Enantioselective S-Oxidation: Synthetic Applications

S-oxidation of 2-aryl-3-phenyl-1,3-thiazolidin-4-ones with Oxone® was investigated. For all compounds evaluated, selective oxidation to the sulfoxide was realized using 3 equivalents of Oxone® at room temperature. Attempts to selectively prepare the sulfones of ortho-substituted 2-aryl-3-phenyl-1,3-thiazolidin-4-ones at high temperature by increasing the equivalents of Oxone® used were typically unsuccessful. These results contrast significantly with ortho-substituted 2-aryl-3-cyclohexyl-1,3-thiazolidin-4-ones evaluated previously. The extent of this selectivity was affected by the substituent and its position on the C2 aromatic ring. The ratio of the sulfoxide and sulfone products was quantified by isolating the products by liquid chromatography.Please find the scheme in PDF file.

Download Full-text

S-oxidation ofS-methyl-esonarimod by flavin-containing monooxygenases in human liver microsomes

Xenobiotica ◽

10.1080/00498250310001624627 ◽

2003 ◽

Vol 33 (12) ◽

pp. 1221-1231 ◽

Cited By ~ 22

Author(s):

N. Ohmi ◽

H. Yoshida ◽

H. Endo ◽

M. Hasegawa ◽

M. Akimoto ◽

...

Keyword(s):

Human Liver ◽

Liver Microsomes ◽

Human Liver Microsomes ◽

S Oxidation

Download Full-text

Electronic Structure of Tyrosyl D Radical of Photosystem II, as Revealed by 2D-Hyperfine Sublevel Correlation Spectroscopy

Magnetochemistry ◽

10.3390/magnetochemistry7090131 ◽

2021 ◽

Vol 7 (9) ◽

pp. 131

Author(s):

Maria Chrysina ◽

Georgia Zahariou ◽

Nikolaos Ioannidis ◽

Yiannis Sanakis ◽

George Mitrikas

Keyword(s):

Electronic Structure ◽

Photosystem Ii ◽

Water Oxidation ◽

Spinacia Oleracea ◽

Higher Plants ◽

Correlation Spectroscopy ◽

Oxygen Evolving Complex ◽

Higher Plant ◽

Proton Coupled Electron Transfer ◽

S Oxidation

The biological water oxidation takes place in Photosystem II (PSII), a multi-subunit protein located in thylakoid membranes of higher plant chloroplasts and cyanobacteria. The catalytic site of PSII is a Mn4Ca cluster and is known as the oxygen evolving complex (OEC) of PSII. Two tyrosine residues D1-Tyr161 (YZ) and D2-Tyr160 (YD) are symmetrically placed in the two core subunits D1 and D2 and participate in proton coupled electron transfer reactions. YZ of PSII is near the OEC and mediates electron coupled proton transfer from Mn4Ca to the photooxidizable chlorophyll species P680+. YD does not directly interact with OEC, but is crucial for modulating the various S oxidation states of the OEC. In PSII from higher plants the environment of YD• radical has been extensively characterized only in spinach (Spinacia oleracea) Mn- depleted non functional PSII membranes. Here, we present a 2D-HYSCORE investigation in functional PSII of spinach to determine the electronic structure of YD• radical. The hyperfine couplings of the protons that interact with the YD• radical are determined and the relevant assignment is provided. A discussion on the similarities and differences between the present results and the results from studies performed in non functional PSII membranes from higher plants and PSII preparations from other organisms is given.

Download Full-text