Abstract 1,3-Dimethyl-1,3-diaza-2-fluoro-5,6-benzo-1,3,2-phosphorinane-4-one (1) reacted with (COD)PtCl2 (COD = 1,5-cyclooctadiene) or K2PtCl4 to give the cis-dichloro-platinum(II) complex (2). The reactions of 1 with the tetracarbonyl norbornadiene derivatives of Cr, Mo and W furnished the complexes 3 - 6 . In the case of the chromium and tungsten complexes the trans-isomers 3 and 6 were formed, due to a cis-trans-isomerization. Room temperature and low temperature 31P NMR spectra of a mixture of 5 and 6 show no significant temperature dependence of the cis-trans equilibrium. The reaction of 1 with the pentacarbonyl tetrahydrofuran derivative of W led to the product 7. The spirophosphoranes 8 and 9 were obtained in low yields. The analogous reactions of 10, 15 and 20 with (COD)PtCl2 and the tetracarbonyl norbornadiene derivatives of Cr and Mo furnished the coordination compounds 11-14, 16-18, 21 and 23. In the case of all chromium complexes only the trans-isomers 11,16 and 21 were formed, whereas in the case of molybdenum cis-trans-isomer mixtures 12 and 13, as well as 17 and 18 were obtained. An attempt to obtain the cis-isomer of the molybdenum complex 22 failed. In the case of platinum the expected cis-complexes 14 and 23 were formed, while the attempted synthesis of 19 was unsuccessful. All these results are interpreted in terms of both steric and electronic factors. The ligands 1, 10, 15 and 20 coordinate via phosphorus. The validity of the concept of hard and soft acids and bases (HSAB) was confirmed. The characterization of 2 - 7 , 11-14, 16-18, 21 and 23 rests, especially, on their 1H, 13C and 31P NMR spectra, and their mass and infrared spectra. 31P - 31P coupling constants 2J(PP) for the cis-coordinated complexes 4, 5 and 14 involving two equivalent phosphorus ligands are also reported.
Amino Acid and Peptide Derivatives of Kojic Acid and Their Antifungal Properties
