2-Chloro-4-nitrobenzoic acid → 2-(1,3-Dimethoxy-1,3-dioxopropan-2-yl)-4-nitrobenzoic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 2-chloro-4-nitrobenzoic acid (75 g, 372 mmol) in dimethyl malonate (900 mL) was sparged with nitrogen for 15 min. Sodium methoxide (48.3 g, 894 mmol) was added in one portion and the contents exothermed to 480° C. Fifteen minutes later, copper (I) bromide (5.4 g, 37 mmol) was added in one portion and the contents heated to 70° C. for 24 hrs. The reaction was 70% complete by nmr, the contents heated to 85° C. for 6 hrs to completely consume the 2-chloro-4-nitrobenzoic. Water (900 mL) was added to the cooled reaction followed by hexanes (900 mL). The aqueous layer was separated, toluene (900 mL) added, filtered through celite, and aqueous layer separated. Fresh toluene (1800 mL) was added to the aqueous layer and the biphasic mixture acidified with 6N aqueous HCl (90 mL). A white precipitate formed and the contents stirred for 18 hrs. The product was filtered off and dried to give a white soid (78.1 g, 70%) mp=153° C.

Provenance & Evidence