To a solution of 100 mg of auramycin B in 15 ml of acetone was added 0.3 ml of concentrated hydrochloric acid and hydrolysed at room temperature for 120 minutes. The reaction mixture was neutralised by dilute sodium hydroxide solution and 20 ml of water was added and extracted with 20 ml of chloroform twice. The extracts were combined and concentrated to a small volume in vacuo. The concentrate was chromatographed by a column packed with silica gel (chloroform:methanol, 95:5). The fractions containing auramycin D were concentrated in vacuo to give 38 mg of auramycin D.
