Synthesis and Nitration of 7-Hydroxy-4-Methyl Coumarin via Pechmann Condensation Using Eco-Friendly Medias

Abstract

Abstract.A nitro coumarin derivatives have been synthesized via nitration of 7-hydroxy-4-methyl coumarin which was synthesized via Pechmann condensation resorcinol with a β-ketoester using Amberlyst-15 as a green and efficient catalyst and by caring out the reaction of resorcinol and ethyl acetoacetate (with 1:1 mol ratio) in the presence of 0.2 g of Amberlyst-15 at 110 o C under solventfree conditions. These nitro coumarin derivatives have biological activity and momentousness in the industrial fields. The purified products were determined the melting points and characterized by spectral methods: FT-IR, 1 H-NMR, 13 C-NMR.

A Coumarin−Donepezil Hybrid as a Blood−Brain Barrier Permeable Dual Cholinesterase Inhibitor: Isolation, Synthetic Modifications, and Biological Evaluation of Natural Coumarins

“…[13] The synthesis of 4-methylangelicin was started with commercially available resorcinol (8). The Pechmann condensation [14] of resorcinol with ethyl acetoacetate in sulfuric acid provided 4methylcoumarin 9 that on treatment with allyl bromide gave 10. The regioselective Claisen rearrangement using N,N-diethylaniline gave 8-allyl-4-methyl-7-hydroxy coumarin (11) in a 73 % yield.…”

“…188–190 °C; 1 H NMR (400 MHz, DMSO‐d 6 ) δ (ppm) 10.34 (s, 1H), 6.71 (d, J =8.7 Hz, 1H), 6.69 (d, J =8.9, 1H),), 6.60 (s, 1H), 6.59 (s, 1H), 2.25 (s, 3H); 13 C NMR (101 MHz, DMSO‐d 6 ): δ (ppm) 164.33, 160.76, 155.34, 153.05, 123.81, 113.93, 112.79, 110.75, 101.94, 18.59. ESIMS: m/z 177.3 [M+H] + [14] …”

“…Yield: 84 %; white powder; m.p. 188-190 °C; 1 H NMR (400 MHz, DMSO-d 6 ) δ (ppm) 10.34 (s, 1H), 6.71 (d, J = 8.7 Hz, 1H), 6.69 (d, J = 8.9, 1H),), 6.60 (s, 1H), 6.59 (s, 1H), 2.25 (s, 3H); 13 [14] Synthesis of 7-allyloxy-4-methylcoumarin (10). The mixture of 7hydroxy-4-methylumbelliferone (9, 617 mg, 3.5 mmol), allyl bromide (4.0 μL, 5.25 mmol), and anhydrous K 2 CO 3 (1.09 g, 5.25 mmol) in acetone (50 mL) in presence of N 2 atmosphere was refluxed at 50 °C for overnight.…”

Comparison of Antioxidant Activities of Mono-, Di- and Tri-substituted Coumarins

“…M=(221), M-CO = M +1 (193), M +1 -OH = M +2 (176). FTIR spectrum shows a 3265 cm -1 (O-H) stretching, 1703 cm -1 (C=O) lactone carbonyl stretching, 1569 cm -1 (C=C) double band stretching, and 1314 cm -1 (C-O) stretching (24,25). (24,25).…”

“…The 4-methyl-7hydroxy-8-nitrocoumarin which remains in the filtrate is cooled in the refrigerator and crystallized, then filtered through Büchner funnel (24). (24,25).…”