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951.
Acid hydrolysis and acetylation of 6,8-dialkyl-3-thia-2,4,6,8-tetraazabicyclo[3,3,0]octan-7-one 3,3-dioxides have been studied. 6,8-Dialkyl-3-thia-2,4,6,8-tetraazabicyclo[3,3,0]octan-7-one 3,3-dioxides disproportionate to 4,4'-sulfonyldiiminobis(1,3-dialkylimidazolidin-2-ones) and sulfamide when treated with acid at pH 1 or with acetyl chloride. The kinetics of the disproportionation have been studied.  相似文献   
952.
953.
The solution behaviors of equimolar mixtures of cationic-anionic surfactants have been studied by means of the dynamic light scattering technique and surface tension measurements. The surface activity and the micellization properties are different for systems of different hydrophobic chain length symmetry. For systems of lower symmetry (e.g., C6H13NC5H5Br-C12H25SO4Na mixture), the surface tension at cmc (γcmc) is rather high (above 30 mN m−1) and the mixtures form genuinely homogeneous micellar solutions above the cmc. For the systems of high symmetry (e.g., C8H17NC5H5Br-C8H17SO4Na mixture), γcmc is very low (about 24 mN m−1, near the value of pure hydrocarbon) and in the apparently homogeneous and clear mixtures slightly above cmc, the aggregates grow slowly and eventually form small droplets; as the concentration is further increased, all these solutions become turbid. We have proposed a new concept of conformation energy of aggregates to account for all these phenomena. Mixtures of octyltriethylammonium bromide and sodium octylsulfate form clear homogeneous micellar solutions in keeping with predictions based upon this concept.  相似文献   
954.
A method for the introduction of a 3-indolyl group in compounds with an active methylene group was developed. The corresponding 3-indolyl diketones were obtained by condensation of 1-acetyl-3-indolinone with dimedone, 4-hydroxycoumarin, 1,2-diphenyl-3,5-pyrazolinedione, and barbituric and thiobarbituric acids and subsequent alkaline hydrolysis of the condensation products. The existence of cyclic six-membered 3-indolyl diketones in the enol form and of cyclic five-membered 3-indoly diketones in the keto form was shown by IR and UV spectroscopy. Depending on the conditions, (1-acetyl-3-indolyl)cyanoacetamide, 1,3-bis(1-acetyl-3-indolyl)-1,3,3-tricyano-2-amino-1-propene, and 1-acetyl-3-indolylmalononitrile are obtained in the condensation of 1-acetyl-3-indolinone with malononitrile. 1-Acetyl-3-indolylmalononitrile exists in equilibrium with the keteneimine form and in protic solvents is converted to 3-cyano-8-acetylpyrrolo[2,3-b]indole by intramolecular cyclization.See [1] for communication CX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 360–368, March, 1977.  相似文献   
955.
The condensation of urethane and ethyl acetohydroximate with 2-chloromethyl-1-methylbenzimidazole has given, respectively, N-ethoxycarbonyl-O-(1-methylbenzimidazol-2-ylmethyl)hydroxylamine and ethyl N-(1-methylbenzimidazol-2-ylmethoxy)acetimidate. Acid hydrolysis of the latter has given O-(1-methylbenzimidazol-2-ylmethyl)hydroxylamine. The reactions of its derivatives with HCl have been studied, and it has been shown that 1-methylbenzimidazole-2-aldehyde O-(1-methylbenzimidazole-2-methyl)oxime is formed. The structure of the latter has been shown by an analysis of its PMR spectra.For part II, see ¦1¦.  相似文献   
956.
957.
A simple method was used to prepare a "switchable" electrode surface by using self-assembled monolayers of dodecanethiol on a gold electrode. The dodecane-modified electrode was electrochemically inactive until the monolayer was soaked in solutions of 1,10-phenanthroline or 2,2'-bipyridine. The electroactive form of the electrode could be reverted back to the nonelectroactive form by rinsing the electrode. Surface IR results showed that both dodecanethiol and 1,10-phenanthroline exist in the mixed monolayer.  相似文献   
958.
Previously undescribed pyrimidine betaines with cycloammonium and triphenylphosphonium cations were obtained. A study of the UV, IR, PMR, and mass spectra made it possible to draw a conclusion regarding the noncyclic structure of betaines stabilized by an intramolecular donor-acceptor interaction of the charge-transfer complex (CTC) type.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1687–1690, December, 1978.  相似文献   
959.
The influence of the number of 3, 3, 3-trifluoropropyl(methyl)siloxane links (Φ/Φ) in the cyclotetrasiloxanes ΦmD4-m, where D represents the dimethylsiloxane link and m=0–4, on the rearrangement of these compounds in acetone solution under the action of sodium siloxanolate has been studied. The rearrangement takes place with the formation of a linear polysiloxane the degradation of which yields, in addition to the initial ring, cyclosiloxanes with a different structure. The rate of rearrangement of ΦmD4-m and of the formation of a linear polysiloxane rises with an increase in m from 0 to 3. The equilibrium concentration of the linear polysiloxane formed from ΦmD4-m is inversely proportional to m. Results have been obtained on the kinetics of the formation of the cyclosiloxanes ΦmDn, where m=0–5, n=0–5, and m+n=3–6, in the rearrangement of the rings ΦD3, Φ2D2, Φ3D, and Φ4. The reactivity of the siloxane links rises in the sequence ~ (CH3)2Si-O-Si(CH3)2 ~<~ (CF3CH2CH2)-(CH3) Si-O-Si(CH3)2 ~<(CF3CH2CH2) (CH3)Si-O-Si(CH3) (CH2CH2CF3) ~. Because of the negative inductive effect transferred through the siloxane links, the 3, 3, 3-trifluoropropyl groups strongly activate the siloxane ring with respect to nucleophiiic reagents.  相似文献   
960.
A procedure has been developed for the determination of the concentration of butanol and butyl acrylate in aqueous solutions in the range of 0.5–20 MPC. The procedure is based on static headspace gas-chromatographic analysis on a column filled with the Chromaton N-AW-HMDS sorbent containing 15 wt % of polyethylene glycol adipate with detection by a flame-ionization detector.  相似文献   
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