Vinylation of pyrroles in dimethyl sulfoxide

A number of 1-vinylpyrroles were obtained in up to 97% yields by base-catalyzed addition of substituted pyrroles to acetylene in dimethyl sulfoxide at 80–100°C.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 213–214, February, 1977.     

Long-range spin-spin coupling between protons and fluorine nuclei in trifluoroacetylpyrroles

Conclusions Long-range spin-spin coupling between the fluorine and H⁴ nuclei of the pyrrole ring is realized in the¹H and¹⁹F NMR spectra of 2-organyl-5-trifluoroacetylpyrroles and their N-vinyl derivatives. The predominant conformations of the molecules of the studied compounds were established.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1122–1124, May, 1979.     

Mechanical activation of the KOH-DMSO superbase system and its use in the reaction with cyclohexanone

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2879–2880, December, 1989.     

Pyrroles from ketoximes and acetylene.

2-Aryl- and 1-viny1-2-pyrroles were synthesized by condensation of p-substituted acetophenone oximes with acetylene under pressure in superalkaline media (KOH/DMSO). The initially formed nitrogen-unsubstituted pyrroles can be vinylated in the presence of acetylene. Lithium hydroxide, which is completely inactive in the vinylation step, was found to be a selective catalyst for the construction of a pyrrole ring from oximes of aliphatic aromatic ketones. In the case of aliphatic and cycloaliphatic ketoximes (for example, cyclohexanone oxime) LiOH has virtually no catalytic effect on the reaction. The yields of 1-viny1-2-ary1-pyrroles depend substantially on the substituent in the phenyl ring. The structures of the synthesized compounds were confirmed by the IR, PMR, UV, and ¹³C NMR spectra.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 489–491, April, 1978.     

Pyrroles from ketoximes and acetylene. 24. Acidic hydrolysis of 1-vinylpyrroles

The hydrolysis of 2-methyl-, 2-phenyl-, and 3-methyl-2-phenyl-1-vinylpyrroles and 1-vinyl-4,5,6, 7-tetrahydroindole in the presence of HCl, H₂SO₄, NH₂OH-HCl, acetic acid, and H₂O₂ in aqueous, aqueous dioxane, and aqueous alcohol solutions leads to oligomers with complex structures and compositions, viz., products of acidic catalytic and oxidative condensation of the starting compounds and the resulting pyrroles both with one another and with the liberated acetaldehyde. 2-Phenylpyrrole was obtained in 52% yield from 1-vinyl-2-phenylpyrrole by hydrolysis in a dilute (0.5%) solution [water-dioxane (59)] with excess NH₂OH.HCl, which ties up the acetaldehyde.See [1] for Communication 23.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1631–1639, December, 1982.     

First Example of Construction of a Pyrrole Ring Bonded to a Steroid System by the Trofimov Reaction

The oxime of ⁵-pregnen-3-ol-20-one reacts with acetylene in the KOH-DMSO system to form a mixture of products containing 3-vinyloxy-17-(1-vinyl-2-pyrrolyl)-⁵-androstene as the major product (63% yield) and also the O-vinyloxime of 3-vinyloxy-⁵-pregnen-20-one (10%), 3-vinyloxy-17- and 3-vinyloxy-17-⁵-pregnen-20-one (25%, 1:4 ratio).     

Addition of methyl mercaptoacetate to N-vinylpyrroles

Methyl esters of 2-(pyrryl-1)ethylthioacetic acid were synthesized in 53–71% yield by addition of methyl mercaptoacetate to N-vinylpyrroles. Their reactions with ammonia and hydrazine hydrate were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 481–484, April, 1992.     

Separate detection of homologous surfactants by means of solid-contact unmodified and modified with molecular sieves potentiometric sensors

To improve the selectivity of surfactant sensors, the surface of their membranes was modified with molecular sieves with predetermined pore sizes. Water-soluble anionic, cationic and non-ionic surfactants were used as pore generators in the molecular sieves and introduced into the source membrane at the stage of its formation. The modified sensors enable detection of alkylsulfates homologues and alkylpyridinium with different lengths of the hydrocarbon chain (C₁₀-C₁₈); homologous poly(oxyethylated nonylphenols) differing in the number of oxyethyl groups (m = 10-100).A novel approach to separate detection of surfactant homologues implies the usage of inselective sensors as a multisensor system. The software-supported multisensor approach allows information of both mixture composition and concentrations of separate components in multicomponent systems to be obtained with a certain accuracy. Inselective non-modified sensors with the highest cross-sensitivity were used to design multisensor systems like an “electronic tongue”.The cross-sensitivity parameters of both source and modified sensors were estimated and the possibility of their usage in multisensor systems like an “electronic tongue” for analysis of multicomponent solutions of homologous surfactant is shown. Analytical signals were processed by artificial neural networks.     

Unexpected transformations ofO-vinylacetophenone oxime in the system ButOK-THF

Transformation ofO-vinylacetophenone oxime in the system Bu^tOK-THF was studied. The reaction at 60–65 °C was shown to afford not the anticipated 2-phenylpyrrole, but, instead, 2,4-diphenylpyrrole (21% yield) and oligomer products (40% yield). The latter have the same elemental composition as the startingO-vinyl oxime but do not contain vinyloxy groups or pyrrole fragments. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 615–617, March, 1997.     

Copolymers of 1-vinylimidazole and (meth)acrylic acid: Synthesis and polyelectrolyte properties

New hydrophilic polyampholytes have been synthesized by copolymerization of 1-vinylimidazole with sodium salts of acrylic and methacrylic acids. Copolymerization reactivity ratios of the monomers are equal to: 0.54 ± 0.06 and 1.3 ± 0.3 for 1-vinylimidazole-sodium acrylate, 0.23 ± 0.01 and 2.6 ± 0.2 for 1-vinylimidazole-sodium methacrylate systems, correspondingly. Isoelectric point of the copolymers changes continuously from 2.8 to 6.7 with increasing the 1-vinylimidazole content in contrast to polyampholytes with amino instead of imidazole side groups, whose isoelectric point changes discontinuously with changing composition. Static and dynamic light scattering data point to tendency of polyampholyte macromolecules to aggregation, even at pH values far from isoelectric point.