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Reactivity of the A‐CH=N‐NR‐CX‐B system. 4‐Methyl‐5‐hydroxy‐5‐phenyl‐(or thienyl)‐2,3,4,5‐tetrahydro‐1,2,4‐triazin‐3‐ones and their ring contraction products
Author(s) -
Werber Giuseppe,
Buccheri Francesco,
Vivoicolò,
Bianchini Rosangela
Publication year - 1979
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.5570160127
Subject(s) - chemistry , aqueous solution , ring (chemistry) , glyoxal , reactivity (psychology) , sodium hydroxide , hydrochloric acid , medicinal chemistry , halogenation , triazine , base (topology) , organic chemistry , medicine , mathematical analysis , alternative medicine , mathematics , pathology
The behaviour of some monosemicarbazones of phenyl‐ ( 1a‐c ) and thienyl‐glyoxal ( 2a‐c ) towards cyclizing agents has been investigated. Upon aqueous sodium hydroxide treatment, 4‐melhyl‐semicarbazones 1a and 2a gave the addition products 3 and 4 , respectively, whereas the 2‐methyl‐ and 2,4‐dimethyl derivatives 1b,c and 2b,c gave demolition products only. On the other hand, compounds 1b,c gave the addition product 8 and the triazine 7 , respectively, on treatment with aqueous hydrochloric acid. Bromination of 1a,b gave the bromosemicarbazone 10a and a mixture of 10b and 9 , respectively. Performing the same reaction on 3 and 4 at 115°, the 1,3,4‐oxadiazoles 13 and 14 have been obtained. The behaviour of bromosemicarbazones [ 10a,b ] and of the bromo‐tetrahydrotriazine 9 towards heating or treatment with base has also been investigated.