Über Triphosphorsäurederivate des Cyanamids und des Harnstoffs

Triphosphoric Acid Derivatives of Cyanamide and Urea Cyanamidotriphosphate, P₃O₉NCN^5? ( I ), is obtained by ring opening reaction of the cyclotriphosphate ion, P₃O₉^3?, by cyanamide in alkaline solution. As a pseudochalcogeno-substituted triphosphate, I has similar properties like the triphosphate, P₃O₁₀^5? (Ca²⁺ sequestering; behaviour on acidimetric titration; X-ray powder diffraction of the sodium salt hydrates). In acidic solution I decomposes forming ureidotriphosphate with the anion P₃O₉NHCONH₂^4? ( II ) which cannot be directly obtained from cyclotriphosphate and urea. II is characterized by its chemical analysis, by paper chromatography, by its behaviour in acidic solution and by its IR and ³¹P-NMR spectra. Solid salts of I and II are prepared and the data of their Guinier diagrams are communicated.     

Dischroïsme circulaire des alcaloïdes du groupe de l'hétéroyohimbane

Circular Dischroism of Heteroyohimbane-Type Alkaloids Circular dichroism cannot be used directly to determine the C (3)-configuration of heteroyohimbines. A preliminary chemical transformation is necessary.