Substituted (RS,SR)-1-phenylethyl phenyl sulfoxides (threo) (XC6H4S(O)CH(CH3)C6H4Y) and some substituted (RR,SS)-sulfoxides (erythro) were prepared and kinetic investigation for the thermal decomposition was carried out at 80.0, 90.0, and 100.0 °C in dioxane. Hammett plots for threo-XC6H4S(O)CH(CH3)C6H5 gave positive ρ-values (ρX=0.60–0.64 at three temperatures), while those for threo- and erythro-C6H5S(O)CH(CH3)C6H4Y snowed V-shape lines with bottoms at the m-OCH3 substituent though the effects of the substituents are small. Meanwhile, large kinetic isotope effects for threo- and erythro-C6H5S(O)CH(CD3)C6H4Y (Y=H, p-OMe, m-Cl) (kH⁄kD=4–6) were observed at all temperatures. The activation energies were in the range of 104–121 kJ mol−1 for all sulfoxides, while the activation entropies were relatively large (7–37 J K−1 mol−1) and were correlated with Hammett σ-values to give small negative trend. Reactions of all erythro-isomers examined were 2–3 times faster than those of the corresponding threo-isomers. From these results, it is suggested that the pyrolysis of 1-arylethyl aryl sulfoxides proceeds via a concerted mechanism in which the transition state is variable from an El-like to a conjugated one. In the latter transition state, conjugation of the phenyl group bearing the electron-withdrawing substituent with the developing π-bond electron acidifies the β-proton.

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To develop a simple method to determine the degree of substitution (dS) for starch ester, we prepared starch acetate with various dS values (0—3) and examined the mode of starch-iodine complex formation for the starch acetate by monitoring the ultraviolet-visible (UV-vis) spectra and their Fourier-transform infrared (FT-IR) spectral changes. The effect of acetylation on the formation of the starch-iodine complex was investigated by monitoring the decrease in absorbance at 680 nm (blue value). The blue value decreased by increasing the standard dS value determined by NMR for starch acetate, but two different correlations between the blue values and the dS values were observed for the low- and highly-substituted starch acetate. The FT-IR spectra for starch acetate particles were measured using a diffuse reflection method. The peak areas and absorbances of the bands assigned to the acetyl group showed a poor correlation with standard dS values from the NMR. On the other hand, the FT-IR peaks assigned to sodium acetate produced by saponification of the starch acetate could be detected using the ATR (attenuated total reflection) method; they showed a good correlation with the standard dS values from the NMR. From these results, it was concluded that the ATR method should be available for the dS determination of starch acetate.

To evaluate the ability of dibenzothiophene N-substituted sulfilimines as photochemical nitrene sources, their photolyses in the presence of several trapping reagents, such as sulfides, olefins, and phosphorus compounds, were performed. In the reactions, the corresponding imino-transfer compounds, namely sulfilimines, aziridines, and iminophosphoranes, were formed in good yields, indicating dibenzothiophene N-tosyl and N-acylsulfilimines have a potent nature as nitrogen sources.