E 1595 (OTTO) Ethyl iodide, 99% Cas no 75-03-6 - used as the hydrogen radical promoter. E 1595 (OTTO) Ethyl iodide, 99% Cas no 75-03-6 -used in organic synthesis to introduce an ethyl group into a compound. It reacts with magnesium to form the Grignard reagent, ethylmagnesium iodide which is used in organic synthesis. It is involved in the preparation of 1-ethyl-3-nitro-2-phenyl-indole and also serves as hydrogen radical promoter.