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HETEROCYCLES, Vol. 83, No. 10, 2011
in EtOH (2 mL) gave a mixture of 3d (major isomer) and 3d’ (minor isomer) (31 mg, 20%) in a ratio of
2:1; crystallization from EtOH gave a ratio of 3:1. 1H NMR (3d): 4.25 (d, 1H, J = 9.0 Hz, CH2), 5.10 (d,
1H, J = 9.0 Hz, CH2), 6.74 (d, 1H, J = 9.4 Hz, H8’), 6.886.92 (m, 2H, H5’, H7’), 7.33 (s, 1H, NH),
7.437.51 (m, 2H, Ph), 7.567.62 (m, 1H, Ph), 7.827.88 (m, 2H, Ph), 10.88 (s, 1H, NHCO). 1H NMR
(3d’): 4.26 (d, 1H, J = 9.4 Hz, CH2), 5.11 (d, 1H, J = 9.4 Hz, CH2), 6.736.80 (m, 2H, H6’, H8’), 6,86 (d,
1H, J = 8.3 Hz, H5’), 7.40 (s, 1H, NH), 7.437.51 (m, 2H, Ph), 7.567.62 (m, 1H, Ph), 7.827.88 (m, 2H,
Ph), 10.88 (s, 1H, NHCO). MS (FAB, m/z, %) (3d/d’): 314 (MH+, 100). Anal. Calcd for C16H12ClN3O2
(3d/d’): C, 61.25; H, 3.86; N, 13.39. Found: C, 61.29; H, 3.61; N, 13.62.
7’-Benzoyl-2-phenyl-1’H,5H-spiro[oxazole-4,2’-quinoxalin]-3’(4’H)-one (3e) and 6’-Benzoyl-2-
phenyl-1’H,5H-spiro[oxazole-4,2’-quinoxalin]-3’(4’H)-one (3e’). Following the typical procedure A,
treatment of diamine 1e (212 mg, 1.0 mmol) with acid 2 (226 mg, 1.0 mmol) and Et3N (160 mg, 1.6
mmol) in EtOH (4 mL) gave a mixture of 3e (major isomer) and 3e’ (minor isomer) (118 mg, 31%) in a
1
ratio of 13:1; crystallization from EtOH gave a ratio of 33:1. H NMR (3e): 4.27 (d, 1H, J = 9.4 Hz,
CH2), 5.15 (d, 1H, J = 9.6 Hz, CH2), 7.02 (d, 1H, J = 7.9, H5’), 7.187.24 (m, 2H, H6’, H8’), 7.437.72
(m, 9H, 8H of Ph, NH), 7.837.89 (m, 2H, Ph), 11.18 (s, 1H, NHCO). 1H NMR (3e’): 6.85 (d, 1H, J =
8.3, H8’), 7.35 (dd, 1H, J = 1.9, 8.3 Hz, H7’), 7.97 (s, 1H, NH), 10.96 (s, 1H, NHCO). 13C NMR (3e):
72.9, 84.6, 114.5, 115.2, 121.9, 126.5, 128.2, 128.3, 128.7, 129.1, 129.9, 131.5, 131.9, 132.0, 132.3, 137.9,
163.5, 164.6, 194.7. MS (EI, m/z, %) (3e/e’): 383 (M+, 15). Anal. Calcd for C23H17N3O3 (3e/e’): C, 72.05;
H, 4.47; N, 10.96. Found: C, 71.94; H, 4.37; N, 10.81.
6’,7’-Dichloro-2-phenyl-1’H,5H-spiro[oxazole-4,2’-quinoxalin]-3’(4’H)-one (3f). Following the
typical procedure A, treatment of diamine 1f (89 mg, 0.5 mmol) with acid 2 (113 mg, 0.5 mmol) and Et3N
(80 mg, 0.8 mmol) in EtOH (2 mL) gave 3f (60 mg, 34%). mp 252254 °C (EtOH). 1H NMR : 4.28 (d,
1H, J = 9.4 Hz, CH2), 5.11 (d, 1H, J = 9.4 Hz, CH2), 6.90 (s, 1H, H8’), 7.03 (s, 1H, H5’), 7.447.62 (m,
4H, 3H of Ph, NH), 7.827.88 (m, 2H, Ph), 11.00 (s, 1H, NHCO). MS (EI, m/z, %): 347 (M+, 38). Anal.
Calcd for C16H11Cl2N3O2: C, 55.19; H, 3.18; N, 12.07. Found: C, 54.87; H, 3.25; N, 11.80.
2’-Phenyl-1H,5’H-spiro[benzo[g]quinoxaline-2,4’-oxazole]-3(4H)-one (3g). Following the typical
procedure A, treatment of diamine 1g (158 mg, 1.0 mmol) with acid 2 (226 mg, 1.0 mmol) and Et3N (160
mg, 1.6 mmol) in EtOH (4 mL), gave 3g (91 mg, 28%). mp 284285 °C (DMFEtOH). 1H NMR : 4.34
(d, 1H, J = 9.4 Hz, CH2), 5.16 (d, 1H, J = 9.4 Hz, CH2), 7.10 (s, 1H, H10), 7.207.31 (m, 3H, H5, H7,
H8), 7.427.51 (m, 3H, 2 H of Ph, NH), 7.547.61 (m, 1H, Ph), 7.617.71 (m, 2H, H6, H9), 7.827.87
(m, 2H, Ph), 11.11 (s, 1H, NHCO). MS (EI, m/z, %): 329 (M+, 73). Anal. Calcd for C20H15N3O2: C, 72.94;
H, 4.59; N, 12.76. Found: C, 72.91; H, 4.73; N, 12.93.