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Utility of Pyridine‐2(1 H )‐thiones in the Synthesis of Novel Bis‐Thieno[2,3‐ b ]pyridines and Their Fused Azines
Author(s) -
Sanad Sherif M. H.,
AbdelFattah Azza M.,
Attaby Fawzy A.,
Elneairy Mohamed A. A.
Publication year - 2019
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.3537
Subject(s) - chemistry , pyridine , sodium methoxide , moiety , reagent , molecule , alkylation , medicinal chemistry , carboxamide , stereochemistry , combinatorial chemistry , organic chemistry , methanol , catalysis
The starting materials pyridine‐2(1 H )‐thiones are prepared and reacted with halogen‐containing reagents in ethanolic sodium acetate solution to give the corresponding 2‐ S ‐alkylpyridines, which cyclized upon their boiling in methanolic sodium methoxide solution at reflux to give the corresponding thieno[2,3‐ b ]pyridines in excellent yields. Bis (thieno[2,3‐ b ]pyridine‐2‐carboxamides), incorporating 2,6‐dibromophenoxy moiety, are prepared by the bis‐ O ‐alkylation of thieno[2,3‐ b ]pyridine‐2‐carboxamide derivatives. Two synthetic routes are designed to prepare the target molecules pyrido[3′,2′:4,5]thieno[3,2‐ d ]pyrimidin‐4(3 H )‐ones, pyrido[3′,2′:4,5]thieno[3,2‐ d ][1,2,3]triazin‐4(3 H )‐ones, and their bis‐analogues using thieno[2,3‐ b ]pyridine‐2‐carboxamides and their bis‐analogues. The structure of the target molecules is elucidated using elemental analyses as well as spectral data.