Thermal and photobromination of naphthalene and derivatives have been studied. Several hexabromo- (12, 13, 16 and 17), and tetrabromotetralin derivatives (23, 24, and 25) have been obtained as the major products, besides bromonaphthalene derivatives. Base-promoted elimination reactions of 12, 13, 16 and 17 provided di- (8) tri- (10) and tetrabromo-naphthalenes (22). A convenient method was developed
Selective bromination of 1-bromonaphthalene: efficient synthesis of bromonaphthalene derivatives
作者:Osman Cakmak、Ibrahim Demirtas、Halis T Balaydin
DOI:10.1016/s0040-4020(02)00549-5
日期:2002.7
Selective and specific preparation methods are described for 1,4-dibromonaphthalene, 1,5-dibromonaphthalene and 1,3,5-tribromonaphthalene. The reaction of 1-bromonaphthalene and naphthalene with stoichometric quantities of bromine by using a minimum amount of solvent (methylene chloride) at -30 and -50degreesC smoothly affords 1,4-dibromonaphthalene in 90% yield. Photobromination of 1-bromonaphthalene in CCl4 at -30degreesC gives 1,2,3,4,5-pentabromo-1,2,3,4-tetrahydronaphthalenes, whereas 1,5-dibromonaphthalene is obtained at reflux (77degreesC) in 80% yield under the same conditions. Dehydrobromination of the pentabromide by t-BuOK affords 1,3,5-tribromonaphthalene as a sole product (91%). 1,5-Dibromo- and 1,3,5-tribromonaphthalenes were efficiently converted to the corresponding methoxy naphthalene derivatives. (C) 2002 Elsevier Science Ltd. All rights reserved.