSO4). Concentration in vacuo afforded a slowly crystallizing oil. Recrystallization (CH2Cl2/hexanes) yielded pure 3-Acetyl-5-methyl salicylic acid (Example 529, Table IIIa) as 3.29 g of off white powder (41% recrystallized yield).

Provenance & Evidence