50
3 Experimental Section
3.2.7 12α-Chloro-3-(methoxyimino)-olean-28,13β-olide
(29a)
N
H
H
H
Cl
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
O
31
A round bottom flask, equipped with magnetic stirring bar, was charged
with a solution of 27a (2 mmol, 978 mg, 1 equiv) in pyridine (20 ml). After
addition of methoxyamine hydrochloride (4 mmol, 334 mg, 2 equiv), the
flask was immersed in a preheated oilbath (80 °C), and the reaction was
left stirring at 80 °C for 1.5 h. After cooling to room temperature, the
mixture was diluted with DCM (200 ml). The organics were washed with
HCl solution (1 m in H 2 O) (3 × 125 ml) and dried over MgSO 4 . Removal of
the solvents under reduced pressure, followed by drying in vacuo gave the
target compound as off-white foam (quantitative yield).
1 H-NMR (700 MHz, CDCl 3 ): δ 4.17 (dd, J = 3.9, 2.3 Hz, 1 H, H
12 ),
3.82 (s, 3 H, H
31 ), 2.88 (ddd, J = 15.6, 6.1, 4.1 Hz, 1 H, H
2a ), 2.31–2.24
(m, 2 H, H
2b,11a ), 2.19–2.13 (m, 2 H, H
16a,19a ), 2.06–1.98 (m, 2 H, H
18,19b ),
1.95 (td, J = 13.8, 6.1 Hz, 1 H, H
15b ), 1.75 (m, 3 H, H
1a,9,11b ), 1.64 (dd,
J = 9.3, 3.6 Hz, 2 H, H
22ab ), 1.61–1.52 (m, 2 H, H
6a,7a ), 1.52–1.44 (m, 1 H,
H
6b ), 1.40–1.33 (m, 4 H, H
21a,27 ), 1.34–1.24 (m, 3 H, H
7b,16b,21b ), 1.23 (s,
5 H, H
1b,15b,26 ), 1.16 (s, 3 H, H
23 ), 1.14 (dd, J = 11.9, 2.2 Hz, 1 H, H
5 ),
1.05 (s, 3 H, H
24 ), 0.99 (s, 3 H, H
29 ), 0.96 (s, 3 H, H
25 ), 0.90 (s, 3 H, H
30 ).
13 C-NMR (175 MHz, CDCl 3 ): δ 179.2 (C
28 ), 165.7 (C
3 ), 91.8 (C
13 ),
65.1 (C
12 ), 61.2 (C
31 ), 55.5 (C
5 ), 52.1 (C
18 ), 45.5 (C
17 ), 44.5 (C
9 ), 43.2
(C
14 ), 42.5 (C
8 ), 40.1 (C
4 ), 39.9 (C
19 ), 38.7 (C
1 ), 36.6 (C
10 ), 34.2 (C
7 ), 34.1
(C
21 ), 33.4 (C
29 ), 32.0 (C
20 ), 29.7 (C
11 ), 29.1 (C
15 ), 27.7 (C
23 ), 27.6 (C
22 ),
23.8 (C
30 ), 23.1 (C
24 ), 21.4 (C
16 ), 20.2 (C
27 ), 18.8 (C
26 ), 18.6 (C
6 ), 17.7
3 Experimental Section
3.2.7 12α-Chloro-3-(methoxyimino)-olean-28,13β-olide
(29a)
N
H
H
H
Cl
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
O
31
A round bottom flask, equipped with magnetic stirring bar, was charged
with a solution of 27a (2 mmol, 978 mg, 1 equiv) in pyridine (20 ml). After
addition of methoxyamine hydrochloride (4 mmol, 334 mg, 2 equiv), the
flask was immersed in a preheated oilbath (80 °C), and the reaction was
left stirring at 80 °C for 1.5 h. After cooling to room temperature, the
mixture was diluted with DCM (200 ml). The organics were washed with
HCl solution (1 m in H 2 O) (3 × 125 ml) and dried over MgSO 4 . Removal of
the solvents under reduced pressure, followed by drying in vacuo gave the
target compound as off-white foam (quantitative yield).
1 H-NMR (700 MHz, CDCl 3 ): δ 4.17 (dd, J = 3.9, 2.3 Hz, 1 H, H
12 ),
3.82 (s, 3 H, H
31 ), 2.88 (ddd, J = 15.6, 6.1, 4.1 Hz, 1 H, H
2a ), 2.31–2.24
(m, 2 H, H
2b,11a ), 2.19–2.13 (m, 2 H, H
16a,19a ), 2.06–1.98 (m, 2 H, H
18,19b ),
1.95 (td, J = 13.8, 6.1 Hz, 1 H, H
15b ), 1.75 (m, 3 H, H
1a,9,11b ), 1.64 (dd,
J = 9.3, 3.6 Hz, 2 H, H
22ab ), 1.61–1.52 (m, 2 H, H
6a,7a ), 1.52–1.44 (m, 1 H,
H
6b ), 1.40–1.33 (m, 4 H, H
21a,27 ), 1.34–1.24 (m, 3 H, H
7b,16b,21b ), 1.23 (s,
5 H, H
1b,15b,26 ), 1.16 (s, 3 H, H
23 ), 1.14 (dd, J = 11.9, 2.2 Hz, 1 H, H
5 ),
1.05 (s, 3 H, H
24 ), 0.99 (s, 3 H, H
29 ), 0.96 (s, 3 H, H
25 ), 0.90 (s, 3 H, H
30 ).
13 C-NMR (175 MHz, CDCl 3 ): δ 179.2 (C
28 ), 165.7 (C
3 ), 91.8 (C
13 ),
65.1 (C
12 ), 61.2 (C
31 ), 55.5 (C
5 ), 52.1 (C
18 ), 45.5 (C
17 ), 44.5 (C
9 ), 43.2
(C
14 ), 42.5 (C
8 ), 40.1 (C
4 ), 39.9 (C
19 ), 38.7 (C
1 ), 36.6 (C
10 ), 34.2 (C
7 ), 34.1
(C
21 ), 33.4 (C
29 ), 32.0 (C
20 ), 29.7 (C
11 ), 29.1 (C
15 ), 27.7 (C
23 ), 27.6 (C
22 ),
23.8 (C
30 ), 23.1 (C
24 ), 21.4 (C
16 ), 20.2 (C
27 ), 18.8 (C
26 ), 18.6 (C
6 ), 17.7