Aromatic derived from benzoic acids

With the exception of isochorismic acid the above mentioned acids are aromatic compounds, derived from benzoic acid by an additional hydroxy or amino group in o- or p-position. 

The chemical reactions used to degrade these aromatic compounds are numerous and complex. As was mentioned in Chapter 16, some fungi initiate the attack on lignin with peroxidases and produce soluble compounds that can be attacked by bacteria. In other cases elimination reactions may be used to initiate degradation. For example, some bacteria release phenol from tyrosine by P elimination (Fig. 14-5). However, more often hydroxylation and oxidative degradation of side chains lead to derivatives of benzoic acid or of the various hydroxybenzoic... 

The ditellurium compounds, in which a Te —Te group joins two carbonyl groups, can be considered to be the tellurium analogs of peroxy compounds derived from carbonic acid or benzoic acids (e.g. benzoyl peroxides). Only a few of these compounds are known. During the reduction of aromatic nitro compounds with disodium telluride in dimethylfor-mamide, bis[dimethylaminocarbonyl] ditellurium was formed as a by-product in yields from 5 to 15%. The formation of this compound was attributed to the capture of the dimethylaminocarbonyl radical by the telluride anion and subsequent oxidation of the tellurocarbamoyl species4. 

Shikimic acid (64) is the biosynthetic precursor to an array of aromatic compounds, including benzoic and cinnamic acids/ This pathway is utilized by microorganisms and plants, but not by animals, which obtain essential shikimate building blocks like phenylalanine from their diets/ Red algae are known to be a prolific source of halogenated phenolic metabolites derived from shikimic acid, comprising approximately 5% of known algal metabolites/ ... 

Salicylic acid is a lipophilic beta-hydroxy acid which is used as a peeling agent, compounded as 20-40% solution with ethanol. It is a hydroxyl derivative of benzoic acid and represents a carboxylic add attached to an aromatic alcohol, phenol. It is a white crystalline powder derived from willow bark, winter green leaves, and sweet birch [15]. 

The secondary products derived from anthranilic acid (o-amino benzoic acid) may carry additional substituents at the aromatic ring, e.g., hydroxy groups (see formula for hydroxyanthranilic acid) or at the carboxyl and the amino group. The latter substituents may form additional rings. 

In plants and animals dihydrocinnamic acids (D 22.2.1) are the most important precursors of benzoic acids (for the formation of benzoic acid derivatives from shikimic acid cf. D 8 and D 8.2). The dihydrocinnamic acids are cleaved with the formation of a two carbon fragment and an aromatic aldehyde, which may be... 

Oxazolines (4) are easily prepared from benzoic acids and behave as activating groups in nucleophilic aromatic substitution. Thus, o-methoxy- or o-fluoro-substituents are replaced by the alkyl group of RLi. " The same oxazoline group in the 4-position of pyridine promotes 3-lithiation, whereas in the 3-position it induces nucleophilic alkylation to give 1,4-dihydropyridine derivatives. Benzyl alcohol is lithiated in the 2-position of the benzene nucleus. Solvent effects are suggested to be responsible for the quantitative syn selectivity in the alkylation of lithiated ketimines (5). ... 

Alternatively, adipic acid can be produced through biological conversion of benzoic acid or other aromatics derived from glucose to CM-muconic acid, which can then be converted to adipic acid by hydrogenation. Life cycle analysis of these two processes shows that the biological route can reduce the CO2 equivalent emissions from 17.4 to 14.0 ton CO2 eq/ton adipic acid, even beyond the enviromnental benefits associated with the elimination of the use of benzene derived from fossil resomces [11]. 

Hammen equation A correlation between the structure and reactivity in the side chain derivatives of aromatic compounds. Its derivation follows from many comparisons between rate constants for various reactions and the equilibrium constants for other reactions, or other functions of molecules which can be measured (e g. the i.r. carbonyl group stretching frequency). For example the dissociation constants of a series of para substituted (O2N —, MeO —, Cl —, etc.) benzoic acids correlate with the rate constant k for the alkaline hydrolysis of para substituted benzyl chlorides. If log Kq is plotted against log k, the data fall on a straight line. Similar results are obtained for meta substituted derivatives but not for orthosubstituted derivatives. 

Organic aerosols formed by gas-phase photochemical reactions of hydrocarbons, ozone, and nitrogen oxides have been identified recently in both urban and rural atmospheres. Aliphatic organic nitrates, such dicarboxylic acids as adipic and glutaric acids, carboxylic acids derived from aromatic hydrocarbons (benzoic and phenylacetic acids) and from terpenes emitted by vegetation, such as pinonic acid from a pinene, have been identified. The most important contribution in this held has been that of Schuetzle et al., who used computer-controlled... 

The same group expanded the scope of the aza-Diels-Alder reaction of electron-rich dienes to Brassard s diene 97 (Scheme 37) [60]. In contrast to Danishefsky s diene, it is more reactive, but less stable. Akiyama et al. found chiral BINOL phosphate (R)-3m (3 mol%, R = 9-anthryl) with 9-anthryl substituents to promote the [4 + 2] cycloaddition of A-arylated aldimines 94 and Brassard s diene 97. Subsequent treatment with benzoic acid led to the formation of piperidinones 98. Interestingly, the use of its pyridinium salt (3 mol%) resulted in a higher yield (87% instead of 72%) along with a comparable enantioselectivity (94% ee instead of 92% ee). This method furnished cycloadducts 98 derived from aromatic, heteroaromatic, a,P-unsaturated, and aliphatic precursors 94 in satisfactory yields (63-91%) and excellent enantioselectivities (92-99% ee). NMR studies revealed that Brassard s diene 97 is labile in the presence of phosphoric acid 3m (88% decomposition after 1 h), but comparatively stable in the presence of its pyridinium salt (25% decomposition after 1 h). This observation can be explained by the fact that the pyridinium salt is a weak Brpnsted acid compared to BINOL phosphate 3m. 

Aromatic amides, sometimes referred to as aryiamides, exhibit the same relationship. Note the relationship of benzoic acid Cg H5 COOH with benzamide Q H5 CONH2. Thiamides are derived from amides in which there is substitution of the O atom by a sulfur atom. Thus, acetamide NHa- CO- CH3, becomes thiacetamide NH2- CS- CH3 or acetanilide C6 H5- NH- CO- CH3 becomes thiacetanilide C6 H5- NH- CS- CH3. Sulfonamides arc derived from the sulfonic acids. Thus, bcnzcnc-sulfonic acid Cg H5 SO2- OH becomes benzene-sulfonamide Cg Hs- SOv NH2. See also Sulfonamide Drugs. 

The aroylation of an aromatic system by reaction with phthalic anhydride under Friedel-Crafts conditions is described in Section 6.11.1, p. 1006. The cyclisation of the derived o-aroylbenzoic acid with polyphosphoric acid is a convenient route to substituted anthraquinones. The reaction is illustrated by the formation of 2-methylanthraquinone from o-(p-toluoyl)benzoic acid (Expt 6.132). 

Tannins and lignins are also derived from these pathways but are not included in Table 1. To make the list as simple as possible, all compounds of aromatic nature, viz., simple phenols, benzoic and cinnamic acid derivates, coumarins, flavonoids and quinones are condensed into one group - aromatic compounds. Thus I will attempt to cover systematically the secondary plant growth substances that fall into 11 major groups as shown in Table 1. 

From Derivatives of 2-halogenobenzoic Acids. The syntheses of the previously described benzo-TAs are based on the use of various 2-mercapto-benzoic acid derivatives. In addition, some researchers have reported the use of nucleophilic aromatic substitution of a halogen atom by a sulfur... 

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