Synthesis of 2-aryl-1H-Benzimidazoles and 2-aryl-1H-perimidines Using Arylidene Meldrum's Acid as a Source of the Aryl Group and Oxidant

Abstract

Arylidene Meldrum's acid is employed as a source of the aryl group and oxidant for the synthesis of 2-aryl-1 H–benzimidazoles by a condensation reaction with 1,2-phenylenediamine in refluxing ethanol with good to high yields. Arylidene Meldrum's acids were also used as a source of the aryl group and oxidant for the synthesis of 2-aryl-1 H-perimidines by a condensation reaction with 1,8-diaminonaphthalene in refluxing ethanol with high yields.

One-pot synthesis of dihydroquinolones by sequential reactions ofo-aminobenzyl alcohol derivatives with Meldrum's acids

“…Known compound; 30 white solid; 78% yield (4.50 mmol scale, 1.10 g); lit. mp 127–129 °C; mp 127–128 °C; TLC R f 0.30 ( n -hexane/EtOAc = 3/1); IR (neat): 3052, 2922, 1727, 1585, 1011 cm −1 ; 1 H NMR (400.13 MHz, CDCl 3 ) δ 7.41 (d, J = 8.4 Hz, 2H), 7.22 (d, J = 8.4 Hz, 2H), 3.73 (t, J = 5.0 Hz, 1H), 3.44 (d, J = 5.0 Hz, 2H), 1.75 (s, 3H), 1.59 (s, 3H); 13 C NMR (100.6 MHz, CDCl 3 ) δ 165.1 (C), 136.2 (C), 131.8 (CH, overlapping), 121.4 (C), 105.4 (C), 48.1 (CH), 31.5 (CH 2 ), 28.6 (CH 3 ), 27.3 (CH 3 ); HRMS: m / z [M + H] + calcd for C 13 H 14 BrO 4 : 312.9904; found: 312.9902.…”

“…Known compound; 30 white solid; 98% yield (8.12 mmol scale, 2.81 g); lit. mp 134–135 °C; mp 119–121 °C; TLC R f 0.20 ( n -hexane/EtOAc = 9/1); IR (neat): 3461, 3259, 2917, 1597, 1495, 1384, 1328, 1158, 1090 cm −1 ; 1 H NMR (400.13 MHz, CDCl 3 ) δ 8.00 (bs, 1H), 7.48–7.45 (m, 2H), 7.32–7.29 (m, 3H), 7.22 (dt, J 1 = 8.0 Hz, J 2 = 1.6 Hz, 1H), 7.17–7.13 (m, 3H), 7.02 (dt, J 1 = 7.6 Hz, J 2 = 1.1 Hz, 1H), 6.92 (dd, J 1 = 7.6 Hz, J 2 = 1.1 Hz, 1H), 5.67 (s, 1H), 2.72 (bs, 1H), 2.38 (s, 3H); 13 C NMR (100.6 MHz, CDCl 3 ) δ 143.7 (C), 141.1 (C), 136.7 (C), 136.0 (C), 133.2 (C), 129.7 (CH), 129.2 (CH), 129.1 (CH), 128.8 (CH), 128.0 (CH), 127.3 (CH), 126.5 (CH), 124.7 (CH), 122.2 (CH), 74.8 (CH), 21.6 (CH 3 ); HRMS: m / z [M + Na] + calcd for C 20 H 19 NO 3 SNa: 376.0978; found: 376.0977.…”