Re: [asa] My Brain Hurts

This is one of those situations where only about 2 people who read this will actually understand what it says.

/washes down 2 aspirin with H2O

CWC

_______________________________
Charles W. Carrigan, Ph.D.
Assistant Professor of Geology
Olivet Nazarene Univ., Dept. of Physical Sciences
One University Ave.
Bourbonnais, IL 60914
PH: (815) 939-5346
FX: (815) 939-5071
ccarriga@olivet.edu
http://geology.olivet.edu/

"To a naturalist nothing is indifferent;
the humble moss that creeps upon the stone
is equally interesting as the lofty pine which so beautifully adorns the valley or the mountain:
but to a naturalist who is reading in the face of the rocks the annals of a former world,
the mossy covering which obstructs his view,
and renders indistinguishable the different species of stone,
is no less than a serious subject of regret."
          - James Hutton
_______________________________


>>> "Rich Blinne" <rich.blinne@gmail.com> 4/26/2007 3:06 PM >>>

This week's Nature has a special section on glycochemistry and glycobiology. The lead editorial starts with:


Carbohydrates have long been underappreciated by the scientific community, and many scientists approach the complex structures and elaborate nomenclature of carbohydrates with trepidation.


If you don't believe them check this out:


In addition to carbohydrate donors with anomeric heteroatom derivatives, the use of glycals (12, Fig. 1c) as glycosyl donors has been explored extensively in complex carbohydrate synthesis. The presence of the 1,2-alkene functionality in this substrate allows the use of various electrophilic oxidants (El+) that are reactive to enol ether nucleophiles (12). The resulting activated glycosyl donor 13 is then poised to receive an appropriate nucleophilic glycosyl acceptor (Nu–H) to form the glycoconjugate 14. These methods allow the introduction of various functionalities 'Z' at the C2-position in conjunction with anomeric bond formation. For example, C2-oxygen transfer to glycal donors has proved useful, involving dimethyldioxirane (DMDO)-mediated33 or sulphonium-mediated34 1,2-epoxidation of glycals, followed by anomeric substitution, to generate C2-hydroxy glycosides (15, Fig. 1d). Similarly, I(III)-containing reagents have recently been applied to the generation of selectively protected C2-acyloxyglycosides (16)35. The synthesis of 2-amino-2-deoxyglycosides has drawn considerable attention owing to the abundance and importance of this class of glycoside in naturally occurring glycoconjugates. The venerable C2-azidonitration reaction of glycals36 to afford C2-azido pyranose derivatives (17) has been, and continues to be, a favoured method by which to introduce the C2-N-functionality. Other reactions have subsequently been developed for C2-nitrogen transfer onto the glycal donor, including stereoselective installation of a sulphonamide group (for instance, 18, by iodosulphonamido glycosylation)33, as well as less-used protocols to install a C2-carbamate functionality37 and the naturally occurring C2-acetamido group38.


All I can say is Terry, enjoy. Yes, I know you're a protein guy but at least you have a leg up on the rest of us. I'm getting an ice pack.


 

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Received on Thu Apr 26 16:58:17 2007