Phenyl benzoate equation

The BPO decomposes with a specific rate constant of about 10 /sec, an Arrhenius constant (A) of about 10 , and an activation energy of about 28 kcal/mol (about 115 kJ/mol). As noted earlier, not all radicals initiate new chains. Some terminate prior to initiation forming inactive products, mainly phenyl benzoate (Equation 6.5). Thus, as noted, an efficiency constant (/) is used that reflects the ratio of BPO that actually form chains. 

Generally, the rate of alkaline hydrolysis of a series of substituted phenyl benzoates was decreased in the presence of 0.5 m BiuNBr, the retardation being larger for esters with electron-donating substituents. The data from 22 esters were fitted to a multiparameter equation, the results showing that solvent electrophilicity was the main factor responsible for changes in the ortho, para and meta polar substituent effects with medium.15... 

Flavanols are similarly accessed from 2-(2-(benzoyloxy)acetyl)phenyl benzoates 752 via a Baker-Venkataraman rearrangement to form 3-benzoyloxy flavones followed by deprotection of the hydroxyl group (Scheme 194) <2000JOC583>. 3-Aroyl flavones are prepared form or/ o-hydroxyacetophenones and aroyl chlorides in modest yield, using a Kostanecki-Robinson approach (Equation 305) <2005SC315>. 

Potassium peroxymonosulfate oxidizes benzophenone to phenyl benzoate (yield 77%), cyclopentanone to 8-valerolactone (yield 35%), and cyclohexanone to e-caprolactone (yield 46%) 205. In an excess of sulfuric acid and in the presence of alcohol, the 8-valerolactone is immediately transesterified to ethyl 8-hydroxyvalerate [201 (equation 382). 

Diacyl peroxides, which are known as radical sources, can decompose by an ionic mechanism in the presence of strong acids. Thus, benzoyl peroxide 282 can be converted into phenyl benzoate in a process whose first step involves a Lewis acid catalyzed carboxy inversion reaction to the mixed carbonate 283 (equation 134). ... 

Figure 8.7 Correlation between the base-catalyzed rate of hydrolysis of phenyl benzoates and the of the phenolic leaving group. The pAT values derived from the Hammet equation for phenols.

Equation (a) Phenol first undergoes dissolution in sodium hydroxide solution to result into the formation of sodium phenoxide, which on being subjected to benzoylation yields phenyl benzoate. 

Write equations to show how nitronium ions might be formed using a mixture of nitric and sulfuric acids. 6-188. Which ring of phenyl benzoate would you expect to undergo nitration more readily Explain. 

Magno and Bontenqpelli (24) have reported on the reaction kinetics of electrogenerated 02 in DMF with phenyl benzoate and p-chlorophenyl benzoate second-order rate constants of 3.0W.3 and 25+5 M sec , respectively, were determined by electrochemical techniques. An e.c.e. (electron transfer-chemical reaction-electron transfer) mechanism was shown to be operative and the following mechanism was suggested (equations 19-23) The... 

Write an equation to show the formation of phenyl benzoate in part b i. [1]... 

The presence of B(OH>3 increases the rate of hydrolysis of ionized phenyl salicylate (PS ) by nearly 10 -fold compared to the rate of hydrolysis of phenyl benzoate under essentially similar conditions (Equation 2.34). However, the hydrolysis of PS crtn also occur with measurable rate in the absence of B(OH)3. Nearly 10 -fold rate enhancement due to the presence of boric acid is attributed to the boric-acid-induced intramolecular reaction involving transition state TS,6. An alternative and kinetically indistinguishable mechanism involving transition state TSiy has been ruled out on the basis of the absence of enhanced nucleophilic reactivity of tertiary and secondary amines toward phenyl salicylate in the presence of borate buffer. 

The effects of inert inorganic and organic salts on k bs for alkaline hydrolysis of phenyl benzoate " and phthalimide, as evident from observed data for two typical sets of observations shown in Table 7.10 and Table 7.11, have been explained in terms of the semiempirical kinetic equation Equation 7.50, which... 

Rate constants and Arrhenius parameters for the reaction of Et3Si radicals with various carbonyl compounds are available. Some data are collected in Table 5.2 [49]. The ease of addition of EtsSi radicals was found to decrease in the order 1,4-benzoquinone > cyclic diaryl ketones, benzaldehyde, benzil, perfluoro propionic anhydride > benzophenone alkyl aryl ketone, alkyl aldehyde > oxalate > benzoate, trifluoroacetate, anhydride > cyclic dialkyl ketone > acyclic dialkyl ketone > formate > acetate [49,50]. This order of reactivity was rationalized in terms of bond energy differences, stabilization of the radical formed, polar effects, and steric factors. Thus, a phenyl or acyl group adjacent to the carbonyl will stabilize the radical adduct whereas a perfluoroalkyl or acyloxy group next to the carbonyl moiety will enhance the contribution given by the canonical structure with a charge separation to the transition state (Equation 5.24). 

A tellurium-triggered cyclization of methyl 2-(2-bromoacetoxy)benzoates 671 affords 4-hydroxy coumarins in good yield (Scheme 160) <2005JOC4682>. Similarly, the tellurium-triggered cyclization of 2-formyl and 2-acetyl-phenyl 2-bromoacetates 672 provides coumarins (Equation 271) <2005JOC4682>. 

The conversion of alkynyl(phenyl)iodonium ions to alkynyl esters with carboxylate ions via the MC mechanism (equation 45) has been proposed81. Evidence for the viability of this process is provided by the generation of 3,3-dimethyl-1-cyclopentenyl benzoate in addition to the expected alkynyl benzoate when the iodonium triflate shown in equation 90 is mixed with sodium benzoate in dichloromethane (yields not reported)3. 

The a-chloro-a-sultinyl ketone 20 was prepared from methyl benzoate and chloromethyl phenyl sulfoxide 19 after in situ a-lithiation. Compound 20 is dimetallated by KH and f-BuLi to give the keto dianion 21, which is converted into a potassium/lithium ynolate 22 (equation 7). The resulting metal ynolates are converted into thioesters, carboxylic acids, amides and esters (Section V). 

Alkynyl(phenyl)iodonium carboxylates 99 are even less stable than phosphates 98 and decompose immediately upon generation from iodonium triflates 100 or benzoate 101 with the formation of the desired alkynyl carboxylates 96 (equation 65) k... 

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