Chemistry of gossypol

Summary

The methods adopted by Adamset al. for the methylation of gossypol do not seem to produce a uniform product of the hexamethyl ether having constant properties. The following methods have now been employed: (1) methylation of hexaacetate using dimethyl sulphate and alkali in acetone medium, (2) methylation of gossypol with diazomethane in methyl alcoholic solution, (3) with methyl iodide and potassium carbonate in acetone solution and (4) with dimethyl sulphate and alkali. All the products had the same melting point, 130°, and gave analytical results corresponding to the hexamethyl ether. The methods which do not employ caustic alkali give samples which are less coloured. The methyl ether is unaffected by treatment with hot dilute sulphuric acid and hence does not seem to have the formula corresponding to the structure of glycosides.