[pradeepverma4]

Can any one suggest a suitable stabilser for Niacinamide-N-oxide or a selective chlorinating catalyst.I am trying to Chlorinate Niacinamide-N-Oxide selectively at 2nd position.While chlorinating this molecule with POCl3 in presence of Organic base,part of the N-Oxide breaks and gets converted to 3-Cyanopyridine and other derivatives.

[sjb]

Can any one suggest a suitable stabilser for Niacinamide-N-oxide or a selective chlorinating catalyst.I am trying to Chlorinate Niacinamide-N-Oxide selectively at 2nd position.While chlorinating this molecule with POCl3 in presence of Organic base,part of the N-Oxide breaks and gets converted to 3-Cyanopyridine and other derivatives.

I thought pyridine-N-oxide to 2-chloropyridine was the main reaction path anyway? Are you trying to get 2-chloro or 6-chloro-3-pyridinecarboxamide? Perhaps the POCl₃ is dehydrating the amide preferentially? Not sure if something like N-chlorosuccimide would work? Can you start from a different nicotinic acid derivative - an bulky ester or something?

[explosci]

Why not chlorinate, then N-oxidize?

[orgopete]

The great difficulty in trying to answer the question is our not knowing what is being reacted. For example, if you have an amide, it could become converted to a nitrile. I'd suggest simply hydrolyzing it back to the amide. However, if it is N-substituted, then you will get an imidoyl chloride. None the less, this should also be hydrolyzeable back to an amide, though with greater risk of cleavage. Can you tell us the real reaction or what you are trying to make?