[Bertrand]

Hello everyone !!!
Please, I would like to know how to remove the N-Boc and the Strt group to NH2 and SH respectively in a non-acidic condition.
My compound is very acid sensitive.
Thanks in advance for your suggestion

[wildfyr]

What have you tried so far?

[Bertrand]

for a 100 mg scale, I've tried 5mL of CH2Cl2/CF3COOH/ET3SiH in the ratio 7/2/1, but my compound has decomposed.

[rolnor]

Can you post the structure?

[clarkstill]

Odd to use Boc and Trt in an acid-sensitive molecule...

[Bertrand]

Here is the structure



(mod edit, add as SMILES)

[rolnor]

Here is the structure



(mod edit, add as SMILES)

Is there any special reason you use these acid-sensitive protecting groups? The molecule does not look sensitive to base. Also
I think you could use PG that us removed by fluoride instead?

[Bertrand]

Thanks! I'll try it

[rolnor]

I think of a SEM-group for the thiol(is the deprotected thiol stable? It looks lika a hemi-thio acetal?) for the amine I think of a trimethylsilyelthyloxycarbonyl.
I looked in Aldrich, they don have 2-(trimethylsilyl) ethoxycarbonyl chloride, you can look in Greens book of protection groups, I think its a usefull way to go.

[rolnor]

The 2-(trimethylsilyl)ethoxycarbonyl group is described in Greens book on protecting groups, here is a reference;

L. A. Carpino,
J.-H. Tsao,
H. Ringsdorf,
E. Fell, and
G. Hettrich,
J. Chem. Soc., Chem. Commun., 358 (1978).

The chloride must be freshly prepared, not stable long period.
There is other variants like the succinimidoyl reagent wich is stable, maybe you can buy this.
Its deprotected with CsF/TBAF

[Bertrand]

Hello! Thank you so much... I have the GREENE’S PROTECTIVE GROUPS book of PETER G. M. WUT. I will have a look again on how to use the 2-(trimethylsilyl)ethoxycarbonyl.

[rolnor]

Is the thiol correctly drawn, it looks as if you get a hemi-thioacetal if you remove the trityl?

[Bertrand]

 when I tried the CH2Cl2 / CF3COOH / ET3SiH mixture for the first time, the Boc group disappeared however, the NMR analysis revealed the presence of the trityl. I think the main issue will be getting rid of the trityl group

[rolnor]

when I tried the CH2Cl2 / CF3COOH / ET3SiH mixture for the first time, the Boc group disappeared however, the NMR analysis revealed the presence of the trityl. I think the main issue will be getting rid of the trityl group

I suppose the thio-trityl ether is more difficult to hydrolyze then a regular trityl-ether. How stable is the thio-hemiacetal in the final product? It looks very acid-labile.

[Bertrand]

The thio-hemiacetal is quite stable however I had to work only with dry solvents since the compound has been also shown to be unstable when exposed to prolonged contact with water.