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

HRID 483001Notes

Reaction equation

HRID 483001 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, eluting with ethyl acetate. Product fractions 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, 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-fdb52f6c3d3c427eb951748076efbce1
Source dataset
uspto-grants-1986_03
Patent number
US04576964

Reaction notes

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