I just want to add some points regarding Phthalimeide deprotection.
hi,
I have a compound, which is has three ethylphthalimide attached to each N atoms on TACN(1,4,7-triazacyclononane) respectively. I have been trying to deprotect the pthalimide groups to form primary amines. I tried with hydrazine monohydrate in ethanol and refluxed for 3 nights. However, i could not get the complete deprotected compound. I am not sure what goes wrong. Probably the work up part. Any suggestion?
I found a thesis which showed 1,2-diaminoethane could deprotect pthalimide as well,however I do not have it in my lab,do you think that 1,2-diaminopropane can work the same way?
Have you tried any time with other organic bases like methylamine(40% in water or 25% in methanol)?
The following are the some of the commonly used organic bases.
1.Ethanolamine
2.Methylamine
The advantage of these bases are relatively milder condition when compare to Inorganic bases.
Tetrahedron Lett., 1984, 25, 2093-2096
Transformation: Pthalimide to hydroxy-amide:
NaBH4, 5 eq. i-PrOH:H20 6:1, RT 24 hrs
Transformation: hydroxy-amide to free amine
AcOH, 18 eq. 80 deg Celsius, 2 hours or so.
This is a very elegant method for the phthalimide deprotection.thanks "MissPhosgene" for your timely given literature.
Although the above method requires milder condition reaction rate will be slower when compare to usage or organic bases.
The advantages of this method are as follows:-
1.Relatively milder reaction condition with wide variety of functional group tolerablility
2.As a by product we will be getting phthalide which is having same commercial value.
What ever reagent you use it is better to understand what exactly going in your reaction.
Try to define your reaction under any one of the following cases:-
(i)Reaction is proceeding not going for completion
(ii)Reaction is completing only isolation of product is problem
(i)Reaction is not proceeding due to
(a)Reactant/compound degradation
(b)Side reaction of Reactant/compound
Best of luck!!!