An α-acetoxy ketone reducing enzyme has been purified and characterized from the cell-free extract of bakers’ yeast (Saccharomyces cerevisiae). Only one NADPH-dependent dehydrogenase that catalyzed the reduction of α-acetoxy ketone was found in bakers’ yeast. The molecular weight of the enzyme was estimated to be 36 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme was composed of a single
Syntheses of Combretastatins D-1, D-2, and D-4 via Ring Contraction by Flash Vacuum Pyrolysis
作者:Marina Harras、Wolfgang Milius、R. Alan Aitken、Rainer Schobert
DOI:10.1021/acs.joc.6b02586
日期:2017.1.6
combretastatins D-2 and D-4 as well as a formal synthesis of combretastatin D-1 by a conceptually new route harnessing a ring-contracting flashvacuum pyrolytic extrusion of sulfur dioxide from the respective 16-membered sulfone precursors. Via flashvacuumpyrolysis, even metaparacyclophanes as small and strained as the hitherto unknown oxa[1.5]metaparacyclophane could be prepared as a side product en
Synthesis of Trisubstituted Oxazoles via Aryne Induced [2,3] Sigmatropic Rearrangement–Annulation Cascade
作者:Rahul N. Gaykar、Shiksha Deswal、Avishek Guin、Subrata Bhattacharjee、Akkattu T. Biju
DOI:10.1021/acs.orglett.2c01379
日期:2022.6.17
transition-metal-free, [2,3] sigmatropic rearrangement–annulation cascade of 2-substituted thio/amino acetonitriles with arynes allowing the synthesis of 2,4,5-trisubstituted oxazoles under mild conditions has been demonstrated. The key sulfur/nitrogen ylides were generated by the initial S/N arylation followed by proton transfer, which was followed by the selective [2,3] sigmatropicrearrangement involving the