Materials and methods
General
“All the chemicals were purchased from Aldrich, Sigma-Aldrich, Fluka etc., and were used without further purification, unless otherwise stated. All melting points were measured on a Gallenkamp melting point apparatus in open glass capillaries and are uncorrected. IR Spectra were measured as KBr pellets on a Nicolet 6700 FT-IR spectrophotometer. The NMR spectra were recorded on a Varian Mercury Jeol-400 NMR spectrometer. 1H-NMR (400 MHz), and 13C-NMR (100 MHz) were run in either deuterated dimethyl sulphoxide (DMSO-d6) or deuterated chloroform (CDCl3). Chemical shifts (δ) are referred in terms of ppm and J-coupling constants are given in Hz. Mass spectra were recorded on a Jeol of JMS-600 H. Elemental analysis was carried out on Elmer 2400 Elemental Analyzer; CHN mode”.
General procedure for Knoevenagel condensation Michael addition for the synthesis of 4a–o (GP1)
A mixture of aldehyde 1 (1.5 mmol), 5,5-dimethylcyclohexane-1,3-dione 2, (1.5 mmol), 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (1.5 mmol) and Et2NH (1.5 mmol, 155 μL) in 3 mL of degassed H2O was stirred at room temperature for 1–12 h until TLC showed complete disappearance of the reactants. The precipitate was removed by filtration and washed with ether (3 × 20 mL). Solid was dried to afford pure products 4a–o.
5-((2,4-Dichlorophenyl)(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)methyl)-3-methyl-1-phenyl-1H-pyrazol-4-olate diethylaminium salt 4a
4a was prepared according to the general procedure (GP1) from 2,4-dichlorobenzaldehyde yielding orange powdered materials. m.p: 144 °C; IR (CsI, cm−1): 3451, 2984, 2868, 2719, 2492, 1598, 1501, 1468, 1380, 1262; 1H-NMR (400 MHz, DMSO-d6): 8.08 (d, 1H, J = 7.3 Hz, Ph), 7.93 (d, H, J = 7.3 Hz, Ph), 7.42 (s, 1H, Ph), 7.32–7.04 (m, 5H, Ph), 4.96 (s, 1H, CH = C), 2.85 (q, 4H, J = 7.3 Hz, CH2CH3), 2.12 (s, 3H, CH3), 1.11 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 157.6, 145.5, 142.4, 140.6, 132.1, 131.9, 128.3, 128.0, 126.6, 123.0, 119.1, 100.9, 41.7, 30.9, 13.2, 11.0; LC/MS (ESI): 330.07 [M]+for C18H16Cl2N2; Anal. for C21H24Cl2N3O; calcd C, 62.23; H, 5.97; Cl, 17.49; N, 10.37; Found: C, 62.23; H, 5.97; Cl, 17.49; N, 10.37.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(phenyl)methyl)-5,5-dimethylcyclohex-2-enone diethylaminium salt 4b
4b was prepared according to the general procedure (GP1) from benzaldehyde yielding orange powdered materials. m.p: 102 °C; IR (CsI cm−1): 3448, 3058, 2957, 2732, 2507, 1582, 1579, 1501, 1492, 1454, 1365, 1263; 1H-NMR (400 MHz, DMSO-d6): δ 15.30 (s, 1H, OH), 7.92(m, 3H, Ph), 7.33–7.07 (m, 7H, Ph), 5.75 (s, 1H, benzyl-H), 2.86 (q, 4H, J = 7.3 Hz, CH2CH3), 2.16 (s, 3H, CH3), 2.12 (s, 2H, CH2), 2.09 (s, 2H, CH2), 1.11 (t, 6H, J = 7.3 Hz, CH2CH3), 1.10 (s, 3H, CH3), 1.00 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 157.2, 146.4, 145.8, 145.5, 140.5, 128.4, 128.3, 127.7, 127.2, 119.1, 102.2, 79.2, 41.4, 30.2, 28.8, 12.9, 12.7, 11.00; LC/MS (ESI): 262.1M]+ for C18H18N2; Anal. for C29H38N3O3; calcdC, 73.08; H, 8.04; N, 8.82; Found: C, 73.07; H, 8.05; N, 8.83.
Diethylammonium 5-((4-chlorophenyl)(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)methyl)-3-methyl-1-phenyl-1H-pyrazol -4-olate
4c
4c was prepared according to the general procedure (GP1) from 4-chlorobenzaldehyde yielding orange powdered materials. m.p: 92 °C; IR (CsI cm−1): 3450, 2958, 2868, 2732, 2506, 1702, 1579, 1501, 1487, 1387, 1366, 1318, 1263; 1H-NMR (400 MHz, DMSO-d6): δ 15.30 (s, 1H, OH), 7.34–7.07 (m, 7H, Ph), 5.57 (s, 1H, benzyl-H), 2.91(q, 4H, J = 7.3 Hz, CH2CH3), 2.19 (s, 3H, CH3), 2.18 (s, 2H, CH2), 2.12 (s, 2H, CH2), 0.99(t, 6H, J = 7.3 Hz, CH2CH3), 1.14 (s, 3H, CH3), 1.15 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 157.2, 146.4, 145.8, 145.5, 140.5, 128.4, 128.3, 127.7, 127.2, 119.1, 102.2, 79.2, 41.4, 30.2, 28.8, 12.9, 12.7, 11.00; LC/MS (ESI): 262.1 M]+ for C18H17ClN2; Anal. for C29H36ClN3O3; Calcd C, 73.08; H, 8.04; N, 8.82; Found: C, 73.07; H, 8.05; N, 8.83, Cl, 6.21.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(p-tolyl)methyl)-5,5-dimethylcyclohex-2-enone diethylaminium salt 4d
4d was prepared according to the general procedure (GP1) from p-tolualdehyde yielding orange powdered materials. m.p: 104 °C; IR (CsI, cm−1): 3450, 3017, 2956, 2732, 2506, 1683, 1581, 1501, 1455, 1386, 1318, 1260; 1H-NMR (400 MHz, CDCl3): δ 15.45 (s, 1H, OH), 7.67 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.28 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.20–6.94 (m, 5H, Ph), 5.62 (s, 1H, benzyl-H), 2.31 (s, 3H, CH3), 2.29 (s, 2H, CH2), 2.28 (s, 3H, CH3), 2.23 (s, 2H, CH2), 2.18 (q, 4H, J = 7.3 Hz, CH2CH3), 1.01 (s, 6H, CH3), 0.84 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, CDCl3): δ = 189.8, 168.5, 157.9, 145.9, 140.4, 128.8, 128.7, 128.5, 127.6, 127.3, 121.7, 121.3, 80.3, 41.7, 31.5, 20.9, 12.6, 11.5; LC/MS (ESI): 276.1 [M]+ for C19H20N2; Anal. for C30H40N3O3; calcdC, 73.44; H, 8.22; N, 8.56; Found: C, 73.43; H, 8.23; N, 8.57.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(m-tolyl)methyl)-5,5-dimethylcyclohex-2-enone diethylaminium salt 4e
4e was prepared according to the general procedure (GP1) from m-tolualdehyde yielding orange powdered materials. m.p: 97 °C; IR (CsI, cm−1): 3449, 3033, 2956, 2731, 2506, 1581, 1501, 1387, 1318, 1261; 1H-NMR (400 MHz, DMSO-d6): δ 15.45 (s, 1H, OH), 7.68 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.63 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.28–7.06 (m, 5H, Ph), 5.62 (s, 1H, benzyl-H), 2.30 (s, 3H, CH3), 2.20 (s, 2H, CH2), 2.23 (s, 3H, CH3), 2.18 (s, 2H, CH2), 2.25 (q, 4H, J = 7.3 Hz, CH2CH3), 1.00 (s, 6H, CH3), 0.83 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 168.5, 157.9, 145.9, 140.4, 128.8, 128.7, 128.5, 127.6, 127.3, 121.7, 121.3, 80.3, 41.7, 31.5, 20.9, 12.6, 11.5; Anal. for C30H40N3O3; calcdC, 73.44; H, 8.22; N, 8.56; Found: C, 73.43; H, 8.23; N, 8.57.
2-((4-Bromophenyl)(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyl)-3-hydroxy-5,5-dimethylcyclohex -2-enone diethylaminium salt 4f
4f was prepared according to the general procedure (GP1) from p-bromobenzaldehyde yielding orange powdered materials. m.p: 86 °C; IR (KBr, cm−1): 3449, 2957, 2868, 2731, 250, 1699, 1579, 1501, 1483, 1388, 1263; 1H-NMR (400 MHz, DMSO-d6): δ 15.45 (s, 1H, OH), 7.91 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.35–7.26 (m, 5H, Ph), 7.20–6.96 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 5.50 (s, 1H, benzyl-H), 2.90 (q, 4H, J = 7.3 Hz, CH2CH3), 2.13 (s, 3H, CH3), 2.07 (s, 2H, CH2), 2.05 (s, 2H, CH2), 1.14 (t, 6H, J = 7.3 Hz, CH2CH3), 1.12 (s, 3H, CH3), 0.96 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 157.2, 155.9, 147.0, 145.8, 145.5, 140.7, 130.4, 129.6, 129.5, 128.4, 128.2, 122.9, 119.0, 118.8, 101.7, 79.7, 41.4, 31.9, 30.1, 28.3, 12.9, 128, 11.0; LC/MS (ESI): 340.1 [M]+ for C18H17BrN2; Anal. for C29H37BrN3O3; calcd C, 62.70; H, 6.71; Br, 14.38; N, 7.56; Found: C, 62.71; H, 6.71; Br, 14.39; N, 7.54.
2-((3-Bromophenyl)(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyl)-3-hydroxy-5,5-dimethylcyclohex -2-enone diethylaminium salt 4g
4g was prepared according to the general procedure (GP1) from m-bromobenzaldehyde yielding rose powdered materials. m.p: 97 °C; IR (KBr, cm−1): 3447, 2957, 2868, 2730, 2505, 1584, 1501, 1470, 1388, 1365, 1262; 1H-NMR (400 MHz, DMSO-d6): δ 15.45 (s, 1H, OH), 7.92 (dd, 1H, J = 7.3 Hz, 1.5 Hz, Ph), 7.50 (s, 1H, Ph), 7.35–7.04 (m, 8H, Ph), 5.55 (s, 1H, benzyl-H), 2.89 (q, 4H, J = 7.3 Hz, CH2CH3), 2.15 (s, 3H, CH3), 2.09 (s, 2H, CH2), 2.06 (s, 2H, CH2), 1.14 (t, 6H, J = 7.3 Hz, CH2CH3), 1.10 (s, 3H, CH3), 0.98 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 157.2, 155.9, 149.3, 147.0, 145.8, 145.5, 140.7, 140.2, 129.9, 128.4, 128.3, 123.0, 119.0, 118.8, 101.6, 79.1, 41.4, 31.9, 30.1, 28.3, 12.9, 128, 11.0; LC/MS (ESI): 340.1 [M]+ for C18H17BrN2; Anal. for C29H37BrN3O3; calcd C, 62.70; H, 6.71; Br, 14.38; N, 7.56; Found: C, 62.71; H, 6.71; Br, 14.39; N, 7.53.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(4-nitrophenyl)methyl)-5,5-dimethylcyclohex-2-enone diethylaminium salt 4h
4h was prepared according to the general procedure (GP1) from p-nitrobenzaldehyde yielding paige powdered materials. m.p: 106 °C; IR (CsI, cm−1): 3451, 2958, 2869, 2732, 2503, 1707, 1597, 1513, 1387, 1320, 1267; 1H-NMR (400 MHz, CDCl3): δ 15.40 (s, 1H, OH), 8.02 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.61 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.31–7.19 (m, 5H, Ph), 5.72 (s, 1H, benzyl-H), 2.70 (q, 4H, J = 7.3 Hz, CH2CH3), 2.27 (s, 3H, CH3), 2.24 (s, 2H, CH2), 2.19 (s, 2H, CH2), 1.07 (s, 6H, CH3), 1.02 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, CDCl3): δ = 189.8, 157.9, 145.9, 140.4, 128.7, 128.6, 128.2, 127.9, 127.7, 125.3, 124.8, 121.6, 121.2, 80.3, 42.3, 31.6, 21.7, 11.4; LC/MS (ESI): 307.1 [M]+ for C18H17N3O2; Anal. for C29H37N4O5; calcd C, 66.77; H, 7.15; N, 10.74; Found: C, 66.75; H, 7.16; N, 10.75.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(3-nitrophenyl)methyl)-5,5-dimethylcyclohex2-enone diethylaminium salt 4i
4i was prepared according to the general procedure (GP1) from m-nitrobenzaldehyde yielding white paige powdered materials. m.p: 99 °C; IR (CsI, cm−1): 3447, 3067, 2958, 2731, 2560, 1705, 1597, 1502, 1387, 1348, 1265; 1H-NMR (400 MHz, CDCl3): δ 15.30 (s, 1H, OH), 8.02(dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.61 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.31–7.19 (m, 5H, Ph), 5.72 (s, 1H, benzyl-H), 2.64 (q, 4H, J = 7.3 Hz, CH2CH3), 2.27 (s, 3H, CH3), 2.25 (s, 2H, CH2), 2.18 (s, 2H, CH2), 1.05 (s, 6H, CH3), 1.02 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, CDCl3): δ = 189.8, 157.9, 145.9, 140.4, 128.7, 128.6, 128.2, 127.9, 127.7, 125.3, 124.8, 121.6, 121.2, 80.3, 42.3, 31.6, 21.7, 11.6; LC/MS (ESI): 307.1 [M]+ for C18H17N3O2; Anal. for C29H37N4O5; calcd C, 66.77; H, 7.15; N, 10.74; Found: C, 66.75; H, 7.16; N, 10.75.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(4-methoxyphenyl)methyl)-5,5-dimethylcyclo hex-2-enone diethylaminium salt 4j
4j was prepared according to the general procedure (GP1) from anisaldehyde yielding deep orange materials. m.p: 84 °C; IR (CsI, cm−1): 3451, 2956, 2835, 2732, 2507, 1681, 1598, 1502, 1456, 1366, 1318, 1261; 1H-NMR (400 MHz, CDCl3): δ 15.35 (s, 1H, OH), 7.64 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.27(dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.14–6,68 (m, 5H, Ph), 5.59 (s, 1H, benzyl-H), 3.69 (s, 3H, OCH3), 2.33 (q, 4H, J = 7.3 Hz, CH2CH3), 2.27 (s, 3H, CH3), 2.25 (s, 2H, CH2), 2.17 (s, 2H, CH2), 0.99 (s, 6H, CH3), 0.83 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, CDCl3): δ = 189.8, 157.9, 145.9, 140.4, 136.8, 128.8, 128.6, 125.4, 121.7, 121.3, 114.4, 113.4, 113.2, 80.3, 55.4, 41.7, 31.4, 11.2; LC/MS (ESI): 292.1 [M]+ for C19H20N2O; Anal. for C30H40N3O4; calcd C, 71.12; H, 7.96; N, 8.29; Found: C, 71.11; H, 7.97; N, 8.31.
2-((4-Fluorophenyl)(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyl)-3-hydroxy-5,5-dimethylcyclohex -2-enone diethylaminium salt 4k
4k was prepared according to the general procedure (GP1) from p-fluorobenzaldehyde yielding orange powdered materials. m.p: 99 °C; IR (KBr, cm−1): 3450, 3.35, 2958, 2869, 2731, 2507, 1598, 1580, 1501, 1387, 1262; 1H-NMR (400 MHz, DMSO-d6): δ 15.45 (s, 1H, OH), 7.89–7.83 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.32–7.28(dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.20–6.94 (m, 5H, Ph), 5.53 (s, 1H, benzyl-H), 2.90 (q, 4H, J = 7.3 Hz, CH2CH3), 2.16 (s, 3H, CH3), 2.11 (s, 2H, CH2), 2.07 (s, 2H, CH2), 1.14 (t, 6H, J = 7.3 Hz, CH2CH3), 1.11 (s, 3H, CH3), 0.97 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 189.8, 157.2, 147.0, 145.7, 140.2, 128.6, 128.5, 128.3, 123.3, 119.2, 118.9, 113.6, 102.4, 102.3, 79.2, 41.4, 31.3, 30.1, 28.7, 12.8, 12.6, 11.0; LC/MS (ESI): 280.1 [M]+ For C18H17FN2; Anal. for C29H37FN3O3; calcd C, 70.42; H, 7.54; F, 3.84; N, 8.50; Found: C, 70.43; H, 7.54; F, 3.83; N, 8.49.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(4-(trifluoromethyl)phenyl)methyl)-5, 5-dimethylcyclohex-2-enone diethylaminium salt 4l
4l was prepared according to the general procedure (GP1) from p-trifluoromethylbenzaldehyde yielding yellow powdered materials. m.p: 96 °C; IR (CsI, cm−1): 3451, 2959, 2870, 2733, 2506, 1615, 1598, 1502, 1387, 1325, 1266; 1H-NMR (400 MHz, DMSO-d6): δ 16.45 (s, 1H, OH), 7.94–7.90 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.57–7.44 (dd, 2H, J = 7.3 Hz, 1.5 Hz, Ph), 7.34–7.06 (m, 5H, Ph), 5.76 (s, 1H, benzyl-H), 2.91 (q, 4H, J = 7.3 Hz, CH2CH3), 2.19 (s, 3H, CH3), 2.12 (s, 2H, CH2), 2.10 (s, 2H, CH2), 1.15 (t, 6H, J = 7.3 Hz, CH2CH3),1.11 (s, 3H, CH3), 1.00 (s, 3H, CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 157.2, 147.0, 145.7, 140.2, 128.6, 128.5, 128.3, 123.3, 119.2, 118.9, 113.6, 102.4, 102.3, 79.2, 41.4, 31.3, 30.1, 28.7, 12.8, 12.6, 11.0; LC/MS (ESI): 330.13 [M]+ for C19H17F3N2; Anal. for C30H37F3N3O3; calcd C, 66.16; H, 6.85; F, 10.46; N, 7.72; Found: C, 66.17; H, 6.86; F, 10.45; N, 7.71.
5-((2,6-Dichlorophenyl)(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)methyl)-3-methyl-1-phenyl-1H-py razol-4-olate diethylaminium salt 4m
4m was prepared according to the general procedure (GP1) from 2,6-dicholorobenzaldehyde yielding deep orange powdered materials. m.p: 142 °C; IR (CsI, cm−1): 3459, 3117, 3061, 2973, 2834, 2479, 1657, 1646, 1596, 1500, 1431, 1311, 153; 1H-NMR (400 MHz, DMSO-d6): 8.08 (d, 1H, J = 7.3 Hz, Ph), 7.93 (d, H, J = 7.3 Hz, Ph), 7.42 (s, 1H, Ph), 7.32–7.04 (m, 5H, Ph), 4.96 (s, 1H, CH = C), 2.85 (q, 4H, J = 7.3 Hz, CH2CH3), 2.12 (s, 3H, CH3), 1.11 (t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, DMSO-d6): δ = 161.6, 160.1, 150.0, 148.0, 132.9, 132.7, 131.3, 129.0, 128.9, 128.5, 128.1, 118.1, 117.8, 14.4; LC/MS (ESI): 330.07 [M]+for C18H16Cl2N2; Anal. for C17H12Cl2N2O; calcd C, 61.65; H, 3.65; Cl, 21.41; N, 8.46; Found: C, 61.64; H, 3.63; Cl, 21.40; N, 8.44.
5-((2-Hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)(naphthalen-2-yl)methyl)-3-methyl-1-phenyl-1H-pyraz ol-4-olate diethylaminium salt 4n
4n was prepared according to the general procedure (GP1) from naphthaldehyde yielding orange powdered materials. m.p: 102 °C; IR (CsI, cm−1): 3452, 3053, 2956, 2729, 2500, 1692, 1579, 1502, 1387, 1320, 1268; 1H-NMR (400 MHz, DMSO-d6): 15.32 (s, 1H, OH), 7.96–7.26 (m, 8H, Ph), 5.75 (s, 1H, benzyl-H), 2.27 (q, 4H, J = 7.3 Hz, CH2CH3), 2.20 (s, 3H, CH3), 2.01 (s, 2H, CH2), 2.00 (s, 2H, CH2), 1.06 (s, 6H, CH3), 0.64 (t, 6H, J = 7.3 Hz, CH2CH3);13C-NMR (100 MHz, DMSO-d6): δ = 192.3, 156.1, 146.7, 139.3, 128.7, 128.7, 126, 121.7, 121.30, 103.6, 78.8, 42.1, 31.3, 12.6; LC/MS (ESI): 312.0 [M]+ for C22H20N2; Anal. for C27H36N3O3S; calcd C, 67.19; H, 7.52; N, 8.71; S, 6.64; Found: C, 67.20; H, 7.52; N, 8.73.
3-Hydroxy-2-((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(thiophen-2-yl)methyl)-5,5-dimethylcyclohex2-enone diethylaminium salt 4o
4o was prepared according to the general procedure (GP1) from thiophenaldehyde yielding brown powdered materials. m.p: 87 °C; IR (KBr, cm−1): 3450, 3063, 2956, 2731, 2505, 1681, 1580, 1501, 1387, 1366, 1261; 1H-NMR (400 MHz, CDCl3): δ 15.32 (s, 1H, OH), 7.71–6.64 (m, 8H, Ph), 5.81 (s, 1H, benzyl-H), 2.47(q, 4H, J = 7.3 Hz, CH2CH3), 2.36 (s, 3H, CH3), 2.27(s, 2H, CH2), 2.23 (s, 2H, CH2), 1.12(s, 6H, CH3), 0.98(t, 6H, J = 7.3 Hz, CH2CH3); 13C-NMR (100 MHz, CDCl3): δ = 192.3, 156.1, 146.7, 139.3, 128.7, 128.7, 126, 121.7, 121.30, 103.6, 78.8, 42.1, 31.3, 12.6; LC/MS (ESI): 268.1 [M]+ for: C16H16N2S; Anal. for C27H36N3O3S; calcd C, 67.19; H, 7.52; N, 8.71; S, 6.64; Found: C, 67.20; H, 7.52; N, 8.73; S, 6.65.
Antibacterial activity studies
The antimicrobial studies were carried out according to reported methodology in the following literature reported by Barakat et al. [12, 13, 23] including initial screening and determination of MIC.
In-silico predictions
Pharmacophore modeling
A ligand-based pharmacophore model was developed by using MOE 2017 [24] suite. Where, a training set representing the most active lead analogs [12, 13] was selected, energy minimized and submitted to flexible alignment for analyzing the shared spatial arrangement of their pharmacophoric features. Generated hypotheses were ranked based on their accuracy scoring and atomic overlap. Among the highest ranked hypotheses, the best pharmacophore showing 100% accuracy was selected. This selected model was validated for its predictive efficacy by overlapping representative active analogs over it and calculating the RMSD (root mean square distance) between the query and mapped compounds.
Docking simulation
To predict the most suitable targets and inhibition mechanisms for the antibacterial and antifungal activities of the newly synthesized pyrazole-dimedone derivatives, reference compounds i.e. ciprofloxacin and fluconazole were submitted in Binding DB [25]. Binding DB works on the principle that similar compounds tend to have the same target proteins and seven proteins were chosen; four proteins i.e. Dihydrofolate Reductase (PDB ID 3FYV), Gyrase B (PDB ID 4URM), Thymidylate Kinase (TMK) (PDB ID 4QGG) and Sortase A (PDB ID 2MLM) from S. aureus for antibacterial (ciprofloxacin) and three proteins (Dihydrofolate Reductase (DHFR) (PDB ID 4HOF), Secreted Aspartic Protease (PDB ID 3Q70), and N-myristoyl transferase (PDB ID 1IYL) from C. Albicans for antifungal (fluconazole) compounds. The crystal structures of the seven target proteins were fetched from Protein Data Bank (www.rcsb.org/pdb) and all the proteins were prepared, charged, protonated and minimized via MOE 2016 suite. The chemical structures of synthesized compounds were built and saved in their 3D conformations by Builder tool incorporated in MOE 2016. Further protonation, minimization, charge application and atom-type corrections were also done by MOE 2016. Before docking, the efficiency of docking software was validated via redocking the crystallized ligand back into the pocket of significant antibacterial and antifungal target proteins. After redocking experiment (Additional file 1: Figures S1 and S2), we found MOE as the appropriate software to continue our in silico work with this software.