The synthesis of kermesic acid and isokermesic acid derivatives and of related dihydroxyanthraquinones
作者:Stephen J. Bingham、John H. P. Tyman
DOI:10.1039/a704317a
日期:——
bis(quinone), Thiele acetoxylation of which gives after hydrolysis and permethylation, a mixture of derivatives of kermesic and isokermesic acids in equal proportions. The Diels–Alder addition of 3-chlorojuglone and 3-alkoxycarbonyl-2,4-bis(trimethylsilyloxy)penta-1,3-dienes has led to an improved synthesis of aloesaponarin-I (3,8-dihydroxy-2-methoxycarbonyl-1-methylanthra-9,10-quinone), while juglone itself affords
Cochinellic酐甲基,乙基和苄基酯(4-甲氧基-4-乙氧基和4-苄氧基-羰基-5-羟基-3-甲基邻苯二甲酸酐)是通过2-溴马来酸酐与2-溴马来酸酐的单阶段狄尔斯-阿尔德反应制备的3-烷氧基羰基-2,4-双(三甲基甲硅烷氧基)戊-1,3-二烯。通过类似的加成反应,但与3-乙氧基羰基-2-甲氧基-4-三甲基甲硅烷基氧基戊-1,3-二烯一起获得了相应的5-甲基醚乙酯。在三氟化硼-二乙醚与椰油酰胺酐甲酯的存在下,通过1,4-二甲氧基苯的酰化反应合成6-脱氧kermes甲酯是不成功的。首选途径是通过Diels-Alder将3-烷氧基羰基-2,4-双(三甲基甲硅烷基氧基)戊-1,3-二烯添加到萘他林(或2-氯萘他林)中。六-脱氧kermes的四乙酸铅氧化得到双(醌),其Thiele乙酰氧基化在水解和过甲基化后产生等比例的kermes酸和isokermes酸的衍生物的混合物。Diels–Alde