ExperimentalCompound1was prepared fromLtryptophan methyl ester and 2oxoglutaric acid according to the method reported previously,11and recrystallized from CHCl3to give single crystals of1·CHCl3(1∶1). Thermogravimetric analysis (TGA) was carried out with a Seiko Instruments SSC5200 thermoanalyzer in a nitrogen atmosphere (heating rate 10 K min−1).