Extract with ether in a separatory funnel and neutralise the lower layer with 0.1 N NaOh, extracting this solution in turn with chloroform. The chloroform layer is dried over anhydrous Na2SO4, concentrated, and from it DMT crystallises on addition of petroleum ether. The mother liquor can be chromatographed on an alumina column using benzene-methanol in a 99.8 to 0.2 ratio. Diethylamine is less volatile and poisonous than dimethylamine, so cooling is not necessary, but the fumes are poisonous. Use the same procedure otherwise.
Diethyl derivative is easier to work with.
STEP III Use same procedure and equipment. Use 22g indoleglycoxal diethylamide. The final product is also easier to purify. Absolutely anhydrous ether is essential. A container that has been opened previously is no longer anhydrous.