Organocatalyzed domino reactions: diversity oriented synthesis of pyran-annulated scaffolds using in situ-developed benzylidenemalononitriles

Ag3[PMo12O40]: An efficient and green catalyst for the synthesis of highly functionalized pyran‐annulated heterocycles via multicomponent reaction

“…Also, the singlet peak at 4.14 ppm is related to H‐4. The four aromatic protons appeared at 7.04–7.07 and 6.79–6.82 ppm as doublet peaks …”

“…1 H NMR (300 MHz, DMSO‐ d 6 , δ , ppm): 7.04–7.07 (d, 2H), 6.83 (s, 2H), 6.79–6.82 (d, 2H), 4.14 (s, 2H), 3.72 (s, 3H), 2.22 (d, 2H), 2.08 (d, 1H), 1.08 (s, 3H), 0.97 (s, 3H). 13 C NMR (100 MHz, DMSO, δ , ppm): 196.1, 162.5, 158.8, 158.3, 137.2, 128.6, 120.2, 114.0 2‐Amino‐5‐oxo‐4‐(thiophen‐2‐yl)‐5,6,7,8‐tetrahydro‐4 H ‐chromene‐3‐carbonitrile ( 4o ): FT‐IR (KBr, ν max , cm −1 ): 3363,3323, 3178, 2956, 2374, 2192, 1679, 1664, 1650, 1608,1409, 1359,1209, 1135, 1000, 709, 626, 536, 501.…”

“…The four aromatic protons appeared at 7.04-7.07 and 6.79-6.82 ppm as doublet peaks. [57] To extend our study, we also prepared Ag 3 [PW 12 O 40 ] in accordance with a method previously reported. [66] The catalytic activity of Ag 3 [18,19,67] To reveal the advantages of this catalyst, its catalytic activity in the model reaction involving benzaldehyde, malononitrile and 4-hydroxycoumarin was compared with those of previously reported systems ( Table 4).…”

Applications of pyrazolone in multicomponent reactions for the synthesis of dihydropyrano[2,3-c]pyrazoles and spiro-pyrano[2,3-c]pyrazoles in an aqueous medium

“…In 2017, Ahad and Farooqui demonstrated that the multicomponent domino reaction of aldehydes 10, malononitrile 2, and pyrazolone 16 in presence of aspartic acid as an efficient organocatalyst in aqueous ethanol afforded the dihydropyrano[2,3-c]pyrazole derivatives 14 in 84-91% yield at room temperature (Scheme 38a). 85 In 2019, Khandebharad et al has synthesized several dihydropyrano[2,3-c]pyrazole derivatives 37 in good to excellent yield from the four-component reaction of aldehydes 10, malononitrile 2, ethyl acetoacetate 13, and hydrazine hydrate 9 by using sodium gluconate as recyclable organocatalyst in presence of water as a reaction medium under reflux of 15-45 minutes (Scheme 38b). 86 All aryl, as well as heteroaryl aldehydes with electron-withdrawing and electron releasing group on the different position, were smoothly worked under the optimized reaction condition and a total of 13 compounds were synthesized in 85-92% yield.…”

A catalytic and green method for one-pot synthesis of new Hantzsch 1,4-dihydropyridines

“…MCRs strategy offer a significant importance over linear-strategy synthesis due to their flexible, convergent, atomic efficient nature and provide a maximum structural complexity with a minimum number of synthetic steps [17]. Reportedly, in MCRs a wide range of catalysts has been explored in the synthesis of 1,4-DHP derivatives including l-proline [18,19], aspartic acid [20], p-toluenesulfonic acid monohydrate [21][22][23], TiO 2 nano wires [24], phosphootungstic acid (H 3 PW 12 O 40 ) [25], silica-coated nano-Fe 3 O 4 [26], cellulose sulfuric acid [27], chitosan supported copper(II)sulfate (CSCS) [28], Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s4245 2-020-2165-x) contains supplementary material, which is available to authorized users. porcine pancreatic lipase [29], Magnetic dextrin nanobiomaterial [30], SO 3 H-functionalized nano-MGO-D-NH 2 [31], guanidinylated chitosan magnetic nano catalyst [32], and pyrimidine-2,4-diamine (PDA)-functionalized silica-coated magnetic nanocatalyst (Fe 3 O 4 /SiO 2 -PDA) [33].…”