Reaction LXXIX.—Action of Dimethyl Sulphate on Hydroxy Compounds

Reaction LXXIX. Action of Dimethyl Sulphate on Hydroxy Compounds. 

This reagent has proved especially important in the study of the constitution of the sugars, and of cellulose. A series of methyl-celluloses has been obtained, and by the study of their hydrolysis, or decomposition in a vacuum, some light has been thrown on the structure of the cellulose molecule. (J. S. C. I., 41, 362 R.) In the laboratory dimethyl sulphate is much employed in the methylation of phenols and naphthols. Diethyl sulphate is not so suitable for such alkylations as its lower homo-logue. 

Caution —Dimethyl sulphate is very poisonous and this preparation must be carried out in a good fume cupboard. (See p. 261.) 

Other methyl ethers may be prepared in a similar manner e.g., f-naphthyl methyl ether (M.P. 71°) is formed in good yield from /3-naphthol. 

The next preparation illustrates the preparation of the ethers of the polyhydric phenols. 

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