[steve1729]

I've got a problem...I know not-much about sulfur-chemistry, and I have a raw material that has a couple of methylthio groups on the ring.  I want to replace them with tert-amyl thio groups.  Is there some easy way to replace the methyl- with a tert-amyl- or is this going to be messy?
 

[StarvinMarvin]

I believe you can treat it as if it was a regular methoxy group. First deprotect it (BBr3 in CH2Cl2 or HBr in glacial AcOH) and then treat it with amyl chloride or bromide. I think it should work.

[steve1729]

Thank you.  I now know a little more about sulfur-chemistry, and some of the options.

That kind of process will likely work in a lab environment, but be relatively messy in a manufacturing environment, dealing as it does with very reactive materials and having waste-disposal issues.

Since methanol is much more volatile than tert-amyl alcohol, and the methyl-sulfur bond is weaker than the oxygen-sulfur bond, I contemplate boiling with an excess of tert-amyl alcohol and distilling off the methyl alcohol.  I am under the impression that an acid catalyst would be needed, perhaps an acidic ion-exchange resin so it could be easily separated from the product afterwards, and the excess remaining tert-amyl alcohol removed from the much less volatile product by distillation.  Does that sound like it would work?

[StarvinMarvin]

Acid catalyst is needed for the ether to be broken. Probably ion-exchange resin would be enough to do the trick. But to be honest I never thought about those reactions in technical scale.