Pyridine, 3-amino 2 BENZYLAMINO

So erhalt manz. B, aus 2-Benzylamino-benzoesaure-acyloximid-amiden beim Kochen in Wasser 2-Amino-benzimidazole, wahrend in ethanolischerNatronlauge oder in Pyridin 3-(2-Benzyl-amino-phenyl)-l,2,4-oxadiazole entstehen213. 

In the aldohexose series, 5-(benzylamino)-l,2-0-cyclohexylidene-5-deoxy-L-idurononitrile gives, on acid hydrolysis, an almost quantitative yield of N-benzyl-2-cyano-5-hydroxypyridinium chloride. On partial, catalytic hydrogenation of this aminonitrile, 5-(benzylamino)-I,2-0-cyclohexylidene-5-deoxy-L- do-hexodialdo-l,4-furanose is obtained. This compound is reducible with sodium borohydride to crystalline 5-(benzylamino)-l,2-0-cyclohexylidene-5-deoxy-L-idofur-anose which, on removal of the cyclohexylidene group with acid, forms the intermediate 5-(benzylamino)-5-deoxy-L-idopyranose this then loses three molecules of water per molecule, to give N-benzyl-5-hydroxy-2-(hydroxymethyl)pyridinium chloride. It is therefore clear that the transformation of 5-aminoaldoses into pyridine derivatives in acid solution is not prevented by the monoalkylation of the amino group. 

Die Reaktion lafit sich auf 2-AminomethyI-pyridine und 5-Chlor-2-amino-pyridin sowde auf 2-Methylamino- und 2-Benzylamino-pyridin iibertragen. Dagegen biiden 2,5-Diamino-pyridin, 5-Nitro-2-amino- und 6-Amino-3-carboxy-pyridin keine Dimere. 

Thus, the reaction with methylamine at room temperature furnishes the 2-(methylamino)-3-methyl derivative, that with benzylaminc two products, the 3-benzyl-2-(benzylamino)-2-ethoxy derivative and the 3-benzyl-2-(benzylamino) derivative, and that with hydroxylamine the corresponding 2-ethoxy-3-hydroxy derivative. Similarly, with hydrazine hydrate at room temperature, ethyl 3-[(ethoxythiocarbonyl)amino]pyridine-2-carboxylate is transformed into 3-amino-2-sulfanylpyrido[3,2-c/]pyrimidin-4(3//)-one (8), whilst under reflux the 2-hydrazino compound is obtained. 

---