Research Article
Organic Solid Acid/NaNO2: An Efficient System for the Oxidation of Urazoles and Bis-Urazoles under Mild and Heterogeneous Conditions
Table 1
Oxidation of urazoles (1) and bis-urazoles (3) to their corresponding triazolinediones (2, 4) with either one of the Polymer-supported sulfonic acid (I), sulfamic acid (II) or isocyanuric acid (III) in the presence of NaNO2 in dichloromethane at room temperature.
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aIsolated yields. bIn the presence of a few drops of water. cConversion. d4-Nitrophenyl triazolinedione is very labile. Therefore, it was destructed in the course of passing through a pad of silica gel. |