Oxyfunctionalization of unactivated C–H bonds in triterpenoids with tert-butylhydroperoxide catalyzed by meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex

A system consisting of meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex [Os(TMP)CO] as a precatalyst and tert-butylhydroperoxide (TBHP) as an oxygen donor is shown to be an efficient, regioselective oxidant system for the allylic oxidation, ketonization and hydroxylation of unactivated C–H bonds in a series of the peracetate derivatives of penta- and tetracyclic triterpenoids. Treatment of the substrates with this oxidant system afforded a variety of novel or scarce oxygenated derivatives in one-step. Structures of the isolated components, after chromatographic separation, were determined by spectroscopic methods including GC–MS and shift-correlated 2D-NMR techniques. Factors governing the regioselectivity and the possible mechanism for the oxyfunctionalization of the unactivated carbons are also discussed.     

Increased urinary phosphate excretion in pseudohypoparathyroidism type II with long-term treatment with phosphodiesterase inhibitor.

A 58-year-old woman was diagnosed to have pseudohypoparathyroidism (PHP) type II because of the absence of an increase of urinary phosphate secretion, despite a marked increase in urinary cAMP excretion on the Ellsworth-Howard test. We treated the patient with a cyclic-nucleotide phosphodiesterase inhibitor, theophylline, resulting in increased urinary phosphate and cAMP excretions. Dibutyl cAMP administration induced the increase in the urinary phosphate excretion. In this case, the unresponsiveness of the urinary phosphate secretion to cAMP was recovered by a high dose of cAMP or long-term administration of a phosphodiesterase inhibitor. These data imply that cAMP responsiveness to renal tubular phosphate reabsorption should be more strictly elucidated in the patient with PHP type II.     

Binding Specificity of Hydrolytic Catalytic Antibody: Lessons from the Diverse Immune System

The diverse immune system has the potential to provide numerous antibodies that catalyze a great variety of reactions and exhibit diversity in mechanism and substrate specificity. However, to find such an antibody is not practical, unless we understand the immune response precisely and utilize it. We applied an alternative screening methodology based on the binding specificity of antibodies for the structure of the transition-state analog p-nitrophenyl phosphonate in order to study the built-in diversity of the immune response. This study uncovered the unpredictable binding and substrate specificity of catalytic antibodies derived from the diverse immune response.     

Mass Outbreak of Food Poisoning Disease Caused by Small Amounts of Staphylococcal Enterotoxins A and H

It was believed that food poisoning in Osaka in 2000 was due to small amounts of staphylococcal enterotoxin A (SEA) in reconstituted milk. Results of this study clearly indicate that SEH was also present in the raw material of reconstituted milk, indicating that the food poisoning was caused by multiple staphylococcal enterotoxins.