Model pathways for enzymatic oxidative demethylation—II : Polonovski reaction of N,N-dimethylaniline N-oxide, pummerer reactions of dimethyl, n-butyl methyl and methionine sulphoxide with acetylating agents and their implications in enzymatic demethylation

Abstract

The reaction of N,N-dimethylaniline N-oxide with acetylphenylphosphate proceeds under a mild condition giving o-acetoxy-N,N-dimethylaniline. Similarly, acetylphenylphosphate is also effective in causing the Pummerer reaction of dimethyl sulphoxide giving the corresponding acetoxymethyl sulphide. The reaction of methionine sulphoxide with acetic anhydride gives α- acetoxy derivative of methionine. The resulting ester hydrolyses in the hydrochloric acid into homocysteine,formaldehyde and acetic acid. This demethylation reaction is discussed as a possible model pathway for the enzymatic oxidative demethylation of methionine to homocysteine.