Carbon-carbon coupling of 4,6-dinitrobenzo-furoxan with 3-aminothiophenes: a kinetic and structural study

Article Abstract:

Studies have shown that 3-N-(methylamino)thiophene, 3-aminothiophene and 3-N,N-dimethylaminothiophene are protonated only at the amino groups in dilute acid solutions. Potentiometric measurements carried out in a 50/50 H20/Me2SO mixture and 1H and 13C NMR studies carried out in pure Me2SO-d6 have given the data. A kinetic and structural study has been carried out on carbon-carbon coupling of 4,6-dinitrobenzo-furoxan with 3-aminothiophenes. The hyper-ortho relationship in the thiophene systems has been shown to be important. Ease of electrophilic and nucleophilic reactivity of 3-X thiophenes in sigma-complex formation processes is thus accounted for.

Nitrogen compounds

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Concerted motion in bicyclobutane

Article Abstract:

In bicyclobutane, bridgehead substituents move toward the center as the bridge bond lengthens. Effects of BH2, H, F, and OH in bridgehead positions has been studied through use of quantum-mechanical calculations. How much the bridgehead carbon is inverted is dependent on the electronegativity of the substituent. With electropositive substituents the invertedness is greater and the central bond lengthens as well, with no change related to electronegativity.

Measurement, Cyclic compounds, Butane, Oscillation, Oscillations

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An unusual ground-state stabilization effect and origins of the alpha-effect in aminolyses of Y-substituted phenyl X-substituted benzoates

Article Abstract:

Sources of the alpha-effect for aminolyses of Y-substituted phenyl X-substituted benzoates have been investigated as has an unusual ground-state stabilization effect. The size of the alpha-effect does not always depend on the beta(sub-nuc) value. It is dependent on the electronic nature of the substituent X and Y, however. An electron-donating substituent thus adds to the alpha-effect, which is cut back by an electron-holding substituent.

Amino compounds

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