Catechol ring fission dioxygenation

For 3-chlorobenzoate, an alternative pathway in Alcaligenes sp. strain BR60 may involve 3,4- or 4,5-dioxygenation. Ring fission of the catechols resulted in the production of pyruvate and oxalacetate (Nakatsu and Wyndham 1993). 

The metabolism of 2,3-, 2,4-, and 2,5-difluoro- and 2,3,4-, 2,3,5-, and 2,4,5-trifluorophenol was studied in several species of Rhodococcus using 19F NMR. Catechols were produced both by hydroxylation and by dioxygenation with elimination of fluoride, and 2,3-diflu-oromuconate was formed as the ring fission product from 2,3-difluorophenol before further transformation (Bondar et al. 1998). 

Details of the metabolism of benzene and alkylated benzenes have been established as a result of the classic studies of David Gibson and his collaborators (Gibson et al. 1968 1970). The key intermediate from benzene is catechol that is formed by dioxygenation followed by dehydrogenation (Figure 6.25). Subsequent reactions involve fission of the aromatic ring by two pathways. 

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