2-(2-Nitro-phenyl)4-oxo-pentanoic acid methyl ester → rac-methyl (2R,4S)-2-methyl-1,2,3,4-tetrahydroquinoline-4-carboxylate

HRID 552999Notes

Reaction equation

HRID 552999 reaction equation
[CH3:1][O:2][C:3](=[O:18])[CH:4]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[N+:15]([O-])=O)[CH2:5][C:6](=O)[CH3:7]>[Pd].C(O)C>[CH3:1][O:2][C:3]([C@H:4]1[C:9]2[C:10](=[CH:11][CH:12]=[CH:13][CH:14]=2)[NH:15][C@@H:6]([CH3:7])[CH2:5]1)=[O:18]

Participants

4

Reactant 1

HCID 106107412-(2-Nitro-phenyl)4-oxo-pentanoic acid methyl ester

Product 1

HCID 50853311rac-methyl (2R,4S)-2-methyl-1,2,3,4-tetrahydroquinoline-4-carboxylateYield 68%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

A round bottom flask with magnetic stirrer was charged with 2-(2-nitro-phenyl)4-oxo-pentanoic acid methyl ester (4.74 g, 19.1 mmol) and anhydrous ethanol (50 mL). To the reaction was added 10% palladium on carbon (0.948 g, 20% by weight) and the reaction stirred at room temperature under a hydrogen gas atmosphere (balloon) for 18-20 hours. The reaction was filtered through a pad of celite and the celite pad washed with warm ethanol. The combined filtrates were concentrated in vacuo to afford an off-white colored solid. This material was purified via Isco flash system (0-20% ethyl acetate/hexanes) to yield 2.64 g of cis-2-methyl-1,2,3,4-tetrahydro-quinoline-4-carboxylic acid methyl ester as a white solid (68%). 1H-NMR (CDCl3) δ: 1.23 (3H, d), 1.95 (1H, dd), 2.10-2.18 (1H, m), 3.34-3.46 (1H, m), 3.74 (3H, s), 3.94 (1H, dd), 6.51 (1H, dd), 6.60-6.67 (1H, m), 6.94-7.03 (2H, m). MS m/z: 206 (M+1).

Workup

  1. filtrationThe reaction was filtered through a pad of celite
  2. washthe celite pad washed with warm ethanol
  3. concentrationThe combined filtrates were concentrated in vacuo
  4. customto afford an off-white colored solid
  5. customThis material was purified via Isco flash system (0-20% ethyl acetate/hexanes)

Sources & evidence

ORD record
ord-ca9d22a934294e46859e7096922f5bd5
Source dataset
uspto-grants-2011_05
Patent number
US07951950B2

Reaction notes

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