ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ring Cleavage of 4-(4-Nitrophenylazo)-substituted Pyrazolidine-3,5-diones to α-(4-Nitrophenylhydrazono)semicarbazides with Consecutive ReactionsThe reaction of 1 and 2 with ammonia, methylamine and dimethylamine in aprotic solvents, e. g. diethyl ether, yields the compounds 3 - 8 which can exist in two isomeric forms (form a/b). On conditions which are usually chosen for spectroscopic investigations only form a could be detected. Nevertheless, under the influence of bases like KOH or ammonia in water or alcohol these compounds are mainly converted to semicarbazides (11-15) which means that this reaction must run via form b. Those semicarbazides which are unsubstituted at the N-4 of their semicarbazide-moiety show great tendency to cyclize, thus forming the triazolederivatives 16-18. In contrast to these products, in the case of the N-4-monomethylated semicarbazide 14 the six-membered heterocyclus 19 was obtained. In comparison with 1 and 2, stable intermediates such as 3-8 in the reaction with 21 could not be isolated.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19953370147
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