3.1.3. Synthesis of Targeted Derivatives 1–3
Hydrazones: Aminoguanidine hydrochloride (or nitroaminoguanidine, 1,3-diaminoguanidine hydrochloride, thiosemicarbazide, or semicarbazide hydrochloride; 1 mmol) was dissolved in 8–10 mL of MeOH and then an appropriate aldehyde or ketone (1.1 mmol or 2.2 mmol for the synthesis of disubstituted 1,3-diaminoguanidines 2g and 3c) was added in one portion. The reaction mixture was heated under reflux for 3 h and then let to stir to cool down to room temperature overnight. Then, the reaction mixture was stored at −20 °C for 2 h. If there was present a precipitate, it was collected by filtration. The isolated crystals were suspended in 5% sodium bicarbonate and stirred for 30 min. Then, the suspension was filtered off, the crystals were washed by cold water, diethyl ether and dried. When no spontaneous precipitation was observed, the methanolic solution was diluted by 5% sodium bicarbonate, stored for 1 h at +4 °C. In some cases, the reaction mixture was partly evaporated after basification (e.g., 2a and 3a). The resulting precipitate was collected by filtration, washed by cold water, diethyl ether and dried. The products were crystallized from methanol if necessary.
The imine 3a was prepared in water under reflux for 6 h and the solution was basified using solid sodium carbonate.
Synthesis of the reduced analogue 2d: Aminoguanidine hydrochloride (1 mmol) was dissolved in 10 mL of methanol and then 3,5-diiodosalicylaldehyde (1.1 mmol, 411.3 mg) was added in one portion. After a complete dissolution, sodium cyanoborohydride (100 mg; 1.6 mmol) was added. The mixture was stirred for 48 h at room temperature. Then, the reaction mixture was diluted with 5% sodium bicarbonate and let to stir over night at room temperature. The precipitate was filtered off, washed by water, and dried to obtain pure 2d.
(
E)-2-Benzylidenehydrazine-1-carboximidamide
1a. White solid; yield 78%; mp 178–181 °C (180–182 °C [
13]). IR (ATR): 3460, 3282, 3026, 1699, 1630, 1601, 1501, 1447, 1394, 1366, 1229, 1177, 1123, 1013, 968, 942, 829, 753, 709, 684, 642, 627 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 7.96 (1H, s, CH = N), 7.63 (2H, d,
J = 7.6 Hz, H2, H6), 7.29 (2H, t,
J = 7.6 Hz, H3, H5), 7.21 (1H, t,
J = 7.7 Hz, H4), 5.97 (2H, s, NH
2), 5.62 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 160.91, 143.86, 137.36, 128.89, 128.34, 126.79. Elemental analysis for C
8H
10N
4 (162.20); calculated: C, 59.24; H, 6.21; N, 34.54, found C, 59.21; H, 6.20; N, 34.56.
(
E)-2-(2-Chlorobenzylidene)hydrazine-1-carboximidamide
1b. White solid; yield 81%; mp 160–162 °C (145–146 °C [
13]). IR (ATR): 3455, 3019, 1695, 12627, 1596, 1495, 1393, 1355, 1280, 1224, 1173, 1150, 1109, 1051, 1012, 937, 831, 751, 706, 638, 617 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 8.23 (1H, s, CH = N), 8.09 (1H, dd,
J = 7.5, 2.1 Hz, H6), 7.35 (1H, dd,
J = 7.6, 1.6 Hz, H3), 7.25–7.19 (2H, m, H4, H5), 6.00 (2H, s, NH
2), 5.62 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 161.82, 138.93, 134.45, 132.03, 130.04, 129.36, 127.49, 127.29. Elemental analysis for C
8H
9ClN
4 (196.64); calculated: C, 48.87; H, 4.61; N, 28.49, found C, 48.85; H, 4.57; N, 28.53.
(
E)-2-(3-Chlorobenzylidene)hydrazine-1-carboximidamide
1c. White solid; yield 95%; mp 166–168 °C (164–166 °C [
13]). IR (ATR): 3463, 3008, 1699, 1635, 1593, 1477, 1407, 1358, 1288, 1235, 1180, 1128, 1097, 1071, 1016, 940, 893, 821, 783, 729, 712, 680, 656, 630 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 7.91 (1H, s, CH = N), 7.76 (1H, t,
J = 2.0 Hz, H2), 7.52 (1H, dd,
J = 7.7, 2.0 Hz, H6), 7.29 (1H, t,
J = 7.8 Hz, H5), 7.24–7.21 (1H, m, H4), 6.00 (2H, s, NH
2), 5.55 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 161.60, 141.84, 139.97, 133.91, 130.67, 127.68, 125.73, 125.53. Elemental analysis for C
8H
9ClN
4 (196.64); calculated: C, 48.87; H, 4.61; N, 28.49, found C, 48.86; H, 4.60; N, 28.52.
(
E)-2-(4-Chlorobenzylidene)hydrazine-1-carboximidamide
1d. Yellow solid; yield 96%; mp 220.5–222 °C (206–208 °C [
13]). IR (ATR): 3471, 3366, 3028, 1704, 1640, 1603, 1584, 1544, 1441, 1409, 1348, 1308, 1243, 1229, 1156, 1102, 941, 887, 860, 766, 752, 665, 645 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 7.93 (1H, s, CH = N), 7.67–7.63 (2H, m, H2, H6), 7.34–7.31 (2H, m, H3, H5), 5.94 (2H, s, NH
2), 5.54 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 161.32, 142.23, 136.53, 132.40, 128.88, 128.29. Elemental analysis for C
8H
9ClN
4 (196.64); calculated: C, 48.87; H, 4.61; N, 28.49, found C, 48.91; H, 4.65; N, 28.46.
(E)-2-(3-Chloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide 1e. Yellowish solid; yield 99%; mp 205.5–206.5 °C. IR (ATR): 3448, 3366, 3068, 1674, 1619, 1593, 1545, 1485, 1450, 1409, 1339, 1298, 1273, 1234, 1194, 1174, 1144, 1070, 921, 834, 774, 766, 726, 694, 640 cm−1. 1H NMR (500 MHz, DMSO-d6): δ 12.41 (1H, s, OH), 8.22 (1H, s, CH = N), 7.31 (1H, dd, J = 7.7, 1.6 Hz, H6), 7.26 (1H, dd, J = 7.6, 1.6 Hz, H4), 6.79 (1H, t, J = 7.7 Hz, H5), 6.01 (2H, s, NH2), 5.86 (2H, s, NH2). 13C NMR (126 MHz, DMSO): δ 159.34, 146.64, 129.08, 128.06, 124.38, 121.68, 119.98, 118.95. Elemental analysis for C8H9ClN4O (212.64); calculated: C, 45.19; H, 4.27; N, 26.35, found C, 45.23; H, 4.26; N, 26.33.
(
E)-2-(4-Chloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide [
41]
1f. White solid; yield 88%; mp 182–184.5 °C. IR (ATR): 3454, 3348, 3050, 1697, 1625, 1595, 1494, 1388, 1355, 1280, 1221, 1174, 1115, 1050, 1011, 958, 916, 880, 830, 807, 750, 706, 659, 645, 623 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 11.66 (1H, s, OH), 8.13 (1H, s, CH = N), 7.37 (1H, d,
J = 8.2 Hz, H6), 6.85 (1H, d,
J = 2.1 Hz, H3), 6.83 (1H, dd,
J = 8.2, 2.1 Hz, H5), 5.76 (2H, s, NH
2), 5.56 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 160.05, 158.26, 145.75, 133.08, 130.65, 120.35, 119.50, 115.93. Elemental analysis for C
8H
9ClN
4O (212.64); calculated: C, 45.19; H, 4.27; N, 26.35, found C, 45.21; H, 4.30; N, 26.38.
(
E)-2-(5-Chloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide
1g. White solid; yield 94%; mp 164.5–165.5 °C (167–169 °C [
41]). IR (ATR): 3439, 3340, 3058, 1701, 1631, 1605, 1557, 1480, 1420, 1394, 1366, 1278, 1257, 1242, 1189, 1107, 1026, 942, 916, 870, 829, 819, 784, 710, 658, 646, 630 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 11.26 (1H, s, OH), 8.12 (1H, s, CH = N), 7.47 (1H, d,
J = 2.7 Hz, H6), 7.08 (1H, dd,
J = 8.6, 2.6 Hz, H4), 6.80 (1H, d,
J = 8.7 Hz, H3), 5.81 (2H, s, NH
2), 5.58 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 160.32, 155.93, 144.72, 128.62, 128.10, 123.08, 123.06, 117.83. Elemental analysis for C
8H
9ClN
4O (212.64); calculated: C, 45.19; H, 4.27; N, 26.35, found C, 45.19; H, 4.29; N, 26.33.
(E)-2-(6-Chloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide 1h. White solid; yield 97%; mp 193.5–196 °C. IR (ATR): 3464, 3292, 3009, 1704, 1632, 1601, 1573, 1501, 1386, 1348, 1306, 1265, 1210, 1171, 1115, 1013, 945, 918, 840, 828, 774, 731, 702, 634 cm−1. 1H NMR (500 MHz, DMSO-d6): δ 12.50 (1H, s, OH), 8.48 (1H, s, CH = N), 7.13 (1H, t, J = 8.1 Hz, H4), 6.92 (1H, dd, J = 8.0, 1.1 Hz, H3), 6.83 (1H, dd, J = 8.0, 1.1 Hz, H5), 5.87 (2H, s, NH2), 5.75 (2H, s, NH2). 13C NMR (126 MHz, DMSO): δ 159.99, 158.91, 143.48, 132.06, 129.68, 120.02, 117.06, 115.23. Elemental analysis for C8H9ClN4O (212.64); calculated: C, 45.19; H, 4.27; N, 26.35, found C, 45.15; H, 4.24; N, 26.37.
(E)-2-(2-Hydroxy-5-iodobenzylidene)hydrazine-1-carboximidamide 1i. White solid; yield 98%; mp 171–172 °C. IR (ATR): 3432, 3079, 1654, 1639, 1605, 1579, 1544, 1475, 1456, 1431, 1405, 1358, 1284, 1263, 1239, 1185, 1122, 1085, 952, 889, 826, 783, 742, 7025, 688, 619 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 11.35 (1H, s, OH), 8.10 (1H, s, CH = N), 7.70 (1H, d, J = 2.4 Hz, H6), 7.34 (1H, dd, J = 8.5, 2.3 Hz, H4), 6.63 (1H, d, J = 8.6 Hz, H3), 5.57 (2H, s, NH2), 5.55 (2H, s, NH2). 13C NMR (151 MHz, DMSO): δ 160.23, 157.14, 144.89, 137.28, 136.92, 124.18, 118.85, 81.30. Elemental analysis for C8H9IN4O (304.09); calculated: C, 31.60; H, 2.98; N, 18.42, found C, 31.65; H, 3.02; N, 18.40.
(
E)-2-(3,5-Dichloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide [
12]
1j. Yellowish solid; yield 99%; mp 202.5–203.5 °C. IR (ATR): 3472, 3339, 3025, 1701, 1635, 1557, 1491, 1397, 1359, 1299, 1240, 1175, 1127, 1098, 1088, 1013, 950, 930, 831, 818, 784, 710, 702, 679, 639 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 12.60 (1H, s, OH), 8.37 (1H, s, CH = N), 7.61 (1H, d,
J = 2.7 Hz, H6), 7.22 (1H, d,
J = 2.8 Hz, H4), 7.13 (4H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 157.75, 157.42, 145.29, 145.22, 129.44, 129.38, 125.39, 122.46. Elemental analysis for C
8H
8Cl
2N
4O (247.08); calculated: C, 38.89; H, 3.26; N, 22.68, found C, 38.88; H, 3.26; N, 22.67.
(E)-2-(3-Bromo-5-chloro-2-hydroxybenzylidene)hydrazine-1-carboximidamide 1k. Yellow solid; yield 95%; mp 208–209 °C. IR (ATR): 3471, 3068, 1677, 1634, 1430, 1401, 1343, 1307, 1241, 1226, 1155, 1016, 946, 932, 888, 866, 851, 749, 731, 702, 669, 635 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 12.52 (1H, s, OH), 8.33 (1H, s, CH = N), 7.65 (1H, d, J = 2.7 Hz, H6), 7.36 (1H, d, J = 2.7 Hz, H4), 7.06 (4H, s, NH2). 13C NMR (151 MHz, DMSO): δ 157.72, 157.41, 145.30, 132.16, 126.49, 126.03, 122.28, 81.96. Elemental analysis for C8H8BrClN4O (291.53); calculated: C, 32.96; H, 2.77; N, 19.22, found C, 33.01; H, 2.74; N, 19.26.
(E)-2-(5-Chloro-2-hydroxy-3-iodobenzylidene)hydrazine-1-carboximidamide 1l. Yellow solid; yield 96%; mp 202–203 °C. IR (ATR): 3470, 3441, 3366, 3345, 3074, 1621, 1600, 1570, 1549, 1442, 1424, 1337, 1262, 1222, 1184, 1164, 1102, 978, 940, 867, 823, 737, 708, 688, 632 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 12.57 (1H, s, OH), 8.21 (1H, s, CH = N), 7.61 (1H, d, J = 2.7 Hz, H6), 7.53 (1H, d, J = 2.7 Hz, H4), 6.70 (4H, s, NH2). 13C NMR (151 MHz, DMSO): δ 158.35, 148.89, 145.53, 137.41, 127.74, 127.52, 120.93, 87.86. Elemental analysis for C8H8ClIN4O (338.53); calculated: C, 28.38; H, 2.38; N, 16.55, found C, 22.42; H, 2.39; N, 16.58.
(E)-2-(2-Hydroxy-3,5-diiodobenzylidene)hydrazine-1-carboximidamide 1m. Yellow solid; yield 96%; mp 195–196.5 °C. IR (ATR): 3443, 3419, 3350, 3064, 1674, 1630, 1595, 1562, 1429, 1401, 1333, 1284, 1265, 1244, 1226, 1156, 1051, 1011, 963, 927, 874, 865, 841, 754, 734, 704, 665, 645, 527 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 12.05 (1H, s, OH), 8.30 (1H, s, CH = N), 8.14 (1H, d, J = 2.2 Hz, H6), 8.02 (1H, d, J = 2.1 Hz, H4), 6.78 (4H, s, NH2). 13C NMR (151 MHz, DMSO): δ 155.77, 155.59, 147.80, 144.70, 137.01, 123.66, 91.25, 84.72. Elemental analysis for C8H8I2N4O (429.99); calculated: C, 22.35; H, 1.88; N, 13.03, found C, 22.31; H, 1.89; N, 13.06.
(E)-2-[(5-Nitrofuran-2-yl)methylene]hydrazine-1-carboximidamide 1n. Red solid; yield 90%; mp 236–236.5 °C. IR (ATR): 3447, 3429, 3315, 3063, 1658, 1615, 1558, 1484, 1459, 1381, 1354, 1304, 1233, 1179, 1133, 1024, 980, 959, 919, 820, 811, 749, 732, 725, 670, 613 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 7.80 (1H, s, CH = N), 7.71 (1H, d, J = 4.0 Hz, H4), 7.00 (1H, d, J = 4.1 Hz, H3), 6.16 (4H, s, NH2). 13C NMR (151 MHz, DMSO): δ 162.86, 157.39, 151.09, 129.93, 116.93, 110.32. Elemental analysis for C6H7N5O3 (197.15); calculated: C, 36.55; H, 3.58; N, 35.52, found C, 36.51; H, 3.60; N, 35.53.
(E)-2-[(5-Nitrothiophen-2-yl)methylene]hydrazine-1-carboximidamide 1o. Red-brown solid; yield 93%; mp 223–225 °C. IR (ATR): 3391, 3080, 1652, 1530, 1483, 1436, 1411, 1368, 1339, 1308, 1286, 1224, 1161, 1100, 1046, 1019, 929, 910, 824, 817, 775, 734, 708, 690 cm−1. 1H NMR (500 MHz, DMSO-d6): δ 8.08 (1H, s, CH = N), 8.01 (1H, d, J = 4.4 Hz, H4), 7.15 (1H, d, J = 4.4 Hz, H3), 6.11 (4H, s, NH2). 13C NMR (126 MHz, DMSO): δ 162.02, 152.54, 147.55, 135.36, 131.26, 124.81. Elemental analysis for C6H7N5O2S (213.22); calculated: C, 33.80; H, 3.31; N, 32.85, found C, 33.76; H, 3.33; N, 32.89.
2-(2-Oxoindolin-3-ylidene)hydrazine-1-carboximidamide
1p. Yellow solid; yield 65%; mp >250 °C (247–249 °C [
42]). IR (ATR): 3399, 3350, 3174, 1678, 1622, 1594, 1490, 1470, 1371, 1336, 1273, 1214, 1149, 1106, 1050, 1033, 1011, 930, 889, 835, 789, 749, 705, 677, 650, 616 cm
−1.
1H NMR (500 MHz, DMSO-
d6): δ 10.16 (1H, s, amide N-H), 7.57 (1H, dd,
J = 7.5, 1.2 Hz, H4), 7.09 (1H, td,
J = 8.0, 1.4 Hz, H6), 6.87 (1H, td,
J = 7.5, 1.3 Hz, H5), 6.80–6.71 (5H, m, H7, NH
2).
13C NMR (126 MHz, DMSO): δ 164.88, 158.90, 139.77, 132.24, 127.24, 124.53, 120.65, 118.65, 109.09. Elemental analysis for C
9H
9N
5O (203.21); calculated: C, 53.20; H, 4.46; N, 34.47, found C, 53.23; H, 4.42; N, 34.50.
(E)-2-[(2-Carbamimidoylhydrazineylidene)methyl]-4,6-diiodophenyl acetate 2a. Yellow solid; yield 74%; mp 160–162 °C. IR (ATR): 3400, 1761, 1702, 1684, 1623, 1559, 1544, 1517, 1507, 1490, 1458, 1424, 1339, 1244, 1186, 1130, 1014, 930, 894, 864, 741, 698, 643, 632, 626 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 8.44 (1H, d, J = 2.0 Hz, H3), 8.09 (1H, d, J = 2.0 Hz, H5), 7.88 (1H, s, CH = N), 6.40 (4H, s, NH2), 2.35 (3H, s, CH3). 13C NMR (151 MHz, DMSO): δ 168.75, 159.57, 149.16, 145.90, 137.23, 134.86, 131.85, 95.67, 93.52, 21.27. Elemental analysis for C10H10I2N4O2 (472.02); calculated: C, 25.45; H, 2.14; N, 11.87, found C, 25.47; H, 2.12; N, 11.90.
(E)-2-(4-Hydroxy-3,5-diiodobenzylidene)hydrazine-1-carboximidamide 2b. Greyish solid; yield 91%; mp 197–198.5 °C. IR (ATR): 3445, 3137, 1673, 1630, 1606, 1569, 1439, 1395, 1348, 1316, 1260, 1219, 1169, 1005, 962, 943, 880, 832, 741, 704, 639 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 10.84 (1H, s, OH), 7.92 (2H, s, H2, H6), 7.72 (1H, s, CH = N), 7.59 (2H, s, NH2), 7.06 (2H, s, NH2). 13C NMR (151 MHz, DMSO): δ 156.223, 155.20, 146.74, 138.04, 130.66, 90.97. Elemental analysis for C8H8I2N4O (429.99); calculated: C, 22.35; H, 1.88; N, 13.03, found C, 22.36; H, 1.91; N, 13.00.
(E)-2-(3,5-Diiodobenzylidene)hydrazine-1-carboximidamide 2c. White solid; yield 80%; mp 209–211 °C. IR (ATR): 3465, 3156, 1677, 1632, 1570, 1534, 1421, 1401, 1348, 1224, 1159, 1117, 1091, 1015, 991, 957, 939, 903, 848, 783, 711, 670, 623 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 8.01 (2H, s, H2, H6), 7.84 (1H, s, H4), 7.78 (1H, s, CH = N), 6.05 (2H, s, NH2), 5.56 (2H, s, NH2). 13C NMR (151 MHz, DMSO): δ 161.85, 143.05, 141.95, 140.09, 134.17, 96.71. Elemental analysis for C8H8I2N4 (413.99); calculated: C, 23.21; H, 1.95; N, 13.53, found C, 23.17; H, 1.92; N, 13.49.
2-(2-Hydroxy-3,5-diiodobenzyl)hydrazine-1-carboximidamide 2d. White solid; yield 82%; mp 203–204 °C. IR (ATR): 3452, 3349, 1669, 1650, 1630, 1443, 1345, 1280, 1243, 1229, 1154, 1099, 1075, 1020, 1004, 931, 885, 861, 852, 819, 754, 695, 649 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 7.63 (1H, d, J = 2.2 Hz, H6), 7.13 (1H, d, J = 2.1 Hz, H4), 7.03 (3H, s, NH2), 4.64–4.35 (4H, m, NH-NH, CH2). 13C NMR (151 MHz, DMSO): δ 159.32, 156.71, 142.86, 133.38, 130.67, 89.52, 78.69, 61.19. Elemental analysis for C8H10I2N4O (432.00); calculated: C, 22.24; H, 2.33; N, 12.97, found C, 22.27; H, 2.33; N, 13.01.
(E)-Hydrazineyl[2-(2-hydroxy-3,5-diiodobenzylidene)hydrazineyl]methaniminium chloride 2e. White solid; yield 90%; mp 236–238 °C. IR (ATR): 3397, 3324, 3207, 1697, 1644, 1595, 1454, 1345, 1282, 1266, 1231, 1154, 990, 964, 942, 858, 733, 669, 640, 630 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 11.98 (1H, s, OH), 10.06 (1H, s, NH), 9.47 (1H, s, NH), 8.52 (1H, s, CH = N), 8.06 (1H, d, J = 2.1 Hz, H6), 8.02 (1H, d, J = 2.1 Hz, H4), 7.96 (2H, s, NH2), 4.87 (2H, s, N-NH2). 13C NMR (151 MHz, DMSO): δ 156.70, 155.84, 155.52, 147.70, 137.08, 123.73, 91.22, 84.73. Elemental analysis for C8H10ClI2N5O (481.46); calculated: C, 19.96; H, 2.09; N, 14.55, found C, 20.01; H, 2.12; N, 14.52.
(E)-2-(2-Hydroxy-3,5-diiodobenzylidene)-N-nitrohydrazine-1-carboximidamide 2f. White solid; yield 99%; mp > 250 °C. IR (ATR): 3413, 3221, 1638, 1598, 1578, 1417, 1384, 1363, 1340, 1280, 1231, 1160, 1061, 953, 919, 868, 735, 721, 680, 659, 607 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 11.80 (1H, s, OH), 9.96 (1H, s, NH-NO2), 8.84 (2H, s, NH), 8.26 (1H, s, CH = N), 8.14 (1H, d, J = 2.2 Hz, H6), 8.02 (1H, d, J = 2.1 Hz, H4). 13C NMR (151 MHz, DMSO): δ 158.18, 155.47, 147.67, 144.95, 137.24, 123.97, 91.04, 84.72. Elemental analysis for C8H7I2N5O3 (474.98); calculated: C, 20.23; H, 1.49; N, 14.74, found C, 20.26; H, 1.49; N, 14.70.
Bis[2 -((E)-2-hydroxy-3,5-diiodobenzylidene)hydrazineyl]methaniminium chloride 2g. Yellow solid; yield 50%; mp 234–236 °C. IR (ATR): 3338, 1643, 1625, 1554, 1428, 1368, 1349, 1282, 1264, 1226, 1162, 1080, 958, 940, 925, 863, 734, 655, 641, 625 cm−1. 1H NMR (600 MHz, DMSO-d6): δ 11.18 (4H, broad s, OH, N = NH), 8.34 (2H, s, CH = N), 8.05–7.98 (4H, m, H4, H6), 7.86 (2H, s, NH2). 13C NMR (151 MHz, DMSO): δ 155.88, 147.09, 146.96, 145.74, 137.43, 123.55, 90.06, 84.12. Elemental analysis for C15H12ClI4N5O2 (837.36); calculated: C, 21.52; H, 1.44; N, 8.36, found C, 21.55; H, 1.43; N, 8.38.
(
E)-2-(2-Hydroxy-3,5-diiodobenzylidene)hydrazine-1-carboxamide [
43]
2h. White solid; yield 93%; mp >250 °C. IR (ATR): 3441, 3378, 3054, 2895, 1668, 1588, 1437, 1415, 1338, 1270, 1228, 1162, 1113, 940, 908, 863, 735, 665, 625 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 11.10 (1H, s, OH), 10.41 (1H, s, NNH), 7.93 (1H, s, CH = N), 7.92 (1H, d,
J = 2.1 Hz, H6), 7.83 (1H, d,
J = 2.1 Hz, H4), 6.45 (2H, s, CONH
2).
13C NMR (151 MHz, DMSO): δ 156.14, 155.59, 146.02, 139.45, 137.52, 123.17, 89.21, 83.50. Elemental analysis for C
8H
7I
2N
3O
2 (430.97); calculated: C, 22.30; H, 1.64; N, 9.75, found C, 22.32; H, 1.66; N, 9.76.
(
E)-2-(2-Hydroxy-3,5-diiodobenzylidene)hydrazine-1-carbothioamide [
44]
2i. White solid; yield 84%; mp > 250 °C. IR (ATR): 3442, 3293, 3170, 3032, 1612, 1591, 1539, 1469, 1424, 1356, 1284, 1267, 1230, 1163, 1060, 938, 863, 831, 734, 690, 663, 655, 605 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 11.45 (1H, s, OH), 9.91 (1H, s, NNH), 8.20–8.15 (3H, m, CH = N, H6, CS-NH
A), 8.02 (1H, s, CS-NH
B), 7.97 (1H, d,
J = 2.1 Hz, H4).
13C NMR (151 MHz, DMSO): δ 178.45, 155.48, 147.00, 140.89, 137.14, 124.30, 90.70, 84.63. Elemental analysis for C
8H
7I
2N
3OS (447.03); calculated: C, 21.49; H, 1.58; N, 9.40, found C, 21.51; H, 1.59; N, 9.36.
(
E)-2-(Furan-2-ylmethylene)hydrazine-1-carboximidamide
3a. Brownish solid; yield 97%; mp 162–165 °C (175–178 °C [
13]). IR (ATR): 3446, 3292, 3116, 1637, 1606, 1535, 1490, 1385, 1336, 1159, 1137, 1013, 1004, 983, 942, 913, 887, 808, 783, 740, 731, 724, 662 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 7.81 (1H, s, CH = N), 7.60 (1H, d,
J = 1.6 Hz, H5), 6.57 (1H, d,
J = 3.3 Hz, H3), 6.49–6.47 (1H, m, H4), 5.76 (2H, s, NH
2), 5.50 (2H, s, NH
2).
13C NMR (151 MHz, DMSO): δ 161.01, 152.72, 143.26, 134.06, 112.23, 108.89. Elemental analysis for C
6H
8N
4O (152.16); calculated: C, 31.60; H, 2.98; N, 18.42, found C, 31.65; H, 3.02; N, 18.40.
(
E)-
N-Nitro-2-[(5-nitrofuran-2-yl)methylene]hydrazine-1-carboximidamide
3b. Yellow solid; yield 96%; mp 247–249 °C (249–250 °C [
26]). IR (ATR): 3386, 3147, 1652, 1565, 1510, 1486, 1439, 1381, 1353, 1316, 1280, 1224, 1182, 1150, 1075, 1025, 956, 927, 827, 818, 738, 645 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 12.13 (1H, s, NH-NO
2), 8.93 (1H, s, NH), 8.45 (1H, s, NH), 8.04 (1H, s, CH = N), 7.77 (1H, d,
J = 3.9 Hz, H4), 7.40 (1H, d,
J = 4.0 Hz, H3).
13C NMR (151 MHz, DMSO): δ 158.25, 152.35, 152.21, 135.01, 115.41, 115.04. Elemental analysis for C
6H
6N
6O
5 (242.15); calculated: C, 29.76; H, 2.50; N, 34.71, found C, 29.78; H, 2.49; N, 34.68.
(
E)-2-[(5-Nitrofuran-2-yl)methylene]-
N’-[(
E)-(5-nitrofuran-2-yl)methylene]hydrazine-1-carboximidamide hydrochloride
3c. Orange-red solid; yield 93%; mp >250 °C (275–285 °C decomp. [
45]). IR (ATR): 3389, 3149, 3123, 1666, 1624, 1600, 1564, 1524, 1508, 1481, 1386, 1357, 1326, 1311, 1265, 1251, 1205, 1181, 1148, 1108, 1035, 1022, 964, 946, 829, 819, 780, 737 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 13.02 (2H, s, NH-N=), 8.68 (2H, s, NH
2), 8.51 (2H, s, CH = N), 7.81 (2H, d,
J = 3.9 Hz, H4), 7.53 (2H, d,
J = 4.0 Hz, H3).
13C NMR (151 MHz, DMSO): δ 153.43, 152.58, 151.67, 137.79, 116.18, 115.30. Elemental analysis for C
11H
10ClN
7O
6 (371.69); calculated: C, 35.55; H, 2.71; N, 26.38, found C, 35.51; H, 2.66; N, 26.40.
(
E)-2-[(5-Nitrofuran-2-yl)methylene]hydrazine-1-carboxamide
3d. Yellow solid; yield 73%; mp >250 °C (240–244 °C [
46]). IR (ATR): 3458, 3241, 3136, 1707, 1582, 1503, 1457, 1390, 1348, 1327, 314, 1251, 1199, 1150, 1020, 969, 903, 820, 807, 786, 760, 737 649 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 10.78 (1H, s, CONHN), 7.75–7.73 (2H, m, CH = N, H4), 7.16 (1H, d,
J = 4.0 Hz, H3), 6.53 (2H, s, CONH
2).
13C NMR (151 MHz, DMSO): δ 157.02, 154.22, 151.60, 127.41, 116.04, 112.36. Elemental analysis for C
6H
6N
4O
4 (198.14); calculated: C, 36.37; H, 3.05; N, 28.28, found C, 36.41; H, 3.09; N, 28.25.
(
E)-2-[(5-Nitrofuran-2-yl)methylene]hydrazine-1-carbothioamide
3e. Yellow solid; yield 89%; mp >250 °C (229 °C decomp. [
47]). IR (ATR): 3462, 3300, 3086, 2977, 1602, 1592, 1570, 1537, 1504, 1481, 1451, 1393, 1352, 1273, 1257, 1189, 1104, 1058, 1028, 972, 909, 845, 833, 812, 777, 733, 652 cm
−1.
1H NMR (600 MHz, DMSO-
d6): δ 11.80 (1H, s, CSNHN), 8.48 (1H, s, CS-NH
A), 7.99 (1H, s, CS-NH
B), 7.93 (1H, s, CH = N), 7.75 (1H, d,
J = 3.9 Hz, H4), 7.33 (1H, d,
J = 4.0 Hz, H3).
13C NMR (151 MHz, DMSO): δ 178.95, 153.15, 152.11, 130.33, 115.67, 113.74. Elemental analysis for C
6H
6N
4O
3S (214.20); calculated: C, 33.64; H, 2.82; N, 26.16, found C, 33.61; H, 2.85; N, 26.16.