Patent ID: 8324418

Claim:
A process for the production of an organic dithiopyrophosphate of formula wherein R 1 , R 2 , R 3 , R 4 and R 5 independently are hydrogen, C 1-4 alkyl, chloromethyl or bromomethyl, comprising the steps of (i) reacting a 1,3-diol of formula wherein R 1 , R 2 , R 3 , R 4 and R 5 are as defined above, in an organic solvent with thiophosphoryl chloride in the presence of a base, to obtain a 2-chloro-2-thioxo-1,3,2-dioxaphosphorinane of formula wherein R 1 , R 2 , R 3 , R 4 and R 5 are as defined above, and (ii) partially hydrolyzing the 2-chloro-2-thioxo-1,3,2-dioxaphosphorinane (III) with water in the presence of a base to obtain the corresponding dithiopyrophosphate (I), characterized in that 3-methylpyridine is used both as an organic solvent and as a base in steps (i) and (ii), and wherein steps (i) and (ii) are conducted as a one-pot reaction without isolating the 2-chloro-2-thioxo-1,3,2-dioxaphosphorinane intermediate (III), and wherein in step (i) the thiophosphoryl chloride is added to a solution of the 1,3-diol (II) in 3-methylpyridine and in step (ii) the water is added to the reaction mixture obtained in step (i); and wherein the addition of water is started before the addition of thiophosphoryl chloride is completed.