Hello everyone, recently I am trying to synthesize a dipeptide with a Coumarin derivative of Tryptophan, and the problem is it doesn't contribute in reaction at all.
Tryptophan itself in the same condition participated in reaction but the coumarin derivative does not contribute.
I have tried different agents such as TBTU and DIC/HOBt with PH=8
I tried activating the acid with N-hydroxysuccinimide but it didn't help.
What other parameters I can try or change?
Try to change the pH to 7 or better to 6. Coumarin is not stable under alkaline pH its lactone is structrure is hydrolyzed.
1) Check if you are using necessary protecting steps. When you say that trp "under the same conditions" gives a precipitate, be aware that any a-amino acid will give a diketopiperazine:
{2 RCH(NH2)CO2H -> R2C4H4N2O2
This would be expected to give a ppt with most amino acids trp so the result with trp by itself tells you nothing about the other reaction partners.
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2) There are many coumarin derivatives. Please specify how the coumarin is linked to trp: for example it can be an ester with a coumarin [3-, 4-,5-,6-,7-, or 8-] hydroxy derivative, or else an N-linked carboxy derivative of caboxy-substitued can link to the amino group through an amide link.
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1 Recommendation
Elham Hamidian
Tehran University of Medical Sciences
Philippe Roger Bovy
the structure is described as below
2-acetamido-3-(1-((7-methoxy-2-oxo-2H-chromen-4-yl)methyl)-1H-indol-3-yl)propanoic acid
if you enter this structure in Chemdraw the structure will be illustrated.
Thank you in advance
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Elham Hamidian
Tehran University of Medical Sciences
James Kilgore
The structure is described below
2-acetamido-3-(1-((7-methoxy-2-oxo-2H-chromen-4-yl)methyl)-1H-indol-3-yl)propanoic acid
if you enter this structure in Chemdraw the structure will be illustrated.
I have protected the a-amine group of tryptophan via acetylation
the other amine in indole moiety is protected by the coumarin derivative
the structure of the other derivative that is mentioned above which was synthesized is described below
methyl 2-(2-acetamido-3-(1-benzyl-1H-indol-3-yl)propanamido)propanoate
thank you in advance
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Elham Hamidian
Tehran University of Medical Sciences
Vassilis J. Demopoulos
As far as I'm aware, amidation reaction is conducted in basic PH, so I'm afraid in neutral or acidic PH it won't proceed
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