Vanillin structure

Vanillin structures can be considered to be minor lignin end groups and compounds containing vanillin moieties were isolated from all wood and pulp samples. The yields were, however, much lower than those of either coniferyl alcohol... 

The results indicate the importance of the aldehyde moiety in the vanillin structure for its antimicrobial activity and that the bioconversion of vanillin could be advantageous for the yeasts, but only at levels below MIC. It was observed that increased vanillin concentrations inhibited its own bioconversion, suggesting that the activity required intact cells with metabolic capacity. 

CgHjoO,. A compound of largely historical interest for its role in establishing the structure of many natural products. Methylation of vanillin gives veratraldehyde which may be oxidized to veratric acid. Veratric acid was identified as a degradation product of the alkaloid papaverine. 

Rhombic prism lattice, 8 114t Rhombohedral structure, of ferroelectric crystals, 11 95, 96 Rhombohedron lattice, 8 114t Rhomboidal symmetry, 8 114t Rhone-Poulenc process, 24 482, 485 Rhovanil extra pure vanillin, 25 548t, 549-550... 

The Norwegian company Borregaard makes vanillin by chemo-oxidation of cheap natural lignin. In view of the complexity of the lignin structure this is a remarkable achievement. This semi-synthetic vanillin is, however, not allowed to carry the qualification of natural . Borregaard is the only global producer of lignin-vanillin or wood-sourced vanillin , with a volume of about 2000 t a-1. They obtain 4 kg vanillin from one ton of wood. This vanillin is more expensive than synthetic vanillin, but the flavorist needs lower doses of the extra round flavor . 

Essential oils are organic compounds derived from flowers, seeds, leaves, roots, resins, and citrus fruits. The structures of many fragrant compounds have been studied, and processes for making these valuable compounds in a laboratory have been developed. There are now approximately 5000 synthetically produced chemicals that are available to a perfumer. These chemicals include vanillin, rose oxides, and the damascenes, or rose ketones. 

The remaining shlklmates in Table III also are relatively simple, well known compounds. The phenolic structures of vanillin (125) and gallic acid (127) and the prephenolic structures of the common quinic acid (128) and chlorogenic acid (129) make them candidates for physiological activity. Gallic acid is the monomer for tannins, biological polymers found in the cotton plant (15, 37). 

The degradation products of GOG were (Vm), GC -Dimer, vanillin (II), and dehydrodivanillin (X). The reaction of GOG by laccase III, therefore, brings about the formation of biphenyl structures, the cleavage of C-C bond between a- and -carbons, and the cleavage of -0-4 ether linkages. The mode of these cleavages is similar to that of SOG. 

Reduction. The reductive capacity of P. chrysosporium has been known for a long time. For example, veratraldehyde, veratric acid, vanillin, vanillic acid and analogous structures were converted into the corresponding... 

It should be noted that if the non-phenolic Ca-carbonyl compound contains an aromatic ring without Ca-carbonyl group (i.e., the structure should contain at least two aromatic rings), then the compound will be a substrate for lignin peroxidase and will be degraded according to the mechanisms discussed above. Degradation of this type of compounds can result, for example, in the formation of vanillin and vanillic acid derivatives (see compounds 7a and 8). As has been shown by Eriksson and coworkers... 

Lignin. A polymer found in wood (25—30%). The structure of the lignin monomer is still not completely known. Its similarity to coniferyl alcohol, noted more than 75 years ago (Ref 1), is confirmed by the fact that it can be oxidized to vanillin and hydrogenated to compds of the cyclohexylpropyl type. 

Figure 4.1. The 2-D (left) and 3-D (right) structures of synthetic or naturally occurring vanillin, the chemical that gives vanilla extract its characteristic flavour and smell. Neither representation of the structure provides a guide to the fact that humans like its flavour or smell, or indeed that the human nose can specifically detect the molecule.

Many aldehydes are particularly fragrant. A number of flowers, for example, owe their pleasant odor to the presence of simple aldehydes. The smells of lemons, cinnamon, and almonds are due to the aldehydes citral, cinnamalde-hyde, and benzaldehyde, respectively. The structures of these three aldehydes are shown in Figure 12.21. The aldehyde vanillin, introduced at the beginning of this chapter, is the key flavoring molecule derived from the vanilla orchid. You may have noticed that vanilla seed pods and vanilla extract are fairly expensive. Imitation vanilla flavoring is less expensive because it is merely a solution of the compound vanillin, which is economically synthesized from the waste chemicals of the wood pulp industry. Imitation vanilla does not taste the same as natural vanilla extract, however, because in addition to vanillin many other flavorful molecules contribute to the complex taste of natural vanilla. Many books made in the days before acid-free paper smell of vanilla because of the vanillin formed and released as the paper ages, a process that is accelerated by the acids the paper contains. 

Most pyrogallol derivatives did not precipitate either (Table III). A small precipitation occurred with pyrogallol (which may be considered as a hydroxyresorcinol) and it reacts with vanillin/HCl also (7). However, any additional substitution eliminates this reactivity, e.g., gallic acid (Table IV). Purpurogallin did precipitate with formaldehyde. It is not very soluble in the reaction mixture, and it is a tropolone. Structures of this type might interfere, but in tea and probably in wine the known tropolone derivatives are flavonoids (I, 25). 

This allows branching of the polymer. Monomers of other chain lengths as well as aromatic components related to lignin are also present and polymerized into a high molecular mass branched structure. Suberin is a more complex ligninlike polymer with a high content of phenolic constituents135 such as vanillin (Fig. 25-8). 

For example, vanillin can be obtained via at least five different ways (i) by isolation from the orchid (Vanilla planifolia), which is a very expensive method (ii) by tissue culture followed by extraction (iii) by microbial transformation of eugenol, the main compound of clove (iv) from lignine by synthesis, and (v) from guaiacol, a natural aroma compound, with comparable molecular structure. Only the vanillin obtained via the first three methods is natural. The other routes afford a nature-identical vanillin. 

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