CrO3 in acetic anhydride or acetic acid has been found to transform alkenes to epoxides (Scheme 9).
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Scheme 9 |
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Scheme 10 |
1.3.8 Oxidation of Aromatic Side Chains
The selective oxidation of alkyl chains attached to an aromatic ring can be carried out with CrO3 in acetic anhydride. Thus, p-nitrotoluene is converted into p-nitrobenzylidine diacetate, which on hydrolysis in the presence of acid gives p-nitrobenzaldehyde (Scheme 11).
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Scheme 11 |
Chromyl chloride can oxidize o-, m-, or p-xylenes to give tolualdehyde in 70-80% yield (Scheme 12).
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Scheme 12 |
Several studies focus on the oxidation of aromatic alkyl side chains to give carboxylic acids (Scheme 13).
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Scheme 13 |