Reactions of isoflavone and 2-hydroxyisoflavanone with sodium ethoxide in anhydrous ethanol

Recent observation /1,4/ on the existence and unreactivity of IV under basic conditions, as well as its part in the inhibitory effect on the decomposition into deoxybenzoin is unequivocally proved by comparing the decompositions of I and VI. It is also shown that the decomposition of I is detemined neither by the character of the solvent nor by the nucleophilic character of the reactant, but by the possibility of the formation of IV.

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IV , I VI. , I . , , IV.

     

Solvent effect on reaction rates: Reaction between sodium ethoxide and methyl iodide in ethanol + cyclohexane solvent systems

The kinetics of the reaction between sodium ethoxide and methyl iodide has been studied at 25°C in various cyclohexane-ethanol solvent mixtures with a cyclohexane content of 10 to 50% per volume. The determination of the rate constants att=0 were carried out by a new iterative method proposed in this investigation. The obtained results show that the reaction rate decreases with the increasing cyclohexane content. This behavior can be attributed to various solute-solvent interactions of electrostatic nature. On the other hand, the variation of ion and ion pairs rate constants with solvent composition permits the various solvation effects to be taken into account.     

Mechanisms of elimination reactions—XXVII: The reactions of 1-arylethyldimethylsulfonium bromides with sodium ethoxide in ethanol

Treatment of 1-phenylethyldimethylsulfonium bromide 1 with sodium ethoxide in ethanol at 35° affords four products by five reaction paths: styrene 2 by E2 and α'-β mechanisms, ethyl 1-phenylethyl ether 3 and methyl 1-phenylethyl sulfide 4 by the S_N2 mechanism, and methyl o-ethylbenzyl sulfide 5 by a Sommelet-Hauser rearrangement. Isotope effects of 5.9 and 3.5 for E2 and α'-β reactions were estimated by comparing the deuterium content of methyl sulfide from β-d₃, and α-d₇ (all α-positions exchanged) sulfonium salt. Product analyses on products from the unsubstituted, p-methyl, p-fluoro, p-bromo and m-chloro sulfonium salts were combined with overall rates to calculate partial rates for the formation of each product. These partial rates were fitted to the Hammett equation to give values for each product as follows: 2, 0.95±0.19; 3, ?0.63±0.41; 4, 0.95±0.11; 5, 4.84±0.38. The mechanistic implications of the results are discussed.     

Synthesis of ethylaminopyridines by the reaction of isomeric benzaldehyde pyridylhydrazones with sodium ethoxide

The reaction of isomeric benzaldehyde pyridylhydrazones with alkali metal alkoxides gave 2-, 3-, and 4-ethylaminopyridines. The effect of temperature and reaction time on the yields of products was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 351–353, March, 1972.     

Reaction of N,N,N′-trifluoroamidines of unsubstituted carboxylic acids with sodium ethoxide

Conclusions The N,N,N-trifluoroamidines of unsubstituted aliphatic carboxylic acids react easily with sodium ethoxide to give the corresponding N-fluoroimino ethers and esters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2802–2803, December, 1978.     

Effect of ethanol on the interaction between poly(vinylpyrrolidone) and sodium dodecyl sulfate

The effect of ethanol on the interaction between the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic polymer poly(vinylpyrrolidone) (PVP) has been investigated using a range of techniques including surface tension, fluorescence, electron paramagnetic resonance (EPR), small-angle neutron scattering (SANS), and viscosity. Surface tension and fluorescence studies show that the critical micelle concentration (cmc) of the surfactant decreases to a minimum value around 15 wt % ethanol; that is, it follows the cosurfactant effect. However, in the presence of PVP, the onset of the interaction, denoted cmc(1), between the surfactant and the polymer is considerably less dependent on ethanol concentration. The saturation point, cmc(2), however, reflects the behavior of the cmc in that it decreases upon addition of ethanol. This results in a decrease in the amount of surfactant bound to the polymer [C(bound) = cmc(2) - cmc] at saturation. The viscosity of simple PVP solutions depends on ethanol concentration, but since SANS studies show that ethanol has no effect on the polymer conformation, the changes observed in the viscosity reflect the viscosity of the background solvent. There are significant increases in bulk viscosity when the surfactant is added, and these have been correlated with the polymer conformation extracted from an analysis of the SANS data and with the amount of polymer adsorbed at the micelle surface. Competition between ethanol and PVP to occupy the surfactant headgroup region exists; at low ethanol concentration, the PVP displaces the ethanol and the PVP/SDS complex resembles that formed in the absence of the ethanol. At higher ethanol contents, the polymer does not bind to the ethanol-rich micelle surface.     

Nucleophilic reactions of fluoroolefins. II. Regioselectivity and elimination-addition competition in the reaction of 1-phenylpentafluoropropenes with sodium ethoxide

1-Phenylpentafluoropropene and its para-substituted analogs $\text{1}$ are susceptible to nucleophilic attack at both vinylic carbon atoms C-1 and C-2. They react with ethanolio sodium ethoxide to give predominantly substitution products, 1-ethoxy-1-phenyltetrafluoropropenes $\text{2}$ and 2-ethoxy-1-phenyltetrafluoropropenes $\text{3}$, with only little formation of adducts, $\text{viz}$. 2-ethoxy-1H-1-phenylpentafluoropropanes $\text{4}$. Alkenes $\text{1}$, where the para-substituent X  H,Cl,and CF₃ give additionally 1,2-diethoxy-1-phenyltrifluoropropenes $\text{5}$ and, where X = CF₃ also 2,2-diethoxy-1H-1-phenyltetrafluoropropane $\text{6}$. Overall regioselectivity of nucleophilic attack of the ethoxide ion on alkenes $\text{1}$ exhibits the Hammett type correlation with Ó_p values of substituents X: CH₃O and CH₃ groups favour the attack on the vinylic carbon C-1, while CF₃ and Cl substituents direct the attack on the C-2 carbon of alkenes $\text{1}$. The E and Z isomers of 1-ethoxy and 1,2-diethoxy substituted alkenes $\text{2}$ and $\text{5}$ were formed in comparable amounts, while the E isomers of 2-ethoxy substituted alkenes $\text{3}$ were always formed with a 93 – 97 % selectivity.     

Investigating internal structural differences between micelles and unilamellar vesicles of decanoic acid/sodium decanoate

We report on the dynamics of a chromophore sequestered within the nonpolar regions of micelles and unilamellar vesicles comprised of decanoic acid/sodium decanoate. We find that there is a measurable difference in the motional dynamics of the chromophore perylene in these two nonpolar media, with the vesicle structure forming a somewhat less viscous environment than the micelle. In all cases, the chromophore reorients as a prolate rotor, implying a local environment with a nominally similar shape for both micelle and vesicle structures. These findings demonstrate that the organization of micelles is measurably different than that of bilayers.     

Location of ethanol in sodium dodecyl sulfate aggregates

The hexagonal liquid crystalline phase of SDS (Sodium dode-cyl sulfate)/H2O system changes into lamellar liquid crystal and the effective length of surfactant molecule d0/2 in the lamellar liquid crystal decreases with the addition of ethanol. The micellar aggregation number N of SDS decreases and the micellar diffusion coefficient increases with the added ethanol. Under a constant concentration of SDS, the molecule number ratio of ethanol to SDS in the micelle increases with the concentration of ethanol and even exceeds 10 when ethanol concentration is 1. 085 mol/L. All these results show that ethanol, even though a short chain alcohol and soluble in water, can partly exist in the interphase of the amphiphilic aggregates showing some properties of co-surfactant.     

Reactions of some fluoroaromatics with the ethoxide anion

The reactions of sodium ethoxide in ethanol with various fluoroaromatics, C₆F_6?nH_n, C₆F_5?nH_nNO₂, C₆F₅X (X = CF₃, C₆F₅, COCH₃, CH₂Br), C₆Cl₆ and $\text{m}$H₂C₆Cl₄ have been studied. Partial substitution of the aromatic halogen was observed. The new products have been characterized by elemental analysis, NMR (H?1 and F?19), infrared and mass spectroscopy.     

Study of the cleavage of the N-N bond in the reaction of benzaldehyde pyrazinyl-, pyridazinyl-, and pyrimidinylhydrazones with sodium ethoxide

The reaction of benzaldehyde pyrazinyl-, pyridazinyl-, and pyrimidinylhydrazones with sodium ethoxide was investigated by means of gas—liquid chromatography (GLC) and mass chromatometry. It was established that the previously discovered new type of cleavage of the N-N bond in pyridylhydrazones under the influence of alkali-metal alkoxides also takes place in a number of azine systems, but the yields of the corresponding N-monoalkylamino derivatives of pyrazine, pyrimidine, and pyridazine differ.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1120–1124, August, 1978.     

Exchange of deuterium with OH groups of HY zeolites

The exchange reaction of D₂ with OH groups of HY zeolites was followed both in the solid and gas phase by IR and MS. The rates of D₂–OH and D₂–H₂ exchange increase considerably with dehydroxylation of the sample. The active centers are probably vacancies formed by removal of oxygen from the lattice, they catalyze the dissociation of D₂. Dehydroxylation of the sample is accompanied by the formation of 3 740 cm^–1 hydroxyls, whose exchange with D₂ is slower than that with other OH groups and which affect the kinetics in the gas phase.

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D₂ OH HY - O₂–OH O₂–H₂ . , , , O₂. OH, 3740 ^–1, , OH .

     

Spectral and structural analysis of sodium hydrophosphates and hydroarsenates

Anhydrous sodium hydrophosphates and arsenates and heptahxdrates were svnthesized and characterized by IR spectroscopy and X-ray diffractometry. Anhydrous sodium hxdrophosphate and hydroarsenate were found to be isostmctural. Unit cell parameters of Na₂HAsO₄ are calculated. Assignment of IR bands is given and comparative analysis of spectral and structural characteristics of the compounds is performed.