Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: rekhasharma on April 14, 2010, 11:22:36 AM
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I want to convert 2,5-Bis-triphenylvinyl-benzene-1,4-diol into rifluoro-methanesulfonic acid 4-trifluoromethanesulfonyloxy-2,5-bis-triphenylvinyl-phenyl ester. I am doing this reaction in Pyridine and solvent DCM at zero degree celcius, but I am not getting this product,
I am getting something else, can somebody tell me what are the possibility of product inthis reaction?
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The diol into the bis ester?
How many equivalents of acid are you using? Have you tried different solvents, temperatures etc?
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Since things can go wrong, can you verify your reagents are okay by preparing a simple derivative such as a simple phenol?
I would not have expected the solvent to be a problem except if the solvent contained enough water to react preferentially, especially if your phenol reacted slowly. If you are using a boatload of solvent for a drop of compound, this would be more likely to be the case, but no actual conditions were given.
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Can you please clarify the followings to understand the problem in better way:
1.Your targeted product name is the following "rifluoro-methanesulfonic acid 4-trifluoromethanesulfonyloxy-2,5-bis-triphenylvinyl-phenyl ester"
or only "4-trifluoromethanesulfonyloxy-2,5-bis-triphenylvinyl-phenyl ester"
2. the product name is second("4-trifluoromethanesulfonyloxy-2,5-bis-triphenylvinyl-phenyl ester"),mono ester or diester?(as the starting material having diol)
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This is the product name Trifluoro-methanesulfonic acid 4-trifluoromethanesulfonyloxy-2,5-bis-triphenylvinyl-phenyl ester(di ester)
I am using triflic anhydride 3 equvivalent and pyridine also 3 equivalent. but I am not getting this product.
I want to past the structure for more clearity, so please let me know how I can do that? I drew structures in Chem draw but It doesnt allow to paste it here , so how I can paste the thr proper reaction scheme.
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Thank u for u r reply!This has given a clear idea about your reaction.
You can try with triflic acid chloride with the combination of any base like TEA,DIPEA in an inert solvent like toluene,THF.
The below condition may be helpful to u.
1.Taken alcohol in toluene with 4.0eq. of TEA.
2.At 0°C acid was dissolved and added slowly.
3.NMP was used as co solvent to make the soln. homogeneous.
The rate of the reaction was very fast.
This condition i have used to convert primary alcohol to respective trichloro sulfonate ester
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so far what is you have got, one substituted product? if so , you could seperated the reation for two steps.
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Use a stronger base I'd say.
You're using pyridine to act as a nucleophilic catalyst here? No need for that. Why not use sodium hydride to quantitatively deprotonate the phenolic protons. Then bang in the mesylchloride. That should be nice and clean. If you get your solvent dry enough you can use just 2 eqs of the mesylchloride. No purification required!