Safety Issues with Pyridine Ring Construction
Normally amines/ammonia form the source of the ring nitrogen. Occasionally Hydrazine or more often hydroxylamine are encountered as N synthons.
Concentrated solutions of hydroxylamine in water can be explosive and should be handled appropriately.
Hydrazine can decompose violently in the presence of metal catalysts and is a suspect carcinogen.
This material is labelled as a skin sensitizer and a carcinogen under EU REACH regulation and is on the substances of very high concern (SVAC) list.