New Pyrazole Alkaloids from the Root Bark ofNewbouldia laevis

New Pyrazole Alkaloids from the Root Bark of<i>Newbouldia laevis</i> Pyrazole alkaloids from Newbouldia laevis Naphthaquinones and an alkaloid from roots of Newbouldia laevis A New Alkaloid from the Roots of Alstonia angustifolia Alkaloids of Nemuaron vieillardii (Monimiaceae) Laevisines A and B:  Two New Sesquiterpene−Pyridine Alkaloids from Maytenus laevis Laevisines A and B:  Two New Sesquiterpene−Pyridine Alkaloids from <i>Maytenus laevis</i> Studies on the constituents of Ailanthus altissima SWINGLE. III. The alkaloidal constituents. 5-Methoxy-1-oxo-tetrahydro-β-carboline, an alkaloid from Alstonia venenata Na-formylechitamidine, an alkaloid from Alstonia boonei