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Synthesis of (pyridinyl)‐1,2,4‐triazolo[4,3‐ a ]pyridines
Author(s) -
Moran Daniel B.,
Morton George O.,
Albright J. Donald
Publication year - 1986
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570230422
Subject(s) - chemistry , bipyridine , 2,2' bipyridine , acetic anhydride , pyridine , medicinal chemistry , oxide , phosphorus , 4,4' bipyridine , organic chemistry , catalysis , molecule , crystal structure , hydrogen bond
Methods for the synthesis of (pyridinyl)‐1,2,4‐triazolo[4,3‐ a ]pyridines were developed. The principal route to the required intermediate 2‐chloropyridines was based on rearrangements of mono N ‐oxides of 2,2′‐bipyridine, 2,3′‐bipyridine, 3,3′‐bipyridine, 2,4′‐bipyridine and 4,4′‐bipyridine with phosphorus oxychloride. Reaction of 3,3′‐bipyridine 1‐oxide or 2,2′‐bipyridine 1‐oxide with phosphorus oxychloride gave mixtures of chloro isomers. Reaction with acetic anhydride, 3,3′‐bipyridine 1‐oxide and 2,2′‐bipyridine 1‐oxide gave exclusively [3,3′‐bipyridine]‐2(1 H )‐one and [2,2′‐bipyridine]‐6(1 H )‐one, respectively. 1,2,4‐Triazolo[4,3‐ a ]pyridines with pyridinyl groups at the 5,6,7 and 8 positions were synthesized.