Abstract
When mixed with methanol containing a catalytic amount of sulfuric acid and kept at 10°C for 10 h, benzoylacetone (BA) gave two products methoxylated on the side of the acetyl group (viz., 3, 3-dimethoxy-1-phenyl-1-butanone (AK) and 3-methoxy-1-phenyl-2-buten-1-one (A'E)) but no products methoxylated on the side of the benzoyl group (4, 4-dimethoxy-4-phenyl-2-butanone (BK) and 4-methoxy-4-phenyl-3-buten-2-one (B'E)) or products methoxylated on both carbonyls. Furthermore, BA did not undergo acid-catalyzed methanolysis under our conditions. The reason why acetal formation of the acetyl carbonyl occurs more easily than that of the benzoyl carbonyl, and the relationship of AK and A'E, which is not an intermediate in the formation of AK from BA even though AK can be formed from it, are discussed.
