DE2135349

1338356 Preparation of esteramides of phosphorus acids BAYER AG 14 July 1972 [15 July 1971] 33094/72 Heading C2P Compounds of Formula I where R1 is C 1-6 alkyl, C 2-6 alkenyl, alkoxyalkyl, cycloalkyl, aryl or aralkyl and R1 may have one or more substituents which are stable to the reaction conditions employed, R2 is optionally substituted C 1-6 alkyl, Z and X are oxygen or sulphur and n is 0 or 1, are prepared by reacting a compound of Formula II with a compound of Formula III HOR2 in the presence of an equivalent amount of a strong acid at -10‹ to +70‹ C. The strong acid may be hydrogen chloride, added by passing it in as a gas or by adding it dropwise in the form of a solution in the compound III, or sulphuric acid. The reaction may be carried out in the presence of an inert organic solvent, or in an excess of compound III as diluent. The compound of Formula II may be used in the form of a mixture with ammonium chloride obtained by reacting ammonia with the corresponding dichloride. In comparison examples: (1) no reaction occurs when S - methyl - thiolophosphorodiamidate is refluxed with ethanol for 24 hours; (2) when an excess of HCl is used in the reaction of O-ethylphosphorodiamidate with methanol, a mixture of O - ethyl - O - methyl - phosphoroamidate and O - ethyl - O,O - dimethyl phosphate is produced, the proportion of amide to ester being 3:1 when 2 moles of HCl are used per mole of diamide; and (3) when O-ethyl-N,N1-dimethyl-phosphorodiamidate is reacted with methanol in the presence of an equivalent amount of HCl a mixture of O-ethyl-O,N-dimethyl-phosphoroamidate and O-ethyl-O,O-dimethyl-phosphate is produced, the ester only being produced when an excess of HCl is used. The compounds of Formula I have insecticidal and acaricidal properties and may be used as the active ingredients in conventional pesticidal compositions.