Hydrolysis of diphenyl carbonate

Scheme 1 Hydrolysis of diphenyl-carbonate (1) to give 4-nitro-phenol (2), 4-acetamido-phenol and carbon dioxide. The diphenyl-phosphate (4) was used as TSA to mimic the tetrahedral transition state formed during the hydrolysis...

Similar to catalytic antibodies, we observed some product inhibition. In the case mentioned, the reaction rate was calculated from the amount of released acid. If the calculation is based on phenol release, the rate enhancement turned out to be nearly doubled. Hydrolysis of carbonates should avoid this difficulty. Therefore, diphenyl phosphate was used as template, and the hydrolysis of diphenyl carbonate was then investigated [13]. Compared to solution an enhancement of 982-fold was obtained and typical Michaelis-Menten kinetics were observed (K ,ax = 0.023 mM/min, = 5.01 mM, = 0.0115/min, kaalK = 2.30/min/M). 

Strikovsky AG, Kasper D, Grun M, Green BS, Hradil J, Wulff G (2000) Catalytic molecularly imprinted polymers using conventional bulk polymerization or suspension polymerization Selective hydrolysis of diphenyl carbonate and diphenyl carbamate. J Am Chem Soc 122 6295... 

Diphenyl phosphate N,N -diethyl(4-vinylphenyl)amidine MMA EDMA MeCN, cyclohexanol+dodecanol or toluene Using transition state analog selective hydrolysis of diphenyl carbonate and diphenyl carbamate bulk and suspension polymerization [174)... 

To avoid the issne of product inhibition, Wnlff etal. investigated the hydrolysis of carbonates and carbamates, which release prodncts with no significant affinity for the amidine active site. Rate enhancements for the hydrolysis of diphenyl carbonate and diphenyl carbamate were fonnd to be 588 and 1435, respectively, compared to the nncatalyzed reaction. ... 

Hydrolysis of diphenyl phosphorochloridate (DPPC) in 2.0 M aqueous sodium carbonate is also believed to be a two-phase process. DPPC is quite insoluble in water and forms an insoluble second phase at the concentration employed (i.e. 0.10 M). It seems highly significant that the hydrophobic silicon-substituted pyridine 1-oxides (4,6,7) are much more effective catalysts than hydrophilic 8 and 9. In fact, 4 is clearly the most effective catalyst we have examined for this reaction (ti/2 < 10 min). Since derivatives of phosphoric acids are known to undergo substitution reactions via nucleophilic addition-elimination sequences 1201 (Equation 5), we believe that the initial step in hydrolysis of DPPC occurs in the organic phase. Moreover, the... 

Diphenylacetic acid has been obtained by the reduction of benzilic acid with hydriodic acid and red phosphorus 1 by the treatment of phenylbromoacetic acid with benzene and zinc dust,2 or with benzene and aluminum chloride 3 by the hydrolysis of diphenylacetonitrile 4 by heating a-diphenyldichloroethyl-ene with alcoholic sodium ethylate 5 by heating benzilic acid 6 from diphenylmethane, mercury diethyl, sodium and carbon dioxide 7 by the oxidation of a,a,5,S-tetraphenyl- 8-butine 8 by the decomposition of some complex derivatives obtained from diphenylketene 9 by the hydrolysis of diphenyl-5,5-hydan-toin 10 by the treatment of diphenylbromoacetic acid with copper 11 by the oxidation of dichlorodiphenylcrotonic acid.12... 

An example of this imprinting approach is illustrated in Scheme 1, where a polymer with hydrolytic properties towards the diphenyl-carbonate (1) was imprinted with the corresponding phosphate template (4), which represents a TSA for the hydrolytic reaction. This structure, in fact, mimics the tetrahedral intermediate formed during the hydrolysis of the carbonate, and therefore it allows imprinting a cavity with functional groups placed in the right spatial position. 

Tests in pure water, river water, and activated sludge showed that commercial ttiaryl phosphates and alkyl diphenyl phosphates undergo reasonably facile degradation by hydrolysis and biodegradation (163—165). The phosphonates can undergo biodegradation of the carbon-to-phosphoms bond by certain microorganisms (166,167). 

Information concerning the chemistry of meso-ionic 3-alkyl- and 3-aryl-l,2,3,4-oxatriazol-5-ones (271) is limited, but further investigation may well be encouraged by reports of pronounced hypotensive activity. 3-Cyclohexyl-1,2,3,4-oxatriazol-5-one (271, R = cyclohexyl) is resistant to attack by dilute mineral acid, but warm concentrated sulfuric acid gives cyclohexanol and carbon dioxide. In contrast, acid hydrolysis of 3-phenyl-l,2,3,4-oxatriazol-5-one (271, R = Ph) yields phenyl azide. Meso-ionic 3-cyclohexyl-l,2,3,4-oxatriazol-5-one shows two unusual reactions its photoirradiation in benzene gives cyclohexanone and heating with diphenylacetylene )delds l-cyclohexyl-4,5-diphenyl-1,2,3-triazole (276) rather than the expected 2-cyclohexyl-4,5-diphenyl-1,2,3-triazole. 

A preferred synthetic procedure to PAEH concerns the formation of the bisphenolate salt followed by the addition of the activated difluoro, dichloro or dinitro monomer. As an example, the heterocyclic bisphenol is stirred in a mixture of toluene and an aprotic polar solvent such as DMAc, NMP or diphenyl sulfone at 135-140 °C for several hours in the presence of 10 mol % excess of powdered anhydrous potassium carbonate (stoichiometric amount of sodium or potassium hydroxide can be used) under a Dean-Stark trap in a nitrogen atmosphere. Water is removed by azeotropic distillation. A stoichiometric quantity of the difluoro monomer is then added to the slightly cooled reaction mixture. The toluene is removed and the reaction is stirred at 155°C in DMAc for one to several hours. Polymer isolation is performed as previously described. This procedure minimizes hydrolysis of the difluoro monomer, gel formation and molecular weight equilibration of the polymer. 

However, analogous diorganosilanediols 43b are relatively stable compounds. For example, diphenylsilanediol (44), having no carbon analogue, is an isolable crystalline compound, which is easy to prepare by hydrolysis of diphenyldichlorosilane, diphenyldialkoxysilanes, and other diphenyl-substituted hydrolyzable silanes. 44 was synthesized for the first time by Kipping as early as 191263). 

Steric hindrance must be relatively unimportant in the rate-determining attack of H20 on the carbonium ion in the hydrolyses of 1,3-dioxolanes with only one alkyl or aryl group at the 2-position, for the rate is greatly increased by such a group [161]. However, introduction of a second group at the 2-position leads only to a small rate increase or even to a rate decrease in some examples [165,168]. These observations may indicate some steric hindrance of the bimolecular step. Another explanation would be steric hindrance of resonance stabilization of the alkoxycarbonium ion-like transition state. If one or two of the aromatic rings in the transition state of the hydrolysis of 2,2-diphenyl-l,3-dioxolane is not in the same plane with the bonds of the central carbon and the adjacent oxygen, a smaller Hammett p value must be expected. 

Diphenyl-4-formylmethylidene-4H-tellurin was obtained by hydrolysis of the dimeth-yliminio derivative with aqueous sodium hydrogen carbonate. ... 

Cuprous chloride tends to form water-soluble complexes with lower olefins and acts as an IPTC catalyst, e.g., in the two-phase hydrolysis of alkyl chlorides to alcohols with sodium carboxylate solution [10,151] and in the Prins reactions between 1-alkenes and aqueous formaldehyde in the presence of HCl to form 1,3-glycols [10]. Similarly, water-soluble rhodium-based catalysts (4-diphenylphosphinobenzoic acid and tri-Cs-io-alkylmethylam-monium chlorides) were used as IPTC catalysts for the hydroformylation of hexene, dodecene, and hexadecene to produce aldehydes for the fine chemicals market [152]. Palladium diphenyl(potassium sulfonatobenzyl)phosphine and its oxide complexes catalyzed the IPTC dehalogenation reactions of allyl and benzyl halides [153]. Allylic substrates such as cinnamyl ethyl carbonate and nucleophiles such as ethyl acetoactate and acetyl acetone catalyzed by a water-soluble bis(dibenzylideneacetone)palladium or palladium complex of sulfonated triphenylphosphine gave regio- and stereo-specific alkylation products in quantitative yields [154]. Ito et al. used a self-assembled nanocage as an IPTC catalyst for the Wacker oxidation of styrene catalyzed by (en)Pd(N03) [155]. 

Similar results are observed in model studies if phenyl chloroformate is added to an interfacial reaction mixture containing caustic and a tertiary amine followed by systematic quenching of samples taken over the course of the reaction with a secondary amine. Diphenyl carbonate is produced to the exclusion of phenol or the phenyl dialkyl urethane which results upon quenching with amine. If phase-transfer catalysts are used instead of tertiary amines, then diphenyl carbonate is not produced and urethanes are the major product formed upon quenching samples with the secondary amine. However, if equal molar amounts of phenyl chloroformate and a phenol are added to an interfacial mixture containing either a tertiary amine or a phase-transfer catalyst, then diphenyl carbonate is produced very rapidly. Thus, at least the hydrolysis portion of the cyclization reaction requires a tertiary amine acylation catalyst. 

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