Sodium Dithionite → 6-bromo-2-(4-methoxyphenyl)-7-(4-(pyridin-4-ylmethyl)piperazin-1-yl)-3H-imidazo[4,5-b]pyridine

HRID 416795Notes

Reaction equation

[Br:1][C:2]1[C:3]([N:12]2[CH2:17][CH2:16][N:15]([CH2:18][C:19]3[CH:24]=[CH:23][N:22]=[CH:21][CH:20]=3)[CH2:14][CH2:13]2)=[C:4]([N+:9]([O-])=O)[C:5]([NH2:8])=[N:6][CH:7]=1.[CH3:25][O:26][C:27]1[CH:34]=[CH:33][C:30]([CH:31]=O)=[CH:29][CH:28]=1.[O-]S(S([O-])=O)=O.[Na+].[Na+]>C(O)C>[Br:1][C:2]1[C:3]([N:12]2[CH2:17][CH2:16][N:15]([CH2:18][C:19]3[CH:24]=[CH:23][N:22]=[CH:21][CH:20]=3)[CH2:14][CH2:13]2)=[C:4]2[N:9]=[C:31]([C:30]3[CH:33]=[CH:34][C:27]([O:26][CH3:25])=[CH:28][CH:29]=3)[NH:8][C:5]2=[N:6][CH:7]=1

Participants

Conditions

Temperature: 70 °C

Procedure

To a mixture of 5-bromo-3-nitro-4-(4-pyridin-4-ylmethyl-piperazin-1-yl)-pyridin-2-ylamine (0.047 g, 0.12 mmol) and ethanol (3.0 ml) was added 4-methoxybenzaldehyde (0.026 g, 0.18 mmol) with the aid of ethanol (1.0 ml), followed by a freshly prepared aqueous solution of Na2S2O4 (1M; 0.50 ml, 0.50 mmol). The reaction mixture was stirred at 70° C. for 8.5 h, then allowed to cool to room temperature and concentrated in vacuo. The residue was absorbed on silica gel, and the free-running powder was placed on a 10 g isolute silica column which was eluted with a gradient of methanol (0 to 4%) in ethyl acetate/dichloromethane (v/v; 1:1). The title compound was obtained as a pale yellow solid after trituration with diethyl ether (0.018 g, 31%). 1H-NMR (500 MHz, DMSO-d6) 2.63 (br s, 4H, piperazine N(CH2)2), 3.68 (br s, 4H, piperazine N(CH2)2), 3.62 (s, 2H, NCH2-pyridyl), 3.84 (s, 3H, OCH3), 7.10 (d, J=8.9 Hz, 2H) and 8.14 (d, J=8.8 Hz, 2H) (3,5-C6H4OMe and 2,6-C6H4OMe), 7.40 (d, J=5.9 Hz, 2H, pyridine 3-H and 5-H), 8.20 (s, 1H, imidazo[4,5-b]pyridine 5-H), 8.54 (d, J=5.9 Hz, 2H, pyridine 2-H and 6-H), 13.38 (br s, 1H, imidazo[4,5-b]pyridine N—H);

Workup

temperatureto cool to room temperature
concentrationconcentrated in vacuo
customThe residue was absorbed on silica gel
washwas eluted with a gradient of methanol (0 to 4%) in ethyl acetate/dichloromethane (v/v; 1:1)

Sources & evidence

ORD record: ord-5dcd91b0e4ed499db53af812c99912fb
Source dataset: uspto-grants-2012_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08088761B2

Reaction notes

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