Molecules 2010, 15
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1H, Pyrim-H), 6.91 (d, 2H, J = 9.0 Hz, Ph-H), 7.14 (d, 2H, J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1763,
1208, 1082, 809 cm−1; MS (APCI) m/z: 363.9 (M + 2H)+; Anal. for C18H22N2O6 (%): C 59.66, H 6.12,
N 7.73; found C 59.49, H 6.08, N 7.77.
Methyl 4-(4,6- dimethylpyrimidin-2-yloxy)phenoxy acetate (3f): Yield: 80.1%; m.p. 114.5–116.0 ºC;
1H-NMR δ: 2.39 (s, 6H, Pyrim-CH3), 3.82 (s, 3H, COOCH3), 4.64 (s, 2H, OCH2), 6.75 (s, 1H, Pyrim-
H), 6.92 (d, 2H, J = 9.0 Hz, Ph-H), 7.13 (d, 2H, J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1753, 1200, 1082,
833 cm−1. MS (APCI) m/z: 289.9 (M + 2H)+; Anal. for C15H16N2O4 (%): C 62.53, H 5.59, N 9.71;
found C 62.86, H 5.55, N 9.70.
Ethyl 4-(4,6-dimethylpyrimid in-2-yloxy)phenoxy acetate (3g): Yield: 77.2%; m.p. 90.2–92.1 ºC;
1H-NMR δ: 1.31 (t, 3H, J = 7.2 Hz, CH2-CH3), 2.39 (s, 6H, Pyrim-CH3), 4.28 (q, 2H,
J = 7.2 Hz, COOCH2), 4.62 (s, 2H, OCH2), 6.74 (s, 1H, Pyrim-H), 6.92(d, 2H, J = 9.0 Hz, Ph-H),
7.13(d, 2H, J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1758, 1197, 1078, 845 cm−1; MS (APCI) m/z: 303.9 (M
+ 2H)+; Anal. for C16H18N2O4 (%): C 63.62, H 6.01, N 9.26; found C 64.03, H 5.98, N 9.33.
Propyl 4-( 4,6-dimethylpyrimidin-2-yloxy)phenoxy acetate (3h): Yield: 75.0%; m.p. 95.4–97.3 ºC;
1H-NMR δ: 0.93 (t, 3H, J = 7.2 Hz, CH2-CH3), 1.69 (m, 2H, CH2-CH3), 2.39 (s, 6H, Pyrim-CH3); 4.18
(t, J = 6.6 Hz, 2H, COOCH2), 4.64 (s, 2H, OCH2), 6.74 (s, 1H, Pyrim-H), 6.93 (d, 2H, J = 9.0 Hz, Ph-
H), 7.13(d, 2H, J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1760, 1198, 1078, 849 cm−1; MS (APCI) m/z: 317.9
(M + 2H)+; Anal. for C17H20N2O4 (%): C 64.54, H 6.37, N 8.85; found C 64.84, H 6.28, N 8.76.
Isopropyl 4-(4,6-dimethylpyrim idin-2-yloxy)phenoxy acetate (3i): Yield: 80.9%; m.p. 90.5–92.2 ºC;
1H-NMR δ: 1.28 (d, 6H, J = 6.6 Hz, CH-(CH3)2), 2.39 (s, 6H, Pyrim-CH3), 4.59 (s, 2H, OCH2), 5.15
(m, 1H, COOCH), 6.74 (s, 1H, Pyrim-H), 6.92 (d, 2H, J = 9.0 Hz, Ph-H), 7.12 (d, 2H,
J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1721, 1204, 1073, 854 cm−1; MS (APCI) m/z: 317.9 (M + 2H)+;
Anal. for C17H20N2O4 (%): C 64.54, H 6.37, N 8.85; found C 64.76, H 6.29, N 8.68.
Butyl 4-( 4,6-dimethylpyrimidin-2-yloxy)phenoxy acetate (3j): Yield: 71.3%; m.p. 34.2–36.0 ºC;
1H-NMR δ: 0.92 (t, 3H, J = 7.2 Hz, CH2-CH3), 1.37 (m, 2H, CH2-CH3), 1.65 (m, 2H,
CH2–C2H5), 2.39 (s, 6H, Pyrim-CH3), 4.22 (t, 2H, J = 6.6 Hz, COOCH2), 4.63 (s, 2H, OCH2), 6.74 (s,
1H, Pyrim-H), 6.92 (d, 2H, J = 9.0 Hz, Ph-H), 7.13(d, 2H, J = 9.0 Hz, Ph-H) ppm; IR (KBr): 1752,
1193, 1084, 830 cm−1. MS (APCI) m/z: 331.9 (M + 2H)+; Anal. for C18H22N2O4 (%): C 65.44, H 6.71,
N 8.48; found C 65.14, H 6.74, N 8.21.
3.4. Biological activity
The herbicidal activities of the target compounds were determined using Brassica napus L. and
Digitaria sanguinalis L. as samples of dicotyledonous and monocotyledonous plants, respectively [16,17].
Emulsions of the tested compounds were prepared by dissolving them in
N,N-dimethylformamide (100 μL) with the addition of Tween 20 (2 μL), and then diluting with
distilled water. The germinated seeds were placed on two filter papers in a 9-cm Petri plate, to which 5
mL of tested solution was added in advance. Usually, 15 seeds were used on each plate. The plates