tert-Butyl 4-oxo-3,4-dihydroquinoline-1(2H)-carboxylate → tert-butyl 4-methylene-3,4-dihydroquinoline-1(2H)-carboxylate

HRID 1877393Notes

Reaction equation

HRID 1877393 reaction equation
[CH3:1]C(C)([O-])C.[K+].[C:7]([O:11][C:12]([N:14]1[C:23]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[C:17](=O)[CH2:16][CH2:15]1)=[O:13])([CH3:10])([CH3:9])[CH3:8]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1(C)C=CC=CC=1>[C:7]([O:11][C:12]([N:14]1[C:23]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[C:17](=[CH2:1])[CH2:16][CH2:15]1)=[O:13])([CH3:10])([CH3:9])[CH3:8]

Participants

5

Reactant 2

HCID 23433504tert-Butyl 4-oxo-3,4-dihydroquinoline-1(2H)-carboxylateHCID 23665647Potassium tert-butoxide

Product 1

HCID 67367966tert-butyl 4-methylene-3,4-dihydroquinoline-1(2H)-carboxylateYield 73%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 1140TolueneSolvent2×

Procedure

A solution of methyltriphenylphosphonium bromide (1.92 g, 5.38 mmol, 1.1 equiv; [CAS RN 1779-49-3]) and potassium tert-butoxide (0.60 g, 5.38 mmol, 1.1 equiv; [CAS RN 865-47-4]) in toluene (20 mL) were heated to reflux. After 1 h, 4-oxo-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester (1.21 g, 4.89 mmol, 1.0 equiv; [CAS RN 179898-00-1]), dissolved in toluene (10 mL), was added and heating continued for one additional hour. The reaction mixture was extraction from a sat. solution of NH4Cl (100 mL) with ethyl acetate (3×50 mL) and the combined organic phases dried over MgSO4. Purification by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane/ethyl acetate afforded 0.87 g (73%) of the title compound as a colorless oil. MS (ISP): 246.4 [M+H]+.

Workup

  1. additionwas added
  2. temperatureheating
  3. extractionextraction from a sat. solution of NH4Cl (100 mL) with ethyl acetate (3×50 mL)
  4. dry with materialthe combined organic phases dried over MgSO4
  5. customPurification by silica column chromatography
  6. washeluting with a gradient of heptane/ethyl acetate

Sources & evidence

ORD record
ord-adea94ad97bd4b8f8003ccbacd14bd63
Source dataset
uspto-grants-2012_11
Patent number
US08309734B2

Reaction notes

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