Methyl vinyl ketone → 2H-1-Benzopyran-6-ol, 3,4-dihydro-2-methoxy-2,5,7,8-tetramethyl-

Beteiligte Stoffe

Reaktionsschritte

In the manner described in Example 1, 3.80 g (25 mmol) samples of trimethylhydroquinone were treated in 25 ml of methanol, 5.0 ml of trimethyl orthoformate, and 0.10 ml of 36 N aqueous H 2 SO 4 with 50 mmole portions of the following methyl vinyl ketone substitutes: (a), 2-methoxybutadiene; (b), 3-ketobutanol, (c), 3,3-dimethoxybutene (contaminated with about 20 percent 2-methoxybutadiene); and (d), 4-methoxy-2 -butanone. The reactions were monitored by tlc. Reactions (a),(c) and (d) were complete after 24 hr and were worked up and dried in the manner of Example 1 to give (±)-6-hydroxy-2-methoxy-2,5,7,8 -tetramethylchroman. In reaction (b), a>50 percent conversion to (±)-6-hydroxy-2-methoxy-2,5,7,8-tetramethylchroman was indicated by tlc.

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