Phenols vanillin

Phenol Vanillin Vanillin Vanillic acid Hydroxybenzaldehyde Syringaldehyde Syringaldehyde 4-hydroxybenzoic acid... 

When making vanillin from guaiacol the chemist can smell success because the product will have an intense vanilla odor. One can even flavor cookies with the stuff (true ). This Riemer-Tiemann method is also an excellent way to get salicylal-dehyde from phenol in yields of up to 50%. The chemist does everything the same except uses NaOH instead of KOH. 

Because vanillin is a phenol aldehyde, it is stable to autooxidation and does not undergo the Cannizzarro reaction. Numerous derivatives can be prepared by etherification or esterification of the hydroxy group and by aldol condensation at the aldehyde group. AH three functional groups in vanillin are... 

Vanillin reacts with primary amines in weakly basic media to form fluorescent or colored Schiff s bases whereby colored phenolates are also produced at the same time. 

Aromatic aldehydes react in basic as well acidic medium. Thus vanillin and primary amines yield Schiff s bases (cf. vanillin-potassium hydroxide reagent in Volume 1 a). Colored phenolates are formed at the same time. As would be expected secondary amines, indole derivatives and lysergic acid derivatives do not react. 

The use of HPLC for quantification of phenols is often limited to a single class of phenolics and then often only to low-molecular weight compounds that are available as standards. It is, therefore, often necessary to use colorimetric assays such as the Folin-Ciocalteau assay which rely on the reducing ability of phenols to quantify the amount of total phenolics in a sample (Waterman and Mole, 1994 Singleton et al, 1999 Schofield et al, 2001). The degree of condensation of polyphenols can be quantified by colorimetric assays such as the acid-butanol assay and the vanillin assay (Waterman and Mole, 1994 Schofield et al, 2001). 

The total phenolic content in XRPP was 1.10%. The major components were found to be p-hydroxybenzoic acid (0.44%), vanillin (0.19%), syringic acid (0.13%), and syringaldehyde (0.13%). The contents of p-hydroybenzaldehyde, vanillic acid and ferulic acid were 0.032, 0.015 and 0.020%, respectively. Gallic acid, protocatechuic acid and cinnamic acid were detected in trace amounts. 

Another illustration of the enormous potential of catalytic methodologies in fine chemicals manufacture is the new Rhone-Poulenc process for the flavour ingredient, vanillin (Ratton, 1998). The process involves four steps, all performed with a heterogeneous catalyst, starting from phenol (Fig. 2.37). 

Another phenolic compound isolated from Palmer amaranth was vanillin (4-hydroxy-3-methoxybenzaldehyde). This compound has been previously reported in extracts of soils, plant roots and leaf... 

Chlorinated phenolic compounds. Chlorinated phenolic compounds include phenols, guaiacols, catechols, and vanillins substituted with from one to five chlorine atoms per molecule. Typically, bleaching processes that result in the formation of 2,3,7,8-TCDD and... 

Aryl alcohol oxidase from the ligninolytic fungus Pleurotus eryngii had a strong preference for benzylic and allylic alcohols, showing activity on phenyl-substituted benzyl, cinnamyl, naphthyl and 2,4-hexadien-l-ol [103,104]. Another aryl alcohol oxidase, vanillyl alcohol oxidase (VAO) from the ascomycete Penicillium simplicissimum catalyzed the oxidation of vanillyl alcohol and the demethylation of 4-(methoxymethyl)phenol to vanillin and 4-hydro-xybenzaldehyde. In addition, VAO also catalyzed deamination of vanillyl amine to vanillin, and hydroxylation and dehydrogenation of 4-alkylphenols. For the oxidation of 4-alkylphenol, the ratio between the alcohol and alkene product depended on the length and bulkiness of the alkyl side-chain [105,106]. 4-Ethylphenol and 4-propylphenol, were mainly converted to (R)-l-(4 -hydroxyphenyl) alcohols, whereas medium-chain 4-alkylphenols such as 4-butylphenol were converted to l-(4 -hydroxyphenyl)alkenes. 

Benzoic aldehydes mainly cover syringaldehyde and vanillin. Natural vanilla is prepared from the seeds (beans) of Vanilla planifolia, which may contain about 21 mg/ 100 g FW total phenols, including the major components vanillin (19.4 mg/100 g FW), 4-hydroxybenzaldehyde (1 mg/100 g FW), and vanillic acid (0.4 mg/100 g FW) (Clifford 2000b). In mango, vanillin has been found as free as well as vanillyl glu-coside (Sakho and others 1997). It has also been found in lychees (Ong and Acree 1998) and wines (Moreno and others 2007). For analysis of both brandy and wine aged in oak barrels, the limits of detection were found to be 27.5, 14.25, 14.75, and... 

Vanillin (4-hydroxy-3-methoxybenzaldehyde) in ethanolic solution - as supplied as a flavouring agent - was dimerized by sunlight or more rapidly under a mercury lamp to dehydrodivanillin (3). This is a typical ortho-phenol coupling reaction [20],... 

Several syntheses exist for vanillin. A process recently developed by Rhodia seems to be superior [11]. The process (Scheme 5.2) involves four catalytic steps starting from phenol aromatic ring hydroxylation, O-methylation, hydroxymethyl-ation, and oxidation. The process combines elegance and precision in organic synthesis. 

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). 

Methamidophos, see Acephate Methane, see Acetaldehyde, Benzoic acid, 7 Bromobenzoic acid. 3-Bromobenzoic acid. 4-Bromobenzoic acid. Bromoform, Carbatyl, Catechol, 2-Chlorobenzoic acid. 3-Chlorobenzoic acid. Chloroform, Dibromochloromethane, 2,5-Dichlorobenzoic acid. 1,2-Dichloroethane, Ethylamine, Ethyl bromide. Ethylene dibromide, Ethylenimine, Formic acid, Hydroqninone, 4 Hvdroxvbenzoic acid. Indole, 2-Iodobenzoic acid. 3 lodobenzoic acid. Methyl bromide, 4-Iodobenzoic acid. 2-Methylphenol, 4-Methylphenol, Phenol, Prorocatechuic acid. Svringic acid. Svringaldehvde. TCDD, Tetrachloroethylene, Toluene, Trichloroethylene, Vanillin. Vanillic acid. Vinyl chloride... 

Simple phenolics Phloroglucinol, gentisic acid, vanillin, caffeic acid, ferulic acid... 

Simple phenolics are based on a six-carbon ring. Examples are salicylic acid and salicylaldehyde, vanillin, and thymol (Fig. 11.1). 

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... 

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