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Y.-C. Teo et al. / Tetrahedron 69 (2013) 7279e7284
flash chromatography (70:30 hexane/ethyl acetate) of the crude oil.
H NMR (400 MHz, CDCl3):
(d, J¼10.7 Hz, 1H), 7.46e7.49 (m, 1H), 7.32 (d, J¼19.1 Hz, 2H); 13C
d
9.00 (d, J¼2.4 Hz, 1H), 8.57 (d, J¼5.9 Hz,
NMR (100 MHz, CDCl3):
123.9, 118.2.
d 148.7, 142.7, 135.6, 133.8, 130.7, 128.9,
1H), 8.37 (d, J¼6.1 Hz, 1H), 8.27e8.30 (m, 1H), 7.98 (d, J¼9.4 Hz, 1H),
7.53 (d, J¼3.7 Hz, 1H), 7.46 (q, J¼4.3 Hz, 1H), 7.16 (q, J¼4.2 Hz, 1H),
6.67 (d, J¼3.8 Hz, 1H); 13C NMR (100 MHz, CDCl3):
d 147.8, 147.4,
4.2.8. 5-Bromo-1-(pyridin-3-yl)-1H-pyrrolo[2,3-b]pyridine
(3h).12 Following the general procedure using 5-bromo-7-
azaindole (0.145 g, 0.735 mmol) and 3-iodopyridine (0.226 g,
1.103 mmol) provided 163 mg (81% yield) of the coupling product
as yellow solid after purification by flash chromatography (80:20
hexane/ethyl acetate) of the crude oil. 1H NMR (400 MHz, CDCl3):
144.8, 144.1, 135.5, 131.3, 129.6, 127.1, 124.1, 121.9, 117.5, 103.1.
4.2.2. 1-(Pyridin-3-yl)-1H-indazole (3b).12 Following the general
procedure using indazole (0.087mL, 0.735 mmol) and 3-iodopyridine
(0.226 g, 1.103 mmol) provided 126 mg (88% yield) of the coupling
product as yellow solid after purification by flash chromatography
(90:10 hexane/ethyl acetate) of the crude oil; 1H NMR (400 MHz,
d
8.98 (d, J¼2.2 Hz, 1H), 8.61 (d, J¼3.9 Hz, 1H), 8.39 (d, J¼2.1 Hz, 1H),
8.22e8.25 (m, 1H), 8.12 (d, J¼2.3 Hz, 1H), 7.56 (d, J¼3.7 Hz, 1H),
7.47e7.50 (m, 1H), 6.65 (d, J¼3.8 Hz, 1H); 13C NMR (100 MHz,
CDCl3):
d
9.09 (d, J¼2.5 Hz, 1H), 8.61 (d, J¼4.8 Hz, 1H), 8.25 (s, 1H),
8.06e8.09 (m, 1H), 7.83 (d, J¼8.1 Hz, 1H), 7.74 (d, J¼11.4 Hz, 1H),
CDCl3):
d 149.9, 147.6, 144.6, 144.4, 134.8, 131.4, 131.0, 128.3, 123.9,
7.46e7.50 (m, 2H), 7.25e7.29 (m, 1H); 13C NMR (100 MHz, CDCl3):
123.3, 110.8, 102.3.
d
147.6, 143.7, 138.8, 137.0, 136.6, 129.7, 127.8, 125.6, 124.0, 122.0, 121.6,
110.0.
4.2.9. 1-(Pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine (4a).12 Following
the general procedure using 7-azaindole (0.130 g, 1.103 mmol) and
2-iodopyridine (0.078 mL, 0.735 mmol) provided 137 mg (96%
yield) of the coupling product as yellow solid after purification by
flash chromatography (95:5 hexane/ethyl acetate) of the crude oil.
4.2.3. 1-(Pyridin-3-yl)-1H-indole (3c).12 Following the general
procedure using indole (0.086 g, 0.735 mmol) and 3-iodopyridine
(0.226 g, 1.103 mmol) provided 116 mg (81% yield) of the cou-
pling product as reddish oil after purification by flash chroma-
tography (96:4 hexane/ethyl acetate) of the crude oil. 1H NMR
1H NMR (400 MHz, CDCl3):
d
8.92 (d, J¼7.0 Hz, 1H), 8.41e8.90 (m,
1H), 8.40e8.41 (m, 1H), 8.38 (d, J¼3.9 Hz, 1H), 7.95e7.97 (m, 1H),
(400 MHz, CDCl3):
d
8.85 (d, J¼2.3 Hz, 1H), 8.62 (d, J¼0.9 Hz, 1H),
7.85e7.89 (m, 1H), 7.15e7.18 (m, 2H), 6.65 (d, J¼3.7 Hz, 1H); 13C
7.84e7.87 (m, 1H), 7.71 (d, J¼7.8 Hz, 1H), 7.53 (d, J¼8.1 Hz, 1H),
NMR (100 MHz, CDCl3):
d 150.8, 148.2, 147.5, 143.1, 138.2, 129.1,
7.48 (q, J¼4.3 Hz, 1H), 7.34 (d, J¼3.3 Hz, 1H), 7.19e7.28 (m, 2H),
126.5, 123.9, 120.4, 117.1, 115.7, 102.6.
6.75 (d, J¼3.7 Hz, 1H); 13C NMR (100 MHz, CDCl3):
d 147.3, 145.5,
136.3, 135.6, 131.3, 129.4, 127.3, 124.0, 122.8, 121.3, 120.8, 109.0,
104.7.
4.2.10. 1-(Pyridin-2-yl)-1H-indazole (4b).12 Following the general
procedure indazole (0.130 g, 1.103 mmol) and 2-iodopyridine
(0.078 mL, 0.735 mmol) provided 129 mg (90% yield) of the cou-
pling product as yellow solid after purification by flash chroma-
tography (95:5 hexane/ethyl acetate) of the crude oil. 1H NMR
4.2.4. 3-(1H-Pyrrol-1-yl)pyridine (3d). Following the general pro-
cedure using pyrrole (0.051 mL, 0.735 mmol) and 3-iodopyridine
(0.226 g, 1.103 mmol) provided 43 mg (85% yield) of the coupling
product as yellowish oil after purification by flash chromatography
(90:10 hexane/ethyl acetate) of the crude oil. 1H NMR (400 MHz,
(400 MHz, CDCl3):
d
8.84 (d, J¼8.6 Hz, 1H), 8.53 (d, J¼3.7 Hz, 1H),
8.19 (s, 1H), 8.05 (d, J¼8.3 Hz, 1H), 7.71e7.84 (m, 2H), 7.52 (t,
J¼8.3 Hz, 1H), 7.28 (t, J¼11.5 Hz, 1H), 7.15 (t, J¼6.0 Hz, 1H); 13C NMR
CDCl3):
d
8.73 (s, 1H), 8.48 (d, J¼4.1 Hz, 1H), 7.66 (d, J¼12.2 Hz, 1H),
(100 MHz, CDCl3):
d 154.4, 147.7, 138.9, 138.3, 136.8, 127.9, 126.0,
7.32e7.35 (m, 1H), 7.07 (t, J¼4.3 Hz, 2H), 6.38 (t, J¼4.3 Hz, 2H); 13
C
122.5, 120.7, 119.9, 115.3, 113.5.
NMR (100 MHz, CDCl3):
d 146.6, 141.9, 136.9, 127.3, 123.9, 119.0,
111.3; HRMS calcd for C9H8N2 [Mþ]: 144.0687. Found: 144.0693.
4.2.11. 2-(1H-Pyrrol-1-yl)pyridine (4c).14 Following the general
procedure using pyrrole (0.077 g, 1.103 mmol) and 2-iodopyridine
(0.078 mL, 0.735 mmol) provided 96 mg (90% yield) of the cou-
pling product as reddish oil after purification by flash chromatog-
raphy (97:3 hexane/ethyl acetate) of the crude oil. 1H NMR
4.2.5. 3-(1H-Pyrazol-yl)pyridine (3e).10 Following the general pro-
cedure using pyrazole (0.050 g, 0.735 mmol) and 3-iodopyridine
(0.226 g, 1.103 mmol) provided 88 mg (83% yield) of the coupling
product as off-white solid after purification by flash chromatogra-
phy (65:35 hexane/ethyl acetate) of the crude oil. 1H NMR
(400 MHz, CDCl3):
d
8.39 (d, J¼4.7 Hz, 1H), 7.66 (t, J¼8.6 Hz, 1H),
7.50 (s, 2H), 7.25 (d, J¼8.3 Hz, 1H), 7.04 (t, J¼6.1 Hz,1H), 6.34 (s, 2H);
(400 MHz, CDCl3)
d 8.99 (s, 1H), 8.56 (s, 1H), 8.05e8.09 (m, 1H), 7.98
13C NMR (100 MHz, CDCl3):
111.2.
d 151.3, 148.6, 138.4, 120.1, 118.0, 111.3,
(s, 1H), 7.78 (s, 1H), 7.40e7.43 (s, 1H), 6.53 (s, 1H); 13C NMR
(100 MHz, CDCl3)
108.3.
d 147.3, 141.8, 140.3, 136.4, 126.7, 126.3, 123.8,
4.2.12. 2-(1H-Pyrazol-1-yl)pyridine (4d).10 Following the general
procedure using pyrazole (0.075 g, 1.103 mmol) and 2-iodopyridine
(0.078 mL, 0.735 mmol) provided 93 mg (87% yield) of the coupling
product as yellowish oil after purification by flash chromatography
(96:4 hexane/ethyl acetate) of the crude oil. 1H NMR (400 MHz,
4.2.6. 3-(3-Methyl-1H-pyrazol-1-yl)pyridine (3f).13 Following the
general procedure using 3-methyl pyrazole (0.059 mL, 0.735 mmol)
and 3-iodopyridine (0.226 g, 1.103 mmol) provided 87 mg (74%
yield) of the coupling product as off-white solid after purification
by flash chromatography (78:22 hexane/ethyl acetate) of the crude
CDCl3)
d
8.56 (d, J¼2.5 Hz, 1H), 8.38 (d, J¼4.0 Hz, 1H), 7.97 (d,
oil. 1H NMR (400 MHz, CDCl3):
d 8.95 (s, 1H), 8.51 (s, 1H), 8.02
J¼8.3 Hz, 1H), 7.73-7.79 (m, 2H), 7.11e7.20 (m, 1H), 6.44 (t, J¼2.1 Hz,
1H); 13C NMR (100 MHz, CDCl3)
121.2, 112.3, 107.6.
d 151.4, 147.9, 141.9, 138.5, 126.9,
(d, J¼12.3 Hz, 1H), 7.85 (d, J¼2.4 Hz, 1H), 7.36e7.40 (m, 1H), 6.30
(d, J¼2.4 Hz, 1H), 2.39 (s, 3H); 13C NMR (100 MHz, CDCl3):
d 151.4,
146.8, 140.0, 136.5, 127.2, 125.8, 123.8, 108.3, 13.5.
4.2.13. 2-(1H-Imidazol-1-yl)pyridine (4e).15 Following the general
procedure using imidazole (0.050 g, 0.735 mmol) and 2-
iodopyridine (0.117 mL, 1.103 mmol) provided 70 mg (65% yield)
of the coupling product as brownish oil after purification by flash
chromatography (10:90 hexane/ethyl acetate) of the crude oil. 1H
4.2.7. 3-(1H-Imidazol-1-yl)pyridine (3g).10 Following the general
procedure using imidazole (0.050 g, 0.735 mmol) and 3-
iodopyridine (0.226 g, 1.103 mmol) provided 43 mg (41% yield) of
the coupling product as yellow oil after purification by flash chro-
matography using methanol of the crude oil. 1H NMR (400 MHz,
NMR (400 MHz, CDCl3)
d
8.49 (s, 1H), 8.36 (s, 1H), 7.82 (t, J¼8.7 Hz,
CDCl3):
d
8.77 (s, 1H), 8.65 (d, J¼4.4 Hz, 1H), 7.96 (s, 1H), 7.76
1H), 7.65 (s, 1H), 7.36 (d, J¼8.2 Hz, 1H), 7.20e7.25 (m, 2H); 13C NMR