Dihydro-4-hydroxy-2 furanone

From the wine aromas of Pollux, Castor, and Riesling grapes, Rapp et al. and Schreier and Paroschy have isolated an undesirable strawberry aroma by GC-MS (80V13, 81MI112). This lactone was characterized as 2,5-dimethyl-4-hydroxy-2,3-dihydro-3-furanone 8 ("furaneol") having an odor threshold of 50-100 ppb. 

Figure 5.2.10. Cellulose pyrolysate obtained at 59CP C by Py-GC/MS. The separation was done on a Carbowax type column. 1 CO2, 2 acetaldehyde, 3 acetone, 4 2-butanone, 5 2,3-butandione, 6 toluene, 7 water, 8 cyclopentanone, 9 methylfuran, 10 3-hydroxy-2-butanone, 11 hydroxypropanone, 12 cyclopent-1-en-2-one, 13 2-methylcyclopentenone, 14 acetic acid, 15 acetic acid anhydride, 16 furancarboxaldehyde, 17 methylcyclopentenone, 18 dimethylcyclopentenone, 19 5-methylfurancarboxaldehyde, 20 2,3-dihydro-2-furanone, 21 furan-2-methanol, 22 3-methylfuran-2-one, 23 2(5H)-furanone, 24 hydroxycyclopentenone, 25 3,5-dimethylcyclopentan-1,2-dione, 26 2-hydroxy-3-methyl-2-cyclopenten-1-one, 27 2-hydroxy-3-ethyl-2-cyclopenten-1-one, 28 2,3-dimethyl-2-cyclopenten-1-one, 29 phenol, 30 dimethylphenol, 31 3 thyl-2,4(3H,5H)-furandione, 32 3-butenoic acid, 33 1,4 3,6-dianhydro-a-D-glucopyranose, 34 5-(hydroxymethyl)-furfural.

Thermolysis of D-fructose in acid solution provides 11 and 2-(2-hydrox-yacetyl)furan (44) as major products. Earlier work had established the presence of 44 in the product mixtures obtained after acid-catalyzed dehydrations of D-glucose and sucrose. Eleven other products were identified in the D-fructose reaction-mixture, including formic acid, acetic acid, 2-furaldehyde, levulinic acid, 2-acetyl-3-hydroxyfuran (isomaltol), and 4-hydroxy-2-(hydroxymethyl)-5-methyl-3(2//)-furanone (59). Acetic acid and formic acid can be formed by an acid-catalyzed decomposition of 2-acetyl-3-hydroxyfuran, whereas levulinic acid is a degradation prod-uct of 11. 2,3-Dihydro-3,5-dihydroxy-6-methyl-4//-pyran-4-one has also been isolated after acid treatment of D-fructose.The pyranone is a dehydration product of the pyranose form of l-deoxy-D-eo f o-2,3-hexodiulose. In aqueous acid seems to be the major reaction product of the pyranone. 

The assignment of (/ )-2,3-dihydro-2-phenylfuran rests on Jones oxidation which furnished (ft)-dihydro-5-phenyl-2(3//)-furanone [(/ )-24]80. The configuration of the corresponding S-enantiomer (obtained by yeast reduction of 4-oxo-4-phenylbutanoic acid) was established by correlation with ethyl (S)-3-hydroxy-3-phenylpropanoate (of known configuration, obtained itself by a baker s yeast reduction) by a sequence featuring an Arndt -Eistert homologization as the key step (see also p 403)19. 

Blank, I., Lin, J., Fumeaux, R., Welti, D.H., and Fay, L.B. 1996. Formation of 3-hydroxy-4,5-di-methyl-2(5H)-furanone (sotolone) from 4-hy-droxy-L-isoleucine and 3-amino-4,5-dimethyl-3,4-dihydro-2(5)-furanone. J. Agric. Food Chem. 44 1851-1856. 

Figure 9 Cavities of the inclusion compounds (a) 2-(5)-ethyl lactate (1 1), (b) 2 (5,)-dihydro-3-hydroxy-4,4-dhnethyl-2(3H)-furanone MeOH H20 (2 1 2 1), (c) 2 (5 )-...

Pantolactone, dihydro-3-hydroxy-4//-dimethyl-2(3//)-furanone (103) which is an important starting material of the synthesis of pantothenic acid, was also easily resolved by complexation with 10a. When a solution of 10a (5.5 g, 9.93 mmol) and rac-103 (2.6 g, 20 mmol) in 1 1 benzene-hexane (20 ml) was kept at room temperature for 1 h, a 1 1 complex of 10a and (.S)-(-)- 03 was obtained, after two recrystallizations from 1 1 benzene-hexane, as colorless needles (2.05 g), which upon heating in vacuo gave (S)-(-)-103 of 99% ee (0.39 g, 30%).40 In order to clarify the mechanism of the precise chiral recognition between 10a and (S)-(-)-103, their inclusion complex crystal was studied by X-ray analysis40 and by AFM technique.41... 

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). 

Response Surface Methodology (RSM) was used to investigate the effects of temperature, pH and relative concentration on the quantity of selected volatiles produced from rhamnose and proline. These quantities were expressed as descriptive mathematical models, computed via regression analysis, in the form of the reaction condition variables. The prevalence and importance of variable interaction terms to the computed models was assessed. Interaction terms were not important for models of compounds such as 2,5-dimethyl-4-hydroxy-3(2H)-furanone which are formed and degraded through simple mechanistic pathways. The explaining power of mathematical models for compounds formed by more complex routes such as 2,3-dihydro-(lH)-pyrrolizines suffered when variable interaction terms were not included. 

Rhamnose and proline were reacted under a wide range of reaction conditions with the expectation of producing volatiles of differing type and ratio. Such large differences were desired to give the best opportunity for the empirical models to account for and explain the variation. If valid, the model terms would be expected to account for differences in product composition and perhaps provide insight into the reaction pathways. Some of the 23 volatiles modeled including 2,3-dimethyl-4-hydroxy-3(2H)-furanone (DMHF), 2-acetoxy-3-pentanone, and four 2,3-dihydro-(lH)-pyrrolizines will be discussed below. 

Fleterocyclics Sotolon [3-hydroxy-4, 5-dimethyl-2-(5H)-furanone] y-Nonalactone [dihydro-5-pentyl-2-(5H)-furanone] y-Caprolactone [dihydro-5-ethyl-2-(3A7)-furanon]... 

Ketopantoyl lactone 2,3-Furandione, dihydro-4,4-dimethyl (8,9) (13031-04-4) D-(-)-Pantoyl lactone 2(3H)-Furanone, dihydro-3-hydroxy-4,4-dimethyl -,... 

Dihydro-4-hydroxy-5- (/ )-l-iodoethyl -5-methyl-2(3W)-furanone (2A) Typical Procedure28 ... 

T, 5/r )-( )-Dihydro-4-hydroxy-5-methyl-3-tetradecylidene-2(3//)-furanone (31, R = n-CI3H27 Epilit-senolide) Typical Procedure14 ... 

Alternate Name (7 )-dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone. 

Figure 5.2.11. Cellulose pyrolysate obtained at 59(P C and separated on a methyl silicone with 5% phenyl silicone type column. 1 acetic anhydride, 2 pentanal, 3 2-hydroxybutanedialdehyde, 4 1,4-dioxadiene, 5 tetrahydro-2-furanmethanol, 6 2-(hydroxymethyl)-furan, 7 3-methyl-2-hexanone, 8 2-methoxy-2,3-dihydrofuran, 9 2(5H)-furanone, 10 1-acetyloxypropan-2-one, 11 hydroxycyclopentenone, 12 5-methylfurfural, 13 2,3-dihydro-5-methylfuran-2-one, 14 1-cyclopentylethanone, 15 2-hydroxy-3-methyl-2-cyclopenten-1-one, 16 3,5-dimethylcyclopentan-1,2-dione, 17 unknown, 18 3-ethyl-2,4(3H,5H)-furandione, 19 6-methyl-1,4-dioxaspiro[2,4]heptan-5-one, 20 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, 21 1,4 3,6-dianhydro-a-D-glucopyranose, 22 5-(hydroxymethyl)-furfural, 23 4-cyclopenten-1,2,3-triol, 24 5-ethyl-3-hydroxy-4-methyl-tetrahydrofuran-2-one, 25 levoglucosan, 26 1,6-anhydro-p-D-glucofuranose.

Dihydro-2(3//) furanone 4-Hydroxy- y-lactone 4-Deoxytetronic acid... 

Hydroxy-6-methoxy-2//-benzopyranone cw-P-Methyl-y-octalactone Dihydro-2(3H)furanone (y-butyrolactone)... 

Treatment with HCl/EtOH gave 4,5-dihydro-3-hydroxy-4,4,5,5-tetramethyl-3-phenyl-2(3tf)-furanone. 

G.2) 2(3/f)-Furanone, dihydro-3-methyl-, 2-methylbutano-4-lactone, tetrahydro-3-methyIfuran-2-one, 2-methyl-4-butanolide, 4-hydroxy-2-methylbutanoic acid lactone, a-methyl-7-butyrolactone 1679-47-6] ( )- [69010-09-9] (/ )- [55254-35-8] (5)- ]65527-79-9]... 

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