Reduction of Carbocyclic Rings

Other Carbocyclic Aromatic Compounds Reduction of Carbocyclic Rings 

Reductases play a cardinal role in the anaerobic degradation of diverse aromatic compounds, for example, (a) the reduction of benzoyl-CoA that is a prelude to the fission of the ring (Harwood et al. 1999) (Chapter 8, Part 3) and (b) the degradation of phloroglucinol via dihydrophloroglucinol to acetate and butyrate (Haddock and Ferry 1989, 1993) (Chapter 8, Part 4). 

The anaerobic degradation of some hydroxybenzoates and phenols involves reductive removal of the phenolic hydroxyl group. The enzyme that dehydroxylates 4-hydroxybenzoyl-CoA in Thauera aromatica is a molybdenum-flavin-iron-sulfur protein (Breese and Fuchs 1998), and is similar to the enzyme from the nonsulfur phototroph Rhodopseudomonas palustris that carries out the same reaction (Gibson et al. 1997). 

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Reduction of carbocyclic rings in aromatic ketones can be accomplished by catalytic hydrogenation over platinum oxide or rhodium-platinum oxide and takes place only after the reduction of the carbonyl group, either to the alcoholic group, or to a methylene group [5S]. 

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