[Chemical constituents from Salix oritrepha Schneid].

OBJECTIVE: To study chemical constituents of the above ground part of Salix oritrepha. METHOD: Using chromatography to isolate compounds and their structure were identified by physical, chemical and spectral techniques. RESULT: Four compounds were isolated and elucidated as beta-sitosterol, beta-sitosteryl-3-O-glucoside, friedelin, luteolin-7-O-glucoside. CONCLUSION: All of them were isolated from S. oritrepha for the first time. Friedelin from the plants of genus Salix for the first time.

Nuclear magnetic resonance and infrared spectroscopic analysis of nedocromil hydrates.

PURPOSE: Nedocromil sodium (NS), which is used in the treatment of reversible obstructive airway diseases, such as asthma, has been found to exist in the following solid phases: the heptahemihydrate, the trihydrate, a monohydrate, an amorphous phase, which contains variable amounts of water, and a recently discovered methanol + water (MW) solvate. Our aim was to apply 13C solid-state nuclear magnetic resonance (NMR) spectroscopy and solid-state Fourier transform infrared (FTIR) spectroscopy to the study of specific interactions in the various solid forms of NS. METHODS: The 13C solid-state NMR and FTIR spectra of the various solid forms of NS were obtained and were related to the crystal structures of NS, the conformations of the nedocromil anion, and the interactions of the water molecules in these crystals. RESULTS: The 13C solid-state NMR spectrum is sensitive to the conformation of the nedocromil anion, while the solid-state FTIR spectrum is sensitive to interactions of water molecules in the solid state. In NS monohydrate, for which the crystal structure has not yet been solved, and in the amorphous phase, the information about the conformations of the nedocromil anion and the interactions of the water molecules are deduced from the 13C solid-state NMR spectra and solid-state FTIR spectra, respectively. CONCLUSIONS: 13C solid-state NMR spectroscopy and solid-state FTIR spectroscopy are shown to be powerful complementary tools for probing the chemical environment of molecules in the solid state, specifically the conformation of the nedocromil anion and the interactions of water-molecules, respectively.

[Direct optical resolution of acidic biphenyl drugs by high performance liquid chromatography on tris(3,5-dimethylphenylcarbamate) of cellulose].

A chiral stationary phase was prepared by coating cellulose-tris(3, 5-dimethylphenylcarbamate) onto aminopropylated silica gel. A series of enantiomeric acidic biphenyl drugs were directly resolved on the chiral stationary phase (CSP) by normal-phase high performance liquid chromatography (HPLC). A hexane-2-propanol eluting system containing 1% of trifluoroacetic acid was used as mobile phase. Efficient optical resolution of the acidic biphenyl drugs has been attained. The factors that influence chiral discrimination such as structural characeristic of the samples and mobile phase were investigated. An interaction model between the stationary phase and the samples was discussed. The results showed that efficient optical resolution of racemic carboxylic acids could be attained by normal-phase HPLC on CSP using a hexane-2-propanol eluting system containing 1% of trifluoroacetic acid.