[Guitarmaniac86]

Hi all,

I want to take adenine and 6-chloro-2-aminopurine and benzoylate them with benzoyl chloride in THF. I have been doing literature searches for this specific reaction to no avail. All I seem to find is protection of these bases with BzCl AFTER incorporation onto a ribose sugar, or there is something at N-7 before benzoylation... I want N-7 as NH only.

I have a prep for add ditBoc to my adenine and it works a charm and mono-tBoc onto my 6-chloro-2-aminopurine, but I am having issues with stability of my Boc groups: They fall off in the reaction mixture. So I am wondering if anyone has a general prep for BzCl.

My temptation is to do it as follows: Add purine to THF, add 0.01 equiv DMAP, add 4 equiv BzCl react for a few hours, then vac off THF, add methanol and sat bicarb, heat to 50 degrees C then partition with chloroform and use the purine crude.

I would rather have a lit prep for this though so I can see if I am barking up the wrong tree or not. Any help would be greatly appreciated.

[TheUnassuming]

Do you mean N9 is protected in the papers you see?

I believe N9 is more active/nucleophilic than the C6 amino group on adenine, which is why people usually block the site before they try to do chemistry at that position.   I'd imagine the same is true for the guanine derivatives as well.

[Guitarmaniac86]

Do you mean N9 is protected in the papers you see?

I believe N9 is more active/nucleophilic than the C6 amino group on adenine, which is why people usually block the site before they try to do chemistry at that position.   I'd imagine the same is true for the guanine derivatives as well.

Apologies, yes I did mean N9, I numbered the ring the wrong way. I did not think about the reactivities so I will follow a lit prep and see how I go.

[TheUnassuming]

Apologies, yes I did mean N9, I numbered the ring the wrong way. I did not think about the reactivities so I will follow a lit prep and see how I go.

No worries, I think the ring numbering system in nucleosides is ridiculous.

Unless you really have your heart set on developing new chemistry, going with the literature is a good idea in this area.  Its fairly well developed/matured, so if you don't see something there is probably a good reason for it.  Note that doesn't mean you shouldn't try things, because you never know! Just don't waste too much time trying to reinvent the wheel as my PI would say.