Methods for the preparation of methyl 3-formyl-1,4-dimethoxy-9,10-dioxo-9,10-dihydroanthracene-2-acetate (1) from quinizarin (8) have been investigated. Reaction of the ester (1) with either a titanium enolate of acetone or with acetone trimethylsilyl enol ether and titanium tetrachloride gave the aldol (29) which was then converted into the pentacyclic lactone mixture (41) and (42). While hydrolysis of (41) and (42) with base for long periods (>30 min) gave α,β -unsaturated ketones , brief (2 min) treatment gave the dimethyl ether (5) of the 4-deoxyanthracyclinone (6) corresponding to the antitumour anthracycline 14A10.
从喹吖啶(8)制备甲基3-甲醛基-1,4-二甲氧基-9,10-二氧-9,10-二氢蒽-2-乙酸酯(1)的方法已经研究。酯(1)与丙酮的钛烯醚盐或与丙酮三甲基硅烯醇醚和四氯化钛反应,生成醛醇(29),然后转化为五环内酯混合物(41)和(42)。将(41)和(42)与碱长时间(>30分钟)水解得到α,β-不饱和酮,短暂处理(2分钟)得到对应于抗肿瘤蒽喜环素14A10的4-去氧蒽喜环酮(6)的二甲醚(5)。