I am using cystamine (free based) to conjugate to a phosphate group on an oligonucleotide. I tried several keyword searches on Google for neutralizing the dihydrochloride at the ends of the cystamine. But, I am unable to find a protocol. I had once found a procedure for the process, but I did not reference it and hence I am unable to find it again.
The procedure I followed was:
Dissolve the cystamine.2HCl in water.
Transfer to a separation funnel and add chloroform.
To this add 1N NaOH.
After shaking vigorously collect the chloroform layer which contains the cystamine.
Repeat extraction couple of times using more chloroform.
Pool fractions - dry with anhyd. MgSO4 - transfer to an RBF.
Evaporate on a RotaVap
Dry on schlenk line and store in an inert environment at 4 deg. C.
However, the extraction was not very efficient. Can anyone refer a protocol for the same?
Thanks a lot for your help!!!!