PHTHALIDE FORMATION: IV. CONDENSATIONS WITH 5-METHOXY-3-METHYLBENZOIC ACID

Abstract
The products of the condensation of 5-methoxy-3-methylbenzoic acid with aqueous formaldehyde and hydrochloric acid in the presence of glacial acetic acid are dependent on the length of the heating period. A very short period of heating (2 minutes) yields 6-methoxy-4-methylphthalide and the two chloromethylphthalides of m.p. 135° and 154 °C, related to the unisolated 4-methoxy-6-methylphthalide. If the period of heating is 20 minutes or longer, the above chloromethylphthalide melting at 135° is formed and in addition some of the 6-methoxy-4-methylphthalide is chloromethylated to 6-methoxy-7-chloromethyl-4-methylphthalide, melting at 179°. The orientation of all three chloromethylphthalides has been established.

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