Hydrogen Bromide → 7-methoxy-2,2,4-trimethyl-1,2-dihydroquinoline

HRID 634906Notes

Reaction equation

HRID 634906 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([NH2:9])[CH:4]=1.O=[C:11]([CH:13]=[C:14]([CH3:16])[CH3:15])[CH3:12].Br>C(O)(=O)C>[CH3:15][C:14]1([CH3:16])[CH:13]=[C:11]([CH3:12])[C:6]2[C:5](=[CH:4][C:3]([O:2][CH3:1])=[CH:8][CH:7]=2)[NH:9]1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 8858Mesityl oxideHCID 108243-Methoxyaniline

Product 1

HCID 6434787-methoxy-2,2,4-trimethyl-1,2-dihydroquinolineYield 39%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

273 g (2.2 mol) m-anisidine and subsequently 221 g (2.2 mol) mesityl oxide were added dropwise at 15-20° C. to 25 ml glacial acetic acid. Then the solution was stirred for ca. 18 hours at room temperature. Subsequently 500 ml hydrobromic acid was added dropwise at 20-30° C. After stirring for 1 h at room temperature the precipitate was filtered. The precipitate which was still wet, was suspended in ca. 1 l acetone, filtered and dried. 200 g 2,2,4-trimethyl-7-methoxy-1,2-dihydro-quinoline hydrobromide was resuspended in a mixture of 1 l water and 500 ml chloroform. The suspension was then neutralized with 10% sodium hydroxide solution. The organic phase was subsequently washed with water, dried over sodium sulfate and evaporated to dryness in a rotary evaporator. The green coloured oil solidified after a short time. The solid was recrystallized from hexane. Colourless crystals formed in a yield of 39% with a melting point of 67° C.-69° C.

Workup

  1. stirringAfter stirring for 1 h at room temperature the precipitate
  2. filtrationwas filtered
  3. filtrationfiltered
  4. customdried
  5. addition200 g 2,2,4-trimethyl-7-methoxy-1,2-dihydro-quinoline hydrobromide was resuspended in a mixture of 1 l water and 500 ml chloroform
  6. washThe organic phase was subsequently washed with water
  7. dry with materialdried over sodium sulfate
  8. customevaporated to dryness in a rotary evaporator
  9. customThe solid was recrystallized from hexane
  10. customColourless crystals formed in a yield of 39% with a melting point of 67° C.-69° C.

Sources & evidence

ORD record
ord-46c0597b4f1047f482fea704b700bfbc
Source dataset
uspto-grants-2001_02
Patent number
US06184379B2

Reaction notes

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