Ethyl 4,6-dichloroquinoline-3-carboxylate → Ethyl 6-chloroquinoline-3-carboxylate

HRID 489623Notes

Reaction equation

HRID 489623 reaction equation
Cl[C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[C:9]([Cl:12])[CH:10]=2)[N:5]=[CH:4][C:3]=1[C:13]([O:15][CH2:16][CH3:17])=[O:14].[BH4-].[Na+]>COC(O)C.C(OCC)(=O)C>[Cl:12][C:9]1[CH:10]=[C:11]2[C:6](=[CH:7][CH:8]=1)[N:5]=[CH:4][C:3]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:2]2

Participants

5

Reactant 2

HCID 1479087Ethyl 4,6-dichloroquinoline-3-carboxylateHCID 4311764Sodium borohydride

Product 1

HCID 22265883Ethyl 6-chloroquinoline-3-carboxylate

Reagents, catalysts & solvents 2

HCID 8857Ethyl AcetateSolventHCID 30156371-MethoxyethanolSolvent

Procedure

Ethyl 4,6-Dichloroquinoline-3-carboxylate [prepared as described in C. C. Price and R. M. Roberts J. Amer. Chem. Soc. 68, 1204 (1964); C. J. Ohnmacht, Jr. J. Med. Chem. 14, 17 (1971)](2.0 g, 7.4 mmol) was added portionwise to a solution of sodium borohydride (1.2 g, 31 mmol) in 15 ml of methoxyethanol at about 0° C. The reaction mixture was warmed to room temperature over 3 hours then diluted with ethyl acetate. After standard aqueous workup (dil HCl; saturated NaHCO3) the organic layer was dried (NaSO4) and concentrated to a residue. The residue was exposed to air oxidation (about 14 days) and extracted repeatedly with boiling heptane. The heptane was removed in vacuo to yield ethyl 6-chloroquinoline-3-carboxylate as a beige solid. 1H NMR [(CDCl3), 300 MHz]: δ 9.38 (bs, 1H), 8.68 (s, 1H), 8.05 (d, 1H), 7.83 (s, 2H), 7.69 (d, 1H), 4.40 (q, 2H), 1.39 (t, 3H). MS(EI): 236(M++H).

Workup

  1. dry with materialAfter standard aqueous workup (dil HCl; saturated NaHCO3) the organic layer was dried (NaSO4)
  2. concentrationconcentrated to a residue
  3. customwas exposed to air oxidation (about 14 days)
  4. extractionextracted repeatedly with boiling heptane
  5. customThe heptane was removed in vacuo

Sources & evidence

ORD record
ord-fd8b53ec3162404c9286df08f3b58f0f
Source dataset
uspto-grants-2005_12
Patent number
US06977263B2

Reaction notes

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