Ortho-Nitrobenzyl Alcohol Derivatives

Various functional groups can be protected and released in high yields, such as alcohols (as ethers), carboxylic acids (as esters), amides (as amides), and amines (as carbamates). In the latter case, however, two drawbacks must be noted  

Related PPGs, but operating with a different mechanism, were introduced some years ago examples are the NPPOC (R = Me), where the side product is a nitrostyr-ene [18-23], and the NPEOC (R= H) [24], 

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Derivatives of ortho-nitrobenzyl alcohol were also used to protect the hydroxy groups of carbohydrates, including in the anomeric position. Thus, the following acetal was quantitatively photolysed to glucose (Scheme 13.5) [27]. 

Mercuration of p-Hydroxy-m-nitrophenyl carbinol.— The carbinol is prepared by the action of bromomethyl alcohol on o-nitro-phenol and then treated with 2 mols. of mercuric acetate in alcohol-acetic acid solution. Fine, pale yellow needles separate, which may be recrystallised from 20 per cent, acetic acid (I,). This compound does not form an inner anhydride as in the preceding ease, although the mercury is in the ortho position to the hydroxyl group. The latter fact w as established by treating the compound with a solution of iodine in potassium iodide, when 3-iodo-4-hydroxy-5-nitrobenzyl alcohol is obtained. Treatment with acetic anhydride yields a monoacetyl derivative (II.) ... 

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