Four diastereomeric diols formed from the oxidation of cis- and trans-cinnamoylcocaine were characterized by nuclear magnetic resonance spectrometry, mass spectrometry, and synthesis. Oxidation of cis-cinnammethyl ester, and trans-cinnamoylcocaine produced (2R,3S)-dihydroxy-3-phenylpropionylecgonine methyl ester and (2S,3R)-dihydroxy-3-phenylpropionylecgonine methyl ester. The recent appearance of these new impurities suggests that some illicit cocaine processors have modified their oxidation procedures of crude cocaine base for transformation into illicit refined cocaine hydrochloride. Cocaine exhibits that contain these compounds produce unique analytical signature profiles with reduced levels of cinnamoylcocaine as well as increased levels of norcocaine. It is unlikely that illicit processors are using mild oxidizers such as osmium due to its extreme toxicity, high cost, slow reaction rates, and the higher expected levels of the diols than are currently seen in illicit samples. It is clear from the signature profiles obtained to date that the majority of the cinnamoylcocaines are being oxidized to water soluble products that do not appear in the refined cocaine hydrochloride. The most likely types of reaction conditions are the adding of aqueous potassium permanganate to cocaine base dissolved in a water miscible solvent such as an alcohol, acetone, or methyl ethyl ketone; or the performance of the oxidation as a bi-phase mixture of a water immiscible organic solvent that contains cocaine base and aqueous potassium permanganate. 2 tables, 4 figures, and 13 references