Abstract: Nowadays the chromogenic substrates are very used for the quality control of different products such as water and food among others. These type of compounds are present as a component of some diagnostic media and allow to carry out the identification of different harmful bacteria. The enzimes excreted by the bacteries produce the lisis of the glycosidic linkage of the substrate showing a blue or magenta coloration [1]. One of these bacteria is the E. Coli that is identified by the 6-chloro-3-indolyl-b-D-glucuronide cyclohexylamine salt (Fig.1), among others[2,3], which present an indolic moiety as the aglycon part.