In a synthesis of 6-hydroxy-7-alkoxy-5-benzofuranyl methyl ketone, a known intermediate in the synthesis of chellin and anti-atherosclerotic analogues thereof, pyrogallol is converted to 3,8,7-benzofurantriol triacetate using zinc chloride and chloroacetanitrile, then catalytically reduced and deactoxylated at the 3-position to yield the corresponding 2,3-dihydrofuran. This substance is subjected to a Fries rearrangement to the corresponding diol, the phenolic hydroxyl group of which is then selectively alkylated. The ketone is selectively alkoxylated at the 4-position using lead atraacetate, ceric ammonium nitrate or thallium (III) nitrate in an alkanol solvent to yield further known chemical intermediates in the preparation of khellin and analogues thereof.
在合成 6-hydroxy-7-alkoxy-5-benzofuranyl methyl ketone(一种合成螯合素及其抗动脉粥样硬化类似物的已知
中间体)的过程中,使用
氯化锌和
氯乙腈将焦醛转化为 3,8,7-
苯并呋喃三醇
三乙酸酯,然后催化还原并在 3 位
脱去乙
氧基,得到相应的
2,3-二氢呋喃。这种物质经过弗里斯重排生成相应的二元醇,然后其
酚羟基被选择性地烷基化。在烷醇溶剂中,使用阿特拉
乙酸铅、
硝酸铈铵或
硝酸铊(III)对
酮的 4-位进行选择性烷
氧基化,进一步生成已知的
化学中间体,用于制备黄柏素及其类似物。