The thio-Mitsunobu reaction: a useful tool for the preparation of 2,5-anhydro-2-thio- and 3,5-anhydro-3-thiopentofuranosides.
The unprotected methyl L-arabinofuranosides, D-ribofuranosides and D-xylofuranosides are transformed into the corresponding S-acetyl-5-thio derivatives by the thio-Mitsunobu reaction. Mesylation and subsequent reaction with sodium hydrogen carbonate led, depending on the configuration of the intermediate, to 2,5-anhydro-2-thio- or 3,5-anhydro-3-thiopentofuranosides. Due to inversion at C-3 or C-2 during the intramolecular nucleophilic displacement the products exhibit L-lyxo-, D-arabino- or D-lyxo-configuration. Analogously, the methyl 2,3-anhydro-D-ribofuranosides yielded 5-thio-S-acetates with intact 2,3-oxirane groups, which were cyclised with sodium hydrogen carbonate by epoxide ring opening and concomitant ring closure to form exclusively 3,5-anhydro-3-thio-D-xylofuranosides. A related 3,5-anhydro-3-seleno-D-lyxofuranoside was obtained by reaction of a 3,5-di-O-mesyl-D-arabinofuranoside with sodium hydrogen selenide. Several X-ray diffraction analyses proved the structures of the products.
Thiosugars. XII. Synthesis of New 3′‐O‐Substituted 2′,5′‐Anhydro‐2′‐thio‐α‐d‐pentofuranosyl Nucleoside Analogues
Methyl 2,5‐anhydro‐3‐O‐(2‐methoxyethyl)‐2‐thio‐β‐d‐arabinofuranoside and methyl 2,5‐anhydro‐3‐O‐(2‐fluorobenzyl)‐2‐thio‐α‐d‐lyxofuranoside were transformed into the corresponding uridine, thymidine, cytidine and adenosine analogues, which exclusively exhibited the α‐configuration irrespective of the anomeric configuration of the donor. The structure, configuration, and conformation of the products was elucidated by X‐ray structure analyses. The nucleoside analogues were tested for antiviral activities. #Part XI: See Ref. 11.
Comparative odor control performance of activated carbon and permanganated alumina
Abstract Activated carbon and permanganated alumina were compared with regard to their effectiveness in reducing the odor levels of air streams containing olefin. ester, aldehyde, ketone, amine, sulfide, mercaptan, decomposed crustacean shell vapor, or state tobacco vapor. In all cases, the odor-reducing effect of the activated carbon was much faster than that of the permanganated alumina. For the odors of stale tobacco and decomposed crustacean shells, the permanganated alumina, after it was reduced to MnO2, gave evidence of prolonged partial odor reduction, probably by serving as a catalyst for oxidation by air.