Synthesis of β‐Truxinate via [2+2] Cycloaddition of Methyl 4‐Nitrocinnamate: Kinetic Study of its Isomerization with DBU

• Published in: ChemistrySelect (Weinheim) 2024-06, Vol.9 (22), p.n/a
• Main Authors: Bahena‐Martínez, José Daniel, Flores, Roberto, Domínguez‐Mendoza, Blanca Eda, Hernández‐Vázquez, Luis Gabriel, Juaristi, Eusebio, Escalante, Jaime
• Format: Article
• Language: English
• Subjects: DBU; Kinetic Isomerization; β-Truxinate; δ-Truxinate; ζ-Truxinate
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202400178

This work concerns the isomerization of the product obtained by dimerization of methyl 4‐nitrocinnamate. Subsequent isomerization was performed using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a base to obtain the corresponding ζ‐ and δ‐truxinate derivatives. The process was monitored by 1H NMR spectroscopy in different deuterated solvents with a wide range of dielectric constants, acetonitrile‐d3, acetone‐d6, tetrahydrofuran‐d8, and benzene‐d6. Each solvent was found to have a distinct influence on the reaction's rate constant k, with acetone‐d6 yielding the highest ratio of ζ‐truxinate derivative. Kinetic analysis of the reaction provided valuable information about the mechanism involved in the isomerization process. In this work, synthesis of β‐truxinate from methyl 4‐nitrocinnamate was realized. Isomerization process of β‐→ζ‐→δ‐truxinate by DBU was studied. The effect of solvent polarity on the proposed reaction mechanism was examined using various deuterated solvents with a wide range of dielectric constants. Furthermore, a kinetic model and values of k of process was determined from the experimental data.