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Novel heterocyclic systems. Part 26 . The synthesis and 13 C‐NMR assignment of 1,8‐diazaphenoxathiin
Author(s) -
Lindsy Charles M.,
Smith Keith,
Martin Gary E.
Publication year - 1987
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.5570240138
Subject(s) - chemistry , nitro , condensation , nuclear magnetic resonance spectroscopy , medicinal chemistry , stereochemistry , organic chemistry , alkyl , physics , thermodynamics
Abstract Although the syntheses of numerous diazaphenoxathiins have been reported, only two dipyrido[1,4]‐oxathiin systems are thus far known, viz. the 1,7‐ and 1,9‐diazaphenoxathiins. The synthesis of a third, 1,8‐diazaphenoxathiin via the condensation of the dianion of 3‐hydroxypyridine‐2(1 H )‐thione with 4‐nitro‐3‐chloropyridine 1‐oxide is now described. A minor quantity of 1,7‐diazaphenoxathiin was obtained as a byproduct of the reaction. Complete assignment of the 13 C‐nmr spectrum was achieved and this conclusively differentiates the 1,8‐compound from the 1,7‐isomer.