4-Decenal

Spudich, J., and Hastings, J. W. (1963). Inhibition of the bioluminescent oxidation of reduced flavin mononucleotide by 2-decenal./. Biol. Chem. 238 3106-3108. 

Investigation of the configurational stability of allylmetals 2a, prepared by means of Rieke metals from geometrically pure l-chloro-2-decenes 1 a in THF, showed that the (Z)- and (ZT)-lithium, -sodium, and -potassium derivatives preserve the configuration of the precursors to a preparatively useful extent below — 90°C, — 50°C, and >0°C, respectively. For the pairs of 3,7-dimethyl-2,6-octadienyl derivatives (Z)- and ( )-2b, which differ less in their thermodynamic stability, the respective temperatures are — 60 °C, — 40 °C and >0°C124. 

As in the case of the base-catalyzed reaction, the thermodynamically most stable alkene is the one predominantly formed. However, the acid-catalyzed reaction is much less synthetically useful because carbocations give rise to many side products. If the substrate has several possible locations for a double bond, mixtures of all possible isomers are usually obtained. Isomerization of 1-decene, for example, gives a mixture that contains not only 1-decene and cis- and franj-2-decene but also the cis and trans isomers of 3-, 4-, and 5-decene as well as branched alkenes resulting from rearrangement of carbocations. It is true that the most stable alkenes predominate, but many of them have stabilities that are close together. Acid-catalyzed migration of triple bonds (with allene intermediates) can be accomplished if very strong acids (e.g., HF—PF5) are used. If the mechanism is the same as that for double bonds, vinyl cations are intermediates. 

Synthetic fire-resistant fluids have been developed to replace petroleum-based fluids for many applications. Although there are several types of these less hazardous fluids, the only synthetic fluids discussed in this profile are phosphate esters and polyalphaolefins. The phosphate esters are tertiary esters of orthophosphoric acid, 0=P(0H)3, and may be triaryl, trialkyl, and alkyl/aryl. The polyalphaolefins are usually based on 2-decene and contain a mixture of oligomers (dimers, trimers, etc.). 

Zamora R, Gallardo E, Hidalgo FJ (2006) Amine degradation by 4, 5-epoxy-2-decenal in model systems. J Agric Food Chem 54 2398-2404... 

Simple synthesis of E)-A -oxo-2-decenal and homologues, which are common components of the defensive secretions of true bugs (Hemiptera)... 

NonenaL 2-decenal and 2-undecenal were concentrated appreciably in fraction FI of the 207 bar/50°C extract, whereas aldehydes associated with lipid oxidation such as pentanaL hexanal and octanal were not concentrated by the extraction method used, probably because these constituents continue to accumulate following extraction or because low volatiles are not extracted well by the SC-COj method used. 

The main component of coriander oil is (+)-linalool (60-80%) [452-460c]. Mono- and polyunsaturated fatty aldehydes, although minor components, contribute to the characteristic aroma of the oil because of their powerful odor. In contrast to the seed oil, coriander leaf oil contains these aldehydes as main constituents, e.g. 2-decenal and 2-dodecenal. 

Additional representatives of six-membered 5-lactones are 5-decalactone 155, constituent of fruits, cheese and dairy products with creamy-coco nut and peachy aroma, jasmolactone 156 as well as 5-2-decenolactone (2-decen-5-olide) 157 (Structure 4.47). 

The influence of the sensitivity of the assessors on AEDA has been studied [11], with the result that the differences in the FD factors determined by a group of six panellists amount to not more than two dilution steps (e.g. 64 and 256), implying that the key odorants in a given extract will undoubtedly be detected. However, to avoid falsification of the result by anosmia, AEDA of a sample should be independently performed by at least two assessors. As detailed in [6], odour threshold values of odorants can be determined by AEDA using a sensory internal standard, e.g. ( )-2-decenal. However, as shown in Table 16.6 these odour threshold values may vary by several orders of magnitude [8] owing to different properties of the stationary phases. Consequently, such effects will also influence the results of dilution experiments. Indeed, different FD factors were determined for 2-methyl-3-furanthiol on the stationary phases SE-54 and FFAP 2 and 2 , respectively. In contrast, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone showed higher FD factors on FFAP than on SE-54 2 and 2, respectively. Consequently, FD factors should be determined on suitable GC capillaries [8]. However, the best method to overcome the limitations of GC-O and the dilution experiment is a sensory study of aroma models (Sect. 16.6.3). 

The closely related 5-decanolide (5-decalactone), not only found in many fruits but also found in dairy products, exhibits a creamy-coconut, peach-like aroma [49] and can be synthesised from the corresponding a,(3-unsaturated lactone 2-decen-5-olide found in concentrations of up to 80% in Massoi bark oil using basidiomycetes or baker s yeast [229]. After about 16 h of fermentation, 1.2 g 5-decanolide was obtained. At the same time, the minor lactone in... 

During a field study of the attraction of scavenging flies to the defensive compounds of true bugs, Aldrich and Barros (1995) found considerable numbers of crab spiders (Thomisidae) in their traps. More detailed study showed that both (E)-2-octenal (12) and (E)-2-decenal (13) were attractive to four American crab spider species ... 

Exercise 12-30 How could you phrase Bredt s rule so it could distinguish between the lack of stability of 16 and the stability of bicyclo[5.5.0]-1,2-decene, both compounds having a double-bonded carbon at a ring junction ... 

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