Para-Ethylphenol

Beilstein Handbook Reference) A13-26063 BRN 1363317 EINECS 204-598-6 4-Ethylphenol FEMA No, 3156 HSDB 5598 Hydroxyphenylethane, p- NSC 62012 p-Ethylphenol para-Ethylphenol Phenol, 4-ethyl-, Needles mp = 45.0 bp = 217,9 Xm = 223, 278 nm (s = 7090,1950, MeOH) slightly soluble in H2O, CHCI3, slightly soluble in Me2CO, very solubie in EtOH, Et20, CeHe, CS2,... 

The oxidation by strains of Pseudomonas putida of the methyl group in arenes containing a hydroxyl group in the para position is, however, carried out by a different mechanism. The initial step is dehydrogenation to a quinone methide followed by hydration (hydroxylation) to the benzyl alcohol (Hopper 1976) (Figure 3.7). The reaction with 4-ethylphenol is partially stereospecific (Mclntire et al. 1984), and the enzymes that catalyze the first two steps are flavocytochromes (Mclntire et al. 1985). The role of formal hydroxylation in the degradation of azaarenes is discussed in the section on oxidoreductases (hydroxylases). 

Naphthyl methylethers are easily converted to methylnaphthols, 5). The a-isomer forms 2- and 4-methyl-a-naphthol, the j3-isomer only l-methyl- 3-naphthol. Ethers with alkyl groups other than methyl sometimes show side reactions due to fragmentation of the migrating group. For example, n-pro-pylphenylether yields mainly ortho- and para-n-propylphenol, but also some ethylphenols and cresols 14). 

IUPAC Nomenclature of Phenols Section 9.1C (a) 2-methylphenol (b) 3-bromophenol (c) 4-ethylphenol (ortho, meta, and para in a,b,c respectively is correct also) d) 4-methoxy-2-nitrophenol... 

Ethylphenol oxidoreductase from Pseudomonas putida JD1 is structurally almost identical to 4-cresol oxidoreductase, but catalyzes the hydroxylation of para-alkylphe-nols with longer aliphatic chains (Table 16.3-12). The hydroxylation reactions enantioselectively produce (-R)-alcohols 64> 65l The regeneration properties of this enzyme are quite similar to 4-cresol oxidoreductase1611. 

Thompson DC, Perera K, London R. Quinone methide formation from para isomers of methylphenol (cresol), ethylphenol, and isopropylphenol relationship to toxicity. Chem Res Toxicol 1995 8 55-60. 

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