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907
which was collected using suction filtration and dried, followed by
recrystallization in aqueous methanol.
4.2.8. 2-(20-Naphthyl)-5-(200-fluorophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6h)
Compounds 6 was synthesized by addition of acetic anhydride
(2 mL) to hydrazone 5 (0.2 mmol), and the resulting solution was
heated to reflux for 1 h. The reaction mixture was poured into ice
water, and the resulting solid product was filtered and washed
with copious amounts of water, drying under air.
Yield 73%; mp 171–173 °C. 1H NMR (CDCl3, 300 MHz): d 8.33 (s,
1H), 7.99 (d, J = 9 Hz, 1H), 7.89 (t, J = 13.5 Hz, 3H), 7.52–7.60 (m,
3H), 7.38–7.47 (m, 2H), 7.34 (s, 1H), 7.11–7.22 (m, 2H), 2.44 (s,
3H). MS (ESI): 335.19 (C20H16FN2O2, [M+H]+). Anal. Calcd for
C20H15FN2O2: C, 71.85; H, 4.52; N, 8.38. Found: C, 71.60; H, 4.61;
N, 8.36.
4.2.1. 2-(20-Naphthyl)-5-phenyl-2-acetyl-2,3-dihydro-1,3,4-
oxadiazoline (6a)
4.2.9. 2-(20-Naphthyl)-5-(300-fluorophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6i)
Yield 67%; mp 148–151 °C. 1H NMR (CDCl3, 300 MHz): d 8.34 (s,
1H), 7.98 (d, J = 9.0 Hz, 1H), 7.88 (t, J = 7.5 Hz, 3H), 7.51–7.58 (m,
4H), 7.40 (t, J = 3.45 Hz, 3H), 7.14 (s, 1H), 2.40 (s, 3H). MS (ESI):
317.12 (C20H17N2O2, [M+H]+). Anal. Calcd for C20H16N2O2: C,
75.93; H, 5.10; N, 8.86. Found: C, 75.59; H, 5.19; N, 8.89.
Yield 85%; mp 170–171 °C. 1H NMR (CDCl3, 300 MHz): d 8.33 (s,
1H), 8.00 (d, J = 8.6 Hz, 1H), 7.91 (t, J = 14.2 Hz, 3H), 7.54–7.62 (m,
3H), 7.35–7.44 (m, 2H), 7.26 (d, J = 13.5 Hz, 1H), 7.12 (d, J = 16 Hz,
2H), 2.43 (s, 3H). MS (ESI): 335.15 (C20H16FN2O2, [M+H]+). Anal.
Calcd for C20H15FN2O2: C, 71.85; H, 4.52; N, 8.38. Found: C,
71.71; H, 4.59; N, 8.46.
4.2.2. 2-(20-Naphthyl)-5-(400-methoxyphenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6b)
Yield 78%; mp 129–131 °C. 1H NMR (CDCl3, 300 MHz): d 8.35 (s,
1H), 8.00 (d, J = 8.7 Hz, 1H), 7.91 (t, J = 9.0 Hz, 3H), 7.55–7.61 (m,
2H), 7.47 (d, J = 8.7 Hz, 2H), 7.11 (s, 1H), 6.94 (d, J = 8.7 Hz, 2H),
3.82 (s, 3H), 2.41 (s, 3H). MS (ESI): 347.13 (C21H19N2O3, [M+H]+).
Anal. Calcd for C21H18N2O3: C, 72.82; H, 5.24; N, 8.09. Found: C,
72.58; H, 5.20; N, 8.16.
4.2.10. 2-(20-Naphthyl)-5-(400-fluorophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6j)
Yield 86%; mp 176–178 °C. 1H NMR (CDCl3, 300 MHz): d 8.35 (s,
1H), 7.99 (d, J = 9 Hz, 1H), 7.90 (t, J = 15.0 Hz, 3H), 7.51–7.59 (m,
4H), 7.10 (t, J = 15.0 Hz, 3H), 2.41 (s, 3H). MS (ESI): 335.11
(C20H16FN2O2, [M+H]+). Anal. Calcd for C20H15FN2O2: C, 71.85; H,
4.52 N, 8.38. Found: C, 71.23; H, 4.56; N, 8.45.
4.2.3. 2-(20-Naphthyl)-5-(200-bromophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6c)
4.2.11. 2-(20-Naphthyl)-5-(200-nitrophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6k)
Yield 80%; mp 143–145 °C. 1H NMR (CDCl3, 300 MHz): d 8.31 (s,
1H), 7.96 (d, J = 9 Hz, 1H), 7.84–7.88 (m, 3H), 7.65 (d, J = 7.8 Hz,
1H), 7.50–7.58 (m, 2H), 7.43 (s, 1H), 7.31–7.39 (m, 2H), 7.28 (s,
1H), 2.41 (s, 3H). MS (ESI): 395.04 (C20H16BrN2O2, [M+H]+). Anal.
Calcd for C20H15BrN2O2: C, 60.78; H, 3.83; N, 7.09. Found: C,
60.92; H, 3.90; N, 7.04.
Yield 78%; mp 157–159 °C. 1H NMR (CDCl3, 300 MHz): d 8.33 (s,
1H), 8.12 (d, J = 7.5 Hz, 1H), 7.94 (d, J = 9 Hz, 1H), 7.84–7.90 (m,
4H), 7.65 (d, J = 7.5 Hz, 1H), 7.51–7.57 (m, 4H), 2.46 (s, 3H). MS
(ESI): 362.13 (C20H16N3O4, [M+H]+). Anal. Calcd for C20H15N3O4:
C, 66.48; H, 4.18; N, 11.63. Found: C, 66.97; H, 4.24; N, 11.54.
4.2.4. 2-(20-Naphthyl)-5-(300-bromophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6d)
4.2.12. 2-(20-Naphthyl)-5-(400-nitrophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6l)
Yield 83%; mp 161–162 °C. 1H NMR (CDCl3, 300 MHz): d 8.36 (s,
1H), 8.00 (d, J = 9 Hz, 1H), 7.90 (t, J = 15 Hz, 3H), 7.68 (d, 1H), 7.54–
7.62 (m, 3H), 7.50 (d, J = 7.8 Hz, 1H), 7.32 (d, J = 7.5 Hz, 1H), 7.11 (s,
1H), 2.41 (s, 3H). MS (ESI): 395.08 (C20H16BrN2O2, [M+H]+). Anal.
Calcd for C20H15BrN2O2: C, 60.78; H, 3.83; N, 7.09. Found: C,
60.43; H, 3.85; N, 7.02.
Yield 81%; mp 159–160 °C. 1H NMR (CDCl3, 300 MHz): d 8.35 (s,
1H), 8.27 (d, J = 8.7 Hz, 2H), 7.98 (d, J = 9 Hz, 1H), 7.90 (t,
J = 15.3 Hz, 3H), 7.73 (d, J = 8.8 Hz, 2H), 7.54–7.62 (m, 2H), 7.21
(s, 1H), 2.41 (s, 3H). MS (ESI): 362.11 (C20H16N3O4, [M+H]+). Anal.
Calcd for C20H15N3O4: C, 66.48; H, 4.18; N, 11.63. Found: C,
66.65; H, 4.22; N, 11.46.
4.2.5. 2-(20-Naphthyl)-5-(400-bromophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6e)
4.2.13. 2-(20-Naphthyl)-5-(200-hydroxyphenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6m)
Yield 83%; mp 130–132 °C. 1H NMR (CDCl3, 300 MHz): d 8.35 (s,
1H), 7.99 (d, J = 9.0 Hz, 1H), 7.90 (t, J = 9.0 Hz, 3H), 7.59 (m, 4H),
7.43 (d, J = 8.4 Hz, 2H), 7.11 (s, 1H), 2.41 (s, 3H). MS (ESI): 395.01
(C20H16BrN2O2, [M+H]+). Anal. Calcd for C20H15BrN2O2: C, 60.78;
H, 3.83; N, 7.09. Found: C, 60.11; H, 3.89; N, 7.14.
Yield 55%; mp 137–139 °C. 1H NMR (CDCl3, 300 MHz): d 8.30 (s,
1H), 7.96 (d, J = 8.7 Hz, 1H), 7.88 (d, J = 8.2 Hz, 3H), 7.50–7.59 (m,
3H), 7.44 (t, J = 14.0 Hz, 2H), 7.30 (d, J = 7.5 Hz, 1H), 7.20 (s, 1H),
7.17 (d, J = 8 Hz, 1H), 2.37 (s, 3H). MS (ESI): 333.13 (C20H17N2O3,
[M+H]+). Anal. Calcd for C20H16N2O3: C, 72.28; H, 4.85; N, 8.43.
Found: C, 72.56; H, 4.73; N, 8.51.
4.2.6. 2-(20-Naphthyl)-5-(200-chlorophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6f)
4.2.14. 2-(20-Naphthyl)-5-(200-naphthyl)-2-acetyl-2,3-dihydro-
1,3,4-oxadiazoline (6n)
Yield 69%; mp 140–142 °C. 1H NMR (CDCl3, 300 MHz): d 8.30 (s,
1H), 7.96 (d, J = 8.7 Hz, 1H), 7.86 (t, J = 14.0 Hz, 3H), 7.50–7.58 (m,
2H), 7.40–7.47 (m, 3H), 7.29–7.35 (m, 2H), 2.44 (s, 3H). MS (ESI):
351.09 (C20H16ClN2O2, [M+H]+). Anal. Calcd for C20H15ClN2O2: C,
68.48; H, 4.31; N, 7.99. Found: C, 68.04; H, 4.35; N, 7.91.
Yield 71%; mp 166–167 °C. 1H NMR (CDCl3, 300 MHz): d 8.28 (d,
J = 8.4 Hz, 2H), 7.83–7.99 (m, 7H), 7.63 (t, J = 13.9 Hz, 1H), 7.48–
7.57 (m, 5H), 2.51 (s, 3H). MS (ESI): 367.14 (C24H19N2O2, [M+H]+).
Anal. Calcd for C24H18N2O2: C, 78.67; H, 4.95; N, 7.65. Found: C,
78.89; H, 4.90; N, 7.74.
4.2.7. 2-(20-Naphthyl)-5-(400-chlorophenyl)-2-acetyl-2,3-
dihydro-1,3,4-oxadiazoline (6g)
Yield 75%; mp 148–150 °C. 1H NMR (CDCl3, 300 MHz): d 8.33 (s,
1H), 7.96 (d, J = 9.0 Hz, 1H), 7.88 (t, J = 12.0 Hz, 3H), 7.54–7.60 (m,
2H), 7.46 (d, J = 9.0 Hz, 2H), 7.37 (d, J = 8.4 Hz, 2H), 7.1 (s, 1H), 2.39
(s, 3H). MS (ESI): 351.04 (C20H16ClN2O2, [M+H]+). Anal. Calcd for
4.2.15. 2-(20-Naphthyl)-5-(200-pyridinyl)-2-acetyl-2,3-dihydro-
1,3,4-oxadiazoline (6o)
Yield 62%; mp 142–145 °C. 1H NMR (CDCl3, 300 MHz): d 8.68
(d, J = 4.8 Hz, 1H), 8.33 (s, 1H), 7.99 (d, J = 8.1 Hz, 1H), 7.87 (d,
J = 11 Hz, 3H), 7.76 (t, J = 11 Hz, 1H), 7.49–7.58 (m, 3H), 7.32 (q,
J = 12.6 Hz, 1H), 7.12 (s, 1H), 2.43 (s, 1H). MS (ESI): 318.11
C20H15ClN2O2: C, 68.48; H, 4.31; N, 7.99. Found: C, 68.91; H, 4.33;
N, 7.95.