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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: orthoformate on September 23, 2016, 02:03:31 AM

Title: Salicylate methyl ester methylation
Post by: orthoformate on September 23, 2016, 02:03:31 AM

Hello all,

I have the methyl ester derivative of salicylic acid, and I am trying to methylate the para position phenol with dimethyl sulfate in kcarb/acetone.

I get about half way through the reaction (monitored by TLC, and LC/MS) and a heavy slurry forms and conversion halts. I am thinking I am producing K⁺sulfate and that is saturating the solution, which prevents kcarb from dissolving in the acetone.

I am considering switching to TMS-diazomethane, but I'm hesitant. This methyl sulfate reaction is working well except for the stalling.

All solvents and reagents are prepared fresh prior to use.

Any suggestions?

Title: Re: Salicylate methyl ester methylation
Post by: rolnor on September 23, 2016, 07:16:19 AM

Use phase-transfer conditions, only catalytic amount Q-salt is needed when using dimethylsulphate.

Title: Re: Salicylate methyl ester methylation
Post by: Dan on September 23, 2016, 08:35:15 AM

You could switch solvent to DMF.