On the synthesis and animation of 5‐chloro‐and 5‐bromo‐1,7‐naphthyridine

A new synthesis of 5‐chloro‐ and 5‐bromo‐1,7‐naphthyridine, using 8‐amino‐1,7‐naphthyridine as starting material is described. On amination with potassium amide in liquid ammonia, the 5‐bromo compound undergoes a tele‐amination into 8‐amino‐ and 2‐amino‐1,7‐naphthyridine and a Chichibabin reaction yielding 8‐amino‐5‐bromo‐1,7‐naphthyridine. The reaction with the 5‐chloro compound occurs at a much lower rate than the 5‐bromo compound and only gives 8‐amino‐5‐chloro‐1,7‐naphthyridine in a small yield. Convincing 1 H‐nmr evidence is presented, showing that the 5‐bromo‐ and 5‐chloro‐1,7‐naphthyridine give addition of the amide ion at position 8 and that the 5‐chloro compound also gives addition at position 2.