D 1335 (OTTO) Diacetyl, 98% Cas 431-03-8 - used to form triazine and pteridine ring systems. D 1335 (OTTO) Diacetyl, 98% Cas 431-03-8 - used as a precursor to α-diones. 1-Hexanol and diacetyl are strong inhibitors of the CO2-sensitive neurons in the Drosophila melanogaster fruit fly and the Culex mosquito, a vector of several deadly diseases.