154418-91-4Relevant academic research and scientific papers
On the Bromination of Thieno-fused 1,5-Naphthyridines and their Isomeric N-Oxides Using Dibromoisocyanuric Acid in Fuming Sulfuric Acid
Malm, Johan,Hoernfeldt, Anna-Britta,Gronowitz, Salo
, p. 521 - 526 (2007/10/02)
Thieno-1,5-naphthyridine (3), thieno-1,5-naphthyridine 5-oxide (7), thieno-1,5-naphthyridine (5) and thieno-1,5-naphthyridine 5-oxide (9) could conveniently be brominated at room temperature using dibromoisocyanuric acid in fuming sulfuric acid.Bromination occurred in good to moderate yields at the β position in the thiophene ring.Thieno-1,5-naphthyridine 9-oxide (12) and thieno-1,5-naphthyridine 9-oxide (13) also gave substitution in the thiophene ring at 95 deg.It was also found that 12 was deoxygenated under these reaction conditions.Direct oxidation of the brominated thienonaphthyridines with m-chloroperbenzoic acid gave the 5-oxides in high yield.
ON THE BROMINATION OF THE THREE ISOMERIC THIENOFUSED 1,5-NAPHTHYRIDINES AND THEIR 5-N-OXIDES
Malm, Johan,Hoernfeldt, Anna-Britta,Gronowitz, Salo
, p. 331 - 346 (2007/10/02)
Thieno-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-1,5-naphthyridine (7), its 5-N-oxide (11) and thieno-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.
