How can niacin be decarboxylated to pyridine?

Question

Under reflux? With what catalysts?

Answer 1

Your reference mentioned  "Nicotinic acid is decarboxylated by heating with copper chromite to give carbon dioxide (C-7) and pyridine".

But the use of Copper chromite is not straight forward.  It often requires elevated temperatures.  Sometimes it is intentionally poisoned with quinoline, when the catalyst is used for decarboxylation reactions.

In the cited reference by T.A. Scott from 1967:

"Nicotinic acid (I) is decarboxylated efficiently by heating with copper chromite, provided that certain precautions are taken.  Sublimation and

decarboxylation of nicotinic acid both commence at 235°; even with a very slow gas flow rate, it is possible to drive nicotinic acid through several inches of heated copper chromite supported on asbestos, with only slight decarboxylation.  Consequently, the nicotinic acid was intimately mixed with five times its weight of copper chromite catalyst and the mixture suspended in silicone oil.  Decarboxylation was complete after heating this mixture for l hr."