Intramolecular anodic olefin coupling reactions: Using competition studies to probe the mechanism of oxidative cyclization reactions

Article abstract of DOI:10.1021/ol100317t

A competition experiment was designed so that the relative rates of anodic cyclization reactions under various electrolysis conditions can be determined. Reactions with ketene dithioacetal and enol ether-based substrates that use lithium methoxide as a base were shown to proceed through radical cation intermediates that were trapped by a sulfonamide anion. Results for the oxidative coupling of a vinyl sulfide with a sulfonamide anion using the same conditions were consistent with the reaction proceeding through a nitrogen-radical.

Full text of DOI:10.1021/ol100317t

Supporting Information
Intramolecular Anodic Olefin Coupling Reactions: Using
Competition Studies to Probe the Mechanism of Oxidative
Cyclization Reactions
Hai-Chao Xu and Kevin D. Moeller*
Department of Chemistry, Washington University, St. Louis, MO 63130
General procedure for electrolysis reactions:
LiOMe (1.0 M in MeOH, 0.5 equiv) was added to a methanol solution of the substrate
(0.03 M, 1 equiv) and the electrolyte Et4NOTs (0.1 M) in a three-neck round bottom flask
at rt under argon atmosphere. Two of the three septa were replaced by a reticulated
vitreous carbon anode (100 PPI) and platinum wire cathode. The solution was sonicated
for 10 min. The electrolysis reaction was carried out at constant current of 6.0 mA until
complete consumption of the starting material (the progress of the reaction was
1
monitored by H-NMR). When complete, the reaction was concentrated under reduced
pressure if Et4NOTs was used as electrolyte. And then the residue was chromatographed
through a silica gel column (slurry packed using 1% triethylamine in hexane solution) to
give the desired product. In the case in which LiClO4 was used as electrolyte, water and
ether was added. The ether layer was separated and aqueous layer extracted with ether.
The combined organic solution was dried and concentrated. The residue was
chromatogaphed in a way described above to afford the desired product.
Spectra Data:
S
S
O
N
Ts
8a
IR (neat, cm-1) 1355, 1100, 836, 754; 1H NMR (300 MHz, CDCl3)  7.97 (d, J = 8.4 Hz,
2H), 7.26 (d, J = 8.4 Hz, 2H), 4.11 (td, J = 11.4, 3.6 Hz, 1H), 3.76 (dd, J = 5.1 Hz, 1H),
3.56-3.26 (m, 4H), 2.96-2.83 (m, 2H), 2.70-2.59 (m, 2H), 2.38 (s, 3H), 2.10-1.68 (m,
8H); 13C NMR (75 MHz, CDCl3)  143.2, 138.9, 129.6, 128.1, 98.9, 74.9, 62.8, 52.4,
37.4, 31.0, 27.5, 26.5, 25.1, 24.6, 23.5, 21.7; ESI HRMS m/z (M+Na)+ calcd 422.0899,
obsd 422.0887.
S
S
OMe
N
Ts
OH
8b
S1

IR (neat, cm-1) 3647, 1154, 670, 589; 1H NMR (300 MHz, CDCl3)  7.74 (d, J = 8.1 Hz,
2H), 7.22 (d, J = 8.1 Hz, 2H), 4.11-4.03 (m, 1H), 3.74 (t, J = 5.7 Hz, 2H), 3.55-3.46 (m,
13
1H), 3.35 (s, 3H), 2.88-2.64 (m, 6H), 2.12-1.71 (m, 8H); C NMR (75 MHz, CDCl3) 
142.2, 140.2, 128.8, 127.7, 102.2, 83.1, 63.3, 54.2, 52.7, 38.2, 31.1, 28.7, 28.1, 24.2, 22.3,
21.8; ESI HRMS m/z (M+Na)+ calcd 454.1151, obsd 454.1144.
S
S
NTs
O
8c
IR (neat, cm-1) 1330, 1050, 657, 572; 1H NMR (300 MHz, CDCl3)  7.82 (d, J = 8.4 Hz,
2H), 7.21 (d, J = 8.4 Hz, 2H), 4.22-4.17 (m, 1H), 4.04-3.98 (m, 1H), 3.76-3.62 (m, 2H),
3.08-3.04 (m, 1H), 3.00-2.91 (m, 1H), 2.79-2.62 (m, 2H), 2.58-2.51 (m, 1H), 2.39 (s,
13
3H), 2.01-1.90 (m, 2H), 1.88-1.71 (m, 5H), 1.69-1.60 (m, 1H), 1.57-1.50 (m, 1H); C
NMR (75 MHz, CDCl3)  142.4, 141.3, 128.8, 127.9, 89.5, 69.8, 45.2, 35.7, 33.7, 27.9,
26.9, 26.98, 23.6, 22.8, 21.8; ESI HRMS m/z (M+Na)+ calcd 422.0899, obsd 422.0882.
S
S
OMe
O
NHTs
8d
IR (neat, cm-1) 3283, 1193, 1159, 1058; 1H NMR (300 MHz, CDCl3)  7.73 (d, J = 8.1
Hz, 2H), 7.30 (d, J = 8.1 Hz, 2H), 4.54 (t, J = 6.3 Hz, 1H), 3.94-3.90 (m, 2H), 3.50 (s,
3H), 3.03-2.87 (m, 4H), 2.83-2.70 (m, 2H), 2.42 (s, 3H), 2.03-1.46 (m, 10 H); 13C NMR
(75 MHz, CDCl3)  143.5, 137.3, 129.7, 127.4, 102.6, 92.8, 71.2, 53.6, 41.1, 33.7, 33.0,
27.6, 27.2, 27.1, 24.6, 24.0, 21.8; ESI HRMS m/z (M+Na)+ calcd 454.1151, obsd
454.1173.
MeO
O
N
Ts
10a
IR (neat, cm-1) 1102, 670, 587, 545; 1H NMR (300 MHz, CDCl3)  7.73 (d, J = 8.1 Hz,
2H), 7.27 (d, J = 8.1 Hz, 2H), 4.82 (s, 1H), 3.96-3.90 (m, 1H), 3.50 (td, J = 11.4, 3.6 Hz,
1H), 3.41-3.30 (m, 5H), 2.48-2.43 (m, 1H), 2.41 (s, 3H), 1.95-1.87 (m, 1H), 1.71-1.53
(m, 5H); 13C NMR (75 MHz, CDCl3)  143.0, 139.0, 129.7, 127.3, 105.2, 69.7, 66.4,
56.7, 50.4, 34.7, 32.3, 25.2, 23.3, 21.7; ESI HRMS m/z (M+Na)+ calcd 348.1240, obsd
348.1251.
S2

MeO
OMe
N
Ts
OH
10b
IR (neat, cm-1) 3495, 1328, 669, 592; 1H NMR (300 MHz, CDCl3)  7.72 (d, J = 8.4 Hz,
2H), 7.27 (d, J = 8.4 Hz, 2H), 4.66 (s, 1H), 3.61-3.56 (m, 2H), 3.52 (s, 3H), 3.41-3.28 (m,
13
5H), 2.40 (s, 3H), 2.35-2.28 (m, 1H), 2.12-2.03 (m, 1H), 1.81-1.41 (m, 6H); C NMR
(75 MHz, CDCl3)  143.0, 138.9, 129.6, 127.2, 110.5, 73.9, 63.3, 59.3, 57.5, 50.9, 32.2,
31.7, 27.4, 23.7, 21.7; ESI HRMS m/z (M+Na)+ calcd 380.1502, obsd 380.1498.
MeO
OMe
O
NHTs
10d
IR (neat, cm-1) 3276, 1080, 815, 662, 550; 1H NMR (300 MHz, CDCl3)  7.72 (d, J = 8.4
Hz, 7.29 (d, J = 8.4 Hz, 2H), 4.90 (t, J = 6.0 Hz, 1H), 4.00 (s, 1H), 3.80-3.75 (m, 2H),
3.48 (s, 3H), 3.41 (s, 3H), 2.95-2.87 (m, 2H), 2.41 (s, 3H), 2.06-1.73 (m, 3H), 1.56-1.45
(m, 5H); 13C NMR (75 MHz, CDCl3)  143.4, 137.3, 129.8, 127.3, 110.0, 86.6, 69.2,
58.6, 57.1, 44.0, 33.4, 30.9, 26.9, 23.8, 21.7; ESI HRMS m/z (M+Na)+ calcd 380.1502,
obsd 380.1494.
MeS
O
N
Ts
12a
Two isomers were obtained. Isomer 1: IR (neat, cm-1) 1329, 1005, 662, 591, 574; 1H
NMR (300 MHz, CDCl3)  7.79 (d, J = 8.1 Hz, 2H), 7.27 (d, J = 8.1 Hz, 2H), 5.18 (s,
1H), 4.03-3.98 (m, 1H), 3.53 (td, J = 11.1, 3.0 Hz, 1H), 3.37-3.27 (m, 2H), 2.65-2.58 (m,
13
1H), 2.43-2.35 (m, 4H), 2.24 (s, 3H), 1.96-1.62 (m, 6H); C NMR (75 MHz, CDCl3) 
143.2, 138.5, 129.6, 127.5, 92.4, 69.7, 69.3, 49.9, 35.4, 33.9, 25.3, 23.5, 21.7, 14.6; ESI
HRMS m/z (M+Na)+ calcd 364.1012, obsd 364.1033. Isomer 2: IR (neat, cm-1) 1338,
1068, 660, 592, 546; 1H NMR (300 MHz, CDCl3)  7.79 (d, J = 8.1 Hz, 2H), 7.26 (d, J =
8.1 Hz, 2H), 4.79 (s, 1H), 4.15 (td, J = 11.7, 3.9 Hz, 1H), 3.54-3.48 (m, 1H), 3.38-3.28
(m, 2H), 3.18 (td, J = 12.9, 5.4 Hz, 1H), 2.68 (ddd, J = 12.6, 6.0, 2.1 Hz), 2.40 (s, 3H),
2.04 (s, 3H), 1.90-1.57 (m, 5H), 1.48 (td, J = 12.0, 8.1 Hz, 1H); 13C NMR (75 MHz,
CDCl3)  143.2, 138.3, 129.6, 128.0, 88.8, 70.2, 58.5, 50.2, 38.2, 29.0, 24.6, 21.7, 21.5,
13.7; ESI HRMS m/z (M+Na)+ calcd 364.1012, obsd 364.1022.
S3

MeS
OMe
N
Ts
OH
12b
1
IR (neat, cm-1) 3512, 1322, 667, 590; H NMR (300 MHz, CDCl3, 1:4 mixture of
isomers)  7.90 (d, J = 8.1 Hz, 0.4H), 7.74 (d, J = 8.1 Hz, 1.6H), 7.27 (d, J = 8.1 Hz, 2H),
4.98 (s, 0.2 H), 4.69 (s, 0.8H), 3.64-3.63 (m, 1.6H), 3.49-3.43 (m, 2.2H), 3.43-3.27 (m,
0.8H), 3.17 (s, 2.4H), 2.40 (s, 3H), 2.33 (s, 0.6H), 2.21-2.12 (m, 5H), 1.88-1.54 (m, 6H);
13C NMR (75 MHz, CDCl3)  142.9, 138.9, 129.6, 127.2, 97.6, 76.0, 63.2, 56.0, 51.2,
33.7, 33.4, 27.7, 23.8, 21.7, 16.9; ESI HRMS m/z (M+Na)+ calcd 396.1274, obsd
396.1266.
MeS
NTs
O
12c
IR (neat, cm-1) 1336, 1161, 1091, 655, 574; 1H NMR (300 MHz, CDCl3)  7.71 (d, J =
8.4 Hz, 2H), 7.28 (d, J = 8.4 Hz, 2H), 5.00 (s, 1H), 3.89 (t, J = 6.6 Hz, 2H), 3.56-3.50 (m,
1H), 3.01 (td, J = 12.6, 3.3 Hz, 1H), 2.42 (s, 3H), 2.14-1.91 (m, 7H), 1.74-1.62 (m, 2H),
13
1.51-1.45 (m, 2H); C NMR (75 MHz, CDCl3)  143.8, 137.4, 129.8, 127.7, 84.0, 71.2,
68.1, 40.6, 35.1, 31.5, 25.9, 23.8, 21.8, 16.0; ESI HRMS m/z (M+Na)+ calcd 364.1012,
obsd 364.1026.
MeS
OMe
O
NHTs
12d
IR (neat, cm-1) 3267, 1326, 1093, 662, 550; 1H NMR (300 MHz, CDCl3)  7.74 (d, J =
8.1 Hz, 2H), 7.29 (d, J = 8.1 Hz, 2H), 5.07-5.02 (m, 1H), 4.14 (s, 1H), 3.89-3.79 (m, 2H),
3.45, 3.44 (2s, 3H), 2.95-2.90 (m, 2H), 2.42 (s, 3H), 2.17, 2.12 (2s, 3H), 2.07-1.49 (m,
8H); 13C NMR (75 MHz, CDCl3)  143.4, 137.3, 129.9, 127.3, 96.5, 95.2, 88.2, 87.9,
69.5, 69.3, 58.0, 57.6, 43.9 (d), 34.5, 34.4, 33.2, 32.4, 26.9 (d), 24.1, 21.7, 15.7, 14.5; ESI
HRMS m/z (M+Na)+ calcd 396.1274, obsd 396.1269.
Synthesis of the Substrates:
S4

S
S
O
a
b
O
HO
S
OTBS
HO
OTBS
O
c
S-1
S-2
S
HO
NHTs
7
Reaction conditions: a. ICH2CH2CH2OTBS, t-BuLi, Et2O, -78 °C, 48%; b. 2-
trimethylsilyl-1,3-dithane, n-BuLi, 52%; c. 11 . TsNHBoc, Ph3P, DEAD, THF, rt, 2.
LiMe, -20 °C, Et2O, 3. TBAF, THF, rt, 81%.
Synthesis of S-1: To a solution of tert-butyl(3-iodopropoxy)dimethylsilane (6.0 g, 20
mmol) was added t-BuLi solution (1.7 M in pentane, 23.5 mL, 40 mmol) at -78 °C under
argon atmosphere. The resulting mixture was stirred at -78 °C for 0.5 h and then rt for 1
h. In another flask, a solution of butyrolactone (1.7 g, 20 mmol) in Et2O was cooled to -
78 °C and treated with the above lithium reagent. Water was added after 15 min and the
cold bath was removed. Ether layer was separated and the aqueous phase extracted with
ether. The combined organic solution was dried over MgSO4, filtered, and concentrated.
The residue was chromatographed through silica gel (eluted with acetone/hexane, 1:4) to
give S-1 (2.5 g, 48%) and. IR (neat, cm-1) 3411, 1713, 1255, 1100, 836; 1H NMR (300
MHz, CDCl3)  3.63-3.56 (m, 4H), 2.57-2.47 (m, 4H), 1.83-1.74 (m, 4H), 0.86 (s, 9H),
0.03 (s, 6H); 13C NMR (75 MHz, CDCl3)  211.8, 62.4, 62.3, 39.8, 39.4, 27.0, 26.7, 26.1,
18.5, -5.2; ESI HRMS m/z (M+Na)+ calcd 283.1700, obsd 283.1689.
Synthesis of S-2: n-BuLi (1.6 M in hexanes, 13.2 mL, 21.2 mmol) was added drop-wise
to a solution of 2-trimethylsilyl-1,3-dithiane (3.93 mL, 21.2 mmol) in THF (40 mL). The
resulting mixture was stirred at -78 °C for 0.5 h and then 0 °C for an additional 0.5 h. The
reaction was then cooled to -78 °C and treated with S-1 (1.84 g, 7.07 mmol). Upon
complete addition, the reaction was allowed to warm to rt slowly and stirred overnight.
The reaction mixture was poured into water (50 mL) and extracted with ether. The
combined extractions were dried over MgSO4 and evaporated. Chromatography through
silica gel afforded S-1 (0.50 g, 27%) and S-2 (1.34g, 52%). IR (neat, cm-1) 3868, 1254,
1102, 835, 775; 1H NMR (300 MHz, CDCl3)  3.59-3.55 (m, 4H), 2.85-2.79 (m, 4H),
13
2.40-2.29 (m, 4H), 2.14-2.04 (m, 3H), 1.65-1.54 (m, 4H), 0.85 (s, 9H), 0.02 (s, 6H); C
NMR (75 MHz, CDCl3)  144.3, 120.9, 63.1, 62.1, 31.7, 30.9, 30.6, 30.5, 30.4, 29.9,
26.2, 25.2, 18.5; ESI HRMS m/z (M+Na)+ calcd 385.1662, obsd 385.1651.
1 Henry, J. R.; Marcin, L. R.; McIntosh, M. C.; Scola, P. M.; Harris, G. D.; Weinreb, S. M. Tetrahedron
Lett. 1989, 30, 5709–5712.
S5

Synthesis of 7: Diethyl azodicarboxylate solution (40 wt% soluion in toluene, 3.40 mL,
7.50 mmol) was added drop-wise to a solution of S-2 (1.06 g, 2.92 mmol), N-(tert-
butoxycarbonyl)-p-toluenesulfonamide (1.22 g, 4.50 mmol) and triphenylphosphine (2.36
g, 9.00 mmol) in THF (40 mL) at rt. After stirred overnight, the solvent was removed and
the residue filtered through a pad of silica gel to give a mixture of the desired product and
Ph3P. The mixture was then dissolved in Et2O (24 mL) and treated with LiMe (9.10 mL,
14.5 mmol) at -20 °C. Water was added slowly after 15 min and the cold bath was then
removed. The organic layer was separated and aqueous phase extracted with ether. The
combined organic solution was dried with MgSO4, filtered and concentrated. The residue
was dissolved in THF (15 mL) and treated with TBAF (4.80 mL, 4.80 mmol) at rt. The
reaction was kept at rt for 2 h and then poured into water (40 mL). Ether was added and
organic layer separated. The water layer was extracted with ether. The organic solutions
were combined, dried with MgSO4 and concentrated under reduced pressure. The residue
was chromatographed (silica gel, ether) to give 7 (0.95 g, 81%). IR (neat, cm-1) 3499,
3278, 1323, 814, 662, 550; 1H NMR (300 MHz, CDCl3)  7.74 (d, J = 8.4 Hz, 2H), 7.30
(d, J = 8.4 Hz, 2H), 4.81 (t, J = 6.0 Hz, 1H), 3.61-3.55 (m, 2H), 2.97-2.91 (m, 2H), 2.86-
2.81 (m, 4H), 2.42 (s, 3H), 2.34-2.26 (m, 4H), 2.14-2.06 (m, 2H), 1.79 (t, J = 5.7 Hz,
1H), 1.66-1.50 (m, 4H); 13C NMR (75 MHz, CDCl3)  143.6, 142.8, 137.3, 130.0, 127.4,
122.0, 62.2, 43.0, 31.0, 30.6, 30.5, 29.8, 28.0, 25.0, 21.8; ESI HRMS m/z (M+Na)+calcd
424.1045, obsd 424.1043.
MeO
MeO
O
b
a
HO
OTBS
HO
OTBS
TsHN
OH
S-1
S-3
9
Reaction conditions: a. Ph3PCH2OMeCl, NaHMDS, THF, 59%; b. 1. TsNHBoc, Ph3P,
DEAD, THF, rt, 2. LiMe, -20 °C, Et2O, 3. TBAF, THF, rt, 70%.
Synthesis of S-3: To a suspension of methoxymethyltriphenylphosphonium chloride
(27.4 g, 80.0 mmol) in THF (160 mL) was added NaHMDS solution (1.0 M in THF, 80.0
mL, 80.0 mmol) at 0 °C. The resulting reaction mixture was stirred at 0 °C for 0.5 h and
then treated with S-1 (5.2 g, 20.0 mmol). The reaction was stirred overnight and warmed
to rt. Water was added, followed by ether. The organic layer was separated and aqueous
layer extracted twice with ether. The combined organic layers were dried with MgSO4
and concentrated in vacuo. Chromatography through silica gel gave S-3 as a 2:3 mixture
of isomers (3.40 g, 59%). IR (neat, cm-1) 3363, 1255, 1100, 836; 1H NMR (300 MHz,
CDCl3)  5.78 (s, 0.4H), 5.73 (s, 0.6H), 3.56-3.52 (m, 4H), 3.49 (s, 1.2H), 3.46 (s, 1.8H),
2.10 (t, J = 7.2 Hz, 1.2H), 2.02, (t, J = 7.8 Hz, 1.8H), 1.92-1.83 (m, 2H), 1.59-1.50 (m,
4H), 0.84 (s, 9H), -0.01 (s, 6H); 13C NMR (75 MHz, CDCl3)  142.8, 142.6, 117.4, 116.9,
63.4, 62.8, 62.5, 61.5, 59.5, 59.3, 31.4, 31.3, 31.2, 29.9, 28.0, 27.7, 26.1, 23.3, 22.6, 18.5,
-5.1; ESI HRMS m/z (M+Na)+ calcd 311.2013, obsd 311.2006.
Synthesis of 9: Compound 9 was synthesized from S-3 by following the same procedure
described for the synthesis of 7. IR (neat, cm-1) 3499, 3280, 1323, 1128, 662, 550; 1H
NMR (300 MHz, CDCl3)  7.70, 7.68 (2d, J = 8.1, 8.4 Hz, 2H), 7.25 (d, J = 7.8 Hz, 2H),
5.72 (s, 1H), 5.44-5.36 (m, 1H), 3.54-3.43 (m, 5H), 2.82 (q, J = 8.1 Hz, 2H), 2.68 (t, J =
S6

6.3 Hz, 0.6H), 2.37 (s, 3.4H), 2.03-1.96 (m, 2H), 1.79 (t, 7.5 Hz, 2H), 1.55-1.41 (m, 4H);
13C NMR (75 MHz, CDCl3)  143.5, 143.4, 143.2, 137.5, 137.2, 129.9, 129.8, 127.3,
127.2, 116.1, 115.8, 62.4, 61.6, 59.6, 42.8, 42.4, 31.1, 29.9, 28.4, 28.0, 27.5, 26.9, 23.4,
22.4, 21.9; ESI HRMS m/z (M+Na)+ calcd 350.1397, obsd 350.1406.
MeS
MeS
O
b
a
HO
OTBS
HO
OTBS
TsHN
OH
S-1
11
S-4
Reaction conditions: a. Ph3PCH2SMeCl, n-BuLi, THF, 34%; b. 1. TsNHBoc, Ph3P,
DEAD, THF, rt, 2. LiMe, -20 °C, Et2O, 3. TBAF, THF, rt, 75%.
Synthesis of S-4: To a suspension of (methylthiomethyl)triphenylphosphonium chloride
(21.5 g, 60.0 mmol) in THF (150 mL) was added drop-wise n-BuLi solution (1.6 M in
hexanes, 37.5 mL, 60.0 mmol) at 0 °C under argon atmosphere. After complete addition,
solution was stirred at 0 °C for 0.5 h and then treated with S-1 (5.2 g, 20 mmol). The
reaction was stirred at rt for 4 days. Brine and ether was added at 0 °C. The organic phase
was separated and aqueous lay extracted with ether. The organic solutions were
combined, dried over MgSO4, and concentrated. Chromatography on silica gel afforded
S-1 (1.00 g, 19%) and S-4 (2.10 g, 34%). IR (neat, cm-1) 3350, 1255, 1102, 836; 1H NMR
(300 MHz, CDCl3)  5.58 (s, 1H), 3.56 (t, J = 6.6 Hz, 4H), 2.25 (br, 1H), 2.18 (s, 3H),
2.15-2.06 (m, 4H), 1.67-1.54 (m, 4H), 0.85 (s, 9H), 0.01 (s, 6H); 13C NMR (75 MHz,
CDCl3)  139.6, 121.2, 63.3, 62.5, 33.0, 31.0, 30.9, 8.6, 26.1, 18.5, 17.4, -5.0; ESI HRMS
m/z (M+Na)+ calcd 327.1784, obsd 327.1790.
Synthesis of 11: Compound 11 was synthesized from S-4 by following the same
procedure described for the synthesis of 7. IR (neat, cm-1) 3494, 3280, 1321, 1157, 661,
550; 1H NMR (300 MHz, CDCl3)  7.71 (d, J = 8.1 Hz, 2H), 7.26 (d, J = 8.1 Hz, 2H),
5.54 (s, 1H), 5.40 (t, J = 6.0 Hz, 1H), 3.56-3.50 (q, J = 5.7 Hz, 2H), 2.89-2.82 (q, J = 6.6
Hz, 2H), 2.38-2.34 (m, 4H), 2.17 (s, 3H), 2.09 (t, J = 6.9 Hz, 2H), 2.00 (t, J = 8.1 Hz,
2H), 1.61-1.50 (m, 4H); 13C NMR (75 MHz, CDCl3)  143.6, 138.3, 137.2, 129.9, 127.3,
122.1, 62.2, 42.9, 33.3, 30.3, 28.0, 21.7, 17.4; ESI HRMS m/z (M+Na)+ calcd 366.1168,
obsd 366.1162.
S7

S8

S9

S10

S11

S12

S13

S14

S15

S16

S17

S18

S19

S20

S21

S22

S23

S24

S25

S26

S27

S28

S29

S30