Ferretti Francesco, Fouad Manar Ahmed, Abbo Cecilia, Ragaini Fabio
Dipartimento di Chimica, Università Degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy.
Chemistry Department, Faculty of Science, Alexandria University, P.O. Box 426, Alexandria 21321, Egypt.
Molecules. 2023 Jul 15;28(14):5424. doi: 10.3390/molecules28145424.
4-Quinolones are the structural elements of many pharmaceutically active compounds. Although several approaches are known for their synthesis, the introduction of an aryl ring in position 2 is problematic with most of them. The reductive cyclization of -nitrochalcones by pressurized CO, catalyzed by ruthenium or palladium complexes, has been previously reported to be a viable synthetic strategy for this aim, but the need for pressurized CO lines and autoclaves has prevented its widespread use. In this paper, we describe the use of the formic acid/acetic anhydride mixture as a CO surrogate, which allows us to perform the reaction in a cheap and commercially available thick-walled glass tube without adding any gaseous reagent. The obtained yields are often high and compare favorably with those previously reported by the use of pressurized CO. The procedure was applied to a three-step synthesis from commercially available and cheap reagents of the alkaloid Graveoline.
4-喹诺酮是许多具有药物活性的化合物的结构单元。尽管已知有几种合成方法，但大多数方法在2位引入芳基环都存在问题。此前有报道称，钌或钯配合物催化下的加压CO对β-硝基查尔酮进行还原环化是实现这一目标的可行合成策略，但由于需要加压CO管路和高压釜，限制了其广泛应用。在本文中，我们描述了使用甲酸/乙酸酐混合物作为CO替代物，这使我们能够在廉价且市售的厚壁玻璃管中进行反应，而无需添加任何气态试剂。所获得的产率通常很高，与之前使用加压CO报道的产率相比具有优势。该方法应用于从市售廉价试剂出发，经三步合成生物碱Graveoline。
