Polybrominated methoxy- and hydroxynaphthalenes

Authors : Kiymet Berkil AKAR, Osman ÇAKMAK, Tuncay TUNÇ

Pages : 332-346

View : 15 | Download : 13

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Regio- and stereoselective synthesis are described for convenient preparation of hydroxy- and methoxynaphthalenes starting from naphthalene insert ignore into journalissuearticles values(\textbf{1});. \textit{cis,cis,trans}-2,3,5,8-Tetrabromo-4-methoxy-1,2,3,4-tetrahydronaphthalen-1-ol insert ignore into journalissuearticles values(\textbf{6});, \textit{cis,cis,trans}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene insert ignore into journalissuearticles values(\textbf{7});, and \textit{cis,cis,cis}-2,3,5,8-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydronaphthalene insert ignore into journalissuearticles values(\textbf{8}); were obtained with silver-induced substitution of \textit{trans,cis,trans}-1,2,3,4, 5,8-hexabromo-1,2,3,4-tetrahydronaphthalene insert ignore into journalissuearticles values(\textbf{3});. Base-promoted aromatization of dimethoxides \textbf{7} and \textbf{8} afforded 3,5,8-tribromo-1-methoxynaphthalene insert ignore into journalissuearticles values(\textbf{9}); and 2,5,8-tribromo-1-methoxynaphthalene insert ignore into journalissuearticles values(\textbf{10});. The reaction of \textbf{6 }with sodium methoxide formed compounds \textbf{10 }and 3,5,8-tribromonaphthalen-1-ol insert ignore into journalissuearticles values(\textbf{16});. Bromination of \textbf{9} and\textbf{ 16} with Br$_{2}$ in dichloromethane at room temperature produced 2,3,5,8-tetrabromo-1-methoxynaphthalene insert ignore into journalissuearticles values(\textbf{14}); and 2,3,4,5,8-pentabromonaphthalen-1-ol insert ignore into journalissuearticles values(\textbf{18});, respectively, while compound \textbf{10} did not react in the same conditions. Pyridine-induced elimination of hexabromide \textbf{3} afforded 1,4,6\textbf{-}tribromnaphthalene insert ignore into journalissuearticles values(\textbf{21}); in 99{\%} yield and thermolysis of the hexabromide \textbf{3} gave mainly 1,4,6,7-tetrabromonaphthalene insert ignore into journalissuearticles values(\textbf{22});. Tetrabromide \textbf{22} was transformed to 1,4,6,7-tetramethoxynaphthalene insert ignore into journalissuearticles values(\textbf{23}); by copper-assisted nucleophilic substitution reaction.
Keywords : Methoxynaphthalene, silver induced substitution, base promoted elimination, hydroxynaphthalene, bromonaphthalene