2396
Helvetica Chimica Acta ± Vol. 83 (2000)
(9 ml). After addition of another amount of BuLi soln. (0.79 ml, 1.98 mmol) at À58, the mixture was stirred at
r.t. for 5 h. The usual workup, CC (silica gel; hexane/AcOEt 4 :1) and crystallization from Et2O/hexane yielded
pure 5d (0.042 g, 21%). Yellow crystals. M.p. 1948. Rf (hexane/AcOEt 1:1) 0.45. UV/VIS (EtOH): See Table 1.
IR (KBr): 3370m (OH), 3191m, 2975w, 1598s, 1549w, 1446m, 1364m, 1258m, 1127s, 1066m, 87 1w, 7 87w, 7 42m,
1
685w, 633s, 567m, 469w. H-NMR (600 MHz, CDCl3): See Table 2. 13C-NMR (150 MHz, CDCl3): See Table 3.
.
EI-MS: 405 (24, [M 1] ), 404 (100, M ), 389 (53, [M À Me] ), 378 (18), 364 (52), 248 (15, [M À (PhSO2
Me) ]), 247 (15), 219 (12), 202 (11), 189 (28), 178 (21), 165 (32), 152 (14), 77 (6, [Ph] ). Anal. calc. for
C24H20O4S (404.49): C 71.23, H 4.98, S 7.93; found: C 70.90, H 4.79, S 7.84.
2.1.6. 7,12-Dimethyl-3-(morpholinosulfonyl)benzo[a]heptalene-2,4-diol (5d'). According to GP, methyl
morpholino sulfone (0.413 g, 2.50 mmol) was reacted with BuLi soln. (1.10 ml, 2.75 mmol) and 15d (0.149 g,
0.499 mmol) in THF (11 ml). After addition of another amount of BuLi soln. (0.80 ml, 2.00 mmol) at À58, the
mixture was stirred at r.t. for 5 h. The usual workup, CC (silica gel; hexane/AcOEt 3 :1) and crystallization from
Et2O/CH2Cl2/hexane gave 5d' (0.085 g, 41%). Yellow crystals. M.p. 2198. Rf (hexane/AcOEt 1:1) 0.37. UV/VIS
(EtOH): See Table 1. IR (KBr): 3202s (OH), 3014w, 2981m, 2936m, 2911m, 2872m, 1946w, 1769w, 1600s, 1566s,
1505w, 1436s, 1388s, 1363s, 1300m, 1258s, 1174m, 1106s, 1066m, 1005w, 946s, 87 0m, 849w, 7 38s, 7 03s, 632m, 558m,
516m, 47 0w. 1H-NMR (600 MHz, CDCl3): See Table 2. 13C-NMR (150 MHz, CDCl3): See Table 3. EI-MS: 414
.
(25, [M 1] ), 413 (100, M ), 373 (9), 262 (16, [M À (C4H8NO3S H] ), 247(9), 236 (11), 234 (10), 222 (22),
189 (11), 165 (9). Anal. calc. for C22H23NO5S (413.49): C 63.90, H 5.61, N 3.39, S 7.75; found: C 64.41, H 6.69,
N 3.26, S 7.55.
3. [13C]-Labelling Experiments. ± 3.1. Formation of [13C]H3SO2Ph. According to a procedure of Wildeman
and van Leusen [16], a suspension of PhSO2Na (1.22 g, 7.43 mmol) in 1,2-dimethoxyethane (9 ml) was reacted
with [13C]H3I (99 atom-% 13C; 1.00 g, 7.00 mmol) and Bu NBr (0.12 g, 0.37mmol). The mixture was stirred
4
under N2 at 408 for 8 h. Thereafter, it was poured on ice and extracted with Et2O (3 Â 50 ml). The org. phase was
washed with H2O and with brine, and dried (MgSO4). After removal of the solvent in a rotatory evaporator, the
residue was crystallized from Et2O/hexane to give [13C]H3SO2Ph (0.812 g, 5.17mmol, 74%). White crystals. M.p.
88.0 ± 88.58. Rf (Et2O/hexane 3 :1) 0.32. 1H-NMR (CDCl3): 3.05 (d, 1J 138.2, [13C]H3). 13C-NMR (CDCl3):
140.63 (d, 2J 8.9, C(1) of Ph); 44.46 ([13C]H3).
3.2. Methyl 9-Isopropyl-1,6-dimethyl-3-[2-(phenylsulfonyl)[2-13C]acetyl]heptalene-4-carboxylate (19a*).
BuLi soln. (1.62 ml, 4.05 mmol) was slowly added at À58 to a soln. [13C]H3SO2Ph (24.9atom-% 13C; 0.67g,
4.28 mmol) in dry THF (30 ml). After stirring at À58 for 30 min, a white precipitate had been formed. The
mixture was cooled to À788, and a soln. of 15a (0.915 g, 2.69 mmol) [11] in THF (5 ml) was added dropwise.
After stirring for 1 h at À708, the mixture was acidified with 1n aq. HCl soln. and extracted with Et2O (3 Â
100 ml). The org. phase was washed with H2O (3 Â 200 ml) and with brine (1 Â 200 ml), and dried (MgSO4).
The solvent was removed, and the residue was chromatographed (silica gel (250 g); Et2O/hexane 1 :1).
Crystallization from Et2O/hexane gave 19a* (0.622 g, 1.34 mmol, 50%) as yellow crystals. In addition, 20a**
(0.092 g, 0.16 mmol, 6%) and starting material 15a (0.356 g, 1.05 mmol, 39%) were isolated.
Data of 19a*: M.p. 140 ± 1418. Rf (hexane/AcOEt 2 :1) 0.30. 1H-NMR (CDCl3): 8.08 (dt, 3J 7.0,4J 1.7, Ho
of Ph); 7.62 (m, Hp of Ph); 7.53 (m, Hm of Ph); 7.44 (dd, 3J 6.5, 5J 0.9, HÀC(3)); 6.28 (d, 3J 6.6, HÀC(8));
6.24 (dd, 3J 6.4, 4J 1.3, HÀC(7)); 6.15 (dd, 3J 6.5, 4J 1.4, HÀC(2)); 5.84 (s,HÀC(10)); 4.66/4.64
12
(AB, JAB 17.9, [ C]H2SO2; ABX, JAB 17.9, JAX JBX 136.5, [13C]H2SO2); 3.51 (s, MeOCO); 2.49
5
(sept., J 6.9, Me2CH); 2.049 (t, 4J ꢀ J 1.1, MeÀC(1)); 1.821 (s, MeÀC(6)); 1.090/1.059 (2d, 3J 6.9, 6.8,
Me2CH); 13C-NMR (CDCl3): 194.10 (s, OCÀC(5)); 166.86 (s, OCÀC(4)); 150.26/144.39 (2s); 141.60 (d);
139.94, 139.48 (2s); 133.55 (d); 132.07, 131.97, 130.81 (3s); 129.43, 129.04, 128.70 (3d); 127.91 (s); 125.86, 125.68,
124.78 (3d); 65.15 (enhanced t, CH2SO2); 52.01 (q, MeOCO); 35.71 (d, Me2CH); 25.15, 23.69, 23.01, 22.60 (4q).
Data of 8-Isopropyl-6,11-dimethyl-2-(phenylsulfonyl)-3-[(phenylsulfonyl)[13C]methyl][2-13C]cyclopen-
ta[a]heptalen-1(1H)-one (20a**): M.p. 221 ± 2228 (dec.). Rf (hexane/AcOEt 2 :1) 0.18. 1H-NMR (CDCl3):
8.24 (dt, 3J 7.0, 4J 1.5, Ho of PhSO2ÀC(2)); 8.08 (dt, 3J 7.1, 4J 1.5, Ho of PhSO2CH2ÀC(3)); 7.70 (tt, 3J
7.4, 4J 1.4, Hp of PhSO2CH2ÀC(3)); 7.59 (m, Hp of PhSO2ÀC(2), Hm of PhSO2CH2ÀC(3)); 7.51 (tt, 3J 7.4,
4J 1.6, Hm of PhSO2ÀC(2)); 6.88 (d, 3J 7.0, HÀC(4)); 6.40 (dd, 3J 7.0,4J 1.2, HÀC(10)); 6.27( dd, 3J 7.2,
12
4J 1.2, HÀC(5), HÀC(9)); 6.15 (d, 4J 1.1, HÀC(7)); 5.25/5.14 (AB, JAB 12.7, [ C]H2ÀC(3); ABX, JAB
12.7, JAX JBX 141.7, [ C]H2ÀC(3)); 2.49 (sept., 3J 6.8, Me2CH); 2.145 (d, 4J 0.6, MeÀC(6)); 2.132
(s, MeÀC(11)); 1.109, 1.091 (2d, 3J 6.9, 6.8, Me2CH); 13C-NMR (CDCl3): 180.24 (s, CO); 152.27, 148.57,
144.48, 140.59, 140.20, 139.55, 138.22 (7s); 137.79 (enhanceds, C(2)); 134.32, 133.71 (2d); 132.63 (s); 131.85 (d);
131.51 (s); 129.69, 129.44, 129.27, 128.66, 128.45, 126.71, 126.63 (7d); 125.18 (s); 52.34 (enhanced t, CH2SO2);
35.91 (d, Me2CH); 25.84, 24.39, 22.99, 22.87(4 q).
13