An Efficient Green Protocol for Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones Using SBA‐16/GPTMS‐TSC‐CuIunder Solvent‐Free Conditions

Synthesis of a Pyrrolo[1,2-a]quinazoline-1,5-dione Derivative by Mechanochemical Double Cyclocondensation Cascade

N-heterocyclic compounds, such as quinazolinone derivatives, have significant biological activities. Nowadays, as the demand for environmentally benign, sustainable processes increases, the application of compounds from renewable sources, easily separable heterogeneous catalysts and efficient, alternative activation methods is of great importance. In this study, we have developed a convenient, green procedure for the preparation of 3a-methyl-2,3,3a,4-tetrahydropyrrolo[1,2-a]quinazoline-1,5-dione through a double cyclocondensation cascade using anthranilamide and ethyl levulinate. Screening of various heterogeneous Brønsted acid catalysts showed that Amberlyst^® 15 is a convenient choice. By applying mechanochemical activation in the preparation of this N-heterotricyclic compound for the first time, it was possible to shorten the necessary time to three hours compared to the 24 h needed under conventional conditions to obtain a high yield of the target product.

Synthesis and characterization of novel hercynite@sulfuric acid and its catalytic applications in the synthesis of polyhydroquinolines and 2,3-dihydroquinazolin-4(1H)-ones

Herein, we report the synthesis of hercynite@sulfuric acid as a novel nanomagnetic solid acid catalyst, containing the sulfuric acid catalytic sites on the surface of hercynite MNPs as the catalytic support. The as-synthesized nanocomposite was meticulously characterized using a wide range of physicochemical techniques; including, FT-IR, XRD, EDX, X-ray-mapping, SEM and VSM analysis. The catalytic activity of this nanomagnetic material was considered for the synthesis of the diversely substituted polyhydroquinolines and 2,3-dihydroquinazolin-4(1H)-ones under solvent free conditions and also cyclocondensation reactions in ethanol, respectively affording good to excellent yields. Moreover, it is worth mentioning that the heterogeneity of the catalyst was measured through its excellent reusability and hot-filtration test.

Selective Synthesis of 2-(1,2,3-Triazoyl) Quinazolinones through Copper-Catalyzed Multicomponent Reaction

We describe here our results from the copper-catalyzed three component reaction of 2-azidobenzaldehyde, anthranilamide and terminal alkynes, using Et3N as base, and DMSO as solvent. Depending on the temperature and amount of Et3N used in the reactions, 1,2,3-triazolyl-quinazolinones or 1,2,3-triazolyl-dihydroquinazolinone could be obtained. When the reactions were performed at 100 °C using 2 equivalents of Et3N, 1,2,3-triazolyl-dihydroquinazolinone was formed in 82% yield, whereas reactions carried out at 120 °C using 1 equivalent of Et3N provided 1,2,3-triazolyl-quinazolinones in moderate-to-good yields.