2 -Furanone, dihydro-3-hydroxy-4,4-dimethyl

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 -,... 

G.8) 2(5//)-Furanone, 3,4-dimethyl-, 2,3-dimethyIbut-2-eno-4-lactone, 2,5-dihydro-3,4-dimethylfuran-2-one, 2,3-dimethyl-2-buten-4-olide, 2,3-dimethyl-4-hydroxy-2-butenoic acid, 7-lactone 11575-46-81... 

H)-Furanone, dihydro-4-methyI-3 2H)-Furanone, dihydro-5-methyl-5-propyl-3(2W)-Furanone, 2,5-dimethyl-3(2W)-Furanone, 3-ethyl-4-hydroxy-5-methyI-... 

Ketopantoyl lactone 2,3-Furandione, d1hydro-4,4-dlmethyl (8,9) (13031-04-4) D-(-)-Pantoyl lactone 2(3H)-Furanone, dihydro-3-hydroxy-4,4-d1methy1 0- (8) 2(3H)-Furanone, d1hydro-3-hydroxy-4,4-dimethyl- (9) (599-04-2) Ch1oro(l,5-cyclooctadiene)rhodium (I) dimer Rhodium, di-v-ch1orobis(l,5-cyclooctadiene) di- (8) Rhodium, di-y-chiorobis[(1,2,5,6- )-l,5-cyclooctadiene] di- (9) (12092-47-6)... 

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. 

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. 

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... 

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]... 

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

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.

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. 

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