Strong sequential transfer processes in 0+ → 0+ (p,t) reactions on Pb isotopes

A marked difference of experimental analyzing powers $\text{A (θ)}\text{for}{}^{208}\text{Pb}\text{(}\text{p}\text{,}\text{t}\text{)}{}^{206}\text{Pb}\text{(0}{}_{\mathrm{<mtext>g</mtext>}}{}^{\mathrm{+}}\text{and}\text{0}{}_2{}^{\mathrm{+}}\text{)}$ reaction is explained by considering sequential transfer as wesses as well as the one-step process. The calculated A(0θ) for the 0₂⁺ state is very sensitive to the wave functions employed. An enhancement of the cross sections for the ground-state transitions of three Pb isotopes is found to be due to sequential transfer processes.     

Alkylation of toluene with methanol over a zeolite disc synthesized through solid state reactions

Outstandingpara-xylene selectivity in the alkylation of toluene with methanol was observed for a new, disc-shaped ZSM-5 zeolite catalyst synthesized by solid state reactions.     

Total synthesis of an immunosuppressive glycolipid, (2S,3S,4R)-1-O- (alpha-d-galactosyl)-2- tetracosanoylamino-1,3,4-nonanetriol

[reaction: see text] A practical and efficient total synthesis of (2S,3S,4R)-1-O-(alpha-d-galactosyl)-2-tetracosanoylamino-1,3,4-nonanetriol, OCH 1b, a potential therapeutic candidate for Th1-mediated autoimmune diseases, is described. The synthesis incorporates direct alkylation onto epoxide 5 and stereospecific halide ion catalyzed alpha-glycosidation reaction. A key intermediate 10 was obtained in only eight steps and 37% overall yield from commercially available d-arabitol 2, and the total synthesis of 1b was accomplished in 12 steps and 19% overall yield. This method will enable the synthesis of a variety of phytosphingolipids, especially that with the shorter sphingosine side chain than 1a, in a highly stereoselective manner.     

A concise synthesis of (3S,4S,5R)-1-(α-d-galactopyranosyl)-3-tetracosanoylamino-4,5-decanediol, a C-glycoside analogue of immunomodulating α-galactosylceramide OCH

A concise and convergent synthesis of the C-glycoside analogue 2b of immunomodulating α-galactosylceramide OCH 1b starting from readily available 2,3,4,6-tetra-O-benzyl-d-galactose 3 and l-arabinose 6 is described. The synthesis features the nucleophilic addition of an α-ethynyl sugar 5 to the phytosphingosine-precursor aldehyde 9 and would be applicable to a variety of C-glycoside analogues of interest.