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Journals and Conferences
The first total synthesis of (+)-sieboldine A was completed in 20 steps from readily available (3aS,6aR)-3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan-2-one (5). Key steps are as follows: (a) a pinacol-terminated 1,6-enyne cyclization reaction to form the cis-hydrindanone core (11 --> 12), (b) formation of the spiro tetrahydrofuran ring by stereoselective DMDO… (More)
This article describes synthetic studies that culminated in the first total synthesis of the Lycopodium alkaloid sieboldine A. During this study, a number of pinacol-terminated cationic cyclizations were examined to form the cis-hydrindanone core of sieboldine A. Of these, a mild Au(I)-promoted 1,6-enyne cyclization that was terminated by a semipinacol… (More)
Infection by parasitic nematodes is widespread in the developing world causing extensive morbidity and mortality. Furthermore, infection of animals is a global problem, with a substantial impact on food production. Here we identify small molecule inhibitors of a nematode-specific metalloprotease, DPY-31, using both known metalloprotease inhibitors and… (More)
Gigahertz- to terahertz-frequency infrared and Raman spectra contain a wealth of information concerning the structure, intermolecular forces, and dynamics of ionic liquids. However, these spectra generally have a large number of contributions ranging from slow diffusional modes to underdamped librations and intramolecular vibrational modes. This makes it… (More)
Chloptosin (1) is a structurally interesting anticancer agent that was isolated by Umezawa et al. from a culture broth of Streptomyces. It was found to induce apoptosis in both the apoptosis-resistant human pancreatic adenocarcinoma cell line AsPC-1 and also in several apoptosis-sensitive cancer cell lines. In addition, chloptosin exhibits strong… (More)
[reaction: see text] The enantiomers of spiro[4.4]nonane-1,6-diol have been transformed by different reaction pathways into the two possible carbaspironucleoside epimers with natural C1' absolute stereochemistry.
Since their first discovery in 1959, natural products containing the piperazic acid motif have been isolated from a variety of sources and exhibit diverse biological activity profiles. This review provides information about their isolation and biological activities, and presents an overview of recent total syntheses of these molecules.
Here we describe in full our investigations into the synthesis of the dimeric cyclohexapeptide chloptosin in 17 linear steps. Particularly, this work features an organocatalytic tandem process for the synthesis of the embedded piperazic acids, in which a differentially protected azodicarboxylate is used together with pyrrolidinyl tetrazole as the catalyst.… (More)