(4-acetyloxy-5,8-dioxonaphthalen-1-yl) acetate

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5,8-bis(acetyloxy)-1,4-napthalenedione (4.28 g) and 2-formyl-1,2,3,4-tetrahydro-3-isoquinoline carboxylic acid (1.60 g) in acetic anhydride (65 ml) were heated at 100° C. (20 minutes). The reaction mixture was cooled at about 20° C. (1 h), and the solid was collected by filtration, washed with ether (3×30 ml) and dried in vacuo. The crude product was dissolved in dichloromethane and the solution was loaded onto a column of silica gel (175 g) packed in dichloromethane. The column was eluted with 5% (v/v) ethyl acetate in dichloromethane and fractions containing the major component were evaporated to dryness, and further dried in vacuo at 55° C. to give the title compound as a yellow-green solid (1.34 g), m.p. 228°-232° C. (dec), λmax (in CH2Cl2) 242 nm (ε40,700), 377 nm (ε6,400). the solid was collected by filtration washed with ether (3×30 ml) dried in vacuo The crude product was dissolved in dichloromethane The column was eluted with 5% (v/v) ethyl acetate in dichloromethane and fractions containing the major component were evaporated to dryness further dried in vacuo at 55° C.