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K. Ladomenou et al. / Tetrahedron 63 (2007) 2882–2887
Evaporation of the solvents was accomplished on a rotary
evaporator.
N,N-diisopropylethylamine (0.6 mL, 3.5 mmol) and BPEA
5 (0.57 g, 2.5 mmol). The resulting mixture was stirred for
18 h at 40 ꢀC under argon. Then CH2Cl2 (30 mL) was added
to the mixture and washed with water (4ꢁ30 mL). The or-
ganic layer was dried over magnesium sulfate, filtered, con-
centrated, and the residue was chromatographed on a silica
gel column (CH2Cl2/ethanol 50:3) to obtain 14 as a purple
4.1.1. Synthesis of ligands 5 and 6. A solution of 2-vinyl-
pyridine (25.4 mL, 0.23 mmol) and ammonium chloride
(24.6 g, 0.46 mmol) in water (70 mL) and methanol (10 mL)
was heated for 8 h under reflux. Then the reaction mixture
was cooled at 0 ꢀC and basified with 30% w/w aqueous
NaOH solution (60 mL). The water layer was then washed
with chloroform (5ꢁ20 mL). The combined organic extracts
were dried over sodium sulfate, filtered, and the solvent was
evaporated to obtain a yellow oil. The resulting mixture was
then distilled under reduced pressure (w0.07 Torr) to give
first at 100–120 ꢀC 2-(pyridin-2-yl)ethanamine 6 (8.43 g,
30%) as a colorless oil and then at 130–150 ꢀC bis(2-(pyri-
din-2-yl)ethyl)amine (BPEA) 5 (26.1 g, 50%) as a pale
1
solid (45 mg, 88%). H NMR (500 MHz, CDCl3): d 9.59
(s, 1H), 8.86 (d, J¼8 Hz, 1H), 8.77 (d, J¼4.5 Hz, 2H),
8.66 (d, J¼4.5 Hz, 2H), 8.63 (m, 4H), 8.50 (d, J¼8.5 Hz,
1H), 8.20 (d, J¼7 Hz, 1H), 8.00 (t, J¼7 Hz, 1H), 7.94
(m, 2H), 7.85 (m, 3H), 7.46 (t, J¼7.5 Hz, 1H), 7.20 (s,
2H), 7.15 (s, 2H), 6.47 (m, 2H), 5.91 (t, J¼7.5 Hz, 2H),
3.67 (d, J¼7.5 Hz, 2H), 2.70 (s, 2H), 2.58 (s, 6H), 1.70 (s,
6H), 1.41 (s, 6H), 1.37 (m, 4H), 0.50 (br s, 4H), ꢂ2.40 (s,
2H). 13C NMR (125 MHz, CDCl3): d 170.3 (C), 158.0 (C),
152.2 (C), 148.7 (CH), 139.9 (C), 139.4 (C), 139.0 (C),
138.4 (C), 138.1 (C), 137.8 (CH), 136.8 (C), 135.7 (CH),
135.2 (CH), 131.7 (C), 131.5 (CH), 130.1 (CH), 128.2
(CH), 124.4 (CH), 123.0 (CH), 122.1 (CH), 120.9 (CH),
120.6 (CH), 119.6 (C), 114.8 (C), 114.4 (C), 58.9 (CH2),
54.7 (CH2), 35.3 (CH2), 22.0 (CH3), 21.8 (CH3), 21.7
(CH3). Rf (CH2Cl2/MeOH 9:1): 0.57. MS (EI): m/z¼
1026.3 [M+H]+ (100%) for C66H59N9O3. Anal. Calcd for
C66H59N9O3: C, 77.24; H, 5.79; N, 12.28. Found: C,
77.18; H, 5.82; N, 12.27. UV–vis: labs (CH2Cl2)
(3, mMꢂ1 cmꢂ1) 419 (304.6), 514 (16.5), 548 (4.8), 590
(4.9), 647 (2.4).
1
yellow oil. Compound 5. H NMR (500 MHz, CDCl3): d
8.37 (m, 2H), 7.43 (td, J1¼7.5 Hz, J2¼2 Hz, 2H), 7.02 (d,
J¼8 Hz, 2H), 6.96 (td, J1¼5 Hz, J2¼1 Hz, 2H), 2.94 (t, J¼
6.5 Hz, 4H), 2.85 (t, J¼6.5 Hz, 4H), 1.64 (br s, 1H). 13C
NMR (125 MHz, CDCl3): d 160.6 (C), 149.6 (CH), 136.6
(CH), 123.6 (CH), 121.5 (CH), 49.6 (CH2), 38.8 (CH2). Rf
(CH2Cl2/MeOH/Et3N 9:1:0.3): 0.37. Anal. Calcd for
C14H17N3: C, 73.98; H, 7.54; N, 18.49. Found: C, 73.91;
H, 7.58; N, 18.88. Compound 6. 1H NMR (500 MHz,
CDCl3): d 8.40 (d, J¼5.0 Hz, 1H), 7.46 (td, J1¼7.5 Hz, J2¼
2.0 Hz, 1H), 7.03 (d, J¼7.5 Hz, 1H), 6.98 (m, 1H), 2.97
(t, J¼7.0 Hz, 2H), 2.79 (t, J¼7.0 Hz, 2H), 1.24 (br s, 2H).
13C NMR (125 MHz, CDCl3): d 160.4 (C), 149.7 (CH),
136.6 (CH), 123.7 (CH), 121.5 (CH), 42.4 (CH2), 42.3
(CH2). Rf (CH2Cl2/MeOH/Et3N 9:1:0.3): 0.48. Anal. Calcd
for C7H10N2: C, 68.82; H, 8.25; N, 22.93. Found: C,
68.89; H, 8.21; N, 22.97.
4.1.4. Synthesis of porphyrin 18. A mixture of a,b-mono-
aminoporphyrin 12b (89 mg, 0.2 mmol), triethylamine
(56 mL, 0.4 mmol), and triphosgene (20 mg, 0.07 mmol) in
dry dichloromethane (150 mL) was stirred for 1 h under
argon at room temperature, after which ligand 9 (89 mg,
0.2 mmol) was added and the stirring continued overnight.
The reaction was monitored by thin layer chromatography
(4% methanol in dichloromethane). The residue was purified
by column chromatography (1–3% methanol in dichloro-
methane). The desired porphyrin was eluted with 2% meth-
anol in dichloromethane to give a purple solid (153 mg,
4.1.2. Synthesis of ligand 9. Piperidine (9.5 mL, 96 mmol)
was added to a solution of 8 (0.4 g, 0.6 mmol) in DMF
(20 mL) at room temperature. The resulting solution was
stirred for an hour and the reaction was monitored by thin
layer chromatography (CH2Cl2/MeOH 9:1). The solvent
was then removed under vacuum and the mixture was
dissolved in CH2Cl2 (40 mL) and extracted with water
(2ꢁ20 mL), dried over sodium sulfate, filtered, and con-
centrated under vacuum. The resulting crude product was
purified by chromatography (2–20% methanol in dichloro-
methane). The product was eluted with 10% methanol in di-
chloromethane to give 9 as a pale yellow oil (253 mg, 94%).
1H NMR (500 MHz, CDCl3): d 8.49 (m, 2H), 7.55 (m, 2H),
7.14 (d, J¼7.5 Hz, 1H), 7.08 (m, 4H), 7.00 (d, J¼8.0 Hz,
1H), 6.85 (d, J¼8.5 Hz, 2H), 3.82 (m, 2H), 3.46 (m, 2H),
3.23 (m, 1H), 3.00 (m, 1H), 2.89 (m, 3H), 2.84–2.70 (m,
2H), 2.62 (br s, 2H), 1.25 (s, 9H). 13C NMR (125 MHz,
CDCl3): d 175.4 (C), 159.5 (C), 158.4 (C), 154.4 (C),
150.1 (CH), 149.6 (CH), 136.9 (CH), 133.1 (C), 130.2
(CH), 124.6 (CH), 124.0 (CH), 123.9 (CH), 122.1 (CH),
121.9 (CH), 78.6 (C), 53.2 (CH), 47.5 (CH2), 46.8 (CH2),
42.4 (CH2), 37.8 (CH2), 36.4 (CH2), 29.2 (CH3). Rf
(CH2Cl2/MeOH 9:1): 0.29. MS (EI): m/z¼469.9 [M+Na]+
(100%) for C27H34N4O2. Anal. Calcd for C27H34N4O2: C,
72.62; H, 7.67; N, 12.55. Found: C, 72.69; H, 7.73; N,
12.51.
1
62%). H NMR (500 MHz, CDCl3): d 8.74–8.67 (m, 6H),
8.59 (m, 2H), 8.48 (dd, J1¼8.0 Hz, J2¼1.5 Hz, 1H), 8.44
(d, J¼8.5 Hz, 1H), 8.30 (m, 2H), 8.22 (d, J¼7.0 Hz, 1H),
7.96 (m, 3H), 7.77 (t, J¼8.0 Hz, 1H), 7.42 (t, J¼7.5 Hz,
1H), 7.35 (m, 2H), 7.27 (m, 2H), 7.24 (m, 2H), 6.88 (m,
4H), 6.77 (d, J¼7.0 Hz, 2H), 6.64 (d, J¼7.5 Hz, 2H), 5.98
(s, 1H), 4.64 (m, 1H), 4.50 (d, J¼7.5 Hz, 1H), 3.41 (m,
1H), 3.18 (m, 1H), 3.09 (m, 2H), 2.68 (m, 2H), 2.61 (m,
6H), 2.45 (m, 4H), 1.87 (s, 3H), 1.84 (s, 3H), 1.82 (s, 6H),
1.16 (s, 9H), ꢂ2.54 (s, 2H). 13C NMR (125 MHz, CDCl3):
d 172.0 (C), 159.1 (C), 158.1 (C), 154.5 (C), 154.3 (C),
152.0 (C), 149.7 (CH), 149.4 (CH), 140.0 (C), 139.9 (C),
139.7 (C), 139.6 (C), 138.3 (C), 137.5 (CH), 136.9 (C),
136.8 (CH), 136.7 (CH), 135.3 (CH), 131.8 (C), 131.4 (C),
131.3 (CH), 130.2 (CH), 130.0 (CH), 129.9 (CH), 128.3
(CH), 128.2 (CH), 124.5 (CH), 124.4 (CH), 123.8 (CH),
123.7 (CH), 122.0 (CH), 121.9 (CH), 121.7 (CH), 120.7
(CH), 119.6 (C), 119.5 (C), 114.5 (C), 114.1 (C), 78.6 (C),
51.5 (CH), 48.0 (CH2), 46.9 (CH2), 39.8 (CH2), 37.5
(CH2), 36.1 (CH2), 29.1 (CH3), 22.3 (CH3), 22.2 (CH3),
21.9 (CH3). Rf (CH2Cl2/MeOH 95:5): 0.32. MS (EI):
m/z¼1232.0 [M+H]+ (100%) for C78H74N10O5. Anal. Calcd
for C78H74N10O5: C, 76.07; H, 6.06; N, 11.37. Found: C,
4.1.3. Synthesis of porphyrin 14. To a solution of porphyrin
13 (45 mg, 0.05 mmol) in dry CH2Cl2 (3 mL) were added