Abstract
Effects based upon kinds of methylenating agent, solvent and base used, were remarkably observed in methylenation of catechol (1a), pyrogallol (1b), 1, 2-dihydroxy-3-methoxy-(1c) and 1, 2-dihydroxy-4, 5-dimethoxybenzenes (1d), 2, 3-dihydroxy-4-methoxy-(1e), 3, 4-dihydroxy-(1f) and 3, 4-dihydroxy-5-methoxybenzaldehydes (1g) and 3, 4-dihydroxy-5-bromobenzaldehyde (1h), on this heterogeneous reaction system. In addition to these effects, however, there was remarkable fluctuation in yields dependent on reaction operation, but itwas elucidated that the methylenedioxy derivatives were obtained in good yields from inexpensive methylene dichloride and the above aromatic compounds in a short period, when concentrations of (1a1h) have been regulated below 1 M in the reaction system according to a procedure devised by the present authors.
