Synthesis and characterization of 1-methyl-1-silaindane and 1-methyl-1-germaindane

New synthetic routes to 1-methyl-1-silaindane (1b) and 1-methyl-1-germaindane (1b) were developed and the desired products were obtained in good isolated yield. Compounds 1a and 1b were fully characterized by mass spectroscopy, ¹H and ¹³C{¹H} NMR, and infrared spectroscopy.     

1-Phenyl-1-halo-1-silacyclohexanes

The approaches to synthesis of 1-phenyl-1-halo-1-silacyclohexanes C₅H₁₀Si(Ph)X (X = F, Cl, Br) have been examined. 1-Phenyl-1-chloro-1-silacyclohexane has been prepared via the known reaction of phenyltrichlorosilane with dimagnesium derivative of 1,5-dibromopentane; up to 20% of 1-bromo-1-phenyl-1-silacyclohexane admixture is formed along with the target product. The minor product formation has been prevented using an alternative method of chlorination of 1-phenyl-1-silacyclohexane with N-chlorosuccinimide. 1-Phenyl-1-fluoro-1-silacyclohexane has been obtained in close to quantitative yield via the reaction of 1-phenyl-1-chloro-1-silacyclohexane with SbF₃ and in 70% yield via its reaction with HF. The synthesis of 1-phenyl-1-bromo-1-silacyclohexane via bromination of 1-phenyl-1-chloro-1-silacyclohexane with N-bromosuccinimide has given the target product as a minor one, the major product being disiloxane formed due to hydrolysis of the Si–Br bond.     

Theoretical rotational-vibrational spectra of theX 3 B 1,a 1 A 1 andb 1 B 1 states of NH 2 +

Summary The three-dimensional potential energy functions have been calculated from highly correlated multireference configuration interaction electronic wavefunctions for theX ³ B ₁,a ¹ A ₁, andb ¹ B ₁ states of the NH ₂ ⁺ ion. For the quasi-linear electronic ground state this information and the electric dipole moment functions have been used to calculate spectroscopic constants, line intensities and rotationally resolved absorption spectra. For thea ¹ A ₁-b ¹ B ₁ bent/quasi-linear Renner-Teller system ro-vibronic energy levels have been obtained from a variational approach accounting for anharmonicity, rotation-vibration and electronic angular momenta coupling effects. The vibronic levels are given for energies up to 13 500 cm^–1 for the bending levels and up to 8000 cm^–1 for the stretching and combination levels.Dedicated in the honor of Prof. Werner Kutzelnigg     

1-烷基-1'-乙酰基二茂铁的合成

用新方法合成了1-烷基-1'-乙酰基二茂铁, 该法与传统方法相比易于得到单一产物. 通过7种1-烷基二茂铁甲酸与三氯化磷作用形成酰氯, 再与乙酰乙酸乙酯的钠盐进行反应, 皂化脱羧得到1-烷基-1'-乙酰基二茂铁化合物, 用元素分析、红外光谱、核磁共振氢谱确定了化合物的结构.     

The potentials of zero charge of Pd(1 1 1) and thin Pd overlayers on Au(1 1 1)

The potential of zero charge (pzc) of Pd(1 1 1) has been determined in dilute NaF solutions by measuring the Gouy–Chapman minimum of the double-layer capacity. For a massive Pd(1 1 1) single crystal electrode a pzc of −0.12 V vs. SCE has been found. The corresponding values for thin Pd(1 1 1) overlayers on Au(1 1 1) have also been determined. While the pzc of the first, pseudomorphic Pd layer on Au(1 1 1) is −0.09 V vs. SCE, the pzc of a five monolayers thick Pd film on Au(1 1 1) is practically identical to the pzc of the massive Pd(1 1 1) electrode. By comparing pzc's and work functions for Au(1 1 1) and Pd(1 1 1), the dipole contribution to the potential drop across the Pd(1 1 1)/water interface is estimated.     

The X˜1A1, a˜3B1, a˜1B˜1, and B˜1A1 electronic states of SiH2

Four electronically low-lying states of silylene (SiH₂) have been studied systematically using high level ab initio electronic structure theory. Self-consistent field (SCF), two-configuration (TC) SCF, complete active space (CAS) SCF, configuration interaction with single and double excitations (CISD), and CASSCF second-order (SO) CI levels of theory were employed with eight distinct basis sets. The zeroth-order wave functions of the ground (X˜ ¹A₁ or 1 ¹A₁) and B˜ ¹A₁ (or 2 ¹A₁) excited states are appropriately described by the first and second eigenvectors of the TCSCF secular equations. The TCSCF-CISD, CASSCF, and CASSCF-SOCI wave functions for the B˜ ¹A₁ (or 2 ¹A₁) state were obtained by following the second root of the CISD, CASSCF, and SOCI Hamiltonian matrices. At the highest level of theory, the CASSCF-SOCI method with the triple zeta plus triple polarization augmented with two sets of higher angular momentum functions and two sets of diffuse functions basis set [TZ3P(2f,2d)+2diff], the energy separation (T₀) between the ground (X˜ ¹A₁) and first excited (a˜ ³B₁) states is determined to be 20.5 kcal/mol (0.890eV,7180cm⁻¹), which is in excellent agreement with the experimental T₀ value of 21.0 kcal/mol (0.910eV,7340cm⁻¹). With the same method the T₀ value for the a˜ ¹B₁−X˜ ¹A₁ separation is predicted to be 45.1 kcal/mol (1.957 eV,15780 cm⁻¹), which is also in fine agreement with the experimental value of 44.4 kcal/mol (1.925 eV,15530 cm⁻¹). The T₀ value for the B˜ ¹A₁−X˜ ¹A₁ separation is determined to be 79.6 kcal/mol (3.452 eV,27 840 cm⁻¹). After comparison of theoretical and experimental T₀ values for the a˜ ³B₁ and a˜ ¹B₁ states and previous studies, error bars for the B˜ ¹A₁ state are estimated to be ±1.5 kcal/mol (±525 cm⁻¹). The predicted geometry of the B˜ ¹A₁ state is r_e(SiH)=1.458 and θ_e=162.3^∘. The physical properties including harmonic vibrational frequencies of the B˜ ¹A₁ state are newly determined. Received: 10 March 1997 / Accepted: 2 April 1997     

Rearrangements of 1-(1-methylprop-1-en-1-yl)-1,2-dimethylacenaphtyylenonium ions

It was discovered by means of dynamic NMR that the 1-(cis-1-methylprop-1-en-1-yl)-1,2-dimethylacenaphthylenonium ion generated under conditions of “long life” for carbocations underwent fast (ΔG^#35.8 kJ mol^?1 at ?103°C) degenerate 1,2-shift of the cis-dimethylvinyl group. Quantum-chemical calculations by DFT method predict lower rate of 1,2-shift for the trans-dimethylvinyl group compared to cis-dimethylvinyl group and dependence on the cations conformation of the rates of these processes and of the rearrangement mechanism into the ions of phenalenyl type.     

Synthesis and Evaluation of Serinolamide Derivatives as Sphingosine-1-Phosphate-1 (S1P1) Receptor Agonists

Sphingosine-1-phosphate-1 (S1P₁) receptor agonists are well-known drugs for treating multiple sclerosis (MS) caused by autoreactive lymphocytes that attack the myelin sheath. Therefore, an effective therapeutic strategy is to reduce the lymphocytes in the blood by inducing S1P₁ receptor internalization. We synthesized serinolamide A, a natural product of the sea, and performed S1P₁ receptor internalization assay to evaluate functionally antagonistic S1P₁ receptor agonist activity. In order to synthesize derivatives with better efficacy than serinolamide A and B, new derivatives were synthesized by introducing the phenyl ring moiety of fingolimod. Among them, compounds 19 and 21 had superior S1P₁ agonistic effects to serinolamide. We also confirmed that compound 19 effectively inhibited lymphocyte outflow in peripheral lymphocyte count (PLC) assay.     

Novel synthesis of 1-aryl-1-trifluoromethylallenes

3,3-Bis(phenylthio)-1,1,1,2,2-pentafluorobutane 1 was reacted with aryllithium reagents (6 equiv) in ether at low to room temperature for 1-6 h to provide 2-aryl-1,1,1-trifluoro-3-phenylthio-2-butene 2 in 80-96% yields. Bromination of 2 with NBS in acetonitrile at reflux for 1-7 h afforded the corresponding allylic bromides 3 in 61-96% yields. Treatment of 3 with MCPBA (1.5 equiv) in methylene chloride at reflux temperature for 1-12 h resulted in the formation of 1-aryl-1-trifluoromethylallenes 4 in 74-96% yields.     

1-Trimethylsilyl-, 1-Trimethylgermyl- und 1-Trimethylstannyl-3,4-dimethylphospholen

1-Trimethylsilyl-, 1-Trimethylgermyl-, and 1-Trimethylstannyl-3,4-dimethylphospholene 1-Lithium-3,4-dimethylphospholen reacts with Me₃SiCl and Me₃GeCl yielding 1-trimethylsilyl-3,4-dimethylphospholene ( 1 ) and 1-trimethylgermyl-3,4-dimethylphospholene ( 2 ) respectively. 2 and 1-trimethylstannyl-3,4-dimethylphospholene ( 3 ) are formed using the reaction of 1 with Me₃GeCl and Me₃SnCl respectively. The ¹H, ¹³C and ³¹PNMR-spectra as well as the mass spectra of the new compounds are discussed.     

Electrophilic condensation of 1-hydroperfluoropropylene and 1-hydroperfluoro-1-butene with fluoroethylenes

Conclusions 1-Hydroperfluoropropylene reacts with tetrafluoroethylene in the presence of SbF₅ to form the corresponding 11 and 12 adduct olefins. The condensation is accomplished at both the CFH and CF₂ groups of the starting propylene. Under analogous conditions, 1-hydroperfluoro-1-butene condenses with fluoroethylenes exclusively at the CFH group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1591–1594, July, 1982.     

Synthesis and NMR analysis of 2,4-dichloro-1-pentene and of 2,4-dichloro-1-pentene-1-d1

The compound 2,4-dichloro-1-pentene-1-d₁ ( 1 ) was synthesized starting from and CH?CNa. In the last stage of the synthesis on activated carbon-HgCl₂ catalyst), ( 3 ) were formed together with ( 1 ). The NMR parameters of ( 1 ), its cis and trans isomers and ( 2 ) were obtained in C₆D₆ solution at 100 MHz. Theoretical spectra of ( 1 ) at 60 MHz were simulated with the aid of a computer, using as input the NMR parameters obtained at 100 MHz and good agreement with the experiment was obtained.     

Temperature dependence of adlayers on Pt(1 1 1) and Au(1 1 1) in a sulfuric acid solution studied by in situ IRAS

Temperature dependence studies of adsorption of sulfuric acid species on Pt(1 1 1) and Au(1 1 1) electrodes were carried out using in situ infrared reflection absorption spectroscopy. A temperature-dependent shift of the interconversion potential between HSO₄⁻/H₃O⁺ and H₂SO₄ on a Pt(111) electrode was observed. A temperature-dependent frequency shift of the absorption bands of HSO₄⁻ was also observed on both Pt(1 1 1) and Au(1 1 1) electrodes in the potential region where a √3×√7 structure evolved. Modelling experiments in ultrahigh vacuum revealed that ordering of the overlayer water molecules played an important role in the frequency of the absorption bands of HSO₄⁻.     

Conversion of cepham-1-oxide into 1-oxadethiacepham

3-Exomethylenecepham-1-oxides $\text{1}$ were converted into the 3-exomethylene-1-oxadethiacepham in three step process including the novel bond cleavage of the tetrahydrothiazine ring of $\text{1}$ with 2-mercaptobenzothiazle or 2-mercapto-benzoxazole.     

The mechanism of thermal dehydrochlorination. Pyrolysis of 1-Chloro-1-fluoroethane and 1-chloro-1, 1-difluoroethane

The thermal decompositions of 1-chloro-1-fluoroethane and 1-chloro-1,1-difluorethane at atmospheric pressure have been studied in the temperature range 500–600°C in a flow system. The dehydrochlorinations are homogenous in a carbonaceous reactor and unimolecular. The rate constants are given by and The criteria for molecular or chain processes in thermal dehydrochlorinations are discussed.     

1, 5-Rearrangement of enol acylates of aryl 1H.-1, 2, 4-triazol-1-ylmethyl ketones

The rearrangement of enol acylates of aryl 1H-1, 2, 4-triazol-1-ylmethyl ketones at 140–150°C in acetic anhydride is studied. The migration of the acyl group to the C(5) atom of the heterocycle is found to be intramolecular. The characteristics of the original and final products are presented. X-ray structural studies of the enol acetates of 2, 4-dichlorophenyl 1H-1, 2, 4-triazol-1-ylmethyl ketone and 2, 4-dichlorophenyl 5-acetyl-1H-1, 2, 4-triazol-1-ylmethyl ketone are carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 560–564, March, 1993.     

Synthesis of 5-substituted 1-aryl-1H-pyrazole-4-acetonitriles, 4-methyl-1-phenyl-1H-pyrazole-3-carbonitriles and pharmacologically active 1-aryl-1H-pyrazole-4-acetic acids

Lithium aluminum hydride reduction of 5-substituted or unsubstituted ethyl or methyl 1-aryl-1H-pyrazole-4-carboxylates gave, generally in excellent yields, 5-substituted or unsubstituted 1-aryl-1H-pyrazole-4-methanols which afforded the corresponding 1-aryl-4-(bromomethyl)-1H-pyrazoles with hydrobromic acid in acetic acid solution. These crude intermediates gave by reaction with potassium cyanide in dimethylsulfoxide solution 1-aryl-1H-pyrazole-4-acetonitriles only in the case of 5-unsubstituted compounds, otherwise mixtures of 5-substituted 1-aryl-1H-pyrazole-4-acetonitriles and 4-methyl-1-phenyl-1H-pyrazole-3-carbonitriles were generally obtained. Acetonitriles IIIa,b,i,l gave in excellent yields the corresponding 1-aryl-1H-pyrazole-4-acetic acids Va,b,i,l by alkaline hydrolysis. Compounds Vb,i,l showed in the writhing test appreciable analgesic properties, associated with low acute toxicity; moreover, compound VI exhibited a statistically significant antiinflammatory activity in the carrageenan-induced edema assay.     

Angular distributions of photoelectrons in resonantly enhanced multiphoto ionization via the 7s[1 1/2]0 1 and 8s[1 1/2]0 1 states of Xe

Photoelectron angular distributions have been measured for the three-photon resonant one-photon ionization, (3+1), of Xe via the 7s[1 1/2]⁰ ₁ and 8s[1 1/2]⁰ ₁ states. The results are in good agreement with the theoretical predictions of Tang and Lambropoulos [13] for the 8s[1 1/2]⁰ ₁, but not for the 7s[1 1/2]⁰ ₁ state. Furthermore, the results are compared to those which have been obtained by Blazewicz et al. [1] for the three-photon resonant two-photon ionization, (3+2), of Xe via the 6s[1 1/2]⁰ ₁ state.     

Copolymerization of 4-methyl-2-pentyne with 1-trimethylsilyl-1-propyne and 1-trimethylgermyl-1-propyne with Nb-containing catalysts

It has been shown that the copolymerization of 4-methyl-2-pentyne with 1-trimethylsilyl-1-propyne or 1-trimethylgermyl-1-propyne with the use of niobium pentachloride-based catalytic systems in the presence of Ph₃Bi, Et₃SiH, and Bu₄Sn as cocatalysts yields corresponding copolymers of various compositions. The technique of determining the composition of copolymers from their IR spectra has been developed. The reactivity ratios of the monomers have been estimated. It has been demonstrated that these values increase in a sequence 4-methyl-2-pentyne > 1-trimethylsilyl-1-propyne > 1-trimethylgermyl-1-propyne.     

Allylic oxidation of 1-methyl-1-cycloheptene

Conclusions The oxidation of 1-methylcycloheptene by SeO₂ and Hg(OAc)₂ gave a mixture of 1-hydroxymethyl-2-cyclohepten-1-ol and 3-methyl-2-cyclohepten-1-ol.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2134–2136, September, 1986.