Diels Alder Reaction
Mostrando 25-30 de 30 artigos, teses e dissertações.
-
25. Enrichment for RNA molecules that bind a Diels-Alder transition state analog.
RNA molecules that bind a transition state analog for a Diels-Alder reaction (Kd = 0.35 +/- 0.05 mM) were isolated from a starting pool of approximately 10(14) sequences by affinity chromatography. After the initial rise and plateau of the amount of RNA that eluted with soluble analog, a step gradient elution was used to further enrich the pool for sequences
-
26. Asymmetric hetero-Diels–Alder reaction catalyzed by dirhodium(II) carboxamidates
Chiral dirhodium(II) carboxamidates are highly efficient catalysts for reactions between a variety of aldehydes and activated dienes. Catalyst loadings as low at 0.01 mol % have been realized with enantioselectivities up to 97%. Kinetic investigations reveal a pronounced electronic influence on the rate of the hetero-Diels–Alder reaction with a Hammett ρ
National Academy of Sciences.
-
27. Total synthesis of (–)-spinosyn A
A convergent, highly stereoselective total synthesis of (–)-spinosyn A (1) is described. Key features of the synthesis include the transannular Diels–Alder reaction of macrocyclic pentaene 11 and the transannular Morita–Baylis–Hillman cyclization of 12 that generates tetracycle 26. The total synthesis of (–)-spinosyn A was completed by a sequence i
National Academy of Sciences.
-
28. A structural basis for the activity of retro-Diels–Alder catalytic antibodies: Evidence for a catalytic aromatic residue
The nitroxyl synthase catalytic antibodies 10F11, 9D9, and 27C5 catalyze the release of nitroxyl from a bicyclic pro-drug by accelerating a retro-Diels–Alder reaction. The Fabs (antigen-binding fragments) of these three catalytic antibodies were cloned and sequenced. Fab 9D9 was crystallized in the apo-form and in complex with one transition state analogue
The National Academy of Sciences.
-
29. Enantioselective Diels–Alder reactions catalyzed by hydrogen bonding
Like molecules of life (e.g., proteins and DNA), many pharmaceutical drugs are also asymmetric (chiral); they are not superimposable on their mirror images. One mirror image form (enantiomer) of a drug can have desirable activity, the other not. Consequently, the development of methods for the selective synthesis of one enantiomer is of great scientific and
National Academy of Sciences.
-
30. ACTION OF ORGANIC ANHYDRIDES ON MYCOBACTERIA
Fite, George L. (U. S. Public Health Service Hospital, Carville, La.), Carolyn K. Wrinkle, and Donald J. Lartigue. Action of organic anhydrides on mycobacteria. J. Bacteriol. 83:1305–1305. 1962.—The bacilli of leprosy, murine leprosy, and tuberculosis lose acid-fastness when treated with maleic anhydride, without loss of morphological integrity. Mycobact