[cyanide]

i want to recrystallize my macrocyclic diamide product contaminated with triphenylphosphine oxide...the problem is i dont have the right solvent for the recrystallization...can you suggest guyz....thank you and more power to this forum

[Mitch]

Can't you use a column to separate out the TPO from the diamide first?

[kiwi]

a good way to get most of the TPPO out is to dissolve the crude in a minimum of dichloromethane, then add that dripwise to stirred hexane, the TPPO crashes out, filter, vac down. Repeat if you want, or throw it on a column to polish the last away. But obviously if your compound is too polar, this workup can be bad.

[Mitch]

TPPO is one of the hardest suckers to remove in general. Plus, it sticks to gc columns, so you can't trust their results with respect to that compound. Often, if it doesn't interfere with the next step I just go ahead and leave it in as an impurity.

[cyanide]

hi mitch...so you mean no other means of removing completely the TPO as a contaminant?....how about recrystallization?can this be helpful in removing TPO from my procudct?...is TPO soluble in ether?..i was thinking of dissolving my sample in ether, but im not sure if TPO is soluble in it, co'z Macrocyclic diamdie i think is not soluble in it?am i correct? thanx

[mikkoel]

From memory TPPO is insoluble in ether and hexane. What is usually done is what kiwi described or trituration with ether or hexane. TPPO should crash out and you can filter it off.

[CEDLIN]

You could try the reaction again with solid supported triphenyl phosphine.  In my experience this works well and all you have to do is filter off the solid supported TPPO.