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Pigments that contain the aromatic phenazine nucleus such a spyocyanine (I), chlororaphin (a 3:1 molecular compound of phenazine-1-carboxamide (II) and its 9,10 dihydro derivative), iodinin (III) and phenazine-1-carboxylic acid present an interesting biogenetic problem for which no definitive proposals have yet been made though a significant amount of work on the biosynthesis of pyocyanine (I) has been reported.
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Carter et al. (1961) studied this question.
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