A new entry to bis-Troger's bases

This paper reports the use of p-phenylenediamine to prepare bis-Troger's bases. The methyl, nitro-substituted bis-Troger's base 5, already previously prepared by another procedure, was obtained in fewer steps, although with no improvement in the yield of the desired syn isomer. The symmetric dinitro-substituted bis-Troger's base 17, which cannot be prepared by the older method, was then synthesized. Its structure was determined by mass spectrometry, 2D NMR spectroscopy, and, in the case of the syn isomer, by X-ray crystallography. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.