Pyridine → Methyl 6-(2,4-dichlorophenyl)-5-(4-chlorophenyl)pyridine-2-carboxylate

HRID 916959Notes

Reaction equation

[CH3:1][O:2][C:3]([C:5](=[CH:26][CH:27]=[CH:28][C:29]1[CH:34]=[CH:33][C:32]([Cl:35])=[CH:31][CH:30]=1)[N:6]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)=[O:4].[Cl:36][C:37]1[CH:44]=[C:43]([Cl:45])[CH:42]=[CH:41][C:38]=1[CH:39]=O.N1C=CC=CC=1.N1C=CC=CC1>C(#N)C>[Cl:36][C:37]1[CH:44]=[C:43]([Cl:45])[CH:42]=[CH:41][C:38]=1[C:39]1[N:6]=[C:5]([C:3]([O:2][CH3:1])=[O:4])[CH:26]=[CH:27][C:28]=1[C:29]1[CH:30]=[CH:31][C:32]([Cl:35])=[CH:33][CH:34]=1

Participants

Conditions

Temperature: 60 °C

Procedure

The residue of 3-methoxycarbonyl-6-(4-chlorophenyl)-1,1,1-triphenyl-2-aza-1λ5-phosphahexa-1,3,5-triene (10.2 mmol) from Step D was dissolved in acetonitrile (40 mL) and 2,4-dichlorobenzaldehyde (1.78 g, 10.2 mmol) was added. The reaction was heated to 60° C. under a condenser (left open to the air) for 20 h. HPLC/MS indicated a mixture of the desired title pyridine and dihydropyridine intermediate 394 (M+1), 396 (M+3), Rt=4.75 min). The reaction was heated a further 4 h and was then concentrated. The residue was purified by flash column chromatography on silica gel eluted with 0 to 20% ethyl acetate in hexanes to afford methyl 6-(2,4-dichlorophenyl)-5-(4-chlorophenyl)pyridine-2-carboxylate. HPLC/MS: 392 (M+1), 394 (M+3); Rt=4.16 min. 1HNMR (CDCl3): δ 4.039 (s, 3H), 7.09 (br d, J=8.5 Hz, 2H), 7.26 (br d, J=8.4 Hz, 2H), 7.28 (d, J=2 Hz, 1H), 7.30 (dd, J=2.0 and 8.3 Hz, 1H), 7.34 (d, J=8.3 Hz, 1H), 7.90 (d, J=8 Hz, 1H), 8.26 (d, J=8.0 Hz, 1H).

Workup

temperatureThe reaction was heated a further 4 h
concentrationwas then concentrated
customThe residue was purified by flash column chromatography on silica gel
washeluted with 0 to 20% ethyl acetate in hexanes

Sources & evidence

ORD record: ord-2f0afcd3bf3344c3b64d6605f4a9c9da
Source dataset: uspto-grants-2007_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07271266B2

Reaction notes

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