Cinnamic aldehyde, reaction

Claisen reaction Condensation of an aldehyde with another aldehyde or a ketone in the presence of sodium hydroxide with the elimination of water. Thus benzaldehyde and methanal give cinnamic aldehyde, PhCH CH-CHO. 

There are at least two routes currently being used to produce natural benzaldehyde. Principal flavor houses are reported to market a product which is derived from cassia oil. The chief constituent of cassia oil is cinnamic aldehyde which is hydrolyzed into its benzaldehyde and acetaldehyde constituents. This is a fermentative retroaldol reaction. Whether this hydrolysis allows the final benzaldehyde product to be considered natural is of great concern. The FDA has reportedly issued an opinion letter that benzaldehyde produced from cassia oil is not natural (15). 

Cinnamic aldehyde, C HgO, is the principal odorous constituent of dnnamon and cassia oils, and is manufactured to a considerable extent, artificially. It can be extracted from the oils in which it occurs by means of sodium bisulphite, the sodium bisulphite compound being decomposed with dilute sulphuric acid, and distilled in a current of steam. The preparation of artificial cinnamic aldehyde, which is used in perfumery as a substitute for the natural oils, is usually carried out. by a condensation of benzaldehyde and acetaldehyde, according to the following reaction —... 

Sadtler concluded finally that double bonds seem to aid in bringing about reaction when close to the. CHO group, e.g., citral, cinnamic aldehyde, and that proximity of the benzene nucleus to the. CHO group, as. in the case of benzaldehyde and vanillin, was also probably a factor, while the only active ketones were those containing double bonds near to the. CO group. 

Semioxamazide.—A gravimetric method for the estimation of cinnamic-aldehyde in cassia and cinnamon oils, but which appears to apply only to this aldehyde, has been devised by Hanus based on the formation of a crystalline semioxamazone when cinnamic aldehyde is treated -with semioxamazide, the reaction being—... 

As shown in Schemes 10-44 and 10-45, two products may be formed in a Meerwein reaction Scheme 10-44 shows a simple aryl-de-hydrogenation of cinnamic aldehyde, whereas Scheme 10-45 shows an aryl-de-hydrogenation combined with the addition of HC1 to the double bond of the methyl ester of cinnamic acid. No systematic studies have been made as to which of the two products will be formed in a given reaction, what experimental conditions will favor one or the other product, and what substituents or other structural characteristics of the alkene influence the ratio of the two types of product. The addition product can, in most cases, easily be converted... 

For the Cu(OTf)2-promoted reaction between ethyl diazoacetate and cinnam-aldehyde dimethyl acetal, products 143-145 account for only 35% the total yield. C/C and C/H insertion products 151 and 152 are obtained additionally in 49 and 14% yield, respectively154). It was assumed that the copper compound acts through Lewis-acid catalysis here, just as it is believed to do when orthoesters are used as substrates 160). According to this, catalyst-induced formation of a methoxy-... 

Diazoacetaldehyde dimethylacetal (12) has been used as a substitute for diazoacetaldehyde in 1,3-dipolar cycloadditions with l-benzopyran-2(//)-ones (40), styrene, methyl methacrylate, 1-cyanocyclopentene, and methyl cyclohexene-1-carboxylate (41). The resulting A -pyrazolines were readily transformed in two steps into cyclopropanecarbaldehydes [e.g., 13 —> 14 (Scheme 8.4)]. In a similar manner, 3-phenylcyclopropane-l,2-dicarbaldehyde was obtained from the reaction of 12 with dimethyleneketal of cinnamic aldehyde. 

This topological rule readily explained the reaction product 211 (>90% stereoselectivity) of open-chain nitroolefins 209 with open-chain enamines 210. Seebach and Golinski have further pointed out that several condensation reactions can also be rationalized by using this approach (a) cyclopropane formation from olefin and carbene, (b) Wittig reaction with aldehydes yielding cis olefins, (c) trans-dialkyl oxirane from alkylidene triphenylarsane and aldehydes, (d) ketenes and cyclopentadiene 2+2-addition, le) (E)-silyl-nitronate and aldehydes, (f) syn and anti-Li and B-enolates of ketones, esters, amides and aldehydes, (g) Z-allylboranes and aldehydes, (h) E-alkyl-borane or E-allylchromium derivatives and aldehydes, (i) enamine from cyclohexanone and cinnamic aldehyde, (j) E-enamines and E-nitroolefins and finally, (k) enamines from cycloalkanones and styryl sulfone. 

The analogous reaction which accompanies the reduction of cinnam-aldehyde in alkaline solutions is more amenable to experimental study. This reaction follows scheme (39) ... 

Arenediazonium o-benzenesulfonamide 89 was found to be a new and efficient reagent for the Heck-type arylation reactions of some common substrates containing C-C multiple bonds, i.e., ethyl acrylate, acrylic acid, acroleine, styrene, and cyclopentene <2006T3146>. The reactions are carried out in the presence of Pd(OAc)2 and afford arylated products, for example ethyl cinnamates, cinnamic acids, cinnamic aldehydes, and stilbenes, possessing an ( -configuration, and 1-arylcyclopentenes, in good to excellent yields (Equation 27). 

Three mechanisms are implicated in CUS immunologic (ICU), nonimmunologic (NICU), or uncertain mechanism.20 ICU is a type I hypersensitivity reaction that is IgE mediated and is associated with atopy. NICU is the more common variety of CUS. NICU due to cosmetics is most commonly caused by fragrances (e.g., cinnamic aldehyde) and preservatives (e.g., benzoic acid and sorbic acid).2 Parabens have been documented by passive transfer to cause ICU.21... 

Crossed aldol condensations between aliphatic aldehydes on the one hand and benzaldehyde or cinnamic aldehyde or their derivatives on the other also are possible. The reaction components can even be mixed together. The aldol adducts are formed without chemo-... 

In the first type, which includes aldehyde C12 lauric and phenylacetaldehyde, the balance of the reaction lies in favor of the combined molecule. In the second, however, to which belong aldehyde C12 MNA, cyclamen aldehyde, hydratropic aldehyde, and Lilial, the balance lies more toward the original material. Most ketones also behave in this way. The third type, which includes amyl and hexyl cinnamic aldehydes, do not undergo the aldol reaction and are therefore more stable. Aldehydes such as anisaldehyde and Triplal, in which the —CHO is linked directly to a ring structure, are also less reactive. 

Crossed aldol condensations between aliphatic aldehydes on the one hand and benzaldehyde or cinnamic aldehyde or their derivatives on the other also are possible. The reaction components can even be mixed together. The aldol adducts are formed without chemoselectivity, as a mixture of isomers, but their formations are reversible. The Elcb elimination to an a,/3-unsaturated carbonyl compound is fast only if the newly created C=C double bond is conjugated to an aromatic system or to another C=C double bond already present in the substrate. This effect is due to product-development control. All the starting materials thus react in this way via the most reactive aldol adduct. 

No colour appears with some aldehydes, for example, furfural and cinnamic aldehyde. Bitto has suggested this reaction may be used for the identification of aldehydes and ketones (see also p. 239). 

Addition to unsaturated aldehydes results either in the 1 2- or in the lj4-addition product depending on the reaction conditions. Thus, in the case of cinnam-aldehyde the lj2-addition product is produced in the presence of BFj OEt and the lj4-addition product is obtained in the presence of MejSiCl (Scheme 2.46) [97]. 

Cinnamic aldehyde reacts as benzaldehyde does and is important as a synthetic reagent in the same classes of reactions. 

An additional number of characteristic aldehyde reactions will be taken up later in practice. Benzaldehyde is prepared technically on the large scale. Its most important application is for the manufacture of the dyes of the Malachite Green series, and of cinnamic add (see these preparations). >... 

L-Phenylalanine,which is derived via the shikimic acid pathway,is an important precursor for aromatic aroma components. This amino acid can be transformed into phe-nylpyruvate by transamination and by subsequent decarboxylation to 2-phenylacetyl-CoA in an analogous reaction as discussed for leucine and valine. 2-Phenylacetyl-CoA is converted into esters of a variety of alcohols or reduced to 2-phenylethanol and transformed into 2-phenyl-ethyl esters. The end products of phenylalanine catabolism are fumaric acid and acetoacetate which are further metabolized by the TCA-cycle. Phenylalanine ammonia lyase converts the amino acid into cinnamic acid, the key intermediate of phenylpropanoid metabolism. By a series of enzymes (cinnamate-4-hydroxylase, p-coumarate 3-hydroxylase, catechol O-methyltransferase and ferulate 5-hydroxylase) cinnamic acid is transformed into p-couma-ric-, caffeic-, ferulic-, 5-hydroxyferulic- and sinapic acids,which act as precursors for flavor components and are important intermediates in the biosynthesis of fla-vonoides, lignins, etc. Reduction of cinnamic acids to aldehydes and alcohols by cinnamoyl-CoA NADPH-oxido-reductase and cinnamoyl-alcohol-dehydrogenase form important flavor compounds such as cinnamic aldehyde, cin-namyl alcohol and esters. Further reduction of cinnamyl alcohols lead to propenyl- and allylphenols such as... 

By the time comprehensive reviews by Wilds (29) in 1944 and Djerassi (30) in 1953 became available, MPV reactions were a standard reductive technique in the organic chemistry community. For example, a 1945 patent (20) describes the utility of using aluminum alkoxides in the presence of an organic nitrogen as a weak base for the reduction of carbonyl groups on oxo compounds such as 7-hydroxy-cholesterol acetate, benzaldehyde, cinnamic aldehyde, and citronellal. 

CINNAMIC ALDEHYDE (104-55-2) Combustible liquid (flash point 231°F/ 111°C). A strong reducing agent. Contact with oxidizers, sodium hydroxide can cause fire and explosion. Incompatible with strong acids, strong bases, alkaline earth and alkali metals elevated temperatures will increase reaction. Attacks iron, aluminum, plastics, and coatings. 

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