The stereocontrolled synthesis of the southern lactone 17 of
boromycin and of the northern segments of both boromycin and aplasmomycin
are described. The syntheses begin with enantioselective
epoxidation of 3-buten-2-ol (42) to provide the optically active
2(S),3(R) epoxy alcohol 43. The absolute configuration was confirmed
by preparing 43 from (-)-2,3-dihydroxybutyric...
The thermolysis of trans-1 -trimethylsiloxy- 1-vinylcyclotridec-
3-ene (VI-OTMS) led to the formation of two major products: 4-vinylcyclotridecanone
(VII) and cyclopentadec-5-en-l-one (VIII) after
hydrolysis. Ketone VII is produced by a concerted [3, 3] sigmatropic
shift, while ketone VIII is formed by a [1, 3] sigmatropic shift with
a concerted or diradical...
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....
Ultrafast spectroscopy has recently gained momentum as a powerful, noninvasive characterization toolset capable of studying a diverse array of samples with applications in chemistry, physics, biology, engineering, and more. Two popular ultrafast spectroscopic techniques include femtosecond transient absorption (fs-TA) and femtosecond stimulated Raman spectroscopy (FSRS). The latter of these techniques...
Polyoxometalates (POMs) are anions consisting of three or more early transition metals ™ (Gr V and VI) oxoanions (in their highest oxidation state) linked together by a shared oxygen bond to form a 3D framework. Polyoxometalates (POMs) are a rapidly growing class of metal oxo clusters with a wide range...