2- pyrroles conformational analysis

R 43 C. Schmuck and L. Geiger, Carboxylate Binding by Guanidiniocarbonyl Pyrroles From Self-Assembly to Peptide Receptors , p. 1485 R 44 X. Cai and C. Dass, Conformational Analysis of Proteins and Peptides , p. 1841 Vol. 8, 2004... 

Solid state analysis of crystals obtained of receptor with acetate from water/methanol solutions reveal that once again the guanidiniocarbonylpyrrole cation exists in an extended conformation however in contrast to the proposed solution state model, the pyrrole NH points away from the guanidium NHs with the acetate anions bound by two separate receptor groups with solvent molecules helping to create a series of 2D arrays (figure 23c). 

The conformation of the above palladium(II) hexaphyrin complexes was assigned on the basis of n.O.e. measurements. Once their analysis was complete, it was suggested that the observed outward rotation of two of the pyrrole rings and concomitant Z-E isomerization of two formal C = C bonds occurs, so as to avoid forcing the Pd(II) center into a square planar coordination geometry. While this... 

Interest in alkaloids of the nicotine group appears to be on the increase. A review has appeared covering tobacco-specific nitrosamines, which may be causative factors in tobacco-related cancers. The solution conformation, and proton, deuterium, carbon-13, and nitrogen-15 n.m.r. spectra of nicotine and its 2- and 4-isomers, have been studied. A new synthesis of nornicotine and nicotine has been described, and a quantitative carbon-13 n.m.r. spectral analysis of nicotine that is labelled at positions 1, 2, and 3 with carbon-13 been presented. The synthesis and mass spectrometry of several structurally related nicotinoids have been reported. Nicotine is dehydrogenated on irradiation in benzene solution in the presence of benzophenone to l -methyl-2 -(3-pyri-dyl)pyrrole. ° Nornicotine has been synthesized in four steps from 3-bromo-pyridine and N-3-butenyl-phthalimide, using a palladium-catalysed vinylic... 

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