The Methylenation of Catechols

Abstract

On the methylenation of 1, 2-dihydroxy-4, 5-methylenedioxybenzene Cl ap, 1, 2-dihydroxy-3- methoxy-4, 5-methylenedioxybenzene C. / bj, 2, 3-dihydroxy-4-methoxyacetophenone Cl cp, 1, 2- dihydroxy-3- C/ dj, 1, 2-dihydroxy-4- C/ ep, 1, 2-dihydroxy-3, 4-dimethoxy-5- 1 fp, 1, 2-dihydroxy-3-methoxy-5- [l g], 1, 2-dihydroxy-4, 5-dimethoxy-3- [1 h]p, and 1, 2-dihydroxy-4, 5- methylenedioxy-3-allylbenzene C. / ij, in a noncatalyst heterogeneous reaction system, high purity methylenedioxy derivatives were obtained in good yields for a short reaction period using the cheapest methylenation agent, methylene chloride, in DMSO as a solvent, while concentra- tions of Cl a-0 had been regulated to be lowered in the reaction system according to a procedure devised by the present authors.