After feeding of 24-epi-castasterone to the cockroach Periplaneta americana an organ-specific epimerization of the brassinosteroid to 2,24-diepi-castasterone could be detected in female insects. The metabolite being observed only in the ovaries and not in the testes of the insect was identified by GC/MS in comparison with a synthesized authentic sample. Contrary, 24-epi-brassinolide is not meta...

The present study, for the first time, presents a feasible protocol for the preparation of β-cyclodextrin/ imidazolium based dicationic ionic liquid, [βCD/Im](OTs)2, and its application as an efficient and eco-friendly microvessel and host ionic liquid system for the regioselective ring opening of the epoxides in water. No evidence for the formation of diol by-products or side reacti...

The present study, for the first time, presents a feasible protocol for the preparation of β-cyclodextrin/ imidazolium based dicationic ionic liquid, [βCD/Im](OTs)2, and its application as an efficient and eco-friendly microvessel and host ionic liquid system for the regioselective ring opening of the epoxides in water. No evidence for the formation of diol by-products or side reacti...

When grown in the presence of bile acids, two strains of Clostridium limosum were found to contain significant amounts of NADP-dependent 7a/7/3-hydroxysteroid dehydrogenase and NAD-dependent 7a-hydroxysteroid dehydrogenase which were active against conjugated and unconjugated bile acids. No measurable activity could be found when deoxycholic acid (3a, 12a-dihydroxy-5/3-cholan-24-oic acid) was u...

Substitution reactions that employ primary-carbamoyl-protected arylmethanethiols are described. The enantiodetermining step was found to occur in the post-deprotonation step as a dynamic thermodynamic resolution with a chiral bis(oxazoline) ligand. The configurationally labile lithium complexes were trapped with various electrophiles to yield different substitution products in good to excellent...

A one-pot synthesis of enantiomerically pure syn-1,3-diacetates starting from readily accessible racemic diastereomeric mixtures of 1,3-diols has been realized by combining (i) enzymatic transesterification, (ii) ruthenium-catalyzed epimerization of a secondary alcohol in a diol or diol monoacetate, and (iii) intramolecular acyl migration in a syn-1,3-diol monoacetate. The in situ coupling of t...