Pfizer Handbook of Microbial Metabolites 502 



This is reminiscent of the phenoxazones such as cinna- 



HOCH, COOH OCH3 COOH 



I /NH2 I 



HO— CH2— C— O— CH2 

 Phenazine Cinnabarin Griseolutein A 



barin and actinocinin. The analogy perhaps can be de- 

 veloped farther, since a streptomycete pigment has been 

 found with an amino group in the 2-position. 



The resemblance is sufficient to suggest anthranilic acid 

 or related substances as intermediates in the biosynthesis 

 of phenazines. Oxidative decarboxylations of aromatic 

 acids to phenols are not unknown among obligate aerobes 

 of the type that produce phenazines. Also 3-oxyanthra- 

 nilic acid might account for some of the phenolic hydroxyl 

 groups. 



As for the coupling reaction, perhaps something akin 

 to phenolic-free radical coupling takes place. Photoirra- 

 diation of aniline at low temperatures has been reported 

 to produce phenazine.* Also tetraphenylhydrazine heated 

 to 90° apparently dissociates to a free radical which re- 

 arranges to (among other things) a dihydrophenazine.^ 



NHo 



light ^;;?=\^N^ 



low temperature ^-^'^^N 



// \ ^ // \ // % 



_/ Heat \_/\... r^^^^^f^^^ 



N— N ^ N- 



// \\/ \r\ r\^ 



'A. N. Terenin, Acta Physicochim. S.S.S.R. 1.-5 1 (1940); Chem. 

 Abstr. 35 1701 (1941). 



■'"' G. W. Wheland, "Advanced Organic Chemistry," John Wiley 

 and Sons, Inc., New York, 1949, pp. 727-728. 



