J. Malm, A.-B. Börnfeldt, S. Gronowitz
1994
Citations
0
Influential Citations
8
Citations
Journal
Heterocycles
Abstract
Thieno [3,4-c]-1,5-naphthyridine (1) and its 5-N-oxide (5) were conveniently brominated at room temperature with tetrabutylammonium perbromide in the presence of a large excess of sodium hydrogen carbonate. Compound(1)gave the 1- and 3-bromo derivatives in a 4:1 ratio, while 5 was regioselectively brominated in the 3-position. Thieno[2,3-c]-1,5-naphthyridine (7), its 5-N-oxide (11) and thieno[3,2-c]-1,5-naphthyridine (14) did not react under these conditions, but gave products in the reaction with bromine in refluxing thionyl chloride. Compound (7) gave the 1-bromo derivative as main product and interestingly the 1,7-dibromo derivative as by-product. The reaction of 11 and 14 with bromine in thionyl chloride gave mainly chlorinated products