Studies on furan derivatives. XIV. Nucleophilic substitution of methyl 5-nitro-2-furancarboxylate and 5-Nitrofuran-2-nitrile

Methyl 5-alkoxy-2-furancarboxylates, methyl 5-alkylthio-2-furancarboxylates and methyl 5-phenylthio-2-furancarboxylate were prepared by nucleophilic substitution of methyl 5-nitro-2-furancarboxylates. Also, 5-phenoxyfuran-2-nitriles and 5-phenylthiofuran-2-nitriles were prepared.     

Analyses of particle production in hadron-nucleus reactions at several GeV with a two-moving-source model

Spectra of protons and pions emitted in the target-rapidity region in hadron-nucleus reactions at 3 and 4 $\text{GeV}\text{c}$ were observed in wide momentum- and angular-acceptance measurements. Fitting to the data with the two-moving-source model well reproduced experimental proton spectra with the slope parameters of 50–60 MeV for one component and 110–125 MeV for another. The slope parameters for pions were 120–165 MeV, larger than those for protons. Energy depositions of GeV particles were estimated by integrating energies carried away through the particle production     

From penicillin to penem and carbapenem. III C1-unit introduction at C-4 position of azetidinone

Monocyclic β-lactams ($\text{1}$) were converted into 4-cyano derivative $\text{2}$ (C₁-unit introduction) under two phase reaction conditions. The cyano group in $\text{2}$ was successively transformed into $\text{3}$ and $\text{4}$, which are thought to be important precursors for the carbapenem synthesis.     

Spin structure of the nucleon

Based on an infinite sublayer quark model, we determine the fraction of nucleon spin carried by subquarks.