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A new example of a racemate showing unusual enantiomeric resolution phenomenon, in which simple recrystallization of the racemate leads to remarkable enantiomeric enrichment of either enantiomer up to 100% ee in the mother liquor, has been found. This compound is (±)-[2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]-ethyl]dimethylsulfonium p-nitrobenzenesulfonate [EtOCH2CH(OH)CH2OC6H4NHCOCH2CH2SMe2+O2NC6H4SO3−] [(±)-SN]. By repeating recrystallization of (±)-SN and the resulting deposited crystals successively and collecting the resulting enantiomerically enriched mother liquors with the same chirality sense, highly efficient enantiomeric resolution of the racemate into its separate enantiomers has been accomplished. The relationship between the occurrence of this enantiomeric resolution phenomenon and the crystal properties has been investigated with respect to SN and its aryl- and alkylsulfonate derivatives. The mode of enantiomeric resolution of (±)-SN was similar to that of para-substituted benzenesulfonate derivatives (±)-ST (4-MeC6H4SO3−) and (±)-SC (4-ClC6H4SO3−) previously reported, whereas the unsubstituted derivative (±)-SB (C6H5SO3−) and alkysulfonate derivatives (±)-SO (n-C8H17SO3−) and (±)-SM (CH3SO3−) did not show such an enantiomeric resolution phenomenon. The crystalline form of the former racemates that underwent the enantiomeric resolution was racemic compounds, while the latter were mixed crystals (solid solutions) composed of the respective optical antipodes. Chirality 9:220–224, 1997. © 1997 Wiley-Liss, Inc.

A novel π-donor, 1,2:5,6-bis(ethylenedithio)pyracylene (2), was prepared by dithioacetalization of 1,5-pyracenedione with 1,2-ethanedithiol followed by ring expansion on treatment with tellurium tetrachloride. 2 showed two reversible low oxidation potentials by cyclic voltammetry. Single crystal X-ray analysis of 2 revealed unique three dimensional donor networks.

The first 7,10-Dithiafluoroanthene has been prepared from acenaphthenone in three steps, via ring expansion reaction of acenaphthenone ethylenedithioacetal. It was shown to be good π-donor and form highly conducting cation radical salts with PF 6 − . X-ray crystallographic analysis of the salt showed columnar stack structure of donors and the salt showed high electrical conductivity at room temperature.