A study of the alkaloids ofVeratrum lobelianum
Conclusions1) At the beginning of vegetation, the total alkaloids in the epigeal part ofVeratrum lobelianum is 2.5% of the weight of the dry raw material, and at the end of vegetation, 0.036%.2) The new alkaloids veralosine, veralosinine, and veralosidine have been isolated from the epigeal part of the plant.3) On the basis of a study of chemical properties, IR, UV, NMR, and mass spectra, and also its conversion into tetrahydrosolasodine, structure and configuration I has been proposed as the most probable for veralosidine.
Structure of a new ester-alkaloid from Veratrum grandiflorum (Maxim.) Loesener fil. (Alkaloids of Japanese Veratrum genus plants. IV.).
A new ester-alkaloid isolated from the rhizomes of Veratrum grandiflorum (MAXIM.) LOESENER fil., m.p. 235°, [α]15D-10.9°, was found to be 16-angelate of the alkamine which had been obtained from Veratrum oxysepalum TURCZ. and characterized by Shimizu as zygadenilic acid δ-lactone.
High-Performance Liquid Chromatographic (HPLC) and HPLC-Mass Spectrometric (MS) Analysis of the Degradation of the Luteinizing Hormone-Releasing Hormone (LH-RH) Antagonist RS-26306 in Aqueous Solution
The kinetics of the degradation of an LH-RH antagonist, RS-26306,1, in aqueous solution from pH 1 to pH 11 were studied by reverse-phase HPLC. The pH–rate profiles at 50, 60, and 80°C were U-shaped with the rate law of kobs = kHaH + kw + kOHaOH. The predicted 25°C shelf life at the pH of maximum stability, pH ∼5, is greater than 10 years. The products from the degradation were analyzed by HPLC-MS using thermospray ionization. Below pH 3, the primary product, 2, forms from the acid-catalyzed deamidation of the C-terminal amide. Above pH 7, epimerization of the individual amino acids is the principal reaction. Between pH 4 and pH 6, intramolecular serine-catalyzed peptide hydrolysis becomes important, yielding a tripeptide, 3, and a heptapeptide, 4. At the pH of maximum stability all three pathways for degradation are observed.