Reversed phase paper chromatography of p-nitrophenyl methylphosphonates and sulfur analog

On account of differences in lipophilic character it is possible to separate p -nitrophenyl methylphosphonates and their sulfur analogs by reversed phase paper chromatography. Whatman No. 1 filter paper was impregnated with silicone oil 550; the upper layer of a chloroform-ethanol-water (5:5:3, v/v) system served as mobile phase. The relation R M = log (1/ R F —1) holds for homologous series of O-alkyl p -nitrophenyl methylphosphonates (I) and S-alkyl p -nitrophenyl methylphosphonothiolates (II) up to the n -pentyl homologues. Using a combination of Gibbs' and Dragendorff reagents it was possible to distinguish the phosphonates, phosphonothiolates and phosphonothionates.