Ethyl 4-Oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate → Ethyl 6,7-Dihydro-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate

HRID 1704817Notes

Reaction equation

HRID 1704817 reaction equation
[O:1]=[C:2]1[N:7]2[CH:8]=[CH:9][C:10]3[C:15]([C:6]2=[N:5][CH:4]=[C:3]1[C:16]([O:18][CH2:19][CH3:20])=[O:17])=[CH:14][CH:13]=[CH:12][CH:11]=3.[H][H]>C(O)(=O)C.[Pd]>[O:1]=[C:2]1[N:7]2[CH2:8][CH2:9][C:10]3[C:15]([C:6]2=[N:5][CH:4]=[C:3]1[C:16]([O:18][CH2:19][CH3:20])=[O:17])=[CH:14][CH:13]=[CH:12][CH:11]=3

Participants

5

Reactant 2

HCID 13851097Ethyl 4-Oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylateHCID 178418361HCID 178418361, compound

Product 1

HCID 22758857Ethyl 6,7-Dihydro-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Procedure

A mixture of ethyl 4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate (2.68 g., 0.010 mole) in acetic acid (200 ml.) containing 10% palladium on carbon (1.0 g.) was shaken with hydrogen at an initial pressure of about 4 kg. cm.-2 until the theoretical pressure drop was reached (3.3 hours). The mixture was filtered and the filtrate flash evaporated to dryness to leave an oil, which upon dilution with toluene and reconcentration to dryness gave colorless crystalline material, m.p. 117°-125°. Two recrystallizations from ethanol raised the m.p. to 139°-141°. This material was combined with product of similar purity which separated from the first ethanolic mother liquor, and the lot recrystallized from cyclohexane to give the analytical sample, m.p. 138.5°-140°.

Workup

  1. custom(3.3 hours)
  2. filtrationThe mixture was filtered
  3. customthe filtrate flash evaporated to dryness
  4. customto leave an oil, which upon dilution with toluene and reconcentration to dryness
  5. customgave colorless crystalline material, m.p. 117°-125°
  6. customTwo recrystallizations from ethanol
  7. temperatureraised the m.p. to 139°-141°
  8. customseparated from the first ethanolic mother liquor
  9. customthe lot recrystallized from cyclohexane
  10. customto give the analytical sample, m.p. 138.5°-140°

Sources & evidence

ORD record
ord-f46a86c92afc4f09b3c8cd68b93c6d47
Source dataset
uspto-grants-1978_11
Patent number
US04127720

Reaction notes

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