Polymorphic Characterization, Pharmacokinetics, and Anti-Inflammatory Activity of Ginsenoside Compound K Polymorphs.

Polymorphism exhibits different physicochemical properties, which can impact the bioavailability and bioactivity of solid drugs. This study focused on identifying the polymorphs of ginsenoside compound K (CK) and studying their different behaviors in pharmacokinetics (PK) and pharmacodynamics (PD). Four CK polymorphs (form I, II, III, and IV) from organic solvents were characterized by scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD).

New norsesquiterpene and sesquiterpene from a soft coral of the genus Nephthea.

A new norsesquiterpene nephthediol (1) and a new sesquiterpene nephthetetraol (2) were isolated with guaianediol (3) from a soft coral of the genus Nephthea. Their structures were deduced on the basis of spectroscopic methods.

Synthesis and molecular structure of ethyl [N-tosyl-(R)-prolyloxy]-2(S)-[4-cyano-8,8-ethylenedioxy-5-oxo-5,6,7,8-tetrahydroindolizin-3-yl] acetate, a key intermediate in the total synthesis of (20S)-camptothecins.

The synthesis of optically active [N-tosyl-(R)-prolyloxy]-2(S)-[4-cyano-8,8-ethylenedioxy-5-oxo-5,6,7,8-tetrahydroindolizin-3-yl] acetate (4a), a key intermediate for the total asymmetric synthesis of 20(S)-camptothecin anticancer drugs, is described. Its structure was characterized by 2D-NMR techniques and the absolute configuration was further confirmed for the first time by X-ray crystal structure analysis.

Non-nucleoside HIV reverse transcriptase inhibitors, Part 6[1]: synthesis and anti-HIV activity of novel 2-[(arylcarbonylmethyl)thio]-6-arylthio DABO analogues.

2-(Arylcarbonylmethyl)thio-6alpha-naphthylmethyl derivatives of dihydro-alkoxy-benzyl-oxopyrimidines (DABO) were newly found to exhibit activity against both HIV-1 and HIV-2. To further explore their structure-activity relationship, the modified S-DABO analogues (5a-g and 6e-f) with a 1-naphthylthio or phenylthio group at the C-6 position were synthesized. S-Alkylation of 5-ethyl-2-thiouracil with substituted 2-bromo-acetophenones provided crude 2-[(arylcarbonylmethyl)thio]-5-ethyl-(3H)-uracil 2a-e, which was directly subjected to toluenesulfonylation with TsCl to afford disulfonate 4a-e.

Synthetic studies on d-biotin, part 9. An improved asymmetric synthetic route to d-biotin via Hoffmann-Roche lactone-thiolactone approach.

An efficient and highly stereoselective total synthesis of d-biotin has been achieved starting from cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid (2) with an overall yield of 33%. Polymer-supported oxazaborolidine-catalyzed asymmetric reduction of meso-cyclic imide 4 constitutes the key synthetic step in introducing stereogenic centers into the d-biotin molecule.

New tetracyclic diterpenoid and new ceramides from the soft coral Sinularia conferta.

The new tetracyclic diterpenoid confertdiate (1) and two new ceramides, (2) and (3), have been isolated from the soft coral Sinularia conferta, collected from Sanya Bay, Hainan Island, China. Their structures have been elucidated by spectroscopic analysis, and comparison of the 13C NMR data with those of the known diterpenoid isomandapamate confirmed the structure of 1.

3-Bromomethyl-3-ethyl-3,4,6,7,8,8a-hexahydro-1H-pyrrolo[2,1-c][1,4]oxazine-1,4-dione.

In the title compound, C10H14BrNO3, the six-membered lactone ring is in a boat conformation, with the two carbonyl groups cis to one another across the boat basal plane. C-H..