Description
Bispyrithione is a pyrithione derivate used as bactericide and fungicide. The drug was marketed under the name Crimanex in the form of shampoo for the treatment of dandruff, however it is no longer available on the manufacturer website (Drossa Pharm . It is currently used as a pesticide.
Application
Bispyrithione is a new antidandruff agent behind zinc pyrithione. It has similar chemical structure to zinc pyrithione, thus performs the same bactericidal property, with unique bactericidal actions, especially to mycetes, mild fungus and microzymes. It also can effectively disinfect oval bacil, candia albicans and other mycetes, while normal antimicrobials can't. It is not sensitive to metal ion and dissolves in water more easily than zinc pyrithione, which improves the compatibility and leads to best bactericidal effect. In 2-in-1 shampoo, it doesn't affect the pearly effect but enhance color stability.
Synthesis
1, drop into successively the 600g2-chloropyridine in the 5000ml four-hole boiling flask, 100g maleic and acid anhydrides, 600g hydrogen peroxide (35%) are opened to stir and are warmed up to 60 ℃ of successive reactions 12 hours, make 2-chloropyridine-N-oxide water solution.
2, the 2-chloropyridine that uses the 4000g2-methyl chloride to divide four extractions to make-N-oxide water solution merges extraction phase, and condensing crystal makes sterling 2-chloropyridine-N-oxide compound.
3, the 2-chloropyridine that purification is obtained-N-oxide compound, 430g sodium sulphite, the 2000g high purity water, drop into successively in the 5000ml four-hole boiling flask, open and stir, be warming up to 70 ℃, along with the carrying out of reaction added a part of yellow soda ash in good time, the PH of adjustment system is stabilized in 9～10, and reaction finishes 70 ℃ of insulations 2 hours, and insulation finishes to cool.Make the pyrithione sodium water solution.
4, use an amount of dilute sulphuric acid to adjust the PH to 2 of pyrithione sodium water solution system, separate out a large amount of white crystals.Filtrated stock cleans solid, namely gets pyrithione.
5, the pyrithione that the reaction of upper step is obtained, the 1000g ultrapure water drops in the plastic cup, the unlatching dispersed with stirring is even, then slowly splash into 220g hydrogen peroxide (35%), reaction is 1 hour about 50 ℃, make finished product Bispyrithione 497g (99.72%, five step of content overall yield of reaction: 74.6%).
