Pentane-2.4-dione

Several other non-nitrogenous products have been identified as products of the Maillard reaction. These include butanol, butanone, butane-dione, and pentane-2,3-dione as well as dihydroxyacetone, glycer-aldehyde, and D-erythrose. Obviously, the same products are present after mild acidic or basic degradation of carbohydrates. Thus, the necessity of an amine or amino acid in the mechanism of their formation is uncertain. 

Pentan-2-one, 1-acetoxy Sd (roasted)" Pentan-3-one, A-acetoxy Sd (roasted)"" Pentane-2-3-dione Sd (roasted)" Pent-trans-2-en-4-one Sd (roasted)" Phenethyl alcohol Sd Hu" ... 

A triketone is also an intermediate in a synthesis of 6-methyI-4-oxopyran-2-carboxylic acid from pentane-2,3-dione in which one carbonyl group is initially protected as the ketal (67JOC4105). Acylation by ethyl oxalate is accomplished under basic conditions, and ring closure and hydrolysis of the ketal are effected with acid. 

Hydroxy-4-methyl-4-penten-2-one (1) was prepared from 3-chloro-mesityl oxide using a modified procedure from the literature [ref.4], A reference sample of 4-methyl-4-penten-2,3-dione (2) was prepared from using the copper acetate method [ref.2], 4-methyl-pentan-2,3-dione (3) was purchased from Wiley Co. 2-Hydroxy-4-methyl-4-penten-3-one (4) was synthesized in 30% yield from 2-propenyl-magnesium bromide and 2-hydroxy-propionitrile in tetrahydrofurane. The structures of all compounds were confirmed by H-. C-NMR- and mass spectroscopy [ref. 5],... 

There is one scale that is of particular relevance here and that is one that seeks to determine the coordinating ability of the solvent to metal centers.5,6 The 2max for the lowest energy d —> d band of the square planar cation of [Cu(acac)(tmen)][BPh4] where acac = pentane-2,3-dione and tmen = A /VjAA V -tetramethylethylenediamine Fig. 3 correlates well with solvent... 

For example, when pent-2-yne is treated with a cold, dilute solution of neutral permanganate, the product is pentane-2,3-dione. 

Pentane-2,3-dione 2-Ethyl-3,5-dimethyl and 3-ethyl-2,5-dimethyl 330... 

These can be tentatively assigned from mechanistic projections, based on thermal generation studies (2) and assignment to the molecular ion as butan-2,3-dione (ion 87, diacetyl), 1-hydroxy butan-2,3-dione (ion 103), 4-hydroxy pentan-2,3-dione (ion 117), (5-hydroxymethyl) furfural (ion 127), y-pyranone or 4-furanone (ion 145), deoxyosone (ion 163). In comparison when the reaction is conducted in the presence of leucine (Ipil/min water) the primary ions formed are ion 74, 88,142, and 156 (Figure 3). 

Remarkable regioselectivity is noted in the condensation of pentane-2,3-dione and its 2-oxime with triamine (171). The diketone yields exclusively the 7-ethyl-6-methylpyrazino[2,3-c]... 

D.45A) (D.45A) 2,3-Pentanedione, pentane-2,3-dione, ethyl methyl diketone, acetyl propionyl 600-14-6] FEMA 2841... 

Acetyl propane. See Methyl isopropyl ketone Acetyl 2-propanone. See Acetylacetone Acetylpropionic acid 3-Acetylpropionic acid p-Acetylpropionic acid. See Levulinic acid Acetylpropionyl. See Pentane-2,3-dione Acetyl pyrazine. See 2-Acetyl pyrazine 2-Acetyl py razi ne... 

Methylethyl) cyclohexadiene-1 -ethyl formate. See4-(1-Methylethyl) cyclohexadiene-1-ethanol formate (1-Methylethyl) cyclohexane. See Isopropylcyclohexane (1-Methylethyl) cyclopentane. See Isopropylcyclopentane Methyl ethyl diketone. See Pentane-2,3-dione Methylethyl disulfide. See Diisopropyl disulfide 1-Methylethyl docosanoate. See Isopropyl behenate... 

Methyl ethyl glycol. See Propylene glycol Methyl ethyl glyoxal. See Pentane-2,3-dione 1-Methylethyl hexandecanoate. See Isopropyl palmitate... 

Octyl octanoate Octyl phenylacetate Octyl propionate Palmitic acid Paraldehyde PEG-10 sorbitan laurate PEG-3 sorbitan oleate PEG-3 sorbitan stearate Pelargonyl vanillylamide Pentadecalactone Pentane-2,3-dione 4-Pentenoic acid 1-Penten-3-ol Pentyl 2-furyl ketone Perillaldehyde Perillyl acetate Perillyl alcohol a-Phellandrene Phenethyl alcohol Phenethyl anthranilate... 

Pentadecane 2,2,4,6,6-Pentamethylheptane Pentane-2,3-dione 1 -Penten-3-ol Perillaldehyde... 

Octyl acetate Pentane-2,3-dione Phenethyl alcohol Phenylacetaldehyde 2-Phenylethyl methyl ether... 

Isopropenyl acetate Methyl crotonate Methyl methacrylate Pentane-2,3-dione 4-Pentenoic acid Tiglic acid y-Valerolactone Vinyl propionate (C5H802)x Polyethylacrylate Polymethyl methacrylate C5H8O3... 

The formation of off-flavours in beer has been reviewed [40], Autoxidation of the lipids present in beer produces carbonyl compounds with very low taste thresholds. In particular, linoleic acid is oxidized to trihydroxyoctadecenoic acids (Table 22.7) which break down into 2-/mAz.y-nonenal. This aldehyde and related compounds impart a cardboard flavour to beer at very low concentrations. Other carbonyl are formed from the lipids in beer by irradiation with light including the C9, Cjo, and Cu-alka-2,4-dienals (thresholds 0 5, 0 3 and 0 01 ppb respectively) [40]. The level of diacetyl and pentane-2,3-dione in a range of commercial beers is given in Table 22.11. Quantities in excess of 0 15 ppm impart a buttery flavour more noticeable in lagers than in ales. Bacterial contamination and petite mutants of yeast result in high levels of diacetyl. The sulphur compounds characterized in beer are listed in Table 22.19 with some threshold data. Dimethyl sulphide is the major volatile... 

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