Oxidative dehydrogenation of 4-arylurazoles

Article abstract of DOI:10.1023/A:1016197427657

4-Arylurazoles are selectively oxidized with Fe₂(NO ₃)₃·9H₂O to the corresponding Δ¹-1,2,4-triazoline-3,5-diones.

Full text of DOI:10.1023/A:1016197427657

Russian Journal of Applied Chemistry, Vol. 75, No. 2, 2002, p. 332. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 2, 2002,
p. 342.
Original Russian Text Copyright
2002 by Wamhoff, Zlotskii, Saprygina.
BRIEF
COMMUNICATIONS
Oxidative Dehydrogenation of 4-Arylurazoles
H. Wamhoff, S. S. Zlotskii, and V. A. Saprygina
Kekulé Institut fur Organische Chemie und Biochemie der Universitat Bonn, Bonn, Germany
Ufa State of University of Petroleum Engineering, Ufa, Bashkortostan, Russia
Reaktiv Research Institute, Ufa, Bashkortostan, Russia
Received July 9, 2001
Abstract 4-Arylurazoles are selectively oxidized with Fe2(NO3)3 9H2O to the corresponding 1-1,2,4-tri-
azoline-3,5-diones.
Recently there has been growing interest in 1-1,2,4-
triazoline-3,5-diones, which are extremely active di-
enophiles and are successfully used in syntheses of
fused and polysubstituted heterocycles [1 3]. Also,
these compounds react with olefins to form the cor-
responding secondary amines [4, 5]. The most ver-
satile and widely used route to 1-1,2,4-triazoline-3,5-
diones is oxidation of the corresponding urazoles
(1,2,4-triazolidine-3,5-diones).
HCl was added to pH 2, and the resulting bright red
liquid was diluted with an equal volume of ice-cold
water. The precipitate was filtered off, washed with
water, and vacuum-dried. Target compounds IIa IIc
were obtained in 65 75% yields; their constants
agreed with published data [9, 10].
ACKNOWLEDGMENTS
The study was performed within the framework
of the Academic Exchange Program of the German
Academy (DAAD), grant A/99/09940.
Along with the use of powerful oxidants, such as
tert-butyl hypochlorite [6], trichloroacetyl isocyanate
[7], or nitrogen dioxide [8], procedures have been
developed for oxidation with N-bromosuccinimide
[9, 10] and halogens [11]:
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