Organophosphorus compounds. Part V: The resolution of O‐alkyl hydrogen methylphosphonothioates with (+)‐ and (−)‐α‐phenylethylamine

A series of four O‐alkyl hydrogen methylphosphonothioates, (RO)MeP(S)OH, was resolved using both (+)‐ and (−)‐α‐phenylethylamine. Because it gives better results, is rapid and of general applicability the method is to be preferred to that in which alkaloids are used as resolving bases. In one case optical purities of the isolated enantiomers were determined after conversion into acetylcholinesterase inhibitors.