Hydrogen Bromide → 6-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone

HRID 1590784Notes

Reaction equation

HRID 1590784 reaction equation
C[O:2][C:3]1[CH:15]=[CH:14][C:6]([C:7]([CH2:9][CH2:10][C:11](O)=[O:12])=O)=[CH:5][CH:4]=1.Br.O.[NH2:18][NH2:19]>O.C(O)C>[OH:2][C:3]1[CH:15]=[CH:14][C:6]([C:7]2[CH2:9][CH2:10][C:11](=[O:12])[NH:18][N:19]=2)=[CH:5][CH:4]=1

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 24654Hydrazine hydrate (1:1)HCID 766134-Methoxy-gamma-oxobenzenebutanoic acid

Product 1

HCID 1358275406-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinoneYield 41,053.602%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Conditions

Temperature
110 °C

Procedure

A mixture of 25.0g (0.120 mmol) of 3-(4-methoxybenzoyl)propionic acid and 175 ml of 48% HBr is heated under N2 at 110° C. for 5 hrs. After cooling, the mixture is diluted with an equal volume of water and exhaustively extracted with EtOAc (5×100 ml). The organic phase is washed with saturated NaCl, dried (MgSO4), filtered and the solvent removed to leave a white solid. After recrystallization from EtOAc, 16.8 g of 3-(4-hydroxybenzoyl)propionic acid, m.p. 157°-159° C., is obtained. Yield, 72. A mixture of 10.0 g (51.5 mmol) of the acid prepared above and 6.2 ml (128 mmol) of 98% hydrazine monohydrate in 172 ml of ethanol is heated at reflux overnight under N2. The resulting white solid is collected by suction filtration to give 9.37 g of 6-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone as a white powder, m.p. >300 ° C.

Workup

  1. temperatureAfter cooling
  2. extractionexhaustively extracted with EtOAc (5×100 ml)
  3. washThe organic phase is washed with saturated NaCl
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered
  6. customthe solvent removed
  7. customto leave a white solid
  8. customAfter recrystallization from EtOAc, 16.8 g of 3-(4-hydroxybenzoyl)propionic acid, m.p. 157°-159° C.
  9. customis obtained
  10. customYield
  11. temperatureis heated
  12. temperatureat reflux overnight under N2
  13. filtrationThe resulting white solid is collected by suction filtration

Sources & evidence

ORD record
ord-5f431a2fb7894b1ab125231eb689210b
Source dataset
uspto-grants-1993_04
Patent number
US05204463

Reaction notes

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