Observation by UV−Visible and NMR Spectroscopy and Theoretical Confirmation of 4-Isopropyltropolonate Ion, 4-Isopropyltropolone (Hinokitiol), and Protonated 4-Isopropyltropolone in Acetonitrile

Abstract

Protonated 4-isopropyltropolone (H2L+) was produced by the addition of methanesulfonic or trifluoromethanesulfonic acid to 4-isopropyltropolone (hinokitiol: HL) dissolved in a protophobic aprotic solvent, acetonitrile, with poor solvation of anions and cations. The formation was confirmed by UV−visible and 13C NMR spectroscopy as well as theoretical calculations using the Gaussian03 quantum chemistry package. The 13C chemical shifts of all C-atoms in the seven-membered ring were properly assigned for H2L+ and HL as well as for the deprotonated species, L−. The influence of residual water in the organic solvent was regarded as negligible because such a water is in the “dihydrogen ether” condition.

New heterobimetallic ferrocenyl derivatives: Evaluation of their potential as prospective agents against trypanosomatid parasites and Mycobacterium tuberculosis

“…Due to the closeness of these protons to the metal center, this doublet shifts significantly to higher fields after coordination [64]. A similar behavior was observed for proton 3 of the hinokitiol complexes [56,65].…”

Suppressing carboxylate nucleophilicity with inorganic salts enables selective electrocarboxylation without sacrificial anodes

“…S12 and S13 †). [65][66][67] Collectively, these experiments demonstrate the coordination of Mg 2+ cations to carboxylate groups, leading to suppression of nucleophilicity.…”

Chemoselective Schmidt Reaction Mediated by Triflic Acid: Selective Synthesis of Nitriles from Aldehydes

“…Nevertheless, the most satisfactory results were obtained by using CH 3 CN as solvent . Although CH 3 CN is known to react with TfOH, it is used as solvent in several organic reactions . Therefore, we carried out further reactions with NaN 3 (1.5 equiv), TfOH (3 equiv) using CH 3 CN as solvent at room temperature.…”