Synthesis and characterization of carboranyl Schiff base compounds from 1-amino-o-carborane

•Reaction of Li2C2B10H10 with PhCH2N3 affords 1-amino-o-carborane.•Condensation of 1-amino-o-carborane with aldehydes produces Schiff base compounds.•The Schiff bases were studied by various methods including X-ray diffraction.

The improved synthesis of 1-amino-o-carborane (4) and its reactivity towards aldehydes are reported. The reaction of dilithio-o-carborane with two equivalents of benzyl azide, after treatment with acid, yields compound 4 in 72% isolated yield, whereas the diamino analog was not obtained. In the presence of magnesium sulfate and p-toluenesulfonic acid, the condensation reactions of 4 with various aldehydes produce the corresponding carboranyl Schiff base compounds in good yields. The new carborane products have been characterized by means of IR and NMR spectroscopy, mass spectrometry and elemental analysis. The structures of three of these Schiff base compounds have been established by X-ray crystallographic method.

Graphical abstractThe reaction of dilithio-o-carborane with benzyl azide, after treatment with acid and heating, yields 1-amino-o-carborane (4) in 72% isolated yield. The condensation of 4 with various aldehydes produce the corresponding carboranyl Schiff base compounds with direct cage–nitrogen bond in good yields.Figure optionsDownload full-size imageDownload as PowerPoint slide