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

Abstract

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.

Design, preparation and application of the semicarbazide-pyridoyl-sulfonic acid-based nanocatalyst for the synthesis of pyranopyrazoles

“…In addition, the successful synthesis of Fe 3 O 4 @SiO 2 core–shell was confirmed by the presence of a broad peak at 2θ = 20°–30° which is due to the amorphous silicon layer, demonstrating that the magnetic moiety structure was protected in the core where SiO 2 cover did not alter the crystal structure of the magnetic Fe 3 O 4 nanoparticles 58 . In addition, after anchoring the OSi(CH 2 ) 3 - N (3-pyridoyl sulfonic acid)semicarbazide functional groups, the peaks were found to have background noise levels increased, that coming from the amorphous added sulfonic acid functionalities 59 . Finally, based on the Scherrer equation (D = Kλ/(β cos θ), the average crystallite size of FSiPSS nanocomposites was found to be about 16.27 nm.…”

5,5’-Indigodisulfonic acid as an efficient catalyst for the synthesis of 2,3-dihydroquinazolinone derivatives

“…Yellow solid, TLC Rf = 0.13 (PE/EA = 2:1), m.p. = 194-196 °C (literature [35] 195-197 °C). 1 13 C NMR spectra are consistent with the literature [1] .…”

A novel cubic Zn‐citric acid‐based MOF as a highly efficient and reusable catalyst for the synthesis of pyranopyrazoles and 5‐substituted 1H‐tetrazoles

“…[7-] In this context, one-pot synthesis of heterocycles has emerged as a green chemistry method and atom utilization efficiency due to the incorporation of two separate reaction steps. [3,[11][12][13][14] Over the last decade, numerous homogeneous and heterogeneous materials including transition metal-containing catalysts for direct synthesis of pyranopyrazoles and 5-substituted 1H-tetrazoles have been developed using several organic and inorganic catalytic complexes such as palladium, copper, and nickel. [15][16][17][18][19][20][21][22][23] However, most of these methods outlined above suffer from disadvantages due to harsh operational conditions, limited substrate scope, using expensive and noble metal, toxic reagents, low efficiency, and environmental impacts.…”