Is your diamine liquid ? I would suggest to avoid any solvents. First try the diamine and Ts-PEG without additional base, and higher temperatures. If you can, use excess of diamine and portionwise addition of Ts-PEG - and ultrasonic bath if your TS-PEG is solid; longer US warms the reaction mixture what is not a problem. If this does not work, perhaps DBU is better than DMAP as base. If none of these helps then try to use trifluoromethanesulfonyl-PEG, Tf is even better leaving group.

no my diamine is solid and Ts-PEG is liquid. Is it possible without using solvent.

OK, put the two reagents together, close tightly the vial/flask, ans sonicate until you get a homogeneous solution. If no reaction or too  much dipegylated diamne is obtained, add base, perhaps try dissolve the diamine in the base, then add the Ts-PEG. As I wrote you before, DBU seems to to be better than DMAP.

Thanks Laszlo

Lszlo. how much time and US frequency should be used.?

Hi Irrum,

Sorry, I do not know the frequency. I used a US cleaner (with timer). I assume that all uses the same frequency. I used it to accelerate the dissolution, because my compounds were soluble practically only in DMF and HNMe2 (the decomposition product of DMF) had been very disturbing. So I left away the DMF and I put together the two components and sonicated until I got homogeneous solutions (either up to 12 hrs or more). If I saw starting materials on TLC I heated the homogeneous reaction mixture for a couple of hrs.

I used as much as possible concentrated solutions (usually ~ 30 % for the insoluble). In my cases it meant approx. 3-4x molar excess of the amine/halogen or the reverse.

THANKS