Hydrolysis of phenyl chloroformate

Micellar Effects on the Spontaneous Hydrolysis of Phenyl Chloroformate 133... 

In contrast to reaction (5-158), addition of micelle-forming surfactants can also slow down chemical reactions. For example, the spontaneous hydrolysis of phenyl chloroformate at 25 °C according to Eq. (5-158a) is retarded by a factor of ca. 16 on addition of sodium dodecylsulfate (SDS) above the one. Below the erne, the SDS... 

Rodriguez, A., Graciani, M. del M., Munoz, M., Moya, M.L. Water-ethylene glycol alkyltrimethylammonium bromide micellar solutions as reaction media study of spontaneous hydrolysis of phenyl chloroformate. Langmuir 2003, 79(18),... 

The effects of [cationic micelles] (micelle-forming surfactants are hexade-cyltrimethylammonium bromide, CTABr, tetradecyltrimethylammonium bromide, TTABr, and dodecyltrimethylanunonium bromide, DTABr) on the rates of spontaneous hydrolysis of phenyl chloroformate in water-ethanediol (ED) solvents have been rationalized in terms of pseudophose (PP) model, i.e.. Equation 3.2 with replaced by Experimentally observed values of k M decrease... 

The rate of spontaneous hydrolysis of phenyl chloroformate decreases with increase in the concentration of micelles of various anionic, nonionic, and cationic surfactants. A comparison of the kinetic data in nonionic micellar solutions to those in anionic and zwitterionic micellar solutions makes it clear that charge effects of micelles is not the only factor responsible for the variations in the reaction rates. Depletion of water in the interfacial region and its different characteristics as compared to bulk water, the presence of high ionic concentration in the Stem layer of ionic micelles, and differences in the stabilization of the reactant state and the transition state by hydrophobic interactions with surfactant tails can also influence reactivity. 

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. 

Queen153 has recently measured the activation parameters A//, A5 and ACp for the hydrolyses of Me, Et, /z-Pr, /-Pr, and phenyl chloroformates and dimethyl carbamyl chloride in pure water (Table 22), and concluded that a change of mechanism (SN2 to SN1) takes place with increasing electron donation to the chlorocarbamyl group the data, which include solvent isotope effects, are consistent with a unimolecular hydrolysis of isopropyl chloro-formate and dimethyl carbamyl chloride and a bimolecular hydrolysis of the other four compounds. 

The triazolopyrimidine-2-sulfonamides 45 were prepared from the 1,2,4-triazole 40 by reaction with phenyl chloroformate to give 41, whose chlorination gave 42, then transformed to the amide 43. Hydrolysis of... 

Methods for the conversion of derivatives of morphine into their N-nor-com-pounds, using vinyl chloroformate,149 trichloroethyl chloroformate,150 and phenyl chloroformate,151 have been patented. Norneopine has been prepared from neopine and diethyl azodicarboxylate and by the hydrolysis of 7V-nitrosonor-neopine.152 The conversion of N-nor-bases into N-alkyl-compounds by the reduction of amides has been covered by a further patent.153... 

Japanese chemists (96) have reported the chemical conversion of kobusine into the chloramine (95). The latter was treated with sodium methoxide in methanol to afford compound 96 in which the bridged C-14-C-20 bond was cleaved. Reduction of kobusine with sodium in n-propanol, followed by acetylation afforded compound 88. Treatment of 88 with excess phenyl chloroformate in refluxing o-dichlorobenzene gave the carbamate 89. The latter was hydrogenated over Pd-C in methanol to obtain compound 90 in 94% yield. Further hydrogenation of 90 in the presence of platinum in acidic solution gave 91. Acidic hydrolysis of 91 afforded compound 92. The carbamate 92 was converted to the benzyl derivative 93 by treating with... 

The reaction between 2-ary1-4-hydroxyarsabenzene (8 Ar= CgHj, 4-MeC H ) and phenyl radicals gives the ketone (9), which on acetylation yields the 4-acetoxy-2-aryl-6--phenylarsabenzene (10). Hydrolysis of (10) affords a product, which in ethanol and chloroform appears to contain both tautomers (11) and (12) (Markl and Rampal, ibid., 1978, 1471). 

Hydrolysis of the quaternary salt (181), obtained from adenine and phenyl chloroformate, yields isoguanine (182) as a result of a ring-opening, ring-closure sequence. 

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