methods of breaking disulphide bonds

[Deitiker, Philip R]

Disulfide bonds form as a result of oxidation. If oxygen is present in your solution during the reaction disulfides will slowly form. Oxygen, particularly in the presence of other factors forms hydroxide radicals, or ozone can form radicals that react with disulfides more rapidly. 

To prevent sulfhydryl groups from dimerizing try evacuating solutions that have been heated up to remove oxygen, or displace the oxygen by bubbling nitrogen, and evacuating, bubbling more nitrogen gas, and evacuating, several times. This will remove oxygen from the reaction.  All solutions should be
oxygen free. This will Reduce ("pun intended") the oxidation of sulfides. 

You might also want to look up to see what common biproducts of the reaction are on pubmed or the internet. There may be specific sulfides that are oxygen scavengers that are less reactive with thiols. 

Good luck. 

 

-----Original Message-----
From: methods-bounces from oat.bio.indiana.edu [mailto:methods-bounces from oat.bio.indiana.edu] On Behalf Of Mrinal Singha
Sent: Wednesday, April 23, 2008 2:38 AM
To: methods from magpie.bio.indiana.edu
Subject: methods of breaking disulphide bonds

Respected Sir/Madam

     I am trying to form methyl ester of 4-Mercapto benzoic acid by using thionyl chloride and then adding methanol at room temparature. Although ester is formed but it is also forming disulfide. I want to cleave disulfide bond without cleavage of ester. Please tell me some suitable methods for
this.


       Thank You
   Mrinal singha
   Student of Master of Science( Medicinal Chemistry)
   National Institute of Pharmaceutical Education and Research(NIPER)
   Punjab,India
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