Benzoic acid conjugation

Toluene exposure does not result in the hematopoietic effects caused by benzene. The myelotoxic effects previously attributed to toluene are judged by more recent investigations to be the result of concurrent exposure to benzene present as a contaminant in toluene solutions. Most of the toluene absorbed from inhalation is metabolized to benzoic acid, conjugated with glycine in the liver to form hippuric acid, and excreted in the urine. The average amount of hippuric acid excreted in the urine by persons not exposed to toluene is approximately 0.7-1.0 g/1 of urine. ... 

Benzoic Acid conjugated with Gly forms hippuric acid which is readily excreted in the urine. Gly can continue to be synthesized from CO2 and NH3. 

The benzoic acid conjugate (VIII) did not undergo signihcant hydrolysis but incubation of the starting material under certain conditions resulted in multiple LC peaks, all of which retained the molecular weight of the original conjugate. 

Products of degradation hydrogen, water, carbon dioxide, ketone, unsaturations, hydroperoxides, radicals, chain scissions, crosslinks, quinomethane structures, benzene, acetophenone, benzaldehyde, benzene, formic acid, acetic acid, benzoic acid, conjugated double bonds ... 

Humans eliminated conjugates of 3-phenoxybenzoic acid (CAS no. 3739-38-6), 3-(4 -hydroxyphenoxy) benzoic acid (CAS no. 35065-12-4), and cyclopropane-carboxylic acid (DCCA CAS no. 55701-05-8) in urine according to Woollen et al. (1992). In the Woollen et al. study, cypermethrin was administered orally to six male volunteers as a single dose (3.3 mg cis trans 1 1) and dermally to six volunteers at a dose of 31 mg/800 cm (cis trans 56 44) of skin. Cypermethrin was orally absorbed between 27 and 57% (mean of 36%) based on the elimination of DCCA and four times greater based on the recovery of benzoic acid conjugates. In the case of the dermal studies, 1.2% of the appUed dose was recovered in urine as benzoic acid conjugates. 

Many aromatic compounds are sufficiently basic to be appreciably protonated in concentrated sulphuric acid. If nitration occurs substantially through the free base, then the reactivity of the conjugate acid will be negligible. Therefore, increasii the acidity of the medium will, by depleting the concentration of the free base, reduce the rateof reaction. This probably accounts for the particularly marked fall in rate which occurs in the nitration of anthraquinone, benzoic acid, benzenesulphonic acid, and some nitroanilines (see table 2.4). 

Human sensitization studies were negative at 10% solution (47). Undiluted benzyl alcohol produces moderate dermal irritation in guinea pigs and mild dermal irritation in rabbits (48,49). Severe eye irritation was noted in a rabbit study (50). Acute oral rat LD q values were reported between 1.23 and 3.10 g/kg (50—52). A dermal rabbit LD q value of 2.0 g/kg has been reported (49). Rats died after 2 h when exposed to a 200-ppm vapor concentration (53). Benzyl alcohol is readily oxidized in animals and humans to benzoic acid [65-85-0] which is then conjugated with glycine [56-40-6], and rapidly eliminated in the urine as hippuric acid [495-69-2] (54). 

Physical and Chemical Properties. The (F)- and (Z)-isomers of cinnamaldehyde are both known. (F)-Cinnamaldehyde [14371-10-9] is generally produced commercially and its properties are given in Table 2. Cinnamaldehyde undergoes reactions that are typical of an a,P-unsaturated aromatic aldehyde. Slow oxidation to cinnamic acid is observed upon exposure to air. This process can be accelerated in the presence of transition-metal catalysts such as cobalt acetate (28). Under more vigorous conditions with either nitric or chromic acid, cleavage at the double bond occurs to afford benzoic acid. Epoxidation of cinnamaldehyde via a conjugate addition mechanism is observed upon treatment with a salt of /-butyl hydroperoxide (29). 

Benzoic acid Methyloxonium ion Conjugate acid of benzoic acid Methanol... 

When a values based on the ionization of benzoic acid are used, deviations may occur with + R para-substituents for reactions involving — R electron-rich reaction centers, and with — R para-substituents for reactions involving + R electron-poor reaction centers. The explanation of these deviations is in terms of cross-conjugation , i.e. conjugation involving substituent and reaction center. 

Samples of the 1,4-dihydrobenzoic acid, after both the first and the second distillations, are transparent in the ultraviolet region between 220 mu and 300 m/i, indicating the absence of benzoic acid or conjugated dihydrobenzoic acids. The refractive index cited in Reference 3 is in error. 

There is little information for fluoro-substituted sulfinyl groups. Values of a and ffp for SOCFj based on benzoic acid ionization are 0.63 and 0.69 respectively , compared with values of about 0.52 and 0.49 for SOMe (Table 3). Thus the electronegative fluorine somewhat enhances the electron-attracting influence of the sulfinyl function and makes the order more definitely sulfur lone pair to engage in 7t(pp) conjugation. Values of and ffp for SOCF3 based on anilinium ion dissociation are 0.76 and 1.05 respectively . An increase of 0.13 as between and [Pg.509]

Fig. 4.1. Potential ranges of solvents, (a) h.n.p.s of acids. I, Acetic acid II, benzoic acid III, formic acid IV, salicylic acid V, sulphuric acid VI, p-toluenesulphonic acid, (b) h.n.p.s of conjugate acids of I, n-butylamine II, piperidine III, ethylenediamine (1) IV, ammonia V, ethylenediamine (2) VI, pyridine.

Thermo Fisher). The small cross-bridge, built from a benzoic acid group, provides crosslinking ability at short intermolecular distances. Reaction of one protein via the NHS ester end of the crosslinker provides a stable derivative that can be incubated with a target molecule and then photolyzed to effect the final conjugation (Figure 5.20). 

Acetic acid is a weaker acid than benzoic acid since the Ka for acetic acid (1.8x10"5) is less than the Ka for benzoic acid (6.5 x 10 5). Therefore, when the relative base strengths of their conjugate bases are compared, the acetate ion, CH3COO , is a stronger base than the benzoate ion, CgHsCOO . In other words, a 0.12 M solution of the benzoate ion is more acidic (less basic) than a 0.12 M solution of the acetate ion. 

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