作者:Kıymet BERKİL AKAR、Osman ÇAKMAK、Tuncay TUNÇ
DOI:10.3906/kim-1506-28
日期:——
Regio- and stereoselective synthesis are described for convenient preparation of hydroxy- and methoxynaphthalenes starting from naphthalene (\textbf1}). \textitcis,cis,trans}-2,3,5,8-Tetrabromo-4-methoxy-1,2,3,4-tetrahydronaphthalen-1-ol (\textbf6}), \textitcis,cis,trans}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene (\textbf7}), and \textitcis,cis,cis}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene (\textbf8}) were obtained with silver-induced substitution of \textittrans,cis,trans}-1,2,3,4, 5,8-hexabromo-1,2,3,4-tetrahydronaphthalene (\textbf3}). Base-promoted aromatization of dimethoxides \textbf7} and \textbf8} afforded 3,5,8-tribromo-1-methoxynaphthalene (\textbf9}) and 2,5,8-tribromo-1-methoxynaphthalene (\textbf10}). The reaction of \textbf6 }with sodium methoxide formed compounds \textbf10 }and 3,5,8-tribromonaphthalen-1-ol (\textbf16}). Bromination of \textbf9} and\textbf 16} with Br$_2}$ in dichloromethane at room temperature produced 2,3,5,8-tetrabromo-1-methoxynaphthalene (\textbf14}) and 2,3,4,5,8-pentabromonaphthalen-1-ol (\textbf18}), respectively, while compound \textbf10} did not react in the same conditions. Pyridine-induced elimination of hexabromide \textbf3} afforded 1,4,6\textbf-}tribromnaphthalene (\textbf21}) in 99\%} yield and thermolysis of the hexabromide \textbf3} gave mainly 1,4,6,7-tetrabromonaphthalene (\textbf22}). Tetrabromide \textbf22} was transformed to 1,4,6,7-tetramethoxynaphthalene (\textbf23}) by copper-assisted nucleophilic substitution reaction.
以萘 (textbf1})为起点,描述了方便制备羟基萘和甲氧基萘的区域和立体选择性合成方法。\文顺,顺,反}-2,3,5,8-四溴-4-甲氧基-1,2,3,4-四氢萘-1-醇 (\textbf6})、\textit顺,顺,反}-2,3,5,8-四溴-1,4-二甲氧基-1,2,3,4-四氢萘 (\textbf7})和\textit顺,顺、textittrans,cis,trans}-1,2,3,4,5,8-hexabromo-1,2,3,4-tetrahydronaphthalene(textbf3})的银诱导取代作用,得到了 textitcis,cis,trans}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene (\textbf8})。文bf7}和文bf8}的二甲氧基化物在碱促进下发生芳香化反应,生成了3,5,8-三溴-1-甲氧基萘(\textbf9})和2,5,8-三溴-1-甲氧基萘(\textbf10})。\textbf6 }与甲醇钠反应生成化合物 \textbf10 }和 3,5,8-三溴-1-萘酚(\textbf16})。在室温下,用 Br$_2}$ 在二氯甲烷中将 \textbf9} 和 \textbf16} 溴化,分别生成 2,3,5,8-四溴-1-甲氧基萘(\textbf14})和 2,3,4,5,8-五溴萘-1-醇(\textbf18}),而化合物 \textbf10} 在相同条件下没有反应。吡啶诱导消除六溴化物 \textbf3} 得到 1,4,6\textbf-}三溴萘 (\textbf21}),收率为 99%},热分解六溴化物 \textbf3}主要得到 1,4,6,7-四溴萘 (\textbf22})。通过铜辅助的亲核取代反应,四溴化物 \textbf22} 转化为 1,4,6,7-四甲氧基萘 (\textbf23})。