6
H. ALINEZHAD AND K. PAKZAD
energy dispersive spectroscopy (EDS) detector (IE 300X, Oxford, UK) attached to the
Map. Complete characterization details, providing data on all of the above methods,
were submitted for review and are available from the corresponding author
upon request.
Synthesis of Biginelli products
All the chemicals were procured from Merck, Fluka, and Sigma-Aldrich. The reactions
were monitored by thin layer chromatography (TLC) (silica gel, n-hexane/ethyl acetate
1
3:2). The products were identified and characterized using FT-IR (JASCO-680), H-
NMR and 13C-NMR (Bruker DPX-400 MHz) and melting points (Electrothermal 9100
apparatus). Melting points are corrected.
In the Biginelli procedure, aldehyde (1.0 mmol), urea (1.5 mmol) and b-dicarbonyl
(1.0 mmol) were mixed completely and stirred at 90 ˚C with the addition of a catalytic
amount of CuO NPs (0.01 g) under solventless conditions. The progress of the reaction
was monitored by TLC. After completion of the reaction, the catalyst was separated by
filtration and the solution was poured onto ice. The crude product was filtered and
recrystallized from ethanol to give the analytical sample. All the products were charac-
terized by comparison of melting points with those in the literature. Some selected spec-
tral data follow.
5-Ethoxycarbonyl-4-phenyl-6-methyl-3,4-dihydropyrimidine-2 (1H)-one (6a)
1H NMR (400 MHz, DMSO-d6) d/ppm: 9.16 (1H, s), 7.71 (1H, s), 7.35-7.12 (5H, m),
5.14 (1H, d, J ¼3 Hz), 4.00 (2H, q, J ¼ 6 Hz), 2.24 (3H, s), 1.18 (3H, t, J ¼ 9 Hz); 13C
NMR (400 MHz, DMSO-d6) d/ppm 165.3, 152.1, 148.3, 144.8, 128.3, 127.3, 126.2, 99.2,
59.1, 53.9, 17.7, 14.0; IR (KBr): 3414 (s), 3230 (s), 3109 (m), 2936 (s), 1702 (s), 1649 (s),
1599 (m) cmꢂ1
.
Ethyl 6-methyl-4-(4-nitrophenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (6c)
1H NMR (400 MHz, DMSO-d6) d/ppm: 9.358 (1H, s), 8.222–8.20 (2H, d, J ¼ 9 Hz),
7.512-7.490 (2H, d, J ¼ 9 Hz), 7.90 (1H, s), 5.28 (1H, d, J ¼ 3 Hz), 4.01 (2H, q, J ¼
6 Hz), 2.267 (3H, s), 1.11 (3H, t, J ¼ 6 Hz); 13C NMR (400 MHz, DMSO-d6) d/ppm
164.9, 151.9, 151.6, 149.3, 146.6, 127.5, 123.7, 98.0, 59.3, 53.5, 17.8, 13.8; IR (KBr): 3416
(s), 3237 (s), 3085 (m), 2941 (s), 1728 (s), 1694 (s), 1588 (s), 1509 (m) cmꢂ1
.
4-(4-Methoxyphenyl)-7,7-dimethyl-4,6,7,8-tetrahydro-1H,3H-quinazoline-2,5-dione (7c)
1H NMR (400 MHz, DMSO-d6) d/ppm: 0.91 (3H, s), 1.043 (3H, s), 1.99 (1H, d, J ¼
16 Hz), 2.18 (1H, d, J ¼ 16 Hz), 2.32 (1 H, d, J ¼ 16 Hz), 2.49 (1H, d, J ¼ 16 Hz), 3.659
(3H, s), 4.785 (1H, s, CH), 7.07-6.86 (m, 4H), 7.98 (1H, s), 9.274 (1H, s) ppm; 13C
NMR (400 MHz, DMSO-d6) d/ppm: 27.34, 29.16, 31.56, 32.75, 50.52, 51.84, 55.29,
107.84, 113.39, 128.99, 135.15, 149.52, 153.61, 157.55, 194.86 cmꢂ1; IR (KBr): 3285 (s),
3200 (s), 1640 (s), 1605 (s).