Alpha,beta-unsaturated carbonyl

One development involves the use of vitamin B 2 to cataly2e chemical, in addition to biochemical processes. Vitamin B 2 derivatives and B 2 model compounds (41,42) cataly2e the electrochemical reduction of alkyl haUdes and formation of C—C bonds (43,44), as well as the 2inc—acetic acid-promoted reduction of nitriles (45), alpha, beta-unsaturated nitriles (46), alpha, beta-unsaturated carbonyl derivatives and esters (47,48), and olefins (49). It is assumed that these reactions proceed through intermediates containing a Co—C bond which is then reductively cleaved. 

Fischer, H., Klippe, M., Lerche, H., Severin, T., and Wanninger, G. (1990). Electrophilic beta-bromination and nucleophilic alpha-methoxylation of alpha,beta-unsaturated carbonyl compounds. Chem. Ber. 123, 399-404. 

Wadleigh RW, Yu SJ (1987) Glutathione transferase activity of fall armyworm larvae toward alpha-, beta-unsaturated carbonyl allelochemicals and its induction by allelochemicals. Insect Biochem 17 759-764... 

Iersel ML, Ploemen JP, Struik I, van Amersfoort C, Keyzer AE, Schefferlie JG, van Bladeren PJ. 1996. Inhibition of glutathione S-transferase activity in human melanoma cells by alpha,beta-unsaturated carbonyl derivatives. Effects of acrolein, cinnamaldehyde, citral, crotonaldehyde, curcumin, ethacrynic acid, and trans-2-hexenal. Chem Biol Interact 102 117-132. 

Aqueous solutions of unsaturated carbonyls are hydrolyzed under alkaline conditions to produce additional carbonyl-containing compounds. Alkaline conditions traditionally used to accelerate this reaction cascade can be replaced with elevated temperatures and pressures without greatly affecting the overall hydrolysis of these unsaturated carbonyls. Water-mediated retro-aldol degradation of alpha/beta unsaturated carbonyls appears to be significant as a means to thermally-generate flavor-active carbonyls, as well as lead to deterioration of character-impact compounds possessing these features. 

Base-catalyzed hydration of conjugated carbonyls, followed by retro-aldol fragmentation has been a common strategy for studying the reaction cascade (1-4). The kinetically important step in the base-catalyzed hydration of an alpha/beta unsaturated carbonyl is similar to a nucleophilic substitution reaction at carbon 3. The reaction cascade proceeds rapidly from the conjugated carbonyl through its hydration and subsequent fragmentation. 

Table 1. Some Important Precursors of Alpha/Beta Unsaturated Carbonyls in Food and their Retro-Aldol Degradation Products...

Precursor Alpha/Beta Unsaturated Carbonyl Retro-Aldol Products... 

Table 2. Terminating Retro-Aldol Derived Volatile Flavor from Various Alpha/Beta Unsaturated Carbonyl Generating Precursors...

Overall, this paper provides a basis for water-mediated retro-aldol degradation chemistry contributing to thermally-induced volatile flavors. Although lipids provide the principle starting materials for the generation of alpha/beta unsaturated carbonyls in... 

Chung FL, Hecht SS, Palladino G. 1986. Formation of cyclic nucleic acid adducts from some simple alpha, beta-unsaturated carbonyl compounds and cyclic nitrosamines. IARC Sci Publ 70 207-225. 

Chung FL, Harriott SM, Hecht SS. 1986. Generality of formation of cyclic deoxyguanosine adducts by alpha, beta-unsaturated carbonyl compounds [Abstract], Proc Ann Meet Am Assoc Cancer Res 27 85. 

Boy land, E. and Chasseaud, L.F., Enzymes catalysing conjugations of glutathione with alpha-beta-unsaturated carbonyl compounds, B/ocIiera. J., 109,651,1968. 

Murakami, A. et al., Zerumbone, a Southeast Asian ginger sesquiterpene, markedly suppresses free radical generation, proinflammatory protein production, and cancer cell proliferation accompanied by apoptosis the alpha,beta-unsaturated carbonyl group is a prerequisite. 

The two compounds on the right side of Model 2 are examples of alpha,beta-unsaturated carbonyl compounds (a,P-unsaturated carbonyl compoimds). Explain this name. 

Banerjee AK, Carrasco MC, Pena-Matheud CA. Observations on the dehydrogenation of alpha,beta-unsaturated carbonyl compounds with thallium(lll) acetate. Reel. Trav. Chim. Pays-Bas. 1989 108 94-96. 

Kondo K, Tunemoto D. Sulfonyl carbanions in synthesis. 1. Novel route to alpha, beta-unsaturated carbonyl-compounds. Tetrahedron Lett. 1975 (12) 1007-1010. 

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