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Synthesis of N, N-dimethylaminoethylacetoacetate
In a typical experimental procedure (Rao et al. 2013), a 50 ml round bottomed flask equipped
with a reflux condenser was charged with a homogenous mixture of N.N-
dimethylaminoethanol (4.5 mmol) and methylacetoacetate (3 mmol) and heated at 1100C.
The progress of the reaction was monitored byTLC. After completion of reaction, the
required product, N,N-dimethylaminoethylacetoacetate was purified by silica gel column
chromatography using light petroleum ether and ethylacetate and subsequently used in
Biginelli reaction for DHPM synthesis.
Synthesis of dihydropyrimidine dinones (DHPMs)
A 50 ml round bottomed flask equipped with a reflux condenser was charged with
arylaldehyde (1.0 mmol) and urea/thiourea (1.5 mmol). The precursors were finely powdered
and mixed together and allowed to stir for 30min at room temperature. Subsequently N,N-
dimethylaminoethylacetoacetate (1.5 mmol) were added. The resulting reaction mixture was
heated at 110˚C (oil bath) with constant stirring till the reaction was completed. The progress
of reaction was monitored by TLC using CHCl3:CH3OH (8:2) with two drops of ammonia
solution as a mobile phase. After completion of reaction as indicated on TLC, the contents of
reaction mixture was cooled to room temperature and the crude reaction mixture was crushed
and dissolved in 10ml of 2N HCl (1.8ml in 10ml of H2O). The reaction mixture was washed
with ethylacetate and the aqueous part was neutralized with 10 ml of 2N NaOH. Then
product was extracted by ethylacetate and evaporated at reduced pressure. The obtained crude
solid mass was washed with cold diethylether (15 ml x 3) to remove any unreacted reactants
to afford the pure desired product. All the synthesized dihydropyrimidine dinone (DHPM)
products were characterized and confirmed by spectroscopic techniques.
Synthesis of methyl iodide salts of DHPMs
In a separate experiment, commercially available methyl iodide (b.p = 42.5˚C, 1.5 eq) was
added drop wise to above DHPMs (1.0 eq) in dry acetone in an ice-bath. After complete
addition of the methyl iodide, the resultant reaction mixture was stirred for one hour at room
temperature. The solid salt form of Biginelli’s product was separated out by simple filtration,
washed with dry acetone (5ml x 3) and dried at reduced pressure to remove acetone.
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Table S1. Structure and analytical data of DHPM based molecules
Code/Structure Characterization dataDHPM1 2-(dimethylamino)ethyl-6-methyl-4-(4-ethoxyphenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-
carboxylate: Yield (%): 65, m.p (0C): 178-180. IR (KBr, νMax cm-1) = 3241, 3111, 2973, 2770, 1724, 1706, 1650, 1612, 1513, 1460, 1390, 1225, 1048, 955, 793. 1H-NMR (400MHz, CDCl3): δ 1.374-1.357 (t, J = 6.8Hz, 3H), 2.167 (s, 6H), 2.300 (s, 3H), 2.423-2.438(t, J = 6.0Hz, 2H), 3.990-3.973 (q, J = 6.8Hz, 2H), 4.075-4.090 (t, J = 6.0Hz, 2H), 5.311 (s, 1H), 5.660 (s, 1H), 6.765-6.786 (d, J = 8.4Hz, 2H), 7.176-7.197 (d, J = 8.4Hz, 2H), 8.016 (s, 1H). 13C NMR (CDCl3): δ = 14.940, 18.857, 45.770, 55.309, 57.862, 62.006, 63.611, 101.613, 114.745, 127.944, 136.022, 146.375, 153.260, 158.808, 165.785, ESI-MS: m/z = 348.
DHPM2 2-(dimethylamino)ethyl-6-methyl-4-(4-nitrophenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-carboxylate: Yield (%): 58, m.p (0C): 148-150. IR (KBr, νMax) = 3237, 3114, 2947,2773, 1705, 1644, 1523, 1348, 1223, 1100, 953, 789. 1H-NMR (400MHz, CDCl3): δ 2.209 (s, 6H), 2.360 (s, 3H), 2.474-2.485 (t, J = 4.4Hz, 2H), 4.146-4.157 (t, J = 4.4Hz, 2H), 5.529 (s, 1H), 6.197 (s, 1H), 7.554-7.533 (d, J = 8.4Hz, 2H), 8.145 (s, 1H), 8.180-8.159 (d, J = 8.4Hz, 2H). 13C NMR (CDCl3): δ = 18.876, 45.494, 55.020, 57.756, 61.868, 100.373, 124.016, 127.595, 147.505, 147.557, 150.406, 152.961, 165.153. ESI-MS: m/z=349.574.
DHPM3 2-(dimethylamino)ethyl-6-methyl-4-(4-methylphenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-carboxylate: Yield (%): 68, m.p (0C): 168-170. IR (KBr, νMax) = 3245, 3118, 2949, 2825, 2775, 2361, 1709, 1651, 1462, 1287, 1225, 1102, 783, 501. 1H-NMR (400MHz, CDCl3): δ 2.206 (s, 6H), 2.316 (s, 3H), 2.337 (s, 3H), 2.446-2.460 (t, J = 5.6Hz, 2H), 4.103-4.117 (t, J = 5.6Hz, 2H), 5.369 (s, 1H), 5.642 (s, 1H), 7.095-7.116 (d, J = 7.6Hz, 2H), 7.199-7.218 (d, J = 7.6Hz, 2H), 7.858 (s, 1H). 13C NMR (CDCl3): δ = 18.845, 21.283, 45.808, 55.536, 57.926, 62.032, 101.434, 126.715, 129.561, 137.800, 141.073, 146.853, 153.675, 165.871. ESI-MS: m/z = 318.67.
DHPM4 2-(dimethylamino)ethyl-6-methyl-4-(4-methoxyphenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-carboxylate: Yield (%): 63, m.p (0C): 158-160. IR (KBr, νMax) = 3248, 3118, 2952, 2829, 2775, 1724, 1653, 1513, 1462, 1228, 1177, 1107, 1034, 841, 785. 1H-NMR (400MHz, CDCl3): δ 2.210 (s, 6H), 2.346 (s, 3H), 2.462-2.477 (t, J = 6.0Hz, 2H), 3.785 (s, 3H), 4.119-4.122 (t, J = 6.0Hz, 2H), 5.364 (s, 1H), 5.498 (s, 1H), 6.826-6.838 (d, J = 4.8Hz, 2H), 7.240-7.252 (d, J = 4.8Hz, 2H), 7.511 (s, 1H). 13C NMR (CDCl3): δ = 13.655,18.195, 45.135, 54.773, 57.228, 59.480, 61.398, 101.003, 113.549, 127.311, 135.609, 145.682, 152.516, 158.801, 165.112. ESI-MS: m/z = 334.69.
DHPM5 2-(dimethylamino)ethyl-6-methyl-4-(4-(dimethylamino)phenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate: Yield (%): 70, m.p (0C): 194-196. IR (KBr, νMax) = 3245, 3116, 2946, 2823, 2777, 1719, 1651, 1618, 1526, 1456, 1362, 1342, 1231, 1167, 1083, 788. 1H-NMR (400MHz, DMSO-D6): δ 2.110 (s, 6H), 2.225 (s, 3H), 2.379-2.394 (t, J = 6.0Hz, 2H), 2.840 (s, 6H), 4.000-4.015 (t, J = 6.0Hz, 2H), 5.033 (s, 1H), 6.634-6.655 (d, J = 8.4Hz, 2H), 7.035-7.056 (d, J = 8.4Hz, 2H), 7.579 (s, 1H), 9.086 (s, 1H). 13C NMR (DMSO-D6): δ 17.719, 45.260, 53.206, 57.305, 61.059, 99.829, 112.236, 126.887, 132.566, 147.783, 149.771, 152.328, 159.605, 165.426. ESI-MS: m/z = 347.658.
DHPM6 2-(dimethylamino)ethyl-6-methyl-4-(4-(dimethylamino)phenyl)-2-thio-1,2,3,4-tetrahydropyrimidine-5-carboxylate: Yield (%): 48, m.p (0C): 102-104. IR (KBr, νMax) = 3175, 2951, 2857, 2822, 2362, 1685, 1646, 1612, 1579, 1522, 1462, 1347, 1277, 1110, 1035, 949, 814, 777. 1H-NMR (400MHz, DMSO-D6): δ 2.103 (s, 6H), 2.273 (s, 3H), 2.394-2.408 (t, J = 5.6Hz, 2H), 2.866 (s, 6H), 4.033-4.047 (t, J = 5.6Hz, 2H), 5.053 (s, 1H), 6.646-6.668 (d, J = 8.8Hz, 2H), 7.015-7.037 (d, J = 8.8Hz, 2H), 9.577 (s, 1H), 10.220 (s, 1H). 13C NMR (DMSO-d6): δ 15.149, 17.120, 45.253, 53.417, 57.241, 61.380, 64.904, 101.183, 112.216, 127.124, 131.142, 144.504, 149.988, 165.248, 173.912. ESI-MS: m/z = 363.484.
DHPM7 2-(dimethylamino)ethyl-6-methyl-4-(4-chlorophenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-carboxylate: Yield (%): 52, m.p (0C): 142-144. IR (KBr, νMax) = 3243, 3120, 2950, 2777, 1709, 1649, 1463, 1288, 1223, 1086, 979, 788. 1H-NMR (400MHz, CDCl3): δ 2.203 (s, 6H), 2.339 (s, 3H), 2.450-2.465 (t, J = 6.0Hz, 2H), 4.106-4.121 (t, J = 6.0Hz, 2H), 5.386 (s, 1H), 5.989 (s, 1H), 7.274-7.265 (s, 4H), 8.200 (s, 1H). 13C NMR (CDCl3): δ 18.190, 45.073, 54.454, 57.291, 61.285, 100.287, 127.599, 128.372, 133.192, 141.886, 146.682, 153.127, 165.038. ESI-MS: m/z = 338.49.
DHPM8 2-(dimethylamino)ethyl-6-methyl-4-(4-hydroxyphenyl)-2-oxo-1,2,3,4-tetrahydro pyrimidine-5-carboxylate (Table 6.1, entry 8): Yield (%): 50, m.p (0C): 106-108. IR (KBr, νMax) = 3241, 2955, 1696, 1643, 1458, 1228, 1171, 1098, 761, 659. 1H-NMR (400MHz, DMSO-D6): δ 2.114 (s, 6H), 2.294 (s, 3H), 2.400-2.414 (t, J = 5.6Hz, 2H), 4.020-4.034 (t, J = 5.6Hz, 2H), 5.051 (s, 1H), 6.673-6.694 (d, J = 8.4Hz, 2H), 7.036-7.057 (d, J = 8.4Hz, 2H), 7.611 (s, 1H), 9.111 (s, 1H), 9.327 (s, 1H). 13C NMR (DMSO-D6): δ 17.759, 45.180, 53.309, 57.254, 61.014, 99.682, 114.995, 127.416, 135.332, 148.072, 152.261, 156.549, 165.384. ESI-MS: m/z = 320.59.
DHPM9 2-(dimethylamino)ethyl-6-methyl-4-(3-hydroxyphenyl)-2-thio-1,2,3,4-tetrahydro pyrimidine-5-carboxylate: Yield (%): 30, m.p (0C): 110-112. 1H-NMR (400MHz, DMSO-D6): δ 2.095 (s, 6H),
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2.281 (s, 3H), 2.384-2.413 (t, J = 5.6Hz, 2H), 4.040-4.069 (t, J = 5.6Hz, 2H), 5.084 (s, 1H), 6.633-6.676 (m, 3H), 7.088 (s, 1H), 9.421 (s, 1H), 9.583 (s, 1H), 10.280 (s, 1H). 13C NMR (DMSO-D6): δ 17.272, 45.246, 53.931, 57.232, 61.522, 100.746, 113.349, 114.702, 117.162, 129.593, 144.791, 145.193, 157.519, 165.262, 174.285. ESI-MS: m/z = 335.37.
DHPM10 2-(4-(4-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonyloxy)-N,N,N-trimethylethanaminium: IR (KBr, νMax): 798, 836, 948, 1098, 1226, 1454, 1638, 1686, 2956, 3107, 3218, 3455. 1H NMR (400MHz, DMSO-D6) δ 2.305 (s, 3H), 2.950 (s, 9H), 3.553–3.589 (m, 2H), 3.722 (s, 3H), 4.378 (s, 2H), 5.107-5.115 (d, 2H), 6.867-6.889 (d, J = 8.8 Hz, 2H), 7.159-7.181 (d, J = 8.8 Hz, 2H), 7.774 (s, 1H), 9.297 (s, 1H). 13C NMR (DMSO-D6): δ 18.039, 30.737, 52.760, 52.977, 55.218, 57.180, 64.037, 98.136, 113.880, 127.629, 136.376, 150.331, 151.953, 158.608, 164.824. ESI-MS: m/z = 348.230.
DHPM11 2-(4-(4-chlorophenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonyloxy)-N,N,N-trimethylethanaminium: IR (KBr, νMax): 766, 832, 1072, 1223, 1451, 1637, 1709, 2945, 3093, 3213.1H NMR (400MHz, DMSO-D6) δ 2.309 (s, 1H), 2.966 (s, 9H), 3.561-3.605 (m, 2H), 4.384 (s, 1H), 5.161-5.169 (d, 1H), 7.266-7.287 (d, J = 8.4 Hz, 2H), 7.389-7.410 (d, J = 8.4 Hz, 2H), 7.893 (s, 1H), 9.393 (s,1H). 13C NMR (DMSO-D6): δ 18.057, 29.567, 30.694, 32.086, 52.713, 52.959, 55.793, 57.236, 63.969, 68.529, 97.517, 128.343, 128.495, 131.957, 143.066, 150.813, 151.749, 164.640. ESI-MS: m/z = 352.57.
DHPM12 2-(4-(4-methylphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonyloxy)-N,N,N-trimethylethanaminium: IR (KBr, νMax): 752, 888, 951, 1069, 1089, 1232, 1445, 1642, 1698, 3004, 3259, 3392. 1H NMR (400MHz, DMSO-D6) δ 2.264 (s, 3H), 2.303 (s, 3H), 2.940 (s, 9H), 3.559-3.590 (m, 2H), 4.376 (s, 2H), 5.115-5.122 (s, 1H), 7.133 (s, 4H), 7.803 (s, 1H), 9.309 (s, 1H). 13C NMR (DMSO-D6): δ 18.020, 20.670, 29.592, 52.699, 53.276, 57.163, 68.551, 97.944, 126.320, 129.032, 136.644, 141.282, 150.447, 151.944, 164.805. ESI-MS: m/z = 332.27.
DHPM13 2-(4-(4-nitrophenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonyloxy)-N,N,N-trimethylethanaminium: IR (KBr, νMax): 756, 863, 950, 1103, 1245, 1349, 1523, 1663, 1696, 3218, 3311.1H NMR (400MHz, DMSO-D6) δ 2.324 (s, 3H), 2.972 (s, 9H), 3.537-3.588 (m, 2H), 4.386 (s, 2H), 5.295-5.303 (s, 2H), 7.527-7.549 (d, J = 8.8 Hz, 2H), 8.014 (s, 1H), 8.205-8.227 (d, J = 8.8 Hz, 2H), 9.491 (s, 1H). 13C NMR (DMSO-D6): δ 18.108, 29.566, 52.709, 53.200, 55.801, 57.339, 63.925, 96.977, 123.882, 127.809, 146.804, 151.268, 151.650, 151.595, 164.528. ESI-MS: m/z = 363.13.
DHPM14 2-(4-(4-ethoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbonyloxy)-N,N,N-trimethylethanaminium: IR (KBr, νMax): 795, 835, 1105, 1233, 1475, 1643, 1702, 2976, 3245, 3413, 3506. 1H NMR (400MHz, DMSO-D6): δ 1.282-1.317 (t, J = 7.2 Hz, 3H), 2.304 (s, 3H), 2.947 (s, 9H), 3.552-3.600 (m, 2H), 3.958-4.010 (q, J = 7.2 Hz, 2H), 4.376 (s, 2H), 5.101-5.109 (d, 1H), 6.849-6.871 (d, J = 8.8 Hz, 2H), 7.143-7.164 (d, J = 8.8 Hz, 2H), 7.768 (s, 1H), 9.290 (s, 1H). 13C NMR (DMSO-D6): δ 15.115, 18.469, 30.068, 32.581, 53.114, 53.396, 56.298, 57.638, 63.500, 64.428, 68.980, 96.480, 114.757, 128.058, 136.688, 150.815, 152.388, 158.293, 165.256, 208.854. ESI-MS: m/z = 362.28.
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