Black yet green: A heterogenous carbon-based acid catalyst for the synthesis of biscyclic derivatives under eco-friendly conditions

Abstract

In this study, a simple, cost-efficient and green protocol has been described for the synthesis of biscoumarin and bisdimedone derivatives via one-pot Knoevenagel-Michael reaction of aromatic aldehydes with 4-hydroxycoumarin and dimedone, respectively. This approach has defined a new way of synthesizing products (4a-i and 5a-i) in high yields using carbon sulfonic acid as a heterogeneous solid acid catalyst. All the reactions have been executed in a greener medium in short reaction times with high-to-excellent yields. This organic synthesis adheres to the principles of green chemistry as the catalyst is cheap, gentle toward environment, easy to handle and reusable up to six cycles, easily separable through filtration, green reaction media and high yield of derivatives in short reaction time. The structure of the synthesized compounds was established by spectral analysis.

Glycerol based carbon sulfonic acid catalyzed synthesis, in silico studies and in vitro biological evaluation of isonicotinohydrazide derivatives as potent antimicrobial and anti-tubercular agents

“…Its synthesis was confirmed by different techniques such as FT-IR, FE-SEM, XRD, TGA, DTA, and all the results were in accordance with the previously reported articles. In addition to the investigation on catalytic efficiency of glycerol based carbon sulfonic acid catalyst towards heterocyclic compounds [ 33 – 35 ], a highly efficient pathway for the synthesis of Schiff bases of isoniazid with diversely substituted aldehydes was developed.…”

“…Encouraged by the promising catalytic activity of our previously synthesized and characterized glycerol based carbon sulfonic catalyst [ 33 , 34 , 35 ], a facile protocol for the synthesis of isonicotinohydrazide analogs using glycerol based sulfonic acid as a catalyst has been demonstrated ( Scheme 1 ).

Scheme 1 Synthesis of isonicotinohydrazide analogs using isoniazid and aldehydes.

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Exploring the synthetic potential of a g-C3N4·SO3H ionic liquid catalyst for one-pot synthesis of 1,1-dihomoarylmethane scaffoldsviaKnoevenagel–Michael reaction

“…Dark yellow crystals, yield: 91%, m.p. 193–195 °C, 33 1 H NMR (400 MHz, CDCl 3 ): δ 11.80 (s, 1H, OH), 8.13–8.11 (m, 2H, Ar–H), 7.24–7.22 (dd, J = 9.0, 1.2 Hz, 2H, Ar–H), 5.53 (s, 1H, CH), 2.50–2.30 (dq, J = 27.6, 17.7 Hz, 8H, 4CH 2 ), 1.22 (s, 6H, 2CH 3 ), 1.10 (s, 6H, 2CH 3 ); ESI-MS ( m / z ): 413.18 [M + ].…”

“…Light yellow solid, yield: 87%,m.p. 195–199 °C, 33 1 H NMR (400 MHz, CDCl 3 ): δ 11.79 (s, 1H, OH), 7.56–7.54 (d, J = 8.8 Hz, 2H, Ar–H), 7.17–7.19 (dd, J = 8.8, 1.3 Hz, 2H, Ar–H), 5.50 (s, 1H, CH), 2.49–2.28 (ddd, J = 33.7, 28.0, 17.9 Hz, 8H, 4CH 2 ), 1.21 (s, 6H, 2CH 3 ), 1.09 (s, 6H, 2CH 3 ). 13 C NMR (101 MHz, CDCl 3 ) δ 191.09, 189.67, 144.40, 132.19, 127.69, 119.05, 114.91, 109.78, 47.03, 46.46, 33.30, 31.55, 31.52, 31.52, 29.69, 27.51; ESI-MS ( m / z ): 393.19 [M + ].…”

“…Light yellow solid, yield: 69%, m.p. 198–202 °C, 33 1 H NMR (400 MHz, CDCl 3 ): δ 11.51 (s, 1H, OH), 8.06–8.04 (dd, J = 25.3, 7.6 Hz, 2H, Ar–H), 8.00–7.98 (m, 2H, Ar–H), 7.40 (m, 9H, Ar–H), 7.38–7.36 (m, 2H, Ar–H), 6.93–6.91 (d, J = 8.9 Hz, 2H, Ar–H), 6.04 (s, 1H, CH), 5.03 (s, 2H, CH 2 ); ESI-MS ( m / z ): 518.14 [M + ].…”