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A convenient synthesis of novel pyrido(1′,2′:1,2)imidazo[5,4‐ d ]‐1,2,3‐triazinones from imidazo[1,2‐ a ]pyridines
Author(s) -
Zamora Héctor Salgado,
Rizo Benito,
Campos Elena,
Jiménez Rogelio,
Reyes Alicia
Publication year - 2004
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.5570410114
Subject(s) - chemistry , synthon , pyridine , yield (engineering) , substituent , nitrous acid , ammonia , nitro , medicinal chemistry , primary (astronomy) , bicyclic molecule , stereochemistry , organic chemistry , materials science , alkyl , physics , astronomy , metallurgy
The imidazo[1,2‐ a ]pyridine system was investigated as a synthon for the building of very attractive fused triazines, a planar, angular tri ‐heterocycle with potential biological activity. Thus ethyl 3‐nitroimidazo[1,2‐ a ]pyridine‐2‐carboxylate was treated with ammonia or with an excess of primary amines to generate the corresponding substituted nitro carboxamidoimidazopyridines. The nitro substituent in the latter products, was reduced to yield 3‐amino‐2‐carboxamidoimidazo[1,2‐ a ]pyridine derivatives, which in turn were treated with nitrous acid to furnish 1‐oxo‐2‐substituted pyrido(1′,2′:1,2)imidazo[5,4‐ d ]‐1,2,3‐triazines.