Process for preparing phosphorothioates and phenylphosphonothioates

Claim 1

In the process of preparing a compound corresponding to the formula ##STR32## wherein: R 1 and R 2 are each independently lower alkyl; and R is ##STR33## wherein: n is 0, 1, 2 or 3; and X is nitro, cyano, halo, lower alkyl, lower alkoxy, lower alkylthio or lower alkylsulfinyl, with the proviso that R does not bear more than one nitro group, lower alkylthio group or lower alkylsulfinyl group; by reacting in an inert liquid reaction medium under alkaline conditions (a) a compound corresponding to the formula R--O.sup.⊖ M.sup.⊕ or M.sup.⊕ O.sup.⊖ --C.sub.6 H.sub.4 --S--C.sub.6 H.sub.4 --O.sup.⊖ M.sup.⊕ with (b) a compound corresponding to the formula ##STR34## wherein M is an alkali metal and R, R 1 and R 2 have the aforesaid meaning; the improvement consisting of conducting the process in the presence of a small but catalytic amount of (1) a quaternary ammonium or phosphonium salt having a minimum solubility of at least 1 weight percent in the liquid reaction medium at 25° C and (2) an organic, sterically unhindered, nucleophilic tertiary amine, with the proviso that said amine is not 1,4-diazabicyclo[2.2.2]octane or an N-substituted diazole when (1) is a quaternary ammonium salt.