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The Development of PCC

Pyridinium chlorochromate was first described by Corey and Suggs in 1975. Their article was entitled "Pyridinium Chlorochromate. An Efficient Reagent for Oxidation of Primary and Secondary Alcohols to Carbonyl Compounds".

When chemists develop a new reagent, they test it on a group of compounds that is representative of the types of chemicals that other chemsists are likely to use in their research. Table 1 lists the alcohols that Corey and Suggs oxidized with PCC.

Table 1



% Yield











Here are their descriptions of the procedures used to prepare PCC and to oxidize an alcohol with it:

Preparation of PCC-

"To 184 ml of 6 M HCl (1.1 mol) was added 100 g (1 mol) of CrO3 rapidly with stirring. After 5 min. the homogeneous solution was cooled to 0o and 79.1 g (1 mol) of pyridine was carefully added over 10 min. Recooling to 0o gave a yellow-orange solid which was collected on a sintered glass funnel and dried for 1 hr in vacuuo (yield 180.8 g, 84%). The solid is not appreciably hygroscopic and can be stored for extended periods at room temperature without change."

Oxidation of 1o and 2o Alcohols-

"In a typical small scale experiment pyridinium chlorochromate (1.5 mmol) was suspended in methylene chloride (ca. 2 ml), and the alcohol (1 mmol in 0.5 to 1.5 ml of CH2Cl2) was rapidly added at room temperature. The solution became briefly homogeneous before depositing the black insoluble reduced agent. After 1-2 hours the oxidation, followed by either thin layer chromatography of vapor phase chromatography, was complete. The black reaction mixture was diluted with 5 volumes of anhydrous ether, the solvent was decanted, and the black solid was washed twice with ether (causing it to become granular). Product was isolated simply by filtration of the organic extracts through Florisil and evaporation of the solvent at reduced pressure."

"Reprinted from Tetrahedron Letters, No. 31, Corey, E.J. and Suggs, W., 'Pyridinium Chlorochromate. An Efficient Reagent for Oxidation of Primary and Secondary Alcohols to Carbonyl Compounds', 2647-2650, 1975, with permission from Elsevier Science".

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