Regioselective bromination, debromination and bromine migration in a 2-acetoxymethyl-4,5,7-trialkoxynaphthalene

Dibromination of 2-acetoxymethyl-4-isopropoxy-5,7-dimethoxynaphthalene 10 in buffered solution afforded the 3,8-dibromo derivative 13. Similar monobromination of compound 10 yielded the 8-bromo compound 15, whereas monobromination in the absence of the buffer yielded the isomeric 1-bromonaphthalene 16. Conversion of 15 into 16 was effected with trifluoroacetic acid. Selective monodebromination of the dibromo compound 13 gave rise to a-third isomer, the 3-bromo compound 18.