[Jaume Garcia]

Hi
I am looking for some help about protection of pyridine systems. I have seen that a good idea can be first to methylate the ring and second deprotect with triphenylphosphine. Has anyone some methodology for making this cleavage reaction in the lab? or it is just so easy as puting the methylated pyridine and PPh3 in a flask with solvent and stir?
Thanks for your help in advance.

[orgopete]

It's not clear what you wish to do. A pyridine ring is more inert than the protected forms, so to protect it from further reaction, do nothing. If what you are trying to do is protect the nitrogen from causing further reaction, then alkylation would work. I think it may be easier to make an N-oxide and reduce it off, but the N-oxide will have a greater reactivity than a pyridinium salt. Probably the easiest protection of the nitrogen is with a proton, lower the pH.

[Jaume Garcia]

Thanks for your help
What we need exactly to do is from an amino pyridine protect the pyridine and make it react with a metal and later deprotect it for a further synthetic step. Perhaps the best thing is to alkylate it but then, which methodology can be good for the deprotection?

[orgopete]

If you want to put a carbon on, then I'd pick something with an additional function group that would make removing it easier. Allyl might be good as it can be rearranged (with Pd) to make hydrolysis easy. I suspect compatibility with your other functionality and reactions should dictate what you can use.