4H-pyran-4-one, 3-Hydroxy-2-methyl

FIGURE 7.10 Structures of volatile compounds characterized from toasty caramel aroma released in wine from toasted woods during aging. (1) 3,5-dihydroxy-2-methyl-4H-pyran-4-one (2) 3-hydroxy-2-methyl-4H-pyran-4-one (3) 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) (4) 4-hydroxy-2,5-dimethylfuran-3(2H)-one (furaneol) (5) 2,3-dihydro-5-hydroxy-6-methyl-4H-pyran-4-one (dihydromaltol) (6) 2-hydroxy-3-methyl-2-cyclopenten-l-one (or cyclotene) (Cutzach et al., 1997 ) (7) 3-hydroxy-4,5-dymethyl-2(5H)-furanone (Sotolon Camara et al., 2006a,b,c) (8) 2-furanmethanethiol (furfurylthiol Tominaga et al., 2000). 

SYNS CORPS PRALINE 3-HYDROXY-2-METHYL-4H-PYRAN-4-ONE 3-HYDROXY-2-METHYL-7-PYRONE 3-HYDROXY-2-METHYL-4-PYRONE LARIXIC ACID U3RIXINIC ACID 2-METHYL-3-HYDROXY-4-PYRONE 2-METHYL-3-OXY-7-PYRONE 2-METHYL PYROMECONIC ACID PALATONE TALMON VETOL... 

C6H6CINO 2-amino 4-chlorophenol 95-85-2 458.65 39.926 2 7091 C6H603 3-hydroxy-2-methyl-4H-pyran-4-one 118-71-8 491.40 43.058 2... 

Hydroxy-2-methyl-4H-pyran-4-one (maltol) 5-Hydroxy-2-methyl-4H-pyran-4-one (allomaltol) 5-Hydroxymethylfurancarboxyaldehyde (5-hydroxymethylfurfural) 5-Methylfurancarboxyaldehyde (5-methylfurfural)... 

Maltol 3-Hydroxy-2 methyl-4H pyran-4-one 3-hydroxy-2-methyl-4-py rone 3-hydroxy-2-methyl- y-py-rone larixinic acid Palatone Veltol. C6H603 mol wt 126,11. C 57.14%, H 4.80%, O 38.06%. Found in the bark of young larch trees (Larix decidua Mill.) in pine needles (Abies alba Mill., Pinaoeae), in chicory, in wood tars and oils, in roasted malt. Isoln from these sources and structure Kiliani, Bazlen, Ber. 27, 3115 (1894) Feuerstein, Ber. 34r 1804 (1901) Erdmann, Schaefer, Ber. 43, 2398 (1910) Reichstein. Be it ter, Ber. 63, 824 (1930) cf. Pera toner, Tam-burelic, Chem. Zentr. 76, 11 680 (1905). Also obtained by alkaline hydrolysis of streptomycin salts Schenck, Spiel -... 

H-Pyran-4-one, 6-ethyl-3-hydroxy-2-methyl-4H-Pyran-4-one, 6-ethyl-3-hydroxy-2-propyl-4H-Pyran-4-one-2-carboxylic acid, 5-hydroxy-... 

Synonyms 3-Hydroxy-2-methyl-4H-pyran-4-one 3-Hydroxy-2-methyl-4-pyrone 3-Hydroxy-2-methyl-y-pyrone Larixic acid Larixinic acid 2-Methyl-3-hydroxy-4-pyrone 2-Methyl-3-oxy-y-pyrone 2-Methyl pyromeconic acid Empirical CeHeOs Formula CH3CsH20(0)(0H)... 

Maltol (3-hydroxy-2-methyl-4H-pyran-4-one) is obtained from carbohydrates as outlined in 4.2.4.4.4 and has a caramel-like odor. It has been found in a series of foods (Table 5.17), but in concentrations that were mostly in the range of the relatively high odor threshold of 9mg/kg (water). 

H-Pyran-4-one, 5-hydroxy-2-methyl- = 4H-pyran-4-one, 3-hydroxy-6-methyl- allomaltol 1351, 1352, 1364, 2601a, 3553 ... 

Figure 7.1.1. Chromatogram for the pyrotysate ofgtucose obtained by on-line Py-GC/MS. The peak assignments are 1 furan, 2 2-melhylfuran, 3 2,5-dimethylfuran, 4 3-methyl-2-butanone, 5 water, 6 1-hydroxypropanone, 7 hydroxyacetaldehyde, 8 acetic acid, 9 oxopropanoic acid methyl ester, 10 furancarboxaldehyde, 11 1-(2-furanyl)-ethanone, 12 5-methyl-2-furfural, 13 2-hydroxycyclopent-2-en-1-one, 14 2-hydroxy-3-methyl-2-cyclopenten-1-one, 15 2,3-dihydro-5-hydroxy-6-methyl-4H-pyran-4-one, 16 2-methyl-1,3-benzendiol, 17 2,5-dimethyldioxane, 18 2-hydroxy-3-pentanone, 19 5-formyl-2-fufurylmethanoate, 20 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 21 1,4 3,6-dianhydro-a-D-glucopyranose, 22 5-(hydroxymethyl)-furancarboxaldehyde.

Lasius fuliginosus W-HG Trail following antennal responses (3R)-(-)-3,4-Dihydro-8-hydroxy-3-methyliso-coumarin 129 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one 134 [175]... 

Aytemir, M.D. Cali / U-i Ozalp, M. (2004) Synthesis and Evaluation of Anticonvulsant and Antimicrobial Activities of 3-Hydroxy-6-methyl-2-substituted 4H-Pyran-4-one Derivatives. Arch. Pharm. Pharm, Med. Chem. Vol.337, pp.281-288. 

This overview deals with some of the chemical marker compounds suited to the requirements of quality control laboratories in the citrus industry. Chemical markers include ascorbic acid, dehydroascorbic acid, hydroxymethylfurfural, furfural, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 4-vinyl guaiacol and a-terpineol. Some of these compounds might be applied as useful tools in evaluating quality deterioration due to unsuitable manufacturing and storage as well as for the computation and optimization of the manufacturing processes and parameters. Since they are all chemically reactive compounds, careful evalution of kinetics of these compounds is necessary. 

Chemically, wood tar is a complex mixture that contains at least 200 individual compounds, among which the following have been isolated (1) 2-methoxyphenol, 2-methoxy-4-ethylphenol, 5-methji-2-methoxyphenol, 2,6-xylenol, butyric acid, crotonic acid, l-hydroxy-2-propanone, butyrolactone, 2-methyl-3-hydroxy-4H-pyran-4-one, 2-methyl-2-propenal, methyl ethyl ketone, methyl isopropyl ketone, methyl furyl ketone, and 2-hydroxy-3-methyl-2-cyclopenten-l-one. 

Adedeji et al. (1993) used a direct thermal desorption technique (220°C) to analyse the volatiles from beans that might cause the thermal degradation and transformation of sugar into common volatile compounds such as 3,5-dimethyl-2,4(3H,5H)-furandione and 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one. This last compound was detected at a high concentration (3880 ppm) in Mexican vanilla, being the third most abundant compound after vanillin and 2-furfural, and far more abundant than vanillic acid, p-hydroxy-benzaldehyde or p-hydroxybenzoic acid. 

Only two Anobiidae pheromones have been identified thus far. The drugstore beetle, Stegobium panlceum (L.), pheromone was identified as 2,3-dihydro-2,3,5-trimethyl-6-(l-methyl-2-oxo-butyl)-4H-pyran-4-one (XIV) (44) and the cigarette beetle, Lasloderma serrlcorne F., as 4,6-dimethyl-7-hydroxy-nonan-3-one (XV) (45). The similarity of these structures is worth noting. 

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