Solution Structure of Succinylacetone, An Unsymmetrical β-Diketone, As Studied by ¹³C NMR and GIAO−DFT Calculations

Abstract

The enolization degrees of succinylacetone, an important heme biosynthesis inhibitor, have been determined in CDCl(3) and water solutions using (1)H NMR. The solution structures of SA have been investigated using a combined NMR/theoretical [GIAO DFT PBE1PBE/6-311++G(2d, p) PCM] approach. The populations of both enolic forms undergoing enol-enol equilibriums for SA and a series of unsymmetrical beta-diketones have been established by a quantitative comparison of the experimental (13)C NMR chemical shifts and calculated shielding constants. Moreover, using the same method and considering various trial structures differing in conformation and/or hydration of neutral SA molecule as well as its monoanion and dianion the structures of the most abundant species being present in the investigated water solutions have been deduced.

Orotic Acid in Water Solution, a DFT and 13C NMR Spectroscopic Study

“…Continuing our NMR studies on solution structures of biologically important compounds, − we devote this work to orotic acid, known also as vitamin B-13, which is an important natural product, structurally related to uracil. In living organisms it is a precursor of pyrimidine bases of nucleic acids .…”

NMR and DFT calculation study on structures of 2‐[2‐nitro‐4‐(trifluoromethyl)benzoyl]cyclohexane‐1,3‐dione (NTBC) and its two metabolites isolated from urine of patients suffering from tyrosinemia type I

“…As a result, averaged, population‐weighted spectra are observed in NMR. This problem was widely discussed in the literature and also in several papers from our laboratory 10, 14, 21–26. In Ref.…”

1H NMR Chemical Shift Calculations as a Probe of Supramolecular Host–Guest Geometry

“…1 H NMR (400 MHz, CDCl 3 ): δ 6.97 (s, 1H, ArH), 4.64 (s, 2H, benzyl CH 2 ), 2.31 (s, 6H, ArCH 3 ), 2.26 (s, 6H, ArCH 3 ). 13 2,3,5,6-Tetramethylbenzyltrimethyl Phosphonium Bromide (2[Br]). 2,3,5,6-Tetramethylbenzyl bromide (370 mg, 1.6 mmol, 1 equiv) was dissolved in diethyl ether (75 mL) and sparged with N 2 for 10 min.…”

“…1 H NMR (500 MHz, CD 3 OD): δ 6.96 (s, 1H, ArH), 3.90 (d, J = 16.5 Hz, 2H, benzyl CH 2 ), 2.20 (br, 12H, ArCH 3 ), 1.81 (d, J = 14.4 Hz, 9H, PMe 3 ). 13 ' ASSOCIATED CONTENT b S Supporting Information. 2D EXSY NMR spectrum of guest 2, atom coordinates used for all GIAO NMR shift calculations.…”