What is Pyridinium chlorochromate(PCC)?

Identification

Product Name:    Pyridinium chlorochromate    

Synonyms:    PCC;PYRIDINIUM CHLOROCHROMATE;chromate(1-),chlorotrioxo-,(beta-4)-,hydrogen,compd.withpyridine(1:1);Pyridine, (T-4)-chlorotrioxochromate(1-);Pyridine, chlorotrioxochromate(1-);Urine Luck;pyridinium;PYRIDINIUM CHLOROCHROMATE, CA. 20 WT. % ON BASIC ALUMINA    

CAS:    26299-14-9    

MF:    C5H6ClCrNO3

MW:    215.56    

EINECS:    247-595-5    

Properties

Melting point     205-208 °C(lit.)  

Storage temp.     2-8°C    

Solubility     Soluble in acetone, benzene, dichloromethane, acetonitrile and tetrahydrofuran.    

Form     Crystalline Powder    

Color     Orange    

Sensitive     Moisture Sensitive    

Merck     14,7974    

BRN     7054643    

Stability:    Stable. May react with easily oxidized materials. Incompatible with reducing agents, combustible material, metals, strong reducing agents.    

Used as a Reagent

Pyridinium chlorochromate is usually used to oxidize an allylic methylene group. Pyridinium dichromate (PDC) or pyridinium chlorochromate (PCC) in anhydrous media such as dichloromethane oxidizes primary alcohols to aldehydes while avoiding overoxidation to carboxylic acids.

Oxidation of primary alcohols to aldehydes

Pyridinium-chlorochromate is a stable versatile oxidizing agent for mild and selective oxidation of alcohols. Used to oxidize an allylic methylene group in a synthesis of α,ß-unsaturated lactones from D-glucose using Grubbs-catalyzed ring-closing metathesis.

Pyridinium chlorochromate is used as an oxidizing agent to convert primary and secondary alcohols to aldehydes and ketones respectively. It is involved in the preparation of cyclohexanone, (-)-pulegone and lactones. It plays an important role in the selective mono-oxidation of xylenes to tolualdehydes and arylhydroxyamines to nitroso compounds. Furthermore, it is utilized as an oxidant for amino acids, L-cystine, aniline, cycloalkanols, vicinal and non-vicinal diols as well as in the Babler oxidation reaction.

Reactions

Pyridinium chlorochromate (PCC) is a widespread used oxidation reagent but lacks of selectivity with unsaturated compounds. Furthermore, the workup procedure is quite tedious. Absorption of PCC onto silica gel improves the oxidation but then a reagent excess is necessary to reach appropriate rates. These drawbacks can be overcome by sonication leading to short reaction times and only an small excess of 1.2.-1.5 eq. of PCC is required. Using this reagent has been used to oxidise borneol to camphor in 85% yield.

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