Chlorochromate

If it is passed into a concentrated solution of a chloride, however, a chlorochromate( l) is formed ... 

Conditions that do permit the easy isolation of aldehydes in good yield by oxida tion of primary alcohols employ various Cr(VI) species as the oxidant in anhydrous media Two such reagents are pyndmium chlorochromate (PCC), CsHsNH ClCr03 ... 

PCC IS pyridinium chlorochromate PDC is pyridinium dichromate Both are used in dichloromethane ... 

Different reagents react with different bonds in the same molecule. PCC represents pyridinium chlorochromate. 

Pyridinium chloride, N-(4-pyridyl)-hydrochloride quaternization, 2, 175 reactions with amines, 2, 241 Pyridinium chlorochromates as oxidizing agents, 2, 170 reactions, 2, 34 Pyridinium dichromate as oxidizing agent, 2, 170 Pyridinium l-dicyanomethylide... 

Et3NH ClCi03, CICH2CH2CI, 2 h, it, 60-90% yield. This reagent was reported to work better than PCC (pyridinium chlorochromate). 

Bipyridinium chlorochromate [76899-34-8] M 292.6. Washed with cold cone HCl then H2O (sintered glass funnel) and dried in vacuum (CaCl2) to a free flowing yellow-brown powder. Stored in the dark. [Synthesis 691 1980 Synth Commun 10 951 1980.] SUSPECTED CARCINOGEN. 

Tetrabutylammonium chlorochromate [54712-57-1 ] M 377.9, m 184-185 . Recrystd EtOAc-hexane. IR v 920cm in CHCI3 [Synthesis 749 1983]. Powerful oxidant. 

Oxidation of tim5-4-(2,2,2-tnfluoro-l-hydroxy 1 tnfluoromethylethyl)cyclo-hexanol with pyridinium chlorochromate results m the correspondmg cyclic ketone whereas oxidation with nitnc acid m the presence of a catalyst causes ring cleavage [50] (equation 46)... 

This group is stable to 3 AHCl, 100° 3 ANaOH, 100° H2, 1200 psi O3, MeOH, —78° RaNi, 100° LiAlH4 Jones reagent and pyridinium chlorochromate (PCC). It has also been used for protection of the anomeric hydroxyl during oligosaccharide synthesis. ... 

In this type of cleavage reaction, it appears that the axial benzoate is the preferred product. If water is excluded from the reaction, a bromo benzoate is obtained.The highly oxidizing medium of 2,2 -bipyridinium chlorochromate and MCPBA in CH2CI2 at rt for 36 h effects a similar conversion of benzylidene acetals to hydroxy benzoates in 25-72% yield. ... 

Pyridinium chlorochromate. In this case, the alcohol that is cleaved is simultaneously oxidized to give a ketone. ... 

Secondary alcohols are oxidized easily and in high yield to give ketones. For large-scale oxidations, an inexpensive reagent such as Na2Cr207 aqueous acetic acid might be used. For a more sensitive or costly alcohol, however, pyridinium chlorochromate is often used because the reaction is milder and occurs at lower temperatures. 

Perhaps the most important reaction of alcohols is their oxidation to carbonyl compounds. Primary alcohols yield either aldehydes or carboxylic acids, secondary alcohols yield ketones, but tertiary alcohols are not normally oxidized. Pyridinium chlorochromate (PCC) in dichloromethane is often used for oxidizing primary alcohols to aldehydes and secondary alcohols to ketones. A solution of Cr03 in aqueous acid is frequently used for oxidizing primary alcohols to carboxylic acids and secondary alcohols to ketones. 

Draw the structure of the carbonyl compound(s) from which each of th< following alcohols might have been prepared, and show the products yen. would obtain by treatment of each alcohol with (i) Na metal, (ii) SOCl2, anc (iii) pyridinium chlorochromate. 

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