Comenic acid

Pyrindole — see Pyrrolo[l,2-a]pyridine Pyrithyldlone as sedative, 1, 165 Pyromeconic acid from comenic acid, 3, 710 occurrence, 3, 692... 

Komensaure, /. comenic acid, komisch, a. comic, funny. 

These results unequivocally confirmed position 5 for the phenolic hydroxyl group in both kojic acid (II) and comenic acid (IV). 

Comenic acid (10) - not to be confused with comanic acid, a 2-pyranone carboxylic acid - can be obtained by decarboxylation (by boiling in 50% hydrochloric acid (19)) of meconic acid (8), or from kojic... 

When meconic acid (490) is partly esterified and heated, it loses carbon dioxide and forms comenic acid (491) which is itself decarboxylated (as is meconic acid) to pyromeconic... 

All of the micro-organisms that had been reported before 1964 proved to be less than satisfactory for the production of 96 from D-glu-cose. Among the drawbacks associated with some of the micro-organisms were (a) the production of colored bodies, (b) the generation of such byproducts504-508 as comenic acid (98), rubinic acid (99), rubin-inol (100),504,507 508 and D-lyxuronic acid (101),509 and (c) the use of special procedures to prepare the cells in order to obtain 96. 

Bromination of 4-pyrones (28) also takes place in the 3- and/or 5-posi-tions with substituents modifying the orientation of attack in the usual ways. Comenic acid (29) gave the 6,6-dibromo derivative (84MI11). Oxime derivatives of 3-bromo-4-pyrones were converted by NBS into the 3,5-dibromo derivatives [87IJC(B)225],... 

Comenic acid, bromination, 58, 297 Complex induced proximity effect, in heterocyclic metalations, 56, 160 Complexes, charge transfer tetraphenyl-4,4 -bithiopyranylidene with lj +, -,60, 78,91... 

Comenic acid Not known Not known, literature cited... 

An example of biooxidation is the conversion of the benzyl ether of kojic acid into the benzyl ether of comenic acid by Arthrobacter ureafaciens in a phosphate buffer at pH 12 in up to 97% yield (equation 235) [1044. ... 

According to Heyns and Vogelsang, the monomethyl ether of kojic acid (15) can be converted to comenic acid methyl ether (16) by catalytic oxidation at 65° at a pH of 5 to 6. The free kojic acid is largely decomposed by catalytic oxidation, and yields only a small proportion of comenic acid. 

It has long been known that meconic acid (I) (3-hydroxy-4-oxo-4H-pyrane-2,6-dicarboxylic acid) can be heated in air to 120-220°C to form comenic acid (II) (00). DTA was used to establish the best preparative... 

Comenic acid—C.Hs03(C00H)—is produced by the action of hot HjO, of dilute acids, or of bromin water upon meconic acid. It crystallizes in yellow ish prisms, rather soluble in HaO. It is monobasic. It is decomposed by heat into COa and pyrone. 

Chelidonic acid—C.HaOa(OH)COOH—exists in chelidonium, in combination with the alkaloids sanguinarin and chelidonin. It is a crj stalline solid, and a dibasic acid. Heat converts it into comenic acid, w hich in turn yields pyrone. 

Acetaldehyde and a little hydroquinone added to an aq. suspension of comenic acid adjusted to pH 8-9 with 20%-NaOH, and stirred 20 hrs. at 25-27° -> 6-a-hydroxyethylcomenic acid (Y 88%) suspended in water, rapidly stirred, treated with a soln. of SnClg in coned. HCl, and heated 1.5 hrs. at 75-80° -> 6-ethyl-comenic acid (Y 76%). I. Ichimoto and C. Tatsumi, Agr. Biol. Chem. 34, 961 (1970). 

Kojic acid benzyl ether incubated 2 days at 30-31° on a shaker with Arthro-bacter ureafaciens K-1 cells in a phosphate buffer soln. of pH 7.2 comenic acid benzyl ether. Y ca. 96%. Also with the methyl ether s. I. Ichimoto et al., Agri. Biol. Ghem. (Tokyo) 29, 99 (1965). 

Comenic Acid S-Hydroxy-y-pyrone-i-carb-axylie acid)... 

Maltol (XQ-216), allomaltol (XII-217), kojic acid (XII-218), chelidonic acid (Xn-219), meconic acid (XII-220), and comenic acid (MI-221, R = H) are examples of well-known natural products and their derivatives that have been... 

See Pyromecomc Acid. 5-Hydroxy-y-i>yrone-2-carboxylic Acid. See Comenic Acid. 

A keto-dibromide structure (XLIX) was assigned to the bromination product of comenic acid [33]. When (XLIX) was treated with o-phenyl-enediamide, 4-oxopyrano[2,3-b]quinoxaline-2-carboxylic acid (L) was obtained in quantitative yield. [33]. 

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