Cinnamyl cinnamate derivatives

Cinnamyl cinnamate derivatives were obtained in good to excellent yields by esterification of a,j8-unsaturated aldehydes, including aromatic aldehydes, with cinnamyl bromides in the presence of DBU, K2CO3, THF, and f-BuOH using either atmospheric O2 or Mn02 as the oxidant and IV-heterocyclic carbene (NHC) as the catalyst. The use of 02 indicated that the path of the O2 oxidation via Breslow intermediate (119) (Scheme 12) differs from that for aldehyde oxidation by Mn02 via a tetrahedral intermediate (124) (Scheme 13). ... 

Fig. 3.8. Derivation of some classes of natural products from the final metabolites of the shikimate pathway. In the cases of cinnamic acid and aldehyde derivatives X = H or X = OR. In the case of the cinnamyl alcohol derivatives, reduction occurs only if X = OR. The two phenolic units represent triketide precursors...

Cinnamic alcohol can be dehydrogenated to give cinnamaldehyde and oxidized to give cinnamic acid. Hydrogenation yields 3-phenylpropanol and/or 3-cyclo-hexylpropanol. Reaction with carboxylic acids or carboxylic acid derivatives results in the formation of cinnamyl esters, some of which are used as fragrance materials. 

Styrene and its derivatives, such as a-methylstyrene, atropic acid, cinnamic acid, and cinnamyl alcohol, were readily reduced (acids were added as their salts), yielding the corresponding dihydro derivatives (Table I). However, propenyl-benzene, tmst/m-diphenylethylene, and stilbene absorbed no hydrogen. 

The reductive sequence from an appropriate cinnamic acid to the corresponding cinnamyl alcohol is not restricted to lignin and lignan biosynthesis, and is utilized for the production of various phenylpropene derivatives. Thus cinnamaldehyde (Figure 4.23) is the principal component in the... 

The suffix -yl is normally used in conjunction with alcohols and their derived esters. This is the form given in most of the samples below. The -ic suffix is normally used in conjunction with aldehydes, and for acids. In some cases, however, the two forms are used alternatively, for example, as with cinnamyl or cinnamic alcohol. 

The electron-rich oxygen atom of a secondary amide derivative of cinnamic acid can be as effective as that of a cinnamyl ether or alcohol in directing anr/-Michael additions to some amide Michael acceptors. For example, BuLi adds to the amide 51 to give a 90 10 ratio of anti-Michael Michael addition products 52 53.31 With the alkyne54 the effect is even more pronounced MeLi gives solely the anti-Michael product 55. These reactions are however very sensitive to starting material and reagent structure. 

CIC The powerful odour is dominated by 2-isobutyl thiazole and 3-pentanethiol. The green notes are lipid degradation products like (E)-2-hexenal, hexanal and higher unsaturated aldehydes, the pineapple-pear like fruity notes are derived from methyl hexanoate, ethyl-2-hexenoate and hexyl acetate. The spicy cinnamon notes are represented by 3-phenyl propyl acetate, cinnamyl acetate, methyl cinnamate, ethyl cinna-mate and ciimamaldehyde. Gamma-decalactone and 2,5-dimethyl-4-hydroxy-furan-3(2H)-one and 3-hydroxy-2-butanone add the sweet, creamy body. Beta-famesene, citronellol, 2-phenylethanol, beta-ionone add the sweet, floral, quincelike part and methyl benzoate and ethyl benzoate impart a characteristic medicinal, exotic topnote. 

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... 

Cinnamyl-Z-ecgonine has been obtained by acylation of Z-ecgonine with cinnamic anhydride. Esterification of this cinnamyl-derivative with methanol gave cinnamylcocaine (103). After the physical properties of cinnamylcocaine had been established it was subsequently isolated from Java coca leaves (109) and from Erythroxylum monogynum Roxb. (77). It has been reported (77) that cinnamylcocaine is devoid of mydriatic and anaesthetic properties. 

Phenylpropane derivatives possess the C skeleton of phenylpropane, i.e. an aromatic system to which a side chain of three C atoms is attached. Examples of these are cinnamic acids, cinnamaldehyde, cinnamyl alcohol, coumarins, and, also, the high polymer lignin. 

Figure 1. Proposed metabolic branching points to various phenylpropanoid pathway derivatives based on existing chemotaxonomic / biochemical data. a. Phenylalanine ammonia-lyase, b. Tyrosine ammonia-lyase, c. Cinnamate-4-hydroxylase, d. Hydroxylase, e. 0-Methyltransferase, f. Cinnamoyl-CoA NADP oxidoreductase, g. Cinnamyl alcohol dehydrogenase.

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