Trimethylammonium chlorochromate

The tetraalkylammonium chromates prepared by Gelbard and coworkers a q)eared to be equally effective for all types of alcohols, but under the conditions of Santaniello et al., tetra-n-butylammonium chlorochromate was found to be a selective benzylic and allylic oxidant. It also efficiently converts aliphatic and aromatic thiols to disulfides. Trimethylammonium chlorochromate has also bera reported for the oxidation of allylic alcohols in DMF. ... 

B. With alumina-supported trimethylammonium chlorochromate 5-Hydroxymethyl-2-furfural (1.26 g, 10 mmol) was adsorbed on neutral aluminum oxide (Merck, activity 1, used as received, 30 g), dried, and the resulting solid was groimd together with molecular sieves 4A (0.4 g, previously dried at 350°C for 48 h) and trimethylammonium chlorochromate (TMACC, 5.85 g, 30 minol). The whole solid mixture was suspended in CH2CI2 (20 mL) and sonicated for 1 h at room temperature. The mixture was filtrated and the solid washed with methylene chloride. The organic phases were evaporated and the solid residue, recrystallized as above, afforded the product as white crystals (0.89 g, 72%), mp 108-109°C, identical to the sample above. 

On the other hand, isoquinolinium (iQCC),385b p-methylpyridinium (y-PCC)390 and trimethylammonium (TMACC)391 chlorochromates closely resemble the oxidizing behaviour of PCC. p-Methylpyridinium chlorochro-mate has the distinctive advantage over PCC of containing p-methylpyridine that is less toxic than pyridine. 

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