Direct synthesis of sensitive selenocysteine peptides by the Ugi reaction

Article abstract of DOI:10.1039/c2ob26552d

Ammonia and selenoaldehydes are both problematic components in Ugi reactions. Here we report the efficient direct multicomponent synthesis of sensitive selenocysteine peptides without the use of convertible (protected) primary amines, including suitable deprotection protocols for selenols.

Full text of DOI:10.1039/c2ob26552d

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
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Direct synthesis of sensitive selenocysteine peptides by the Ugi reaction
Muhammad Abbas and Ludger A. Wessjohann*
wessjohann@ipb-halle.de
General: Chemicals and solvents were purchased from commercial suppliers and used
without further purification. Column chromatography was performed on silica 60 (230–400
mesh, 0.040–0.063 mm) from Merck. Thin layer chromatography (TLC) was performed on
Merck silica gel 60 F254 plates (250 µm layer thickness; aluminium sheets; particle size:
0.040–0.063 mm). Compounds were visualized by UV (λ = 254 nm), or by dipping the plates
into a CerMOP-TLC reagent followed by heating. CerMOP-TLC reagent was prepared by
dissolving 12.5 g molybdatophosphoric acid, 5.0 g Ce(SO4)2·H2O and 30 mL of concentrated
1
sulfuric acid in 470 mL of water. H and 13C NMR spectra were recorded on a Varian
Mercury 300 spectrometer at 300 and 75.5 MHz, respectively. The chemical shifts (δ) are
1
given in ppm downfield from TMS (δ = 0 ppm, H) and CDCl3 (δ = 77.0 ppm, 13C),
respectively. Coupling constants J values are given in Hz. For multiplets the following
abbreviations were used: s (singlet), d (doublet), t (triplet), q (quadruplet), m (multiplet or
unresolved signal), br (broad). The high resolution ESI mass spectra were obtained from a
Bruker Apex III Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer
(Bruker Daltonics, Billerica, USA) equipped with an InfinityTM cell, a 7.0 Tesla
superconducting magnet (Bruker, Karlsruhe, Germany), an RF-only hexapole ion guide and
an APOLLO electrospray ion source (Agilent, off axis spray). Nitrogen was used as drying
gas at 150°C. The sample solutions were introduced continuously via a syringe pump with a
flow rate of 120 µL h–1.
Experimental Section:
Diselenide 1a, 1b and the isonitrile 5a were synthesized as reported in the literature.1
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Table S1. Selenopeptides directly synthesized by Ugi-4CR with
ammonium carbonate as ammonia source in trifluorethanol
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General procedure for selenoaldehyde synthesis, 3a–3e: A diselenide 1a or 1b (15 mmol) was
dissolved in 100 ml ethanol at 0°C. To the solution NaBH4 (40 mmol) was slowly added in portions
(30 min) until the solution turns clear or slightly yellow. The reaction mixture was warmed to 25°C for
30 min and than cooled to 0°C. Then alkylhalide (28 mmol) was added and reaction mixture was
stirred at room temperature for 2 h. Afterwards, the solution was filtered, the solvent was evaporated,
intermediate (2a–2e) was dissolved in water and extracted with diethylether. The organic layer was
dried over Na2SO4 and than the solvent was evaporated. The residue is chromatographed on silica gel
(petrol ether : ethyl acetate = 10 : 1). To the obtained acetal 1M HCOOH (40 mL) was added and
heated to 40–50°C for 4 h. After cooling to room temperature product was extracted with ether and
concentrated at 40°C and 5 mbar for 2 h yielding a yellow oil (3a–3e) which was directly used for the
further reactions without purification.
General procedure for Ugi-4CR, 6–15: To TFE (4–5 mL) at 0°C (ice-water cooling bath)
selenenylaldehyde (1.5 mmol) and (NH4)2CO3 (1.2 mmol) are added and stirred for 10 min.
Then, amino acid (1 mmol) and isonitrile (1.5 mmol) are added and the reaction mixture is
stirred for 1 h and then at room temperature for 8 h. The solvent is removed in vacuum and
the gummy product is purified by column chromatography on silica.
1
6: Eluent dichloromethane : methanol : triethylamine (20 : 1 : 0.1). Rf = 0.35. H NMR
(CDCl3, 300 MHz): 7.38–7.31 (m, 5H), 7.22–7.17 (m, 1H), 6.97 (br s, 1H), 5.51–5.47 (m,
1H), 5.10 (s, 2H), 4.67–4.60 (m, 1H), 3.81–3.79 (m, 2H), 3.31–3.02 (m, 3H), 2.84–2.77 (m,
1H), 2.39–2.77 (m, 1H), 2.39–2.34 (m, 2H), 2.01 (s, 3H), 1.70–1.30 (m, 15H) ppm. 13C NMR
(CDCl3, 75.5 MHz): 173.2 (s), 169.7 (s), 156.2 (s), 135.7 (s), 128.4 (d, 2C), 128.0 (d), 127.9
(d, 2C), 80.5 (s), 66.1 (t), 52.4 (d), 44.5 (t), 39.5 (t) 34.1 (t), 28.9 (t), 28.3 (q, 3C), 27.1 (t),
26.3 (t), 24.4 (t), 5.2 (q) ppm. HRMS (ESI): Exact mass calculated for C24H37N3O6SeNa+:
566.1740. Found: 566.1736.
7: Eluent dichloromethane : methanol (20 : 1). Rf = 0.40. 1H NMR (CDCl3, 300 MHz): 8.07–
8.03 (m, 1H), 7.60–7.48 (m, 2H), 7.44–7.37 (m, 1H), 7.22–7.17 (m, 1H), 6.75–6.68 (m, 1H),
5.50–5.43 (m, 1H), 4.68–4.58 (m, 1H), 4.22–4.02 (m, 2H), 3.84–3.65 (m, 2H), 3.13–3.04 (m,
1H), 2.78–2.70 (m, 1H), 1.93–1.54 (m, 5H), 1.46 (s, 9H), 1.41– 1.10 (m, 6H) ppm. 13C NMR
(CDCl3, 75.5 MHz): 169.1 (s), 168.6 (s), 156.1 (s), 147.4 (s), 135.5 (s), 133.4 (d), 132.0 (d),
128.0 (d), 125.6 (d), 80.4 (s), 52.5 (d), 48.8 (d), 44.5 (t), 32.7 (t, 2C) 28.3 (q, 3C), 26.1 (t),
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25.4 (t), 24.8 (t, 3C) ppm. HRMS (ESI): Exact mass calculated for C23H34N4O6SeNa+:
565.1536. Found: 565.1533.
1
8: Eluent petrol ether : ethyl acetate (7 : 3). Rf = 0.15. H NMR (CD3OD, 300 MHz): 8.03–
7.99 (m, 1H), 7.62–7.41 (m, 3H), 7.28–7.17 (m, 5H), 4.53–4.47 (m, 1H), 4.31–4.26 (m, 1H),
4.12 (br s, 2H), 3.62–3.56 (m, 1H), 3.32–3.29 (m, 1H), 3.13–2.98 (m, 1H), 2.89–2.74 (m, 2H),
1.87–1.57 (m, 5H), 1.43–1.12 (m, 14H) ppm. 13C NMR (CD3OD, 75.5 MHz): 173.8 (s), 170.8
(s), 157.3 (s), 149.1 (s), 138.3 (s), 137.0 (s), 134.4 (d), 133.1 (d), 130.2 (d), 129.4 (d), 129.3
(d, 2C), 129.1 (d), 127.6 (d), 126.5 (d) 80.8 (s), 57.6 (d), 54.6 (d), 50.1 (d), 38.9 (t), 33.6 (t,
2C), 28.7 (q, 3C), 26.6 (t), 26.3 (t), 26.1 (t, 2C), 25.2 (t) ppm. HRMS (ESI): Exact mass
calculated for C30H40N4O6SeNa+: 655.2005. Found: 655.1993.
1
9: Eluent dichloromethane : methanol (20 : 1). Rf = 0.35. H NMR (CDCl3, 300 MHz): 7.95
(d, J = 10 Hz, 1H), 7.50–7.40 (m, 1H), 7.38–7.27 (m, 2H), 5.30 (s, 1H), 5.15 (br s, 1H), 4.51
(q, 2H), 4.41–4.14 (m, 4H), 3.85–3.83 (‘d’, 2H), 3.75 (s, 1H), 2.92 (s, 2H), 2.13 (s, 1H), 1.93–
1.65 (m, 5H), 1.44 (s, 9H), 1.28– 1.21 (m, 6H) ppm. 13C NMR (CDCl3, 75.5 MHz): 173.1 (s),
172.1 (s), 171.0 (s), 170.9 (s), 158.3 (s), 148.9 (d), 136.7 (s), 134.3 (d), 133.0 (d), 129.0 (d),
126.4 (d), 80.8 (s), 54.8 (d), 50.0 (d), 44.8 (t), 43.8 (t), 43.5 (t), 33.5 (t), 33.4 (t) 28.7 (q, 3C),
26.5 (t), 26.3 (t), 24.0 (t, 2C), 25.2 (t) ppm. HRMS (ESI): Exact mass calculated for
C27H40N6O8SeNa+: 679.1965. Found: 679.1950.
1
10: Eluent petrol ether : ethyl acetate (7 : 3). Rf = 0.35. H NMR (CDCl3, 300 MHz): 8.06–
7.98 (m, 1H), 7.55–7.26 (m, 9H), 6.80–6.46 (m, 1H), 5.93–5.68 (m, 1H), 4.70–4.58 (m, 1H),
4.21–3.94 (m, 2H), 3.76–3.57 (m, 1H), 2.84–2.59 (m, 1H), 1.88–1.55 (m, 5H), 1.43 (s, 9H),
13
1.35–0.99 (m, 6H) ppm. C NMR (CDCl3, 75.5 MHz): 169.8 (s), 168.5 (s), 155.2 (s), 147.3
(s), 135.4 (s), 133.4 (s), 133.4 (d), 132.0 (d), 128.9 (d, 2C), 128.7 (d), 127.9 (d), 127.0 (d),
126.9 (d), 125.5 (d) 80.4 (s), 59.3 (d), 52.6 (d), 48.6 (d), 32.7 (t), 32.6 (t) 32.5 (t), 28.3 (q, 3C),
25.9 (t), 25.4 (t), 24.7 (t, 2C), 24.6 (t) ppm. HRMS (ESI): Exact mass calculated for
C29H38N4O6SeNa+: 641.1849. Found: 641.1843.
11: Eluent dichloromethane : methanol (5 : 0.1). Rf = 0.10. 1H NMR (pyridine–d5, 300 MHz):
9.18–9.14 (m, 1H), 8.63–8.52 (m, 1H), 8.15–8.10 (m, 1H), 5.95–5.80 (m, 1H), 5.33–4.90 (m,
4H), 4.28–3.93 (m, 3H), 3.28–3.05 (m, 4H), 2.10–1.89 (m, 2H), 1.69–1.10 (m, 16H) ppm. 13C
NMR (pyridine–d5, 75.5 MHz): 170.1 (s), 170.0 (s), 157.0 (s), 135.2 (t), 116.6 (d), 78.9 (s),
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53.9 (d), 49.0 (d), 33.4 (t), 33.2 (t), 28.6 (q, 3C), 25.9 (t), 25.7 (t), 25.5 (t, 2C) ppm. HRMS
(ESI): Exact mass calculated for C19H33N3O4SeNa+: 470.1528. Found: 470.1525.
1
12: Eluent petrol ether : ethyl acetate (6 : 4). Rf = 0.55. H NMR (CDCl3, 300 MHz): 7.27–
7.19 (m, 3H), 6.84–6.79 (m, 2H), 6.50 (br s, 1H), 5.60 (br s, 1H), 4.60–4.48 (m, 1H), 3.80–
13
3.71 (br s 6H), 2.98–2.65 (m, 3H), 1.43 (s, 9H) 1.32 (s, 9H) ppm. C NMR (CDCl3, 75.5
MHz): 169.1 (s), 169.0 (s, 2C), 158.1 (s), 130.8 (s), 129.8 (d, 2C), 113.7 (d, 2C), 79.9 (s), 55.1
(d), 53.0 (d), 51.5 (s), 44.2 (t), 28.5 (q, 3C), 28.2 (q, 3C), 25.7 (t) ppm. HRMS (ESI): Exact
mass calculated for C22H35N3O5SeNa+: 524.1634. Found: 524.1631.
13: Eluent dichloromethane : methanol (20 : 1). Rf = 0.30. 1H NMR (CDCl3, 300 MHz): 7.75–
7.22 (m, 14H), 7.16–7.11 (m, 1H), 6.49–6.29 (m, 1H), 5.10–5.06 (m, 2H), 4.73–4.62 (m, 1H),
4.45–4.31 (m, 3H), 4.20–4.13 (m, 1H), 4.05–3.94 (m, 1H), 3.84–3.67 (m, 1H), 3.29–3.05 (m,
2H), 3.02–2.81 (m, 2H), 2.38–2.25 (m, 2H), 2.08–1.96 (m, 1H), 1.93 (s, 3H), 1.69–1.20 (m,
13
6H) ppm. C NMR (CDCl3, 75.5 MHz): 173.3 (s), 170.7 (s), 170.1 (s), 156.3 (s), 143.4 (s),
140 9 (s, 3C), 135.6 (s), 128.3 (d, 3C), 128.0 (d), 127.9 (d, 2C), 127.5 (d, 2C), 126.8 (d, 2C),
124.8 (d), 119.7 (d, 2C), 67.3 (t), 66.1 (t), 62.8 (t), 56.3 (d), 52.2 (d), 46.9 (d), 39.5 (t) 33.9 (t),
28.7 (t), 26.9 (t), 22.2 (t), 24.3 (t), 5.1 (q) ppm. HRMS (ESI): Exact mass calculated for
C35H41N3O7SeNa+: 718.2002. Found: 718.2000.
14: Eluent petrol ether : ethyl acetate (7 : 3). Rf = 0.50. 1H NMR (CD3OD, 300 MHz): 7.31–
7.17 (m, 5H), 4.55–4.47 (m, 1H), 4.36–4.25 (m, 1H), 3.69–3.56 (m, 1H), 3.18–3.03 (m, 1H),
13
2.93–2.70 (m, 3H), 2.11–1.57 (m, 8H), 1.45–1.14 (m, 14H) ppm. C NMR (CD3OD, 75.5
MHz): 173.6 (s), 171.0 (s), 157.4 (s), 138.2 (s), 130.2 (d, 2C), 129.3 (d, 2C), 127.6 (d), 80.6
(s), 57.8 (d), 54.3 (d), 50.0 (d), 38.9 (t), 33.6 (t, 2C), 28.8 (q, 3C), 27.4 (t), 26.6 (t), 26.0 (t,
2C), 4.8 (q) ppm. MS (ESI) calcd for C24H37N3O4Se: 511.19; found [M+H]+: 512.5. HRMS
(ESI): Exact mass calculated for C24H37N3O4SeNa+: 534.1841. Found: 534.1834.
15: Eluent petrol ether : ethyl acetate (6 : 4). Rf = 0.25. 1H NMR (CD3OD, 300 MHz): 7.52–
7.14 (m, 5H), 4.60–4.52 (m, 1H), 3.81 (s, 2H), 3.71–3.55 (m, 3H), 2.89–2.70 (m, 1H), 1.89–
1.54 (m, 5H), 1.44 (s, 9H), 1.37–1.09 (m, 5H) ppm. 13C NMR (CD3OD, 75.5 MHz): 171.9 (s),
171.2 (s), 158.2 (s), 140.3 (s), 129.8 (d, 2C), 129.3 (d, 2C), 121.6 (d), 80.7 (s), 54.3 (d), 50.1
(d), 44.8 (t), 33.7 (t), 33.6 (t), 28.8 (q, 3C), 26.2 (t), 26.6 (t), 26.1 (t, 2C), 26.0 (t) ppm. MS
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(ESI) calcd. for C23H35N3O4Se: 497.18; found [M+H]+: 498.6. HRMS (ESI): Exact mass
calculated for C23H35N3O4SeNa+: 520.1685. Found: 520.1679.
1
16: Precipitated with dichloromethane and then filtered to give light yellow solid. H NMR
(pyridine–d5, 300 MHz): 10.5 (d, 1H), 9.37 (d, 2H), 8.95–8.71 (m, 2H), 8.63 (d, 2H), 8.02 (‘t’,
2H), 7.45–7.12 (m, 2H), 4.72–4.51 (m, 1H), 4.62 (d, 4H), 3.97–3.18 (m, 8H), 1.98 (s, 1H)
1.98–1.78 (m, 5H), 1.48 (s, 9H), 1.62–1.21 (m, 6H), 1.20–0.89 (m, 4H) ppm. 13C NMR
(pyridine–d5, 75.5 MHz): 171.0 (s), 169.8 (s), 156.9 (s), 78.9 (s), 54.6 (d), 49.0 (d), 44.6 (d),
32.9 (t), 32.7 (t), 28.4 (q), 25.6 (t, 3C), 25.2 (t, 3C) ppm. MS (ESI) calcd. for C32H56N6O8Se2:
812.25; found [M+Na]+: 833.6. HRMS (ESI): Exact mass calculated for C32H56N6O8Se2Na+:
835.2382. Found: 835.2364.
1
24: Eluent dichloromethane : methanol (5 : 0.1). Rf = 0.30. H NMR (CDCl3, 300 MHz):
5.16–5.15 (m, 1H), 5.05–5.00 (m, 1H), 4.89–4.82 (m, 1H), 4.58 (br s, 1H), 3.89–3.69 (m, 2H),
13
3.61–3.00 (m, 6H), 1.96–1.80 (m, 16H), 1.76–1.54 (m, 8H), 1.47–1.33 (m, 32H) ppm. C
NMR (CDCl3, 75.5 MHz): 171.0 (s), 168.9 (s, 2C), 155.2 (s), 152.1 (s), 138.1 (s), 98.4 (s,
2C), 80.8 (s), 80.2 (s), 74.2 (s), 73.8 (s), 68.9 (d), 66.6 (d), 54.7 (d), 54.1 (d) 49..4 (d), 48.8
(d), 32.8 (t), 32.6 (t, 2C), 32.5 (t, 2C), 32.3 (t), 29.2 (q), 28.8 (q), 28.3 (q, 3C), 28.2 (q, 3C),
28.0 (q), 27.4 (q), 25.4 (t, 3C), 24.8 (t, 3C), 24.6 (t) ppm. MS (ESI) calcd. for
C40H68N6O8S2Se2: 984.29; found [M+H]+: 985.3. HRMS (ESI): Exact mass calculated for
+
C40H69N6O8S2Se2 : 985.2943. Found: 985.2909.
1
26: Eluent dichloromethane : methanol (5 : 0.1). Rf = 0.40. H NMR (CDCl3, 300 MHz):
6.64–6.61 (m, 1H), 4.89–4.86 (m, 1H), 4.49–4.43 (m, 1H), 3.82–3.66 (m, 2H), 3.53–3.43 (m,
2H), 3.17–3.10 (m, 1H), 1.94–1.81 (m, 8H), 1.78–1.12 (m, 9H) ppm. 13C NMR (CDCl3, 75.5
MHz): 173.8 (s), 169.1 (s), 167.4 (s), 74.7 (s), 66.5 (d), 57.4 (d), 48.8 (d), 32.8 (t), 28.6 (q),
26.6 (q), 26.8 (t, 2C), 25.4 (t, 2C), 24.7 (t, 2C), ppm. MS (ESI) calcd. for C16H25N3O3SSe:
419.08; found [M+H]+: 420.2. HRMS (ESI): Exact mass calculated for C16H26N3O3SSe+:
420.0855. Found: 420.0852.
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1H and 13C NMR spectra of 6
Se
O
O
H
H
O
N
N
N
H
O
O
O
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Chemical Shift (ppm)
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
-0.25
64
56
48
40
32
24
16
8
Chemical Shift (ppm)
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
8
0
Chemical Shift (ppm)
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1H and 13C NMR spectra of 7
Se
O
NO2
O
H
H
N
O
N
N
H
O
8.0
0.25
0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Chemical Shift (ppm)
-0.25
-0.50
-0.75
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
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1H and 13C NMR spectra of 8
Se
O
NO2
O
H
H
N
O
N
N
H
O
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Chemical Shift (ppm)
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
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1H and 13C NMR spectra of 9
Se
O
NO2
O
O
H
H
H
O
N
N
N
N
N
H
H
O
O
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
65
60
55
50
45
40
35
30
25
Chemical Shift (ppm)
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1H and 13C NMR spectra of 10
Se
O
NO2
O
H
H
N
O
N
N
H
O
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Chemical Shift (ppm)
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
65
60
55
50
45
40
35
30
25
Chemical Shift (ppm)
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
8
0
Chemical Shift (ppm)
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1H and 13C NMR spectra of 11
Se
O
H
H
N
N
O
N
H
O
O
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Chemical Shift (ppm)
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
130
120
110
100
90
80
70
60
50
40
30
20
Chemical Shift (ppm)
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
Chemical Shift (ppm)
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1H and 13C NMR spectra of 12
O
Se
O
H
N
H
N
O
N
H
O
O
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Chemical Shift (ppm)
0.15
0.10
0.05
0
-0.05
-0.10
-0.15
45
40
35
30
25
20
Chemical Shift (ppm)
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
S13

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 13
Se
O
O
H
N
H
O
N
N
H
O
O
O
HO
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
Chemical Shift (ppm)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
-0.05
-0.10
64
56
48
40
32
24
16
8
Chemical Shift (ppm)
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
8
Chemical Shift (ppm)
S14

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 14
Se
O
H
H
N
O
N
N
H
O
O
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Chemical Shift (ppm)
0.25
0
-0.25
60
55
50
45
40
35
30
25
20
15
10
5
Chemical Shift (ppm)
184
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
8
Chemical Shift (ppm)
S15

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 15
Se
O
H
N
H
O
N
N
H
O
O
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Chemical Shift (ppm)
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
120
100
80
Chemical Shift (ppm)
60
40
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
Chemical Shift (ppm)
S16

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 16
O
O
H
N
N
H
N
O
H
O
Se
Se
O
H
H
N
O
N
N
H
O
O
10.5
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
Chemical Shift (ppm)
0.20
0.15
0.10
0.05
0
-0.05
-0.10
-0.15
55
50
45
40
Chemical Shift (ppm)
35
30
25
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
S17

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 24
H
O
N
N
O
O
O
HN
S
Se
Se
O
S
N
NH
O
O
O
NH
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Chemical Shift (ppm)
0.15
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
75
70
65
60
55
50
45
40
35
30
25
Chemical Shift (ppm)
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
Chemical Shift (ppm)
S18

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
1H and 13C NMR spectra of 26
Se
O
O
O
N
H
N
N
H
S
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Chemical Shift (ppm)
1.0
0.5
0
-0.5
65
60
55
50
45
40
35
30
25
Chemical Shift (ppm)
176
168
160
152
144
136
128
120
112
104
96
88
80
72
64
56
48
40
32
24
16
Chemical Shift (ppm)
S19

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 6
HRMS (ESI) spectrum of 6a
S20

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 7
HRMS (ESI) spectrum of 8
S21

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 9
HRMS (ESI) spectrum of 10
S22

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 11
HRMS (ESI) spectrum of 12
S23

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 13
HRMS (ESI) spectrum of 14
S24

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 15
HRMS (ESI) spectrum of 16
S25

Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry
This journal is © The Royal Society of Chemistry 2012
HRMS (ESI) spectrum of 24
HRMS (ESI) spectrum of 26
References:
1. M. Abbas, J. Bethke and L. A. Wessjohann, Chem. Commun. 2006, 541.
S26