Polypeptidyl derivatives of bovine pancreatic ribonuclease
(RNase) containing two or three tyrosine chains
with an average of two to three residues per chain have
been prepared. The effects of various perturbants such as
neutral salts, ethanol, urea and guanidine hydrochloride
on the thermal transition of the derivatives have been
studied....
An atmospheric pressure argon glow discharge is shown
to detect trace levels of carbohydrates in aqueous flowing
systems, using either of two glow discharge solution
interface configurations. The first configuration consists
of an oscillating glow discharge sustained between a flowing
aqueous cathode and platinum anode. Picomole and micromolar
mass and...
Sulfoxide-ligand exchange (SLE) and asymmetric halogen-metal exchange (AHME) processes were separately examined for the enantioselective synthesis of functionalized alpha-haloalkylmetal (carbenoid) reagents. Carbenoids derived from SLE were used to effect stereospecific reagent-controlled homologation (StReCH) of boronic esters and those generated via AHME were engaged in Darzens-type chemistry with aldehydes.
Abstract for...
The stereospecific reagent-controlled homologation (StReCH) of boronic esters with enantioenriched carbenoid species generated in situ by the addition of organolithium initiators to stereodefined α-chloroalkyl aryl sulfoxides was previously reported. The reaction of an organolithium with an α-chloroalkyl aryl sulfoxide ostensibly generates an α-chloroalkyllithium via sulfoxide-lithium exchange; however, the true nature...
In order to examine some possible tyrosyl interactions, poly-tyrosyl lysozyme and poly-O-methyltyrosyl lysozyme were prepared and their solubilities were compared. Both derivatives exhibited
similar pH dependent solubilities, showing a minimum solubility at
about pH 8. Their solubilities varied with temperature, having a
positive enthalpy of solution. The effect of a...
Enantioenriched sp³-hybridized carbenoid reagents CR1R2MX (X = nucleofuge, M = electrofuge) of different types were investigated for the synthesis of polysubstituted alkyl chains by iterative stereospecific reagent-controlled homologation (StReCH) and for the stereospecific connective synthesis of alkenes by eliminative cross-coupling.
In the first part, putative enantioenriched α-chloroalkyllithiums (CHRLiCl) were employed...