Benzoylpropionic acid, reduction

Catalytic hydrogenation over palladium-on-charcoal with perchloric acid promoter is more satisfactory than the Clemmensen method for the reduction of a-phenyl-/3-benzoylpropionic acid to a,y-diphenylbutyric acid (83%). Several other keto acids have been successfully hydrogenated over this catalyst. ... 

Martin" introduced a generally useful improvement consisting in adding a layer of toluene, which probably is beneficial partly because it keeps undissolved material out of contacl wllh Ihe metal and partly because in the two-phase system reduction occurs ul such a high dilution that polymolecular reactions are inhibited. For the reduction of M) g. of/H-benzoylpropionic acid. Martin amalgamated 120 g. of mossy... 

The following directions for reducing substituted benzoylpropionic acids to the corresponding arylbutyric acids illustrates the technique devized by Martin501 for effecting Clemmensen reduction in the presence of toluene. 

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