Synthetic Access to 3-Substituted Pyroglutamic Acids from Tetramate Derivatives of Serine, Threonine, <i>allo</i>-Threonine, and Cysteine
作者:Halima Bagum、Kirsten E. Christensen、Miroslav Genov、Alexander Pretsch、Dagmar Pretsch、Mark G. Moloney
DOI:10.1021/acs.joc.9b01432
日期:2019.8.16
A general route which provides direct access to pyroglutamates from tetramates, making use of Suzuki coupling on an enol mesylate, followed by reduction, is reported. This work permits direct scaffold hopping from tetramate to substituted pyroglutamates. Some compounds in the library showed modest antibacterial activity against Gram-positive bacteria.
Scalar Cross-Relaxation Detected in the NOESY Spectra of Oxazolidines and Thiazolidines
作者:Tharindi D. Panduwawala、Laia Josa-Culleré、Ilya Kuprov、Barbara Odell、Mark G. Moloney、Timothy D. W. Claridge
DOI:10.1021/acs.joc.6b00458
日期:2016.5.20
Anomalous cross-peaks observed in the NOESY spectra of 2,4-disubstituted thiazolidines and oxazolidines that cannot be attributed to classical dipolar NOE or chemical exchange peaks have been investigated experimentally and computationally and have been shown to arise from scalar cross-relaxation of the first kind. This process is stimulated by the relatively slow modulation of scalar couplings and
The reduction of aromatic ketones by borane in the presence of the inseparable diastereoisomeric mixture of 2-substituted thiazolidine-4-methanol has been investigated. Modest to high enantiomeric excesses were obtained increasing with thiazolidine steric hindrance. (C) 1997 Elsevier Science Ltd.