Pulcherriminic acids

Pulcherrimin, the red pigment from Candida pulcherrima, is a polymeric ferric complex of pulcherriminic acid (9). The structure of... 

Dichloro-3,6-diisobutylpyrazine (237) is the starting material for a very similar synthesis of pulcherriminic acid (10).430 Pulcherri-minic acid, as already mentioned in Section I, is derived from pulcherrimin (9), a metabolite of the yeast Candida javlcherrima. The key step in the synthesis of pulcherriminic acid is the initial step of... 

This substance is obviously related to pulcherriminic acid and the aspergillic acids (see below) and may be regarded as the anhydride formed from one mole of N-hydroxyalanine and one mole of an o-substituted a-p unsaturated analogue of N-hydroxytyrosine. There is no evidence connecting mycelianamide to metal ion metabolism save the statements... 

Mycelianamide nucleus Pulcherriminic acid nucleus Aspergillic acid nucleus Formula 2... 

Pulcherrimin, the ferric chelate of pulcherriminic acid, is believed to consist of a mosaic of dihydroxypyrazinedioxide molecules cemented together by iron atoms as illustrated in Fig. 9 (65). In this form it is highly insoluble. 

Pulcherrimin obtained by extraction of the cells with methanolic KOH as a highly insoluble, amorphous red powder. Absorption maximum at 4900 A. Iron removed with 2N NaOH and crude pulcherriminic acid precipitated with HC1. C12H20O4N2. Forms somewhat unstable, crystalline morpholinium and cyclohexylammonium salts. Addition of iron in acid solution gives a precipitate, CizHuCUNa jFe with infra red spectrum identical to that of crude pulcherrimin. 

Structure based on physical and chemical properties, reductive degradation, the synthesis of model compounds and the synthesis of pulcherriminic acid itself (92). 

Ohta, A. Synthesis of pulcherrimin and pulcherriminic acid. Chem. Pharm. Bull. (Tokyo) 12, 125 (1964). 

Pulcherriminic acid (H 6), 1, 5-dihydroxy-3, 6-diisobutyl-2(l//)-pyrazinone 4-oxide, a Candida sp yeast metabolite, initially as an Fe complex (pul-cherrimin) [957-86-8],... 

Methylation of 2-amino-3-hydroxypyrazine (62) with methyl iodide and sodium methoxide afforded 3-amino-l-methyl-2-oxo-1,2-dihydropyrazine (63), and when an excess of methyl iodide was used, a mixture of compound (63) and its methio-dide (64) was isolated. Reaction with dimethyl sulfate and alkaU gave compound (63) and l,4-dimethyl-2,3-dioxo-l,2,3,4-tetrahydropyrazine (66) the latter was presumed to be formed by hydrolysis of an intermediate quaternary salt since it was also obtained by treatment of the methiodide (64) with aqueous sodium hydroxide. Reaction of 2-amino-3-hydroxypyrazine with ethereal diazomethane produced a mixture of N- and 0-methyl derivatives, (63) and 2-amino-3-methoxy-pyrazine (65). With methyl toluene-p-sulfonate the quaternary salt 2-amino-3-hydroxy-1-methylpyrazinium toluenesulfonate (67) was obtained on alkaline hydrolysis it gave 3-hydroxy-l-methyl-2-oxo-l,2-dihydropyrazine (68) (832). Pulcherriminic acid with diazomethane gave a dimethyl derivative (99). 

Deoxyaspergillic acid was also produced from aspergillic acid by refluxing in acetic acid with red phosphorus and hydriodic acid, and by dry distillation with copper-chromite catalyst (86). Reduction of 2,5-dihydroxy-3,6-diisobutylpyrazine 1,4-dioxide (pulcherriminic acid) with red phosphorus and iodine in refluxing acetic... 

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