Branched-chain Sugars. VIII. On the Configuration of Branched-chain Sugars from Methyl 3-O-Benzoyl-4,6-O-benzylidene-α-D-arabino-hexopyranosid-2-ulose

Stereoselectivities in the Grignard, diazomethane and nitromethane reaction of methyl 3-O-benzoyl-4,6-O-benzylidene-α-D-arabino-hexopyranosid-2-ulose (1) were examined. In contrast to the Grignard reaction of 1 using methylmagnesium iodide to give a single 2-C-methyl derivative (4), the diazomethane reaction followed by reduction afforded another epimer (6). The nitromethan condensation product (10) of 1 was converted into the corresponding 2-C-acetaminomethyl derivative (13). The NMR spectrum of 2-O-acetate of 4 and comparison of the optical rotations of 4, 6, 10 and 13 in cupraramonium solution indicated that 4 and others have D-gluco-and D-manno-configuration, respectively. Discussions were made on the stereoselectivties of these reactions

Relation between Electronic Structure and Thermoelectric Properties of Heusler-Type Ru2VAl Compounds

We investigated Heusler-type Ru2VAl, a candidate material for next-generation thermoelectric conversion, by first-principle calculations of its thermoelectric conversion properties and direct experimental observations of its electronic structures, employing photoemission and infrared spectroscopy. Our results show that Ru2VAl has a wider pseudogap near the Fermi level compared to Fe2VAl. Accordingly, a higher thermoelectric conversion performance can be expected in Ru2VAl at higher temperatures

Relation between Electronic Structure and Thermoelectric Properties of Heusler-Type Ru₂VAl Compounds

We investigated Heusler-type Ru2VAl, a candidate material for next-generation thermoelectric conversion, by first-principle calculations of its thermoelectric conversion properties and direct experimental observations of its electronic structures, employing photoemission and infrared spectroscopy. Our results show that Ru2VAl has a wider pseudogap near the Fermi level compared to Fe2VAl. Accordingly, a higher thermoelectric conversion performance can be expected in Ru2VAl at higher temperatures