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Cyclocondensation of 6‐acetyl‐4,7‐dihydro‐5‐methyl‐7‐phenyl[1,2,4]triazolo[1,5‐ a ]pyrimidine with hydroxylamine and hydrazine
Author(s) -
Desenko Sergey M.,
Komykhov Sergey A.,
Orlov Valery D.,
Meier Herbert
Publication year - 1998
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.5570350434
Subject(s) - chemistry , hydroxylamine , pyrimidine , hydrazine (antidepressant) , yield (engineering) , ring (chemistry) , medicinal chemistry , proton nmr , hydrogen chloride , stereochemistry , organic chemistry , materials science , chromatography , metallurgy
The cyclocondensation of 6‐acetyl‐4,7‐dihydro‐5‐methyl‐7‐phenyl[1,2,4]triazolo[1,5‐ a ]pyrimidine (3) with hydroxylamine or hydrazine leads to 3a,4,9,9a‐tetrahydro‐3,9a‐dimethyl‐4‐phenylisoxazolo‐[5,4‐ d ][1,2,4]triazolo[1,5‐ a ]pyrimidine ( 4a ) and 3a,4,9,9a‐tetrahydro‐3,9a‐dimethyl‐4‐phenyl‐1 H ‐pyrazolo[3,4‐ d ][1,2,4]triazolo[1,5‐ a ]pyrimidine ( 4b ), respectively. In the presence of methanolic hydrogen chloride, 4b undergoes a cleavage of the pyrimidine ring to yield (5‐amino‐1,2,4‐triazol‐1‐yl)(3,5‐dimethylpyrazol‐4‐yl)phenylmethane ( 5 ). The structure determination of the compounds obtained is based on 1 H and 13 C nmr spectra including NOE measurements.