Acetic Anhydride → 7,9-Dimethoxy-1,2,3,4,4a,5-hexahydro-6H-pyrido[1,2-a]quinolin-6-one

HRID 2073991Notes

Reaction equation

HRID 2073991 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([N:11]2[CH2:16][CH2:15][CH2:14][CH2:13][CH:12]2[CH2:17][C:18]([OH:20])=O)[CH:6]=[C:7]([O:9][CH3:10])[CH:8]=1.C([O-])(=O)C.[Na+].C(OC(=O)C)(=O)C>C(O)(=O)C>[CH3:10][O:9][C:7]1[CH:8]=[C:3]([O:2][CH3:1])[CH:4]=[C:5]2[C:6]=1[C:18](=[O:20])[CH2:17][CH:12]1[CH2:13][CH2:14][CH2:15][CH2:16][N:11]12

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 517045Sodium AcetateHCID 15078165[1-(3,5-Dimethoxyphenyl)piperidin-2-yl]acetic acid

Product 1

HCID 133667197,9-Dimethoxy-1,2,3,4,4a,5-hexahydro-6H-pyrido[1,2-a]quinolin-6-one

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Under a nitrogen atmosphere, a mixture of 12.1 g. (0.043 mole) dl-2-[1-(3,5-dimethoxyphenyl)piperidin-2-yl]acetic acid, 100 ml. glacial acetic acid, 6.0 g. sodium acetate and 100 ml. acetic anhydride was stirred at room temperature overnight. The acetic acid and acetic anhydride were removed by evaporation in vacuo, the residue partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution, and the organic phase washed with sodium bicarbonate, water, brine and dried (MgSO4). The extracts were evaporated to dryness to give 13 g. of a green oil. The oil was purified by chromatography on a column containing 300 g. of silica gel (230-400 mesh), eluting with ethyl acetate. Fractions of 300 ml. each were taken. Fractions 7-12 were combined and evaporated to afford 5.5 g. of the desired dl product, M.P. 91°-94° C. 1H-NMR (CDCl3) ppm (delta): 2.50 (m, 2H, CH2CO), 3.79 (s, 3H), 3.81 (s, 3H), 5.90 (m, 2H). After recrystallization from isopropyl ether, 2.6 g. of crystals were obtained, M.P. 92°-93° C.

Workup

  1. additionUnder a nitrogen atmosphere, a mixture of 12.1 g
  2. customThe acetic acid and acetic anhydride were removed by evaporation in vacuo
  3. customthe residue partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution
  4. washthe organic phase washed with sodium bicarbonate, water, brine
  5. dry with materialdried (MgSO4)
  6. customThe extracts were evaporated to dryness
  7. customto give 13 g
  8. customThe oil was purified by chromatography on a column
  9. additioncontaining 300 g
  10. washof silica gel (230-400 mesh), eluting with ethyl acetate
  11. customevaporated
  12. customto afford 5.5 g
  13. customAfter recrystallization from isopropyl ether, 2.6 g
  14. customof crystals were obtained

Sources & evidence

ORD record
ord-4755d66facb94b4eb781219b2f30b87c
Source dataset
uspto-grants-1990_04
Patent number
US04920221

Reaction notes

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