Sonochemically modified ovalbumin enhances enantioenrichment of some amino acids.

As part of our efforts to develop a new method for chiral resolution of amino acids with sonochemically modified proteins, we present result that indicates how ovalbumin microspheres (OAMS) interact specifically with l-amino acids from a racemate in solution, leaving an excess of d-enantiomer in the permeate solution. Among different amino acids that interacted with the OAMS, tryptophan (Trp) was the most successfully resolved with 65% enantiomeric excess. A control experiment with native ovalbumin in solution did not show any chiral resolution of amino acids.

Spinal epidural abscess: in search of reasons for an increased incidence.

Background: Spinal epidural abscess (SEA) is a rare disease with a potentially devastating outcome, and a reported incidence traditionally estimated at 0.2-2 cases/10,000 hospital admissions. Since the implementation in October 2007 of a program to increase medical personnel's awareness of SEA, we have documented a sharp increase in the incidence of SEA at our medical center

Objectives: To investigate the cause of the increased incidence of SEA.

Essential reactive intermediates in nucleoside chemistry: cyclonucleoside cations.

DFT-based modeling as well as experimental examination of model keto nucleosides have revealed that high susceptibility of these compounds to acids is due to formation of intermediate cyclonucleoside cations of low energy. Theoretically established chemical structures of these previously overlooked intermediates explain the reaction courses for a cluster of nucleoside reactions.

The role of an aromatic group in remote chiral induction during conjugate addition of alpha-sulfonylallylic carbanions to ethyl crotonate.

The impact of a remote aromatic nucleus on the stereochemical outcome of the conjugate addition of alpha-sulfonylallylic carbanions to an alpha,beta-unsaturated ester was investigated. alpha-Regioselectivity coupled with anti-diastereoselectivity is accompanied by a prominent preference for relative configuration 3 over 4. The 9-anthryl moiety has shown itself greatly superior over all other groups in this bias.

Intermolecular electrophilic O-amination of alcohols.

We report the first examples of an intermolecular electrophilic O-amination of aliphatic alcohols. Thus, the new reagents, fluorenone oxime tosylate, 5a, or mesylate, 5b, permit O-amination of diverse alcohols in the presence of NaH under mild conditions. By following the formation of the resulting oxime ethers, 6, the reaction was shown to be sensitive to steric effects in the alcohol.