Thermal [4 + 2] Cycloadditions of 3-Acetyl-, 3-Carbamoyl-, and 3-Ethoxycarbonyl-Coumarins with 2,3-Dimethyl-1,3-butadiene under Solventless Conditions: A Structural Study

Molecules

Irma Y. Flores-Larios¹  Lizbeth López-Garrido¹  Francisco J. Martínez-Martínez¹  Jorge González¹  Efrén V. García-Báez¹  Alejandro Cruz¹ 

[1] ¹Facultad de Ciencias Químicas, Universidad de Colima, km 9 Carretera Coquimatlán-Colima, Coquimatlán Colima 28400, Mexico ²Departamento de Química, Unidad Profesional Interdisciplinaria de Biotecnología del Instituto Politécnico Nacional, Av. Acueducto s/n, Barrio la Laguna Ticomán 07340, México D. F., Mexico

关键词: coumarins;    Diels-Alder adducts;    solventless reactions;    6a;    7;    7a;    8a;    9;    9ahexahydro-7a;    8a-dimethyl-6-oxo-6H-5;    8-dioxacyclopropa[b]phenantrenes;   

DOI  :  10.3390/molecules15031513

来源: mdpi

【 摘 要 】

The thermal [4+2] cycloadditions of 3-acetyl-, 3-carbamoyl, and 3-ethoxycarbonylcoumarins with 2,3-dimethyl-1,3-butadiene under solvent free conditions are reported, as well as the epoxidation reactions of some adducts. Discussion is focused on the structural features of the Diels-Alder adducts and their epoxides, based upon NMR, X-ray, and mass spectral data, and supported by ab initio theoretical calculations.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.