Benzophenone oxime, 0-acyl

Finally, as examples of similar types of reactions, photolytic treatment of O-acyl ester (D) of benzophenone oxime, A-acyloxy-phthalimide (E), and O-acyl ester (F) of A-hydroxy-2-pyridone with a mercury lamp generates the corresponding alkyl radicals via decarboxylation. However, these reactions can be used only for the alkylation of aromatics (solvents such as benzene) and reduction [86-89], so their synthetic utility is extremely limited. 

In an analogous manner, the generation of alkyl radicals in benzene solution by the O-acyl oxime method results in the formation of alkylbenzenes with moderate to good yields for simple acids (equation 55). Use of pyridine as solvent leads to the formation of alkylpyridines as mixtures of ortho, meta and para isomers in which the para isomer predominates. The 0-acyI benzophenone oxime chemistry can also be applied to aryl acids in benzene or pyridine, resulting in the formation of mixed biaryls. A closely related method involves photolysis of mixed anhydrides of arenecarboxylic acids with the hydrox-amic acid A -hydroxy-Z-pyridone in benzene solution (equation 56). 

Acyl Benzophenone Oximes and t-Butyl Thioi 5.433 0-Acyi Thiohydroxamates and Tertiary Thiois 5.43.6 Decarbonyiation Methods... 

The photolysis of 0-acyl benzophenone oximes in isopropyl alcohol in the presence of r-butyl thiol leads to overall reductive decarboxylation. Yields for simple aliphatic and amino acids are repotted to be good.i It is especially noteworthy that reductive decarboxylation of 2- and 4-quinolinecarboxylic acids (although not of the 3-isomer, nor 1- or 2-naphthalenecarboxylic acids) was achieved in moderate yield by this method (equation 9). 

Friedel-Crcrfts acylation of micro- and macroporous polystyrene resins yielded conveniently the corresponding benzophenone-derived resins as shown in Scheme 1.5.4.7. These functionaUsed resins could be successfully be converted into trityl-, oxim-derived or the photolabile o-nitrobenzhydryl-derived resins which were quite extensively used in peptide and oUgonucleotide chemistry. In addition, 2-bromo propionylchloride in the presence of AlClj or FeClj was similarly used in acylation reactions with polystyrene resins. The reactions were carried out in solvents like CHjClj, 1,2-dichloroethane or nitrobenzene. 

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