L-Octen-3-one

Other volatile compounds present in oak wood can transmit unpleasant aromas to the wine, such as the sawdust aroma of dry wood that is perceptible in some wines aged in new barrels. The substances that cause these aromas have been identified in both American and European oak wood, for instance, ( )-2-nonenal, 3-octen-l-one, ( )-2-octenal, and 1-decanal. Their connection with the sawdust aroma has been established by olfactometry, and they have been identified in wines suffering from this flaw, though toasting the wood (Chatonnet and Dubourdieu 1998). 

Octen-l-one Mushroom 4-Methylguaiacol Spicy, lightly green, phenolic... 

Some compounds from wood may induce defects to the wine. Carbonyl compounds, such as ( )-2-nonenal, ( )-2-octenal, 3-octen-l-one, and 1-decanal are responsible for the sawdust smell sometimes found in the wine after ageing in new 225-L oak wood barrels (bar-riques) ( )-2-nonenal is reputed as being mainly responsible for the sawdust smell of wine (Chatonnet and Dubourdieu, 1998). 

The theory has been applied to the above reactions of the following substances )3-furylacrolein furfurylideneacetone l-furyl-8-methyl-octene-l-one-3 furfuralacetofuran difurfural acetone vinylfuran furfurol 1 -furylhexadiene-1,3-one-5 l-furyl-5-methylhexene-1 -one-3 furfuralcamphor 3-furylpropanol-l 3-(2 -methyl-5 -furyl)propanol-l ... 

Figure 2 illustrates the experimental setup employed for in vivo and in vitro flower scent sampling and the chromatographic profiles (total ion current) obtained. A total of 40 compounds were identified in Sansevieria trifasdata flower scent and their relative amounts changed during the day. There is no single, dominant component of the scent. Aldehydes (hexanal, heptanal, heptenal, nonanal, octenal, nonadienal, decanal), alcohols, ketones (6-methyl-5-hepten-2-one, 3-octen-2-one), acetates (benzyl, hexyl, octyl, 2-ethyl-l-hexyl, decenyl, decyl, dodecenyl, dodecyl and tetradecenyl), methyl and benzyl benzoate, methyl salicilate, eugenol, and ds,frflns-a-farnesene, were identified as the main scent constituents. 

Volatile decomposition products from autoxidized linoleic acid and methyl linoleate were characterized for their intense aroma and flavor impact by capillary gas chromatography-olfactometry. This technique involves sniffing the gas chromatograph effluent after stepwise dilution of the volatile extract. The most intense volatiles included hexanal, c/ -2-octenal, /ra. s-2-nonenal, l-octene-3-one, 3-octene-2-one and trans-l-ociQmX (Table 4.2). This analytical approach does not, however, consider the effects of complex interactions of volatiles occurring in mixtures produced in oxidized food lipids. 

A mixture of acetyl chloride, AICI3, and methylene chloride stirred briefly under Ng, rran -l-hexenylmercuric chloride added, while backflushing with stirred 5 min. rran.y-3-octen-2-one. Y 97%. F. e. s. R. C. Larock and J. C. Bernhardt, Tetrah. Let. 1976, 3097. 

The male produced aggregation pheromone of the Colorado potato beetle, Lepitnotarsa decemlineata, (5)-l,3-dihydroxy-3,7-dimethyl-6-octen-2-one and its (f )-isomer were synthesized using lipase-catalyzed asymmetric acetylation of +)-2,... 

A somewhat different situation arises in the copolymerization of a racemic monomer with an optically active monomer of similar structure in the presence of a conventional stereospecific (or stereoselective) catalyst (299, 321). Examples concern the copolymerization of racemic 3,7-dimethyl-1-octene with (5)-3-methyl-l-pentene and of racemic jec-butyl vinyl ether with various optically active vinyl ethers. In all cases there was preferential copolymerization of one of the two enantiomers of the racemic monomer with the second monomer and simultaneous formation of an optically active homopolymer containing predominantly the noncopolymerized antipode, according to Scheme 20. The two products are easily separated, due to their different solubilities. 

A special case of asymmetric enantiomer-differentiating polymerization is the isoselective copolymerization of optically active 3-methyl-1-pentene with racemic 3,7-dimethyl-1-octene by TiCl4 and diisobutylzinc [Ciardelli et al., 1969]. The copolymer is optically active with respect to both comonomer units as the incorporated optically active 3-methyl-l-pentene directs the preferential entry of only one enantiomer of the racemic monomer. The directing effect of a chiral center in one monomer unit on the second monomer, referred to as asymmetric induction, is also observed in radical and ionic copolymerizations. The radical copolymerization of optically active a-methylbenzyl methacrylate with maleic anhydride yields a copolymer that is optically active even after hydrolytic cleavage of the optically active a-methylbenzyl group from the polymer [Kurokawa and Minoura, 1979]. Similar results were obtained in the copolymerizations of mono- and di-/-menthyl fumarate and (—)-3-(P-styryloxy)menthane with styrene [Kurokawa et al., 1982],... 

As shown in Table 22 in most examples, the prevailing absolute configuration of the asymmetric carbon atoms of the lateral chains of the first eluted fractions is opposite to the one of the support this indicates that the polymer having the same structure as the support is more strongly adsorbed. However, this is not a general phenomenon, as it is shown by the chromatography of poly-3.7-dimethyl-l-octene obtained from the racemic monomer using poly-(S)-3-methyl-l-pentene as support (118). 

Thermoplastic Polyolefin (TPO) One batch of a thermoplastic polyolefin had a roasty off-odor. The important odorants 2,3-butandione, l-hexen-3-one, methional (3-methylthiopropanal), Z-2-nonenal, E-2-nonenal, l-octen-3-one, octanal, E,E-2,4-nonadienal, E,E-2,4-decadienal, and as the most important off-odorant 2-acetyl-l-pyrroline, could be identified (Mayer and Breuer, 2004b, 2006). 

Many individual flavor chemicals which were isolated and identified from Maillard "side reactions" have been reported in the patent literature. It is evident from these patents that much work has been done to glean specific flavor chemicals from the complexities of the Maillard reaction. 3-Furyl alkyl sulfide, disulfide, and 0-chalcogenalkyl sulfide derivatives are claimed to provide bloody, meaty, and roasted notes to beef broth and beef products (64-66). 3-Methylcyclopent-2-en-l-one was declared for its flavor eiiEancement of beef bouillon (67). Firmenich claimed 2,6-dimethyl-2-octenal and its analogs as possessing meat flavor qualities (68). A method to produce disulfides for application to meat and savory flavors was patented (69). 

As shown in the case of l-octen-3-one in the beginning of this chapter, aroma-active compounds show an interesting indication as media in human-environment interactions the role of this often disliked compound has some similarity to alarm pheromones. Flavor or smell of food can be categorized into food attractant molecules from this point of view. Infants are able to recognize the body odor of their mother and are attracted to it.189 An opposite example is represented by the notorious ability of skunks to spray, in which thiol compounds such as (E)-2-butene-1 -thiol and 3-methyl-l-butanethiol are used as potent repellents190(see Chapter 4.09). 

Photolysis of l,3-dithian-5-ones, for example, 360, and 3-methyl-5-thiacyclo-hex-2-ene-l-one, 361, gives 3-thietanones. A 3-thietanone intermediate was suggested in the photolysis of 3-thiatetralone. Photolysis of 8-thiabicyclo-[3.2.1.]-3-octene-2,6-dione gives a 3-thietanone, 8-thiabicyclo[4.1.1]-4-octene-3,7-dione. Thermolysis of the a-diazoketone 362 gives the 2-exomethylene derivative 363. ... 

However, at 250°, the hydrocarbons 18 or 20 are converted to 2-methyl- and 3-methylbicyclo[3.3.0]-2-octenes (24 and 25) and to the bicyclo[4.3.0]-l-nonene (20) (Fig. 7) 16). The reactions indicated by vertical arrows in Fig. 5 are faster than the horizontal ones, and the hydrocarbons in the same column form quasi-equilibrium mixtures. 

Octene-l-al, 38,62 2-Octenes, 303 2-Octylamine, 554 4-Octyne, 96 2-Octyne-l-ol, 62 4-Octyne-3-one, 96 Olefin inversion, 303-304 Olefin methathesis, 570 Orcinol dimethyl ether, 465 Orcinol monomethyl ether, 465 Osmium tetroxide, 31,575,576 Osmium tetroxide-Potassium chlorate, 361... 

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