Absolute configuration of teucrin-A
ConclusionsThe absolute configuration of teucrin-A, a norditerpenoid fromTeucrium chamaedrys L. has been shown.
Circular dichroism of some steroidal α-ketols and their acetates
Abstract An examination of the CD spectra of certain steroidal α-ketols and their acetates revealed instances where the Cotton effect of the ketone n → π * transition does not obey the octant rule. This was discussed in terms of the conformational preferences of the α-substituents. The relevance of these results to earlier configurational assignments on A-ring α-ketols in the cucurbitacin series was assessed.
Growth and Characterization of β-RDX Single-Crystal Particles
1,3,5-Trinitrohexahydro-s-triazine (RDX) single-crystal particles crystallized in the β phase have been successfully grown by sublimation–recrystallization. Synchrotron X-ray diffraction results confirm that the recrystallized products are β-RDX single crystals. Compared to the traditional solution deposition methods, the sublimation method used in this work breaks through the mass limitations during the growth of β-RDX. The distribution of α- and β-RDX on different substrates reveals that hydrophilic substrates are prone to grow β-RDX single crystals and that hydrophobic substrates prefer α-RDX single crystals. The sublimation rate dominates the growth of pure β-RDX. The mechanisms of the phase transition from β-RDX to α-RDX during the process of sublimation–recrystallization have been studied. The current results can promote the potential application of β-RDX in the propellant, explosives, and military fields.