process for the production of o, o - dialkyl - o - phenylestern of thionophosphorsäuren

摘要

O,O-Dialkyl-O-phenyl-thionophosphonates of formula (where R1 is 1-12C alkyl, opt. interrupted by O or substd. by COOR, or is 3-12C alkenyl; R is lower alkyl, R2 is lower alkyl; and X, Y and Z are H, Cl, Br, I, alkyl or NO2; Z may also be CN, acetyl or -S(O)nR3; R3 is lower alkyl; and n = 0-2) are prepd. by re-esterification of O-O-diphenyl-O-alkyl-thionophosphonates of formula (II) with an alcohol R2OH in the presence of a weak base, pref. dry NH3, as catalyst. (I) are pesticides. In contrast to tert. amines, weak bases do not give rise to the formation of quaternisation prods.