2-Aminopyridine → 2-(3,4-dimethoxyphenyl)-4H-pyrido[1,2-a]pyrimidin-4-one

HRID 4324

Reaction equation

HRID 4324 reaction equation
[C:1]([CH2:13][C:14]([O:16]CC)=O)(=O)[C:2]1[CH:11]=[CH:10][C:7]([O:8][CH3:9])=[C:4]([O:5][CH3:6])[CH:3]=1.[NH2:19][C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][N:21]=1>>[CH3:6][O:5][C:4]1[CH:3]=[C:2]([C:1]2[N:19]=[C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][N:21]3[C:14](=[O:16])[CH:13]=2)[CH:11]=[CH:10][C:7]=1[O:8][CH3:9]

Participants

3

Reactant 2

HCID 104392-AminopyridineHCID 2758465Ethyl 3,4-dimethoxybenzoylacetate

Product 1

HCID 201522922-(3,4-dimethoxyphenyl)-4H-pyrido[1,2-a]pyrimidin-4-oneYield 150.8%

Conditions

Temperature
100 °C

Procedure

Ethyl veratroylacetate (4.5 g) was added dropwise under stirring at 60°-70° C. to a suspension of 2-aminopyridine (0.84 g) in polyphosphoric acid (13.7 g). The reaction mixture was stirred at 100° C. for 3 hrs and poured into ice-water (50 ml). The aqueous solution was extracted with chloroform, washed with water, dried and evaporated to give dark oily residue which was chromatographed on silica gel using n-hexaneethyl acetate. The fractions were evaporated and the resulting residue was triturated with ethanol-isopropyl ether to give 2-(3,4-dimethoxyphenyl)-4-oxo-4H-pyrido[1,2-a]pyrimidine (3.8 g).

Workup

  1. extractionThe aqueous solution was extracted with chloroform
  2. washwashed with water
  3. customdried
  4. customevaporated
  5. customto give dark oily residue which
  6. customwas chromatographed on silica gel using n-hexaneethyl acetate
  7. customThe fractions were evaporated
  8. customthe resulting residue was triturated with ethanol-isopropyl ether

Sources & evidence

ORD record
ord-5c3a5a99c48944198bf063c01ea01967
Source dataset
uspto-grants-1988_02
Patent number
US04725600

Linked notes

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