Acetic Acid → 5-(1-Benzofuran-2-yl)-3,6-dihydro-2H-1,3,4-oxadiazin-2-one

HRID 986753Notes

Reaction equation

HRID 986753 reaction equation
[Na].C(OC([NH:7][N:8]=[C:9]([C:15]1[O:19][C:18]2[CH:20]=[CH:21][CH:22]=[CH:23][C:17]=2[CH:16]=1)[CH2:10][O:11][C:12](=[O:14])C)=O)C.C(O)(=O)C>C(O)C.O>[O:19]1[C:15]([C:9]2[CH2:10][O:11][C:12](=[O:14])[NH:7][N:8]=2)=[CH:16][C:17]2[CH:23]=[CH:22][CH:21]=[CH:20][C:18]1=2

Participants

6

Reactant 3

HCID 176Acetic AcidHCID 5360545Sodium2×HCID 54167147HCID 54167147, compound

Product 1

HCID 212835055-(1-Benzofuran-2-yl)-3,6-dihydro-2H-1,3,4-oxadiazin-2-one

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent3×HCID 962WaterSolvent

Procedure

A solution of sodium (0.45 g.) in ethanol (30 ml.) was added to a stirred solution of acetoxymethyl 2-benzo[b]furyl ketone ethoxycarbonylhydrazone (5.48 g.) in ethanol (30 ml.) and the mixture was stirred at laboratory temperature for 2 days. Further sodium (0.45g.) in ethanol (30 ml.) was added and the mixture was stirred at laboratory temperature for a further 30 hours, diluted with water (300 ml.), adjusted to pH 5 with acetic acid and extracted with 100 ml. and then 50 ml. of ethyl acetate. The combined extracts were washed with saturated aqueous sodium chloride solution, dried and evaporated to dryness and the residue was purified by chromatography on a silica gel column (Merck 7734; 400 g.) using initially a 3:2 v/v mixture of petroleum ether (b.p. 60°-80° C.) and ethyl acetate as eluant. 7500 ml. of this eluant were used, the eluate being discarded, and elution was continued with ethyl acetate (1000 ml.). The eluate was evaporated to dryness under reduced pressure and the residue was stirred with a mixture of methanol and diethyl ether. The mixture was filtered and the solid residue was purified by chromatography on a silica gel column (Merck 9385; column size 25 cm. long and 20 mm. diameter) using a 1:1 v/v mixture of petroleum ether (b.p. 60°-80° C.) and ethyl acetate as eluant. The first 40 ml. of eluate were discarded and the next 90 ml. of eluate were evaporated to dryness under reduced pressure. The residue was stirred with a mixture of diethyl ether and petroleum ether (b.p. 60°-80° C.) and the mixture was filtered. There was thus obtained as solid product 5-(2-benzo[b]furyl)-3H,6H-1,3,4-oxadiazin-2-one, m.p. 209°-211° C.

Workup

  1. stirringthe mixture was stirred at laboratory temperature for a further 30 hours
  2. extractionextracted with 100 ml
  3. washThe combined extracts were washed with saturated aqueous sodium chloride solution
  4. customdried
  5. customevaporated to dryness
  6. customthe residue was purified by chromatography on a silica gel column (Merck 7734; 400 g.)
  7. additiona 3:2 v/v mixture of petroleum ether (b.p. 60°-80° C.) and ethyl acetate as eluant
  8. washelution
  9. customThe eluate was evaporated to dryness under reduced pressure
  10. stirringthe residue was stirred with a mixture of methanol and diethyl ether
  11. filtrationThe mixture was filtered
  12. customthe solid residue was purified by chromatography on a silica gel column (Merck 9385
  13. additiona 1:1 v/v mixture of petroleum ether (b.p. 60°-80° C.) and ethyl acetate as eluant
  14. customof eluate were evaporated to dryness under reduced pressure
  15. stirringThe residue was stirred with a mixture of diethyl ether and petroleum ether (b.p. 60°-80° C.)
  16. filtrationthe mixture was filtered

Sources & evidence

ORD record
ord-6c8d79a992d541a1bbb3f2a0f5c770bd
Source dataset
uspto-grants-1987_12
Patent number
US04716164

Reaction notes

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