(3,4-Dimethoxyphenyl)acetic acid → 3-Methylveratrole

Participants

Reaction Steps

To a stirred solution of 35.6 g (0.24 mole) of 3,4-dimethoxytoluene and 14.6 g (0.11 mole) AlCl3 in 200 ml CS2 there was added dropwise over the course of 1 hr. 0.1 mole 3,4-dimethoxyphenylacetyl chloride (freshly prepared from 3,4-dimethoxyphenylacetic acid). The mixture was stirred overnight at 25°, poured into ice, and the resulting oil extracted into benzene. The extracts were dried and evaporated to yield a black viscous oil from which excess dimethoxytoluene was distilled in vacuo. After the pot residue had cooled, alcohol was added and the mixture was allowed to stand 24 hr at 0°. This allowed isolation of essentially pure ketone 4,5-dimethoxy-2-(3,4-dimethoxyphenylacetyl) toluene as a brown powder (25.4 g or 80% yield based upon the acid chloride). An analytical sample was recrystallized from EtOH-EtOAc to yield 4,5-dimethoxy-2-(3,4-dimethoxyphenylacetyl) toluene as white needles, mp 115°. Nmr (δ): 2.52 (s, 3H), 3.82 (s, 6H), 3.85 (s, 3H), 3.88 (s, 3H), 4.15 (s, 2H), 6.68 (s, 1H), 6.77 (s, 3H), 7.30 (s, 1H). Anal. Calcd for C19H22O5 : C, 69.07; H, 6.71. Found: C, 68.84; H, 6.93.

Provenance & Evidence