Addition reaction of azoles to acetone‐d6: NMR and computational studies

• Published in: Journal of physical organic chemistry 2024-08, Vol.37 (8), p.n/a
• Main Authors: Claramunt, Rosa M., Sanz, Dionisia, Alkorta, Ibon, Elguero, José
• Format: Article
• Language: English
• Subjects: Acetone; acetone addition; Adducts; annular tautomerism; Chemical equilibrium; DFT calculations; DNMR; Heterocyclic compounds; Imidazole; NMR; Nuclear magnetic resonance; Pyrazole; tetrazole; Tetrazoles; Triazoles
• ISSN: 0894-3230; 1099-1395
• DOI: 10.1002/poc.4612

The reactivity of imidazole, pyrazole, 1,2,4‐triazole, 1,2,3‐triazole, and tetrazole with acetone (propan‐2‐one) has been studied by 1H and 13C NMR using acetone‐d6 as solvent at temperatures ranging from 173 to 300 K at 10 K intervals. Simultaneously, the reaction has been theoretically calculated at the B3LYP/6‐311++G(d,p) level, and experimental and theoretical results have been compared. The equilibrium constants between azoles and adducts α,α‐dimethyl‐azole‐methanol were analyzed, assuming that the straight part of the plots –R ln Ke vs. 1/T can be used to determine ΔH and ΔS. Calculated and experimental data are related, but the theoretical values are proportionally higher. The tautomerism of triazoles and tetrazole has been considered in order to discuss the reactions. The reactivity of imidazole, pyrazole, 1,2,4‐triazole, 1,2,3‐triazole, and tetrazole with acetone has been studied by 1H and 13C NMR using acetone‐d6 as solvent at temperatures ranging from 173 to 300 K. Simultaneously, the reaction has been theoretically calculated at the B3LYP/6‐311++G(d,p) level and experimental and theoretical results compared.