Pyridine chlorochromate, molecular formula C5H4N· HCrO3Cl, abbreviated PCC, is the abbreviation of Pyridinium chlorochromate, Chinese alias Sarrett reagent. PCC was first a new selective oxidizer discovered by E.J. Corey after conducting developmental studies of Chemicalbook in 1975. It is mainly used for oxidation of alcohols to aldehydes / ketones, local selective oxidation of groups in carbohydrates, oxidation of borane and oxime (oxime removal reaction) to carboxyl compounds, and direct oxidation of aldehydes by alkenyl tertiary alcohols; It can also make the enol directly oxidized into esters or lactones, etc.