Diethyl (ethoxymethylene)malonate → Ethyl 9-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylate

HRID 1657361Notes

Reaction equation

HRID 1657361 reaction equation
[NH2:1][C:2]1[C:7]([OH:8])=[CH:6][CH:5]=[CH:4][N:3]=1.C([O:11][CH:12]=[C:13]([C:19](OCC)=O)[C:14]([O:16][CH2:17][CH3:18])=[O:15])C>C(C1C=CC=CC=1CC)C>[OH:8][C:7]1[C:2]2=[N:1][CH:19]=[C:13]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[C:12](=[O:11])[N:3]2[CH:4]=[CH:5][CH:6]=1

Participants

4

Reactant 2

HCID 6871Diethyl (ethoxymethylene)malonateHCID 281142-Amino-3-Hydroxypyridine

Product 1

HCID 616445Ethyl 9-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylateYield 93%

Reagents, catalysts & solvents 1

HCID 86571,2-DiethylbenzeneSolvent2×

Procedure

Diethylbenzene Process: A mixture of 66.0 g of 2-amino-3-pyridinol, 220.0 g of diethyl ethoxymethylenemalonate, and 1.0 liter of diethylbenzene was heated so that the internal temperature reached 140° in 1 hour, was kept for 1 hour at 140°, then heated so that the temperature rose to 180° in 1 hour, and then kept 1 hour at 180°. During this entire heating period, 50 ml. of distillate was collected. The solution was allowed to cool spontaneously, was cooled at 0°, filtered, and the solid washed with diisopropyl ether to give 130.0 g of product, after drying at 56° in vacuo. The m.p. was 175°-177° and a mixture m.p. with the product isolated in (a) above was 175°-177°. The ir and pmr spectra of the two samples were superimposable. The yield was 93%.

Workup

  1. temperaturewas heated so that the internal temperature
  2. waitwas kept for 1 hour at 140°
  3. temperatureheated so that the temperature
  4. waitrose to 180° in 1 hour
  5. waitkept 1 hour at 180°
  6. temperatureDuring this entire heating period
  7. distillationof distillate was collected
  8. temperatureto cool spontaneously
  9. temperaturewas cooled at 0°
  10. filtrationfiltered
  11. washthe solid washed with diisopropyl ether

Sources & evidence

ORD record
ord-6637efd088204bffa4fb3ab6d65a2c2b
Source dataset
uspto-grants-1976_06
Patent number
US03960847

Reaction notes

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