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The reaction of oximes of aromatic ketones with phenylacetylene in the presence of superbase systems (MOH-DMSO, where M = Li, Na, K) has been extensively studied for the first time. The effects of alkaline metal cation, the ketoximes structure and the reaction conditions (temperature, duration) on the products composition have been evaluated. Acetophenone oxime reacts with phenylacetylene (MOH-DMSO, where M = Li, Na, K, 140 °C, 6 h) to afford 2,5-diphenyl-1H-pyrrole in 14-18% isolated yield. The reaction of benzylphenylketoxime with phenylacetylene (LiOH-DMSO, 120 °C, 12 h) delivers 2,3,4-, 2,3,5-triphenyl-1H-pyrroles (in 17% total yield) and 2,3,4-triphenyl-1-[(Z)-2-phenylethenyl]-1H-pyrrole (7% yield). [ABSTRACT FROM AUTHOR]

The reaction of pyrrole-2-carbodithioates with methylenoactive nitriles and 2-benzoyl-1-bromoacetylene in the KOH-DMSO system leads to functionally substituted pyrrolothiazoles in 59-85% yield. [ABSTRACT FROM AUTHOR]

Simple grinding of the title substrates with Al2O3 results in highly selective ethynylation of the pyrrole rings. [ABSTRACT FROM AUTHOR]

Abstract: I2-doped and pyrrole ring-iodinated semi-conducting oligomers of N-vinyl-3-alkyl-2-phenylpyrroles have been synthesized by free-radical polymerization of the above monomers (AIBN, 2–5wt%, 60–80°C) and further exposure of the oligomers obtained to I2 vapor. The parent oligomers exhibit paramagnetic and fluorescent properties and stable up to 300–370°C. [ABSTRACT FROM AUTHOR]

According to the (1)H, (13)C and (15)N NMR spectroscopic data and ab initio calculations, the strong N--H...O intramolecular hydrogen bond in the Z-isomers of 2-(2-acylethenyl)pyrroles causes the decrease in the absolute size of the (1)J(N,H) coupling constant by 2 Hz in CDCl(3) and by 4.5 Hz in DMSO-d(6), the deshielding of the proton and nitrogen by 5-6 and 15 ppm, respectively, and the lengthening of the N--H link by 0.025 A. The N--H...N intramolecular hydrogen bond in the 2(2'-pyridyl)pyrrole leads to the increase of the (1)J(N,H) coupling constant by 3 Hz, the deshielding of the proton by 1.5 ppm and the lengthening of the N--H link by 0.004 A. The C--H...N intramolecular hydrogen bond in the 1-vinyl-2-(2'-pyridyl)-pyrrole results in the increase of the (1)J(C,H) coupling constant by 5 Hz, the deshielding of the proton by 1 ppm and the shortening of the C--H link by 0.003 A. Different behavior of the coupling constants and length of the covalent links under the hydrogen bond influence originate from the different nature of the hydrogen bonding (predominantly covalent or electrostatic), which depends in turn on the geometry of the hydrogen bridge. The Fermi-contact mechanism only is responsible for the increase of the coupling constant in the case of the predominantly electrostatic hydrogen bonding, whereas both Fermi-contact and paramagnetic spin-orbital mechanisms bring about the decrease of coupling constant in the case of the predominantly covalent hydrogen bonding.