[Polly Murs]

also, when I ran the rxn in DCM/TEA, I noticed there were some incredibly polar compounds sticking to the baseline... when I thought I had my target compound collected with EtOAc/PE solvent system, I ran 9% MeOH/DCM to elute this other stuff. the unreacted dansyl hydrazine cam e off first (bright yeloow fluorescence), then this other stuff (more of an orange colour). other stuff came off which was more green/blueish colour. I didn't run these on NMR or anything, as I was so sure my compound couldn't be that polar

however, I'll collect everything this time

I read NH4/MeOH/DCM is good for eluting extremely polar compounds...
what % NH4/MeOH should I run?

[Polly Murs]

interesting.
I added some NaI and whacked rxn up to 90C
as it approached 90C the colour went from bright yellow to orange
did some TLCs at various timepoints and looked like product forming

left it overnight, just checked it and it's now a blood red!
the colour changes are probably thermal quenching but just did TLC and see nice fluorescent spot, so looks like it worked (prays)

literature search says rxn temp doesn't need to be so high... 60C should do

[opsomath]

Yeah that is a big jump in temperature, hope your molecule can handle it!
Glad to hear it's working. Why NaI rather than KI...just what you had around?

As long as you're using enough EtOAc in your system that you can really distinguish your product and reactant (ie they're not just sticking to baseline) you should be fine. I just didn't want you to have a false negative based on a bad TLC system.

[Polly Murs]

hi,

I think I've managed to optimise the conditions

NaI is all I could find in the lab, but this and reflux @ 60C looks to have done the trick. my longest chain compound (12 methylene units) is the first one I tried with these conditions, whereas when I did this rxn the first time, there was virtually no product. at 20% EtOAc/pe I'm seeing two quite intense fluorescent spots at Rf around 0.5 or so... I spotted dansly hydrazine aswell and it hardly leaves the baseline. so the work-up gets rid of all the polar crap I was getting last time, but the EtOAc keeps the labelled stuff 

still have to do NMR/MS... so determined to make these reactions work as it's for my MSc project and the compounds are to be tested on cancer cells

thanks opsomath and everyone for suggestions... been a great help

[Polly Murs]

guys,

I'm having trouble naming the final products
have tried various approaches and punched them into chembio, but no luck

here is the structure with the ethyl spacer


thanks

edit: got it!
my baby's name is 3-(-2-(5-dimethylamino-1-naphthylsulfonyl)hydrazino)ethylthymidine 

[Polly Murs]

that approach didn't really work very well. so I need to look at an alternative. the dansyl hydrazine will react well with ketone so idea is to have protected ketone at one end, with bromine at the other end for alkylation of thymidine.

plausible?