One Pot, Four-Component for the Synthesis of Pyrano Pyrazole Derivatives using TBAHS as Green Catalyst and their Biological Evaluation

A Review on Molecular Iodine Catalyzed/Mediated Multicomponent Reactions

“…Substituents present in the aromatic ring of bezaldehyde do not affect significantly the reactivity of the bezaldehyde. Further, scope of this methodology has been extended by Bhosale et al [94] . by way of replacing amine source by 1H‐tetrazol‐5‐amine yielding the desired tetrazolo‐quinoazoline derivatives 92 (Scheme 47).…”

“…Synthesis of pyrimido and thiadiazolo-fused pyrimidine derivatives 60 was also reported in the literature via a three-component reaction of 2-amino-5-phenyl-1,3,4-thiadiazoles, aromatic aldehydes and barbituric acid using iodine as catalyst in CH 3 CN at 70 °C (Scheme 29). [68] Benzaldehydes with electron-rich and electron-poor substituents at ortho, meta, and para positions could be employed in reaction giving product in moderate to good yields. Another iodine catalyzed three-component reaction for the synthesis of fused heterocycles 61 was reported by Hassanabadia et al [69] (Scheme 29).…”

Eco-friendly Synthesis of 1, 4-Dihydropyrano-[2,3-c] Pyrazoles Using Copper Nanoparticles Grafted on Carbon Microsphere as a Heterogeneous Catalyst

“…TLC was carried out with Merck silica gel 60-F-254 aluminum plates. 1 H-NMR and 13 C-NMR spectra were recorded on a Bruker spectrometer using CDCl3, DMSO-d6 as solvent and tetramethylsilane as an internal standard. Mass spectrometric data were recorded by an electron spray ionization (EST) technique on a Q-tofmicro quadruple mass spectrometer (Micro mass).…”

“…6-Amino-3-methyl-4-(3-chlorophenyl)-2,4-dihydropyrano [2,3-c] [2,3-c] 13 C NMR (500 MHz, DMSO d6): δ (ppm) 12.44, 96.15, 119.61, 122.03, 122.15, 128.19, 129.88, 130.13, 130.25, 130.82, 131.14, 133.96, 134.40, 145.15, 145.38, 146.02, 147.88, 159.58; HRMS : 408.07.…”

“…Hence, due to the existence of these precious scaffolds in biologically active molecules (Figure 1), considerable efforts have been documented for the synthesis of these heterocyclic motifs by using various methodologies [10]. From the literature survey, 1,4-dihydro-pyrano[2,3-c]pyrazoles can be synthesized in the presence of catalysts like per-6-amino-β-cyclodextrin [11], nano-Fe3O4-SiO2, (CH2)3imidazole-SO3H]Cl [12], CsF [13], ionic liquid [bmim]OH [14], tungstate sulfuric acid [15], HTMAB [16], and SnS-NP [17]. Myrboh et al reported the synthesis of pyranopyrazoles using L-proline and KF-alumina as a catalyst [18].…”