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Synthesis of thieno[2,3‐ e ]‐1,2,4‐triazines
Author(s) -
Ibrahim Yehia A.,
AbdelHady S. A. L.,
Badawy M. A.,
Ghazala M. A. H.
Publication year - 1982
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.5570190440
Subject(s) - chemistry , triazine , pyridine , thiophene , ring (chemistry) , medicinal chemistry , phosphorus , organic chemistry
3‐Methylmercapto‐5‐oxo‐6‐vinyl‐ and 2‐methyl‐3‐mercapto‐5‐oxo‐6‐vinyl‐2,5‐dihydro‐1,2,4‐triazines were readily converted into the corresponding thieno[2,3‐ e ]‐1,2,4‐triazine in one step by the action of phosphorus pentasulfide in pyridine. 4‐Methyl‐3‐mercapto‐5‐oxo‐4,5‐dihydro‐1,2,4‐triazine is only converted into the 5‐thioxo analog and no thiophene ring product was obtained under the same conditions. Thieno[2,3‐ e ]‐1,2,4‐triazines were also more efficiently obtained by the action of phosphorus petnasulfide in pyridine on the appropriate 6‐acylmethyl‐3‐mercapto‐5‐oxo‐2,5‐dihydro‐1,2,4‐triazine.