Patent ID: 7553984

Claim:
A process for preparing compounds of the formula where R 1 , R 2 and R 3 independently of one another are selected from the group consisting of alkyl groups having 1 to 18 carbon atoms, alkenyl groups having 2 to 18 carbon atoms, aryl groups having 6 to 10 carbon atoms, alkylaryl groups having 7 to 10 carbon atoms, and mixtures thereof, and R 4 is hydrogen or selected from the group consisting of alkyl groups having 1 to 18 carbon atoms, alkenyl groups having 2 to 18 carbon atoms, aryl groups having 6 to 10 carbon atoms, alkylaryl groups having 7 to 10 carbon atoms, and mixtures thereof, said process comprising a) reacting a dithiophosphate of the formula (R 1 O)(R 2 O)PS2Me, where Me is a cation, with an oxidizing agent in acidic solution and then b) reacting the resultant product with an amine of the formula HNR 3 R 4 .