5-Bromo-1-(4-methylbenzyl)uracil (2). A solution of 4-methylbenzyl bromide (5.0 g, 27.02 mmol) in
1,2-dichloroethane (10 ml) was added to a solution of 5-bromo-2,4-bis(trimethylsilyloxy)pyrimidine (prepared
by refluxing 5-bromouracil (5.0 g, 26.18 mmol) in HMDS (100 ml) in the presence of NH4Cl (0.5 g)) in
1,2-dichloroethane (50 ml). The solution obtained was refluxed for 12 h. The product was treated with EtOH (20
ml) and the precipitate formed was filtered off. The filtrate was evaporated to one third volume and diluted with
hexane (20 ml). The precipitate formed was combined with the previous precipitate and recrystallized from a
mixture of EtOH and DMF (2:1) to give the uracil 2 (5.6 g, 74%) as light-yellow, large flaked crystals. 1H NMR
spectrum, δ, ppm: 2.22 (3H, s, CH3); 4.81 (2H, s, CH2); 7.00-7.30 (4H, m, aryl); 8.18 (1H, s, H-6 uracil); 11.40
(1H, br. s, NH).
Compounds 3-5 were prepared similarly.
5-Bromo-1-(3,5-dimethylbenzyl)uracil (3). 1H NMR spectrum, δ, ppm: 2.19 (6H, s, CH3); 4.81 (2H, s,
CH2); 6.88 (1H, s, H-4 aryl); 6.92 (2H, s, H-2,6 aryl); 8.12 (1H, s, H-6 uracil); 11.61 (1H, br. s, NH).
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5-Bromo-1-(3-chlorobenzyl)uracil (4). H NMR spectrum, δ, ppm: 4.89 (2H, s, CH2); 7.14-7.48 (4H,
m, aryl); 8.25 (1H, s, H-6 uracil); 11.62 (1H, br. s, NH).
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5-Bromo-1-(2,4-dichlorobenzyl)uracil (5). H NMR spectrum, δ, ppm: 4.89 (2H, s, CH2); 7.09-7.46
(3H, m, aryl); 8.06 (1H, s, H-6 uracil); 11.54 (1H, br. s, NH).
5-(Benzylamino)-1-(4-methoxybenzyl)uracil (6). A mixture of compound 2 (1.5 g, 5.08 mmol),
benzylamine (2.0 ml, 18.31 mmol) and ethylene glycol (5 ml) was refluxed for 40 min and cooled to room
temperature. The reaction product was crystallized by treating with water (100 ml) and the filtered precipitate
was dried in air and recrystallized from acetone-DMF (1: 1) to give compound 6 (0.7 g, 63%) as fine, colorless
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needles. H NMR spectrum, δ, ppm (J, Hz): 2.19 (3H, s, CH3); 4.01 (2H, d, J = 6, Ph–CH2); 4.60 (2H, s,
CH2–N); 4.79 (1H, m, NH); 6.32 (1H, s, H-6 uracil); 6.94 (4H, m, aryl); 7.14 (5H, m, aryl); 11.27 (1H, br. s,
NH).
Compounds 7-13 were prepared similarly.
1-(4-Methylbenzyl)-5-(phenethylamino)uracil (7). H NMR spectrum, δ, ppm (J, Hz): 2.20 (3H, s,
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CH3); 2.62-2.85 (2H, m, Ph–CH2); 2.85-3.10 (2H, m, CH2–NH); 4.06 (1H, t, J = 6, C–NH); 4.70 (2H, s,
CH2–N); 6.35 (1H, s, H-6 uracil); 6.93-7.23 (9H, m, aryl); 11.27 (1H, br. s, NH).
1
5-(Benzylamino)-1-(3,5-dimethylbenzyl)uracil (8). H NMR spectrum, δ, ppm (J, Hz): 2.12 (6H, s,
CH3); 4.05 (2H, d, J = 6, Ph–CH2); 4.62 (2H, s, CH2–N); 4.87 (1H, t, J = 6, CH2–NH); 6.40 (1H, s, H-4 aryl);
6.72 (2H, s, H-2,6 aryl); 6.78 (1H, s, H-6 uracil); 7.06-7.32 (5H, m, aryl); 11.20 (1H, br. s, NH).
1-(3,5-Dimethylbenzyl)-5-(phenethylamino)uracil (9). 1H NMR spectrum, δ, ppm (J, Hz): 2.15 (6H, s,
CH3); 2.64-2.87 (2H, m, Ph–CH2); 2.87-3.09 (2H, m, CH2–N); 4.23 (1H, t, J = 5.5, CH2–NH); 4.71 (2H, s,
CH2–N); 6.57 (1H, s, H-4 aryl); 6.82 (1H, s, H-6 uracil); 6.86 (2H, s, H-2,6 aryl); 7.04-7.25 (5H, m, C6H5);
11.24 (1H, br. s, NH).
5-(Benzylamino)-1-(3-chlorobenzyl)uracil (10). 1H NMR spectrum, δ, ppm (J, Hz): 4.08 (2H, d, J = 6,
Ph–CH2); 4.72 (2H, s, CH2–N); 4.88 (1H, t, J = 6, CH2–NH); 6.51 (1H, s, H-6 uracil); 6.96-7.37 (9H, m, aryl);
11.30 (1H, br. s, NH).
1-(3-Chlorobenzyl)-5-(phenethylamino)uracil (11). 1H NMR spectrum, δ, ppm (J, Hz): 2.66-2.90 (2H,
m, Ph–CH2); 2.90-3.18 (2H, m, CH2–NH); 4.28 (1H, t, J = 6, CH2–NH); 4.80 (2H, s, CH2–N); 6.67 (1H, s, H-6
uracil); 6.93-7.43 (9H, m, aryl); 11.36 (1H, br. s, NH).
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5-(Benzylamino)-1-(2,4-dichlorobenzyl)uracil (12). H NMR spectrum, δ, ppm (J, Hz): 4.02 (2H, d,
J = 6, Ph–CH2); 4.72 (2H, s, CH2–N); 4.85 (1H, t, J = 6, CH2–NH); 6.16 (1H, s, H-6 uracil); 6.88-7.35 (8H, m,
aryl); 11.40 (1H, br. s, NH).
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1-(2,4-Dichlorobenzyl)-5-(phenethylamino)uracil (13). H NMR spectrum, δ, ppm (J, Hz): 2.66-2.88
(2H, m, Ph–CH2); 2.88-3.14 (2H, m, CH2–NH); 4.16 (1H, t, J = 6, CH2–NH); 4.82 (2H, s, CH2–N); 6.41 (1H, s,
H-6 uracil); 6.97-7.42 (8H, m, aryl); 11.40 (1H, br. s, NH).
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