p-Toluenesulfonic acid → 22-(2-Hydroxy-3,4-dimethoxy-6-methylphenyl)docosanoic acid

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Reaction Steps

13-oxo-22-(2-hydroxy-3,4-dimethoxy-6-methylphenyl)docosanoic acid (5.21 g) is reduced in the presence of p-toluenesulfonic acid (250 mg) and p-toluenesulfonyl hydrazide (2.33 g) in a solvent mixture of dimethylformamide (25 ml)-sulfolane (25 ml)-cyclohexane (25 ml) as in the corresponding step of Reference Example 5. The resultant crude product is recrystallized from methanol to obtain 2.97 g of 22-(2-hydroxy-3,4-dimethoxy-6-methylphenyl)docosanoic acid, m.p. 67° C.-68° C. The physico-chemical constants of this product are all in agreement with those of the crystals obtained in Reference Example 4.

Provenance & Evidence