6-chloro-2,3-dimethoxynaphthalene-1,4-dione

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A benzene (8 ml) solution of 2,3-dimethoxybenzo-1,4-quinone (1.0 g, 5.9 mmol) and 3-chloro-1-methoxy-1,3-butadiene (1.4 g, 12.0 mmol) is stirred for 35 hours under an inert atmosphere. After this time, oxygen or air is briefly bubbled through the solution (20 minutes) and the contents are passed through a silica gel plug to afford 1.07 g (72%) of analytically pure 2,3-dimethoxy-6-chloro-1,4-naphthoquinone, mp 127°-130° C. After this time, oxygen or air is briefly bubbled through the solution (20 minutes)