# what is mechanism for reaction phenol + dimethylsulphate -> anisole

Dimethyl sulphate breaks the oh bond and forms anisole. How does the reaction proceed?? is it oxygen lone pair attacks on sulphur which has partial positive charge?? the reaction takes place in presence of naoh

• Before we can answer your question or provide assistance, the expectation is that you make an effort to solve the problem. And no, dimethyl sulfate does not break the OH bond! – user55119 Jun 14 '19 at 18:31
• oh- ion from naoh takes away acidic hydrogen from phenol and forms phenoxide ion but in the next step will it attack the electrophilic sulphur atom ?? – raj pattnaik Jun 14 '19 at 18:51
• No, it attacks the carbon of one of the methyl groups – Waylander Jun 14 '19 at 19:37
• Treat dimethylsulfate as analogous to methyl iodide. – Zhe Jun 14 '19 at 22:01

The methylation of Phenol using Dimethyl Sulfate is an Electrophilic Methylation and happens through a SN2 nucleophilic attack. Phenol is first deprotonated by the sodium hydroxide as you already thought. The deprotonation of Phenol is favored because the pKa of Phenol is lower than the pKa of water meaning $$\ce{OH-}$$ is a stronger conjugated base than $$\ce{PhO-}$$:
• I found that article, is that the one you mentioned? You're right, the procedure describes 0.344mol of Orcinol reacting with 0.750mol of Dimethyl Sulfate, close to 1:1 ratio for each hydroxyl group. So we would have $\ce{NaSO4CH3}$ amongst the products? I'll edit the mechanism image to account for that. – IanC Jun 14 '19 at 21:25