Acetic Anhydride → HCID 14522075, compound

Participants

Reaction Conditions

Reaction Steps

A 5.0 L flange flask was charged with 3 (706 g, approx. 4.36 mol, 1 eq) and acetic anhydride (99.5%, ex. Fisher, 1300 ml, 1 mol) to give a clear solution. Sulfuric acid (conc. 98%, 150 drops, ˜3 ml, catalytic) was then added very slowly (dropwise) over 30 minutes, with cooling to 0° C. by aid of an ice/water bath to control the exotherm to give a very dark reaction mixture. Maximum internal temperature observed was 45° C. After the addition the reaction mixture was stirred for 30 min, then the reaction mixture was stirred at 99° C. for 3 h. TLC-examination (silica-gel plate, DCM eluent, PMA stain) showed that all the starting material had been consumed. The mixture was cooled to room temperature (r.t.) overnight to give a dark green solution, which was poured onto an ice-water mixture (2.5 L water and 2.5 Kg of ice) with vigorous stirring. The product was extracted with DCM (5.0 L×3), and the combined extracts washed with water (3.0 L×3), dried over Na2SO4, and evaporated to give a black/brown oily residue.

Provenance & Evidence