1.5- Naphthyridine, amino-, formation bromo-, amination

Amino-2-bromo-1,5-naphthyridine (84) may be an intermediate (see Section III,B,l,a for its formation) that undergoes a covalent amination at C-4, yielding the gem 4,4-diamino-2-bromodihydro-l,5-naphthyridinide (153) and an amino debromination at C-2, yielding 85. Ring opening of 153... 

Amination of 5-bromo-l,6-naphthyridine (113) gives as tele product 2-amino-l,6-naphthyridine (51 ),24 but in addition to the intermediacy of anionic cr-adduct (114) (as proved by H-NMR spectroscopy), its formation involves anionic cr-adduct 115, which is formed by a proton shift from 114. The number of atoms between positions 2 and 5 is five, thus this reaction is referred to as an odd tele substitution. Both types of tele substitution involve Addition of the nucleophile as the initial step and Elimination of the leaving group as the last step. However, in the even tele substitution the elimination can be described to take place from a neutral dihydro species, while in the odd tele substitution the elimination must occur from an anionic intermediate. In the naphthyridines several examples of even and odd tele substitutions are found, and in the following sections the results of studies concerned with tele amination are presented. 

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