Method for the preparation of sulfinpyrazone
The present disclosure discloses a method for the preparation of sulfinpyrazone, which is produced in two steps with a total yield of 48%, wherein thiophenol as the starting material is electrocatalytically coupled with dichloroethane to obtain 2-chloroethyl phenyl sulfoxide, which then undergoes a substitution reaction with 1,2-diphenyl-3,5-pyrazolidinedione to produce sulfinpyrazone. Compared with the prior art, the present method is characterized by high yield, short steps, less three wastes, good chemical selectivity, no need to use strong bases and oxidants, safe and simple operation, and easy to realize industrial production.
1 . A method for a preparation of sulfinpyrazone, wherein comprising following synthetic routes:
wherein electrolyte represents an electrolyte, current represents a current, temperature represents a temperature, salt represents a salt, base represents a base, additive represents an additive, and solvent represents a solvent.
2 . The method according to claim 1 , wherein the method comprises following steps:
(1) dissolving thiophenol shown in formula 3 and electrolyte in a mixed solution of 1,2-dichloroethane and water and reacting by passing the current for 1 to 48 hours to obtain 2-chloroethyl phenyl sulfoxide shown in formula 2; and
(2) mixing and dissolving 2-chloroethyl phenyl sulfoxide shown in formula 2, 1,2-diphenyl-3,5-pyrazolidinedione shown in formula 4, the base and the additive in the solvent, and reacting by heating under a nitrogen atmosphere for 1 to 48 hours, and after a reaction is completed, subjecting A reaction mixture to column chromatography to obtain sulfinpyrazone shown in formula 1.
3 . The method according to claim 1 , wherein an anode used in step (1) is selected from one of a group consisting of graphite felt, platinum, and nickel electrodes, and a cathode used in step (1) is selected from a group consisting of graphite felt, platinum, nickel, and a specification of each of the anode and the cathode is 1 cm*1 cm.
4 . The method according to claim 1 , wherein an anode used in step (1) is selected from one of a group consisting of graphite felt, platinum, and nickel electrodes, and a cathode used in step (1) is selected from a group consisting of graphite felt, platinum, nickel, and a specification of each of the anode and the cathode is 1 cm*1 cm.
5 . The method according to claim 2 , wherein the electrolyte in step (1) is any one of tetrabutylammonium bromide, tetrabutylammonium tetrafluoroborate, tetra-n-octylammonium bromide, tetrabutylammonium hexafluorophosphate, lithium perchlorate, ammonium perchlorate, and tetrabutylammonium iodide, and an amount of electrolyte is 0.5-2 times that of thiophenol.
6 . The method according to claim 2 , wherein the water in step (1) is any one of distilled water and deionized water, and an amount thereof is 0.5-10 times that of thiophenol.
7 . The method according to claim 2 , wherein the current in step (1) is 4-30 mA.
8 . The method according to claim 2 , wherein the temperature in step (1) is 30-70° C.; and a volume of 1,2-dichloroethane in step (1) is 5-30 times that of compound 3.
9 . The method according to claim 1 , wherein the solvent in step (2) is selected from one or more of acetone, acetonitrile, and n-hexane.
10 . The method according to claim 2 , wherein the solvent in step (2) is selected from one or more of acetone, acetonitrile, and n-hexane.
11 . The method according to claim 2 , wherein the base in step (2) is selected from any one of cesium carbonate, sodium hydroxide, potassium hydroxide, sodium ethoxide, potassium ethoxide, triethylamine, and diisopropylethylamine; the additive is selected from any one of sodium iodide, potassium iodide, lithium iodide, and ammonium iodide; and a reaction temperature in step (2) is 50-70° C.
12 . The method according to claim 2 , wherein an amount of 1,2-diphenyl-3,5-pyrazolidinedione in step (2) is 1.0-4.0 times that of 2-chloroethyl phenyl sulfoxide; an amount of base is 1.0-4.0 times that of 2-chloroethyl phenyl sulfoxide; an amount of additive is 1-5 times that of 2-chloroethyl phenyl sulfoxide; and an amount of the solvent is 5-10 times that of 2-chloroethyl phenyl sulfoxide.