Secondary beta-bromo alcohols can be transformed directly to ketones in very good yields by a free radical process. Tertiary beta-bromo alcohols do not react while the primary ones are transformed to aldehydes in lower yields. The reaction involves an abstraction of a hydrogen atom alpha to an OH group, followed by elimination of the bromine atom and subsequent tautomerization of an enol to a k...

The electronic and molecular structure of 2,6-bis{/V-(2-hydroxyphenyl)iminomethyl}-4methylphenol (hpimp) is clarified from the measurements of electronic absorption and 'H NMR spectra in various solvents and an X-ray diffraction analysis, together with MO calcula­ tions. Electronic absorption bands of hpimp are at 422, 397.9, 359, 341, 294.3, 265.8, and 224 nm in the non-polar solvent cyclohexa...

Equilibrium constants for keto-enol tautomerisation and migration of hydrogen from carbon to nitrogen to form enamine or zwitterion tautomers have been measured for 2-, 3and 4phenacylpyridines (PyCH,COPh) in aqueous solution at 25 "C. Relative tautomeric stabilities fall in the order ketoimine > enamine > enol and (for the 3-isomer) enol > zwitterion. Values of pKT, (-log KT) where KT = [enamin...

In the title compound C(14)H(17)N(3)O(2), the dihedral angle between the rings is 16.68 (13)°. Although the compound crystallizes in the keto form, the possibility of keto-enamine-enol-imine tautomerism is explained by a strong intra-molecular N-H⋯O hydrogen bond.

The vibronic spectrum of laser desorbed and jet cooled guanine consists of bands from three different tautomers of guanine as revealed by UV–UV and IR–UV double resonance spectroscopy. 1-methylguanine, in which the Keto–Enol tautomerism is blocked, shows hole burning spectra from the 9H-and 7H-Keto form. A comparison of the vibronic pattern of the different tautomers demonstrates that the vibro...

A metal ion that attaches to a peptide backbone has the choice of binding to an amide carbonyl oxygen atom or to an amide nitrogen atom by replacement of the amide proton. Coordination to the nitrogen atom is normally accompanied by elimination of the proton, thereby resulting in deprotonation of the ligand. An alternative possibility, not involving deprotonation, is the unusual amide/iminol ta...