1
384
stirring is continued at room temperature overnight. To the formed red solution, AcOH (1.5 ml) is added and after stirring for
5
min the solvents are evaporated. The residue is diluted with ethyl acetate, washed twice with water and once with saturated
sodium chloride solution. After drying (Na SO ) and evaporating the solvent, the residue is purified by flash chromatography
hexane/ethyl acetate 9:1). 0.50 g (34%) of 3d are obtained. Mp 164–166°C; EI-MS (70 eV): 536 (10), 535 (M , 32), 506
2
4
+
(
(
(
1
17), 505 (46), 504 (12), 474 (10), 304 (36), 116 (100); H NMR (250 MHz, CDCl
part of an AA BB -system, 2H), 7.62 (part of an AA BB -system, 2H), 7.45–7.40 m (3H), 7.25–7.20 m (1H), 7.18 (part of
3
; coupling constants given in Hz): 7.90
0
0
0
0
0
0
0
0
an AA BB -system, 2H), 7.12 (part of an AA BB -system, 2H), 7.05 s (1H), 5.40 s (2H), 3.90 br s (2H), 3.79 s (3H). Physical
data for new compounds 3a–c and 7: For 3a: Mp 125–127°C; H NMR (250 MHz, CDCl
1
0
0
3
): 7.68 (part of an AA BB -system,
0
0
2
2
8
7
H), 7.42–7.39 m (3H), 7.27 m (1H), 7.21 (part of an AA BB -system, 2H), 5.28 s (2H), 4.02 s (3H), 3.88 s (3H), 3.71 s (2H),
.49 s (3H); 13C NMR (250 MHz, CDCl
): see Fig. 2. For 3b: Mp 92–96°C; FD-MS: 376 (M ); H NMR (250 MHz, CDCl
+
1
):
3
3
0
0
0
0
.01 s (1H), 7.89 (part of an AA BB -system, 1H), 7.73 (part of an AA BB -system, 1H), 7.59 m (1H), 7.43–7.37, m (3H),
.26–7.20 m (1H), 5.37 s (2H), 3.80 s (2H), 3.75 s (3H). For 3c: Mp 129–130°C; H NMR (250 MHz, CDCl ): 7.40–7.36 m
3
1
(
3H), 7.21 m (1H), 5.33 s (2H), 4.10 s (3H), 3.87 s (3H), 3.74 br s (2H), 2.51 s (3H). 7: Mp 129–131°C; EI-MS (70 eV): 474
+
1
3
(M , 13), 445 (27), 444 (100), 413 (31), 412 (23), 277 (29), 263 (34), 122 (84); H NMR (250 MHz, CDCl ): 7.54 d (1H, J=6
Hz), 7.52–7.35 m (5H), 7.30–7.25 m (1H), 7.20–7.06 m (2H), 6.85 d (1H, J=6 Hz), 5.36 s (2H), 3.92 s (3H), 3.90 s (2H).
Figure 2. 13C NMR data for 3a and 9.
4
5
. Livingston, M. J.; Chick, M. F.; Shealy, E. O.; Beam, C. F. J. Heterocycl. Chem. 1982, 19, 215.
. Isolation of compound 9: NaH (0.96 g, 22.0 mmol), 1a (2.50 g, 10.5 mmol), and 4 (3.00 g, 10.5 mmol) are reacted as shown
for 3d. After work-up, the residue is filtered on silica gel (ethyl acetate). The first fraction is separated by flash chromatography
(
ethyl acetate:hexane 1:4) to give, in the order of elution, traces of 1a, compound 3a (0.14 g, 3%), 2a (0.19 g, 4%) and
+
1
3
compound 9 (0.11 g, 3%) as resin. Physical data for 9: ESI-MS: 412.19 (M ); H NMR (250 MHz, CDCl ): 7.92 (part of an
0
0
0
0
0
0
AA BB -system, 1H), 7.69 (part of an AA BB -system, 2H), 7.40–7.27 m (4H), 7.03 (part of an AA BB -system, 1H), 6.16
s (D
O exch., 1H), 5.81 s (1H), 5.05 d (1H, J=15 Hz), 4.69 d (1H, J=15 Hz), 4.09 s (3H), 3.66 s (3H), 2.52 s (3H); 13C NMR
250 MHz, CDCl ): see Fig. 2. The second fraction from the filtration contains the acid 5 (2.00 g, 45%).
2
(
3
6
7
. McClure, K. F.; Benbow, J. W.; Danishefsky, S. J.; Schulte, G. K. J. Am. Chem. Soc. 1991, 113, 8185; Benbow, J. W.;
McClure, K. F.; Danishefsky, S. J. Am. Chem. Soc. 1993, 113, 12 305.
. Jackman, L. M.; Sternhell, S. Application of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry; Pergamon,
Oxford, 2nd ed., 1969, p. 88