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New Selenosemicarbazides Derived from Imidazole‐Based Carbohydrazides
Author(s) -
Pieczonka Adam M.,
Ciepielowski Krzysztof,
Cebulska Zofia,
Mlostoń Grzegorz,
Linden Anthony,
Heimgartner Heinz
Publication year - 2013
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200620
Subject(s) - chemistry , imidazole , triazole , decomposition , thermal decomposition , medicinal chemistry , stereochemistry , organic chemistry
Imidazole‐based carbohydrazides, i.e. , 3‐oxidoimidazole‐4‐carbohydrazides 1 and 2‐[(imidazol‐2‐yl)sulfanyl]acetohydrazides 6 , react with aryl isoselenocyanates 4 in MeOH at room temperature to give the corresponding selenosemicarbazides 5 and 7 , respectively, in good yields. On heating 7b in DMF in the presence of air to 100°, 1,3,4‐oxadiazole 8a was formed via cyclization and formal elimination of H 2 Se. Product 8a was also obtained after heating of a mixture of 4a and 6b under the same conditions. On the other hand, on heating of a solution of 7c in MeOH at reflux, a cyclization occurred to give the corresponding 1,2,4‐triazole‐3‐selone 9b . Again, the same product was formed when a mixture of 4b and 6b was heated in MeOH. Surprisingly, analogous cyclizations of selenosemicarbazides of type 5 under the same conditions failed, and only decomposition was observed. The structures of 7a, 7d , and 9b have been established by X‐ray crystallography.