Patent ID: 7294736

Claim:
A process for the preparation of a water-soluble derivative of probucol having the following formula where R 1 and R 2 are the same or different and are —C 1 -C 6 alkyl, —C 3 -C 6 alkenyl or aryl, R 3 , R 4 , R 5 and R 6 are the same or different and are C 1 -C 6 alkyl and Z and Z′ are the same or different and are hydrogen or the group —C(O)—C 1 to C 6 alkyl-C(O)OH where Z and Z′ can not both be hydrogen by (1) the reaction of a probucol compound of the formula where R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are as previously defined with a compound selected from the group consisting of alkali metal hydroxide, alkali metal alkoxide, alkyl ammonium alkoxide, alkyl ammonium hydroxide and mixtures thereof thereby forming an ammonium or alkali metal salt of said probucol compound (2) reacting said salt with a carboxylic acid anhydride to form a reaction mixture and (3) separating said water soluble probucol derivative from said reaction mixture the improvement comprising using as a solvent for reaction step 1 a compound having the formula R—C(O)—R′, where R and R′ are the same or different and are C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 6 -C 12 aryl, C 6 -C 12 aryl substituted with at least one C 1 -C 6 alkyl, C 5 -C 12 heteroaryl or C 5 -C 12 heteroaryl substituted with at least one C 1 -C 6 alky wherein the ratio of said solvent to the probucol derivative by weight is from about 2:1 to about 1:5, wherein the reaction temperature of step 1 is from about 15° to 75° C.