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Table 1 The physicochemical and spectral characteristics of synthesized oxazole derivatives

From: Design, synthesis and biological evaluation of 3-(2-aminooxazol-5-yl)-2H-chromen-2-one derivatives

Compound Spectral characteristics
(1) (3-(2-(3,4,5-Trimethoxy-benzylidene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 204–206; Rf value: 0.35; % yield: 70; IR (KBr cm−1): 3100 (C–H str.), 1419 (C=C str.), 1606 (N=CH str.), 1236 (C–N str.), 1286 (C–O–C str.), 1722 (C=O str.), 2800 (OCH3 str.); 1H NMR (δ, DMSO): 7.22–7.54 (m, 7H, ArH), 8.39 (s, 1H, N=CH), 7.19 (s, 1H, CH of oxazole), 3.89 (s, 9H, (–OCH3)3); 13C NMR (δ, DMSO): 139.2 (oxazole-C), 128.1, 121.3, 120.2, 102.08 (phenyl nucleus), 55.8 (OCH3); M. Formula: C22H18N2O6; MS: m/z 407 (M++1)
(2) 3-(2-(4-Methoxybenzylidene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 190–192; Rf value: 0.34; % yield: 65; IR (KBr cm−1): 3174 (C–H str.), 1452 (C=C str.), 1595 (N=CH str.), 1292 (C–N str.), 1259 (C–O–C str.), 1724 (C=O str.), 3053 (OCH3 str.); 1H NMR (δ, DMSO): 6.94–7.92 (m, 9H, ArH), 8.17 (s, 1H, N=CH), 7.19 (s, 1H, CH of oxazole), 3.84 (s, 3H, –OCH3); 13C NMR (δ, DMSO): 163.8, 131.2, 114.7 (phenyl nucleus), 162.7, 128.8, 128.5, 127.2, 124.8 (coumarin-C), 158.3 (N=CH), 151.9, 137.7, 137.1 (oxazole-C), 55.6 (OCH3); M. Formula: C20H14N2O4; MS: m/z 347 (M++1)
(3) (3-(2-(4-(Phenoxymethyl)-benzylideneamino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 186–188; Rf value: 0.32; % yield: 72; IR (KBr cm−1): 3172 (C–H str.), 1450 (C=C str.), 1602 (N=CH str.), 1382 (C–N str.), 1257 (C–O–C str.), 1720 (C=O str.); 1H NMR (δ, DMSO): 7.00–7.93 (m, 14H, ArH), 8.3 (s, 1H, N=CH), 7.02 (s, 1H, CH of oxazole), 5.08 (s, 2H, –CH2–O); 13C NMR (δ, DMSO): 162.7, 127.8, 124.8 (coumarin-C), 161.1 (N=CH), 152.3, 137.7 (oxazole-C), 132.1, 128.8, 128.4, 127.4, 115.5 (phenyl nucleus), 69.6 (CH2O); M. Formula: C26H18N2O4; MS: m/z 423 (M++1)
(4) (3-(2-(2-Bromobenzylidene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 215–217; Rf value: 0.48; % yield: 68; IR (KBr cm−1): 2937 (C–H str.), 1454 (C=C str.), 1602 (N=CH str.), 1292 (C–N str.), 1224 (C–O–C str.), 1722 (C=O str.), 592 (C–Br str.); 1H NMR (δ, DMSO): 7.25–7.83 (m, 9H, ArH), 7.84 (s, 1H, N=CH), 7.26 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 135.1, 132.2, 131.3, 131.2, 120.4 (phenyl nucleus), 129.3, 128.6 (coumarin-C); M. Formula: C19H11BrN2O3; MS: m/z 396 (M++1)
(5) (3-(2-(3-(Phenoxymethyl)-benzylideneamino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 184–186; Rf value: 0.33; % yield: 75; IR (KBr cm−1): 3190 (C–H str.), 1450 (C=C str.), 1600 (N=CH str.), 1328 (C–N str.), 1292 (C–O–C str.), 1722 (C=O str.); 1H NMR (δ, DMSO): 7.16–7.69 (m, 14H, ArH), 8.4 (s, 1H, N=CH), 7.14 (s, 1H, CH of oxazole), 5.08 (s, 2H, –CH2–O); 13C NMR (δ, DMSO): 158.4, 140.2, 133.2, 128.4, 120.2, 115.6 (phenyl nucleus), 151.1, 140.5, 136.7 (oxazole-C), 129.7, 128.9, 128.4, 126.8, 125.5 (coumarin-C); M. Formula: C26H18N2O4; MS: m/z 423 (M++1)
(6) (3-(2-(4-Chlorobenzylidenea-mino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 194–196; Rf value: 0.29; % yield: 60; IR (KBr cm−1): 3070 (C–H str.), 1452 (C=C str.), 1600 (N=CH str.), 1328 (C–N str.), 1292 (C–O–C str.), 1724 (C=O str.); 1H NMR (δ, DMSO): 6.89–7.68 (m, 9H, ArH), 8.11 (s, 1H, N=CH), 7.37 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 161.1, 129.3, 128.5, 124.8, 119.1 (coumarin-C), 158.3 (N=CH), 151.9 (oxazole-C), 136.1, 131.2 (phenyl nucleus); M. Formula: C19H11ClN2O3; MS: m/z 351 (M++1)
(7) (2-(3-Nitrobenzylideneamino)-oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 236–238; Rf value: 0.51; % yield: 79; IR (KBr cm−1): 2972 (C–H str.), 1454 (C=C str.), 1606 (N=CH str.), 1276 (C–N str.), 1130 (C–O–C str.), 1714 (C=O str.), 1344 (NO2 str.); 1H NMR (δ, DMSO): 6.90–8.69 (m, 9H, ArH), 7.98 (s, 1H, N=CH), 7.14 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO); 148.2, 134.8, 130.9 (phenyl nucleus), 137.1 (oxazole-C), 129.7, 128.4, 123.9 (coumarin-C); M. Formula: C19H11N3O5; MS: m/z 362 (M++1)
(8) (3-(2-(4-Isopropylbenzylidene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 206–208; Rf value: 0.39; % yield: 80; IR (KBr cm−1): 3398 (C–H str.), 1415 (C=C str.), 1604 (N=CH str.), 1253 (C–N str.), 1157 (C–O–C str.), 1720 (C=O str.); 1H NMR (δ, DMSO): 6.88–7.84 (m, 9H, ArH), 8.12 (s, 1H, N=CH), 7.37 (s, 1H, CH of oxazole), {3.11 (m, 1H, CH of –CH(CH3)2), 1.29 (d, 6H, (CH3)2)}; 13C NMR (δ, DMSO): 161.1, 128.5, 119.1 (coumarin-C), 158.3 (N=CH), 151.9, 131.2, 124.6 (phenyl nucleus), 136.1 (oxazole-C); M. Formula: C22H18N2O3; MS: m/z 359 (M++1)
(9) (3-(2-(Thiophen-2-ylmethylene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 179–181; Rf value: 0.49; % yield: 75; IR (KBr cm−1): 3118 (C–H str.), 1454 (C=C str.), 1604 (N=CH str.), 1274 (C–N str.), 1253 (C–O–C str.), 1693 (C=O str.), 715 (C-S str.); 1H NMR (δ, DMSO): 7.38–7.84 (m, 5H, ArH), 7.59 (s, 1H, N=CH), 6.9 (s, 1H, CH of oxazole), {7.6 (d, 1H, CH), 7.17 (t, 1H, CH), 7.68 (d, 1H, CH) of thiophene}; 13C NMR (δ, DMSO): 161.1, 128.5 (coumarin-C), 151.9 (N=CH), 136.1 (oxazole-C), 124.6 (thiophene-C); M. Formula: C17H10N2O3S; MS: m/z 323 (M++1)
(10) (3-(2-3-Phenylallylidene)-amino)-oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 210–212; Rf value: 0.52; % yield: 65; IR (KBr cm−1): 2924 (C–H str.), 1456 (C=C str.), 1680 (N=CH str.), 1294 (C–N str.), 1226 (C–O–C str.), 1710 (C=O str.), 1606 (C=C con); 1H NMR (δ, DMSO): 7.10–7.75 (m, 10H, ArH), 7.51 (s, 1H, N=CH), 7.09 (s, 1H, CH of oxazole), 5.59–6.95 (d, 2H, –CH=CH); 13C NMR (δ, DMSO): 150.9, 141.1 (oxazole-C), 128.7, 128.6, 128.2 (phenyl nucleus), 128.5, 127.1, 123.6 (coumarin-C); M. Formula: C21H14N2O5; MS: m/z 343 (M++1)
(11) (3-(2-(2-Nitrobenzylideneam-ino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 248–250; Rf value: 0.42; % yield: 68; IR (KBr cm−1): 3369 (C–H str.), 1454 (C=C str.), 1604 (N=CH str.), 1274 (C–N str.), 1130 (C–O–C str.), 1703 (C=O str.), 1342 (NO2 str.); 1H NMR (δ, DMSO): 7.24–7.58 (m, 9H, ArH), 7.92 (s, 1H, N=CH), 7.23 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 138.1 (oxazole-C), 137.1, 131.9, 130.3 (phenyl nucleus), 128.1, 126.1, 122.3, 121.5 (coumarin-C); M. Formula: C19H11N3O5; MS: m/z 362 (M++1)
(12) (3-(2-(4-Nitrobenzylideneam-ino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 236–238; Rf value: 0.37; % yield: 74; IR (KBr cm−1): 2972 (C–H str.), 1454 (C=C str.), 1604 (N=CH str.), 1274 (C–N str.), 1170 (C–O–C str.), 1714 (C=O str.), 1340 (NO2 str.); 1H NMR (δ, DMSO): 6.89–8.23 (m, 9H, ArH), 8.16 (s, 1H, N=CH), 7.17 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 131.3, 124.3 (coumarin-C), 130.5, 115.9 (phenyl nucleus); M. Formula: C19H11N3O5; MS: m/z 362 (M++1)
(13) (3-(2-(4-Bromobenzylidene-amino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 179–181; Rf value: 0.39; % yield: 63; IR (KBr cm−1): 3070 (C–H str.), 1452 (C=C str.), 1606 (N=CH str.), 1274 (C–N str.), 1192 (C–O–C str.), 1722 (C=O str.), 592 (C–Br str.); 1H NMR (δ, DMSO): 7.05–7.81 (m, 9H, ArH), 7.85 (s, 1H, N=CH), 7.06 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 135.1 (oxazole-C), 132.2, 131.3, 131.1 (phenyl nucleus), 129.3, 129.1, 124.6 (coumarin-C); M. Formula: C19H11BrN2O3; MS: m/z 396 (M++1)
(14) (3-(2-(3-Hydroxy-4-methoxy-benzylideneamino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 228–230; Rf value: 0.46; % yield: 78; IR (KBr cm−1): 3178 (C–H str.), 1454 (C=C str.), 1606 (N=CH str.), 1259 (C–N str.), 1192 (C–O–C str.), 1722 (C=O str.), 2935 (OCH3 str.); 3408 (OH); 1H NMR (δ, DMSO): 7.18–7.71 (m, 8H, ArH), 8.07 (s, 1H, N=CH), 7.20 (s, 1H, CH of oxazole), 6.76 (s, 1H, –OH), 3.73 (s, 3H, –OCH3); 13C NMR (δ, DMSO): 160.2 (N=CH), 154.3, 127.5, 116.2, 115.8 (phenyl nucleus), 151.1, 140.8, 139.4 (oxazole-C), 128.3, 124.8, 120.1 (coumarin-C); M. Formula: C20H14N3O5; MS: m/z 363 (M++1)
(15) (3-(2-(2,3-Dichlorobenzyli-deneamino)oxazol-5-yl)-2H-chromen-2-one): m.p. °C: 219–221; Rf value: 0.44; % yield: 74; IR (KBr cm−1): 3072 (C–H str.), 1452 (C=C str.), 1604 (N=CH str.), 1253 (C–N str.), 1192 (C–O–C str.), 1722 (C=O str.), 750 (C–Cl str.); 1H NMR (δ, DMSO): 7.30–7.88 (m, 8H, ArH), 8.14 (s, 1H, N=CH), 7.30 (s, 1H, CH of oxazole); 13C NMR (δ, DMSO): 131.5, 131.2 (phenyl nucleus), 128.8 (coumarin-C); M. Formula: C19H10Cl2N2O3; MS: m/z 386 (M++1)