48
3 Experimental Section
to give the target compound as pale yellow solid (0.98 mmol, 495 mg, 98 %).
1 H-NMR (600 MHz, CDCl 3 ): δ 7.51 (s, 1 H, H
3-NOH ), 4.18 (dd, J =
3.9, 2.3 Hz, 1 H, H
12 ), 2.97 (ddd, J = 15.5, 6.1, 4.2 Hz, 1 H, H
2a ), 2.37–2.24
(m, 2 H, H
2b,11a ), 2.19–2.12 (m, 2 H, H
16a,19a ), 2.02 (d, J = 9.1 Hz, 2 H,
H
18,19b ), 1.95 (td, J = 13.7, 6.1 Hz, 1 H, H
15a ), 1.83–1.72 (m, 3 H, H
1a,9,11b ),
1.64 (dd, J = 9.0, 3.5 Hz, 2 H, H
22a ), 1.61–1.45 (m, 3 H, H
7a,6ab ), 1.40–1.26
(m, 7 H, H
7b,16b,21ab,27 ), 1.25–1.19 (m, 5 H, H
1b,15b,26 ), 1.18–1.14 (m, 4 H,
H
5,23 ), 1.06 (s, 3 H, H
24 ), 0.99 (s, 3 H, H
29 ), 0.98 (s, 3 H, H
25 ), 0.90 (s, 3 H,
H
30 ).
13 C-NMR (150 MHz, CDCl 3 ): δ 179.2 (C
28 ), 167.1 (C
3 ), 91.7
(C
13 ), 65.1 (C
12 ), 55.4 (C
5 ), 52.1 (C
18 ), 45.4 (C
17 ), 44.5 (C
9 ), 43.2 (C
14 ),
42.5 (C
8 ), 40.3 (C
4 ), 39.9 (C
19 ), 38.6 (C
1 ), 36.7 (C
10 ), 34.2 (C
7 ), 34.0 (C
21 ),
33.4 (C
29 ), 32.0 (C
20 ), 29.7 (C
11 ), 29.1 (C
15 ), 27.6 (C
23 ), 27.6 (C
22 ), 23.8
(C
30 ), 23.0 (C
24 ), 21.4 (C
16 ), 20.2 (C
27 ), 18.8 (C
26 ), 18.6 (C
6 ), 16.9 (C
2 ),
16.7 (C
25 ). [α]
20
D +27.0 (c 1.0, CDCl 3 ). IR (neat) 3268, 2930, 2866, 1768,
1464. HRMS (ESI-TOF) m/z: [M + Na]
+ Calcd for C 30 H 46 ClNNaO 3
+
526.3058; Found 526.3059.
3.2.6 12α-Bromo-3-(hydroxyimino)-olean-28,13β-olide
(6b)
N
H
H
H
Br
O
O
1
2
3
4
5
6
7
8
9
10
11
12 13
14
15
16
17
18
19
20
21
22
28
24
23
25
26
29
27
30
HO
A round bottom flask, equipped with magnetic stirring bar, was charged
with a solution of oleanolic acid (5) (1.00 mmol, 457 mg, 1.00 equiv) in DCM
(12 ml) and pyridine (15.2 mmol, 1229 μl, 15.2 equiv). After addition of
NBS (1.05 mmol, 187 mg, 1.05 equiv), the reaction was left stirring at 20 °C
for 60 min. trichloroisocyanuric acid (0.80 mmol, 186 mg, 0.80 equiv) was
added subsequently, and the mixture was left stirring at 20 °C for 90 min.