[Polly Murs]

hi,

so the pg I'm using is TIPDS (1,1,3,3-Tetraisopropyldisiloxane-1,3-diyl-)

will these be stable to
i) 10% citric acid (used in work-up)
ii) 0.1% formic acid (hplc buffer)
iii) 0.1% tfa (hplc buffer) ??

while I'm here... the compound is a thymidine analogue, both nitrogens as tertiary amines

I'm new to organic chem, so look forward to your replies

[Polly Murs]

please someone have a crack at this.

first of all I think I made a mistake with the citric acid, as I guess it might have protonated the amines and made my product water-soluble.

so I then added NaHCO3 to raise the pH and got everything back into DCM, dry, filter etc

wanting to purify my compounds now:
- water/acetonitrile gradient run, 95/5 to 5/95 over 30 mins. peaks look alright
- decide to try 0.1% formic acid.... split peaks (is this partial protonation?)
- I then try 1% triethylamine (pH ... peaks split even more, almost like two molecules co-eluting

should I just go back to water?

edit: and of course, the TIPDS issue!

[Polly Murs]

pH of methanolic HCl compared with ammonium formate?