Tubulosine: an antitumor constituent of Pogonopus speciosus.

From the antitumor-bioactive sap of Pogonopus speciosus, tubulosine [1] was isolated, by activity-directed fractionation using the brine shrimp lethality test, as the major antitumor constituent. 1H-nmr assignments, obtained from HETCOR and COSY, and X-ray crystallographic results are reported for the first time. Psychotrine [2] was also isolated, and its spectral data are also reported.

Goniotriol from Goniothalamus giganteus.

The known styrylpyrone, goniotriol, has been isolated from Goniothalamus giganteus. Its bioactivities are reported, and its structure and relative stereochemistry have been determined by X-ray crystallography as 6R-(7R,8R-dihydro-7,8-dihydroxystyryl)-5S,6R-dihydro-5-hydroxy-2-p yrone.

Structural characterization of a metal-based perfusion tracer: copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone).

Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone), Cu(PTSM), has been obtained as a dark red crystalline solid from EtOH-DMSO solvent mixture and structurally characterized by x-ray crystallography. The molecule possesses the expected pseudo-square planar N2S2 metal coordination sphere; however, the copper center also interacts through its axial coordination site with the sulfur atom of an adjacent Cu(PTSM) molecule in the crystal lattice. The structure of this compound is compared with the structures of other metal complexes that have been proposed in the nuclear medicine literature as perfusion tracers.

Effect of beta-alkyl substitution on D-1 dopamine agonist activity: absolute configuration of beta-methyldopamine.

beta-Methyldopamine and its enantiomers and racemic beta-phenyldopamine were synthesized and evaluated for dopamine D-1 agonist activity. In the dopamine-sensitive adenylate cyclase assay, beta-phenyldopamine had about one-sixth the activity of dopamine. Racemic beta-methyldopamine was less potent. The absolute configuration of beta-methyldopamine was determined to be R-(+) and S-(-). Evaluation of (R)-(+)- and (S)-(-)-beta-methyldopamine revealed no enantioselectivity for stimulation of adenylate cyclase.

Conformation of glyburide in the solid state and in solution.

Nuclear magnetic resonance spectroscopy was combined with X-ray crystallography to determine the solution and solid-state conformations of glyburide (C23H28CIN3O5S). In solution, there is apparently free rotation about several of the single bonds. Crystals of glyburide belong to space group P2(1)/n with a = 9.414(3)A, b = 17.591(5)A, c = 14.410(4)A, beta = 93.42(3) degrees, V = 2382(1)A3, R = 0.0694, Z = 4. In the solid, the conformation about all of the bonds is frozen. The torsion angles about some of the important bonds are: C(7)-N(8)-C(9)-C(10), -86 degrees; N(8)-C(9)-C(10)-C(11), -179 degrees (extended); S(17)-N(18)-C(19)-N(20), 178 degrees (extended); and N(18)-C(19)-N(20)-C(21), -179 degrees (extended). Thus, except for the N(8)-C(9) bond, the conformation in the solid state is extended. The solution and solid-state NMR spectra are different as might be expected based on the differences in conformation discussed above.