Ochiai, Eiji published the artcilePolarization of aromatic heterocyclic compounds. LXVI. Reduction of 4-nitro-2-picoline 1-oxide, Safety of 4-Amino-2-picoline, the publication is Yakugaku Zasshi (1947), 158-60, database is CAplus.
Reduction of 4-nitro-2-picoline 1-oxide (I) indicated that it also had certain peculiarities which were observed in the reduction of 4-nitropyridine 1-oxide (C.A. 45, 5151h). Catalytic reduction of I in 10% HCl with 60% Pd-charcoal gave a HCl salt of 4-amino-2-picoline 1-oxide (II), needles, m. 189-91°. Further reduction of the II.HCl in AcOH-Ac2O with 60% Pd-charcoal gave 4-amino-2-picoline (III), slightly hygroscopic cubic crystals, m. 95°; picrate, m. 193°. Catalytic reduction of I to III did not proceed well in HCl and EtOH. Reduction of I in a mixture of H2S-saturated NH4OH and EtOH gave 4,4′-azo-2-picoline 1,1′-dioxide (IV), red needles, m. 224-5°. Reduction of I in 10% NaOH solution with NaNO2 at about 45° gave IV and a small amount of recovered I. MeOH as a solvent gave 4-methoxy-2-picoline 1-oxide, rhomboprisms, m. 78-80°, and no azo compound was formed. Reduction of I in glacial AcOH, EtOH, and H2O with Zn dust also gave IV, while reduction in glacial AcOH with Zn gave 4,4′-azoxy-2-picoline 1,1′-dioxide (V), orange-red crystals, m. 220-1°, and a small amount of recovered I. Reduction in EtOH-glacial AcOH with Zn gave chiefly V with a small amount of IV, and reduction in H2O alone in a sealed tube gave V with recovery of I. Reduction in NaOH solution gave III. Since this reduction, when carried out on a water bath about 1 hr. gave only IV with recovery of I, the reduction was assumed to proceed via the azo compound Reduction of I in HCl with SnCl2 gave IV, as well as III, while reduction in EtOH with Na2S2O4 also gave III.
Yakugaku Zasshi published new progress about 18437-58-6. 18437-58-6 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 4-Amino-2-picoline, and the molecular formula is C6H8N2, Safety of 4-Amino-2-picoline.
Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem