The common method is to react chromium trioxide with hydrochloric acid to produce chlorochromic acid, followed by the addition of pyridine at 0 °C to obtain a stable orange-yellow Pyridinium chlorochromate solid:
Specific reaction steps: Under stirring, chromium trioxide (100 g, 1 mol) is rapidly added to 6 N hydrochloric acid (184 mL, 1.1 mol). After 5 minutes, when the homogeneous solution has cooled to 0 °C, pyridine (79.1 g, 1 mol) is carefully added over a period of more than 10 minutes. The solution is recooled to 0 °C, yielding an orange-yellow solid. The solid is collected in a sintered glass funnel, filtered, and vacuum dried for 1 hour, yielding 250.5 g, 54% .
Pyridinium chlorochromate is orange crystalline powder
Oxidizing agent in organic synthesis.
PCC is pyridinium chlorochromate; PDC is pyridinium dichromate. Both are used in dichloromethane.
Pyridinium chlorochromate is usually used to oxidize an allylic methylene group.
Oxidation of primary alcohols to aldehydes
Pyridinium dichromate (PDC) or pyridinium chlorochromate (PCC) in anhydrous media such as dichloromethane oxidizes primary alcohols to aldehydes while avoiding overoxidation to carboxylic acids.
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.
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.
Dry it in a vacuum for 1hour. It is not hygroscopic and can be stored for extended periods at room temperature without change. If the purity is very suspect, it can be readily prepared. [Corey & Scuggs Tetrahedron Lett 2647 1975, Piancatelli et al. Synthesis 245 1982.] (Possible CARCINOGEN.) § Available commercially on a polymer support.
Prothrombin complex is a double virus–inactivated concentrate, containing equal concentrations of Factors II, VIII, IX, X and Heparin.
Prothrombin Complex Concentrate (PCC) is a combination of several blood clotting factors II, VII, IX and X. PCC is used in the treatment of the congenital bleeding disorders associated with Factors II, VII, IX, and X deficiencies. PCC reverses the effect of warfarin (a coumarin anti-coagulant) and is used in cases of significant bleeding in patients with a coagulopathy, for example, gastrointestinal haemorrhage or intracranial haemorrhage. The PCC is also extensively used in treating acquired coagulation abnormalities secondary to vitamin K deficiency, warfarin ingestion, and various types of liver disease.
Hepatitis, anaphylaxis and thrombosis have been reported as complications of prothrombin complex concentrates administration.
