Photolysis of phenyl azide

The quantum yield for the photodissociation of phenyl azide in the concentration range from 10^–4 to 10^–1 M is 0.4–0.5, while the yield of azobenzene does not exceed 50%.Institute of Chemical Physics, Russian Academy of Sciences 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 752–754, March, 1992.     

含磺酰胺基和羧苯基的异方酰胺的合成

以3-[邻(或对)羧苯胺基]-4-羟基-3-环丁烯二酮(1a, 1b)为底物,与一些磺胺反应, 成功地制得了14个新的不对称取代的异方酰胺。3a～3f和4a～4f结构上的共同特点是, 有药物作用的磺酰胺和邻(或对)氨基苯甲酸的结构单元, 通过方酸四碳环的桥接作用而共存于同一分子之中。     

Plasma polymerization of phenyl isothiocyanate

Thin polymer films were obtained by plasma polymerization of phenyl isothiocyanate. Polymerizations were carried out in rf (13.56 MHz) glow discharge generated in an electrodeless flow system. It was found that this monomer produces uniform films with a wide range of thicknesses, from hundreds of nanometers to tens of micrometers. The deposition rate appeared to be dependent on the substrate distance from the monomer inlet. The chemical structure of plasma polymer was characterized by using elemental analysis, IR spectroscopy, gas chromatography, and mass spectrometry. Elemental analysis showed that the composition of polymer depends on the substrate position in the reactor. It was observed that sulphur content decreased with increasing the substrate distance from the monomer inlet, whereas nitrogen content appeared to increase. The IR data revealed significant decrease in —NCS groups content in the polymer as compared with the monomer spectrum and indicated for the appearance of new absorption bands corresponding to the ? CN and C? H aliphatic, groups. The results account for a strong fragmentation of monomer in plasma involved in decomposition of isothiocyanate group and phenyl ring. The soluble fraction of polymeric material was examined by gas chromatography and then the separated products were analyzed by mass spectrometry. The soluble fraction was found to be composed of numerous low molecular-weight compounds. Identification of their structure revealed the presence of residual monomer, thiophenol, cyanobenzene, diphenyl, diphenyl sulphide, diphenyl disulphide, phenyl thiocyanate, dicyanobenzene, phenatroline, and some other oligomeric products. Formation of these compounds proves high susceptibility of ? NCS group in the monomer towards different fragmentation reactions. The surface free energy and electrical conductivity of polymer films were evaluated. The surface free energy value was very close to those estimated for plasma polymers deposited from other benzene derivatives. The low electrical conductivity manifested by the investigated polymeric material indicated for its dielectric character. The photoelectrical measurements revealed some photoconductivity effect in this material.     

Synthesis of phenyl furyl sulfides and phenyl furyl ethers by nucleophilic substitution of nitrofurans

Phenyl furyl sulfides ( 3a‐j ) and phenyl furyl ethers ( 3k‐n ), which are useful in synthesizing furocondensed 3‐ring compounds, can be synthesized by nucleophilic substitution of nitrofurans having electron withdrawal groups. In our experiments using 5‐nitrofurans having electron withdrawal groups ( 2a‐i ), nucleophilic substitution readily occurred with the benzenethiolate anion of thiosalicylic acid ( 1a ), the benzenethiolate anion of thiosalicylate ester ( 1b ), and the phenylate anions of salicylate esters ( 1c‐d ) to yield phenyl furyl sulfides ( 3a‐j ) and phenyl furyl ethers ( 3k‐n ).     

Polymerization of allyl phenyl ether

Allyl phenyl ether polymerized rapidly and quantitatively to a resin with a structure similar to a phenolic thermoset in the presence of boron trifluoride etherate at 50°C. The structure and properties of this polyphenol were studied. A reaction mechanism involving rearrangement was discussed.     

Transesterification kinetics of phenyl salicylate

The degradation of phenyl salicylate in alkaline aqueous ethanol is shown to proceed via competing transesterification and hydrolysis processes. The transesterified product, ethyl salicylate, also undergoes hydrolysis, but at a slower rate and a kinetic model is presented which allows the simultaneous determination of all three rate constants. These results are contrasted with those of an earlier literature study and show the necessity for specific assay systems in kinetic analysis.     

Mechanism of reaction of phenyl glycidyl ether with phenyl benzoate in the presence of water

The reaction of phenyl glycidyl ether with phenyl benzoate in the presence of water was investigated by adsorption liquid chromatography.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 131–133, January, 1990.     

Transient absorption spectral evidence for phenyl nitrene as the chain propagator in the photo-initiated autocatalytic chain decomposition of phenyl azide and phenyl isocyanate

Transient absorption spectra were recorded 15 ns to 6 μs following a 266 nm laser pulse for phenyl azide and for phenyl isocyanate in aerated acetonitrile and 3-methylpentane solutions. Transient spectra which are independent of concentration and of delay time, are essentially identical for phenyl azide and for phenyl isocyanate, except at higher energies where phenyl azide absorbs, and are assigned as that of triplet phenyl nitrene. Since there is no spectral evidence for a second species, phenyl nitrene is thought the chain propagator in the autocatalytic chain decomposition that occurs for phenyl azide and for phenyl isocyanate.     

13C NMR spectra of p- and m-substituted phenyl N-methyl- and phenyl N,N-dimethyl-carbamates

¹³C NMR spectra of p- and m-substituted phenyl N-methylcarbamates, phenyl N,N-dimethylcarbamates and p- and m-substituted phenyl propionates were recorded, and their para ¹³C SCS (substituent chemical shifts) were analysed by DSP (dual substituent parameters) and DSP-NLR (non-linear resonance) equations. It was found that the fixed substituent Y, ? OCONHCH₃, ? OCON(CH₃)₂ and ? OCOC₂H₅, were all mild in the sense that DSP analysis gave a good correlation, leaving little room for improvement by the DSP-NLR treatment. Further, the three series of compounds gave similar ρ_I and ρ_R values (para derivatives, 3.2–3.3 and 17.7–18.0; meta derivatives, 5.1–5.2 and 21.8–22.0). Examination of the corresponding analyses of similar compounds indicated that the ρ_I and ρ_R values and, hence, their ratio ρ_R/ρ_R = λ, depended primarily on the nature of the atom through which the fixed substituent Y (e.g. α-C, α-N and α-O) was bonded to the aromatic ring when the Y substituents are mild. The extent of this tendency for compounds with active fixed substituents is also discussed.     

Dichlorocyclopropanation of chloro-substituted vinyl phenyl ethers

Conclusions The reaction of chloro-substituted vinyl phenyl ethers with dichlorocarbene generated by the thermolysis of phenyl(trichloromethyl)mercury leads to the corresponding gem-dichlorocyclopropyl derivatives while the reaction of cis--chlorovinyl phenyl ether with chloroform and alkali under phase transfer catalysis conditions gives -trichloromethyl--chloroethyl phenyl ether.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 222–224, January, 1985.     

Chemistry of polycyclic aromatic hydrocarbons formation from phenyl radical pyrolysis and reaction of phenyl and acetylene

An experimental investigation of phenyl radical pyrolysis and the phenyl radical + acetylene reaction has been performed to clarify the role of different reaction mechanisms involved in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) serving as precursors for soot formation. Experiments were conducted using GC/GC-MS diagnostics coupled to the high-pressure single-pulse shock tube present at the University of Illinois at Chicago. For the first time, comprehensive speciation of the major stable products, including small hydrocarbons and large PAH intermediates, was obtained over a wide range of pressures (25-60 atm) and temperatures (900-1800 K) which encompass the typical conditions in modern combustion devices. The experimental results were used to validate a comprehensive chemical kinetic model which provides relevant information on the chemistry associated with the formation of PAH compounds. In particular, the modeling results indicate that the o-benzyne chemistry is a key factor in the formation of multi-ring intermediates in phenyl radical pyrolysis. On the other hand, the PAHs from the phenyl + acetylene reaction are formed mainly through recombination between single-ring aromatics and through the hydrogen abstraction/acetylene addition mechanism. Polymerization is the common dominant process at high temperature conditions.     

Nucleofugality of phenyl and methyl carbonates

A series of X,Y-substituted benzhydryl phenyl carbonates 1 and X,Y-substituted benzhydryl methyl carbonates 2 were subjected to solvolysis in different methanol/water, ethanol/water, and acetone/water mixtures at 25 degrees C. The LFER equation, log k = sf(Ef + Nf), was used to derive the nucleofuge-specific parameters (Nf and sf) for phenyl carbonate (1LG) and methyl carbonate (2LG) leaving groups in a given solvent in SN1 type reaction. Kinetic measurements showed that phenyl carbonates solvolyze one order of magnitude faster than methyl carbonates. Optimized geometries of 1LG and 2LG at B3LYP/6-311G(d,p), B3LYP/6-311++G(d,p), and MP2(full)/6-311++G(d,p) levels revealed that negative charge delocalization in carbonate anions to all three oxygen atoms occurs due to negative hyperconjugation. Phenyl carbonate (1LG) is a better leaving group (Nf = -0.84 +/- 0.07 in 80% v/v aq EtOH) than methyl carbonate 2LG (Nf = -1.84 +/- 0.07 in 80% v/v aq EtOH) because of more pronounced negative hyperconjugation, which is characterized with a more elongated RO-C bond and more increased RO-C-CO angle in 1LG than in 2LG. Calculated affinities of benzhydryl cation toward methyl and phenyl carbonate anions (DeltaDeltaEaff = 11.7 kcal/mol at the B3LYP/6-311++G(d,p) level and DeltaDeltaEaff = 2.7 kcal/mol at the PCM-B3LYP/6-311++G(d,p) level in methanol, respectively) showed that 1LG is more stabilized than 2LG, which is in accordance with greater solvolytic reactivity of 1 than 2.     

Gas phase thermolysis of benzyl t-butyl sulfide,phenyl t-butyl sulfide,and phenyl t-butyl ether

The pyrolysis kinetics of the title compounds has been studied in a stirred-flow reactor over the temperature range 440–530°C and pressures between 5 and 14 torr. Benzyl t-butyl sulfide and phenyl t-butyl ether formed isobutene as product in over 98% yield, together with the corresponding benzyl thiol and phenol. The benzyl thiol decomposes to a large extent into hydrogen sulfide and bibenzyl. In the pyrolysis of phenyl t-butyl sulfide, the hydrocarbon products consisted of 80 ±5% isobutene plus 20% isobutane, while the sulfur containing products were thiophenol and diphenyl disulfide. Order one kinetics was observed for the consumption of the reactants. The first order rate coefficients, based on isobutene production, followed the Arrhenius equations: Benzyl t-butyl sulfide: Phenyl t-butyl sulfide: Phenyl t-butyl ether: For benzyl t-butyl sulfide and phenyl t-butyl ether, the results suggest a unimolecular mechanism involving polar four center cyclic transition states. For phenyl t-butyl sulfide, the t-butyl-sulfur single bond fission mechanism is a parallel, less important process than the complex fission one.     

Synthesis of N-(fluoro phenyl) maleamic acids and N-(fluoro phenyl) maleimides

A series of seven N-(fluoro phenyl) maleamic acids and their N-(fluoro phenyl) maleimides were prepared by the reaction of fluoro phenyl amines ( o-, m-, and p-fluoro, 2.4-, 2.5-difluoro, 2.3.5.6-tetrafluoro and 2.3.4.5.6.-pentafluoro anilines) with maleic anhydride according to substantial modifications made to the reaction conditions used by Searle for the preparation of normal N-aryl maleimides.