A Correlation between Physicochemical Properties and Acute Toxicity of Sulfonium p-Toluenesulfonates as the Lead Compound of Suplatast Tosilate

Abstract

To elucidate the correlation between the physicochemical properties and biological activity of sulfonium compound, the kinetics of H-D exchange and methyl transfer reactions were investigated as its remarkable properties. There was a good correlation between acute toxicity (LD 50 ) and rate constants of H-D exchange or methyl transfer reactions. The control of toxicity is very important in the development of a new drug. The high reactivity of methyl group was not desirable in acute toxicity, therefore, sulfonium p-toluenesulfonates that do not contain unsaturated carbon as a substituent of sulfur were desirable for reducing toxicity. Furthermore it was revealed that OH and COOH groups reduced acute toxicity substantially. The information on toxicity reduction was used in the design of Suplatast Tosilate.

Demonstration of the Existence of Long‐Lived Species in the Cationic Polymerization of 1,3‐Pentadiene Initiated by Aluminium Trichloride in Non Polar Solvent

“…The spectra could not be realized in chloroform as for polypentadienes, due to the insolubility of the salt having the tetrafluoroborate counter‐ion. Note that the sulfonium salts with a structure RS + Me 2 ,X − published in the literature have a chemical shift for the methyl groups between 2.7 and 3.4 ppm depending on the structure of R and the deuterated solvent used 6,11–13. To conclude, all these results support our interpretation of the synthesized polypentadienes NMR spectra.…”