An improved synthetic method of phenazine-1-carboxylic acid

An improved synthetic method of a natural fungicide, phenazine-1-carboxylic acid, was reported. In brief, the process constitutes of (a) one-pot synthesis of 1-methyphenazine (IV) from pyrocatechol and 3-methyl-2-aminoaniline, (b) Wohl-Ziegler bromination of IV, (c) hydrolyzation of 1-bromomethylphenazine (III) in aqueous solution of Na2CO3/N,N-dimethylformamide (1.1:1, v/v), (d) oxidation of 1-phenazinemethanol (II) by O2 under the catalyzation of N-bromosuccinimide. This method provided an effective synthesis of phenazine-1-carboxylic acid in the overall yield of 66 %.