Sulfuric Acid → 5,6,7-Trimethylquinoline-8-carboxaldehyde

HRID 2118852Notes

Reaction equation

C([Li])CCC.Br[C:7]1[C:8]([CH3:19])=[C:9]([CH3:18])[C:10]([CH3:17])=[C:11]2[C:16]=1[N:15]=[CH:14][CH:13]=[CH:12]2.[CH:20](N1CCCCC1)=[O:21].S(=O)(=O)(O)O.C(=O)([O-])[O-].[K+].[K+]>C1COCC1>[CH3:17][C:10]1[C:9]([CH3:18])=[C:8]([CH3:19])[C:7]([CH:20]=[O:21])=[C:16]2[C:11]=1[CH:12]=[CH:13][CH:14]=[N:15]2

Participants

Conditions

Temperature: -40 °C

Procedure

n-Butyl lithium (2.1 equiv; 1.55M in hexane) was added slowly to a suspension of 8-bromo-5,6,7-trimethylquinoline (4.2 g) in anhydrous THF (40 ml) under nitrogen at -90° C. After 3 hr a solution of N-formylpiperidine (2.1 equiv) in anhydrous THF (10 ml) was added to the mixture was warmed to -40° C. over ca. 2 hr. A dilute sulfuric acid solution (1N; 20 ml) was added and the mixture was warmed to room temperature. The mixture was made basic by the addition of potassium carbonate and was then extracted with ether. The dried (MgSO4) organic fraction was evaporated and the residue was purified by column chromatography over alumina with carbon tetrachloride/dichloromethane (1:1 v/v) elution to give 5,6,7-trimethylquinoline-8-carboxaldehyde as a pale yellow solid, mp 162° C. Pmr specturm (CDCl3 ; δ in ppm): 2.48 (3H,s); 2.68 (3H,s); 2.74 (3H,s); 7.43-8.96 (3H,m); 11.61 (1H,s).

Workup

temperaturethe mixture was warmed to room temperature
extractionwas then extracted with ether
dry with materialThe dried (MgSO4) organic fraction
customwas evaporated
customthe residue was purified by column chromatography over alumina with carbon tetrachloride/dichloromethane (1:1 v/v) elution

Sources & evidence

ORD record: ord-20f04164e4d54173a252108b3cce81ac
Source dataset: uspto-grants-1987_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04680400

Reaction notes

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