Acetic Acid → 8-Chloro-1,4-dihydro-[1]-benzopyrano[4,3-c]pyrazole

HRID 35680Notes

Reaction equation

HRID 35680 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:9][C:8](=[CH:11][N:12](C)C)[C:7](=O)[C:6]=2[CH:16]=1.O.[NH2:18]N.C(O)(=O)C>C(Cl)(Cl)Cl.CO>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:9][C:8]3[CH:11]=[N:12][NH:18][C:7]=3[C:6]=2[CH:16]=1

Participants

6

Reactant 3

HCID 176Acetic AcidHCID 24654Hydrazine hydrate (1:1)HCID 44211356-chloro-3,4-dihydro-3-dimethylaminomethylene-4-oxo-2H-1-benzopyran

Product 1

HCID 111600578-Chloro-1,4-dihydro-[1]-benzopyrano[4,3-c]pyrazoleYield 92%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 6212ChloroformSolvent

Procedure

A solution of 6-chloro-3,4-dihydro-3-dimethylaminomethylene-4-oxo-2H-1-benzopyran (1.188 g), hydrazine hydrate (0.325 g), and acetic acid (0 39 g) in a mixture of chloroform (10 ml) and methanol (20 ml) was stirred overnight at room temperature and then evaporated in vacuo. The residual solid was washed with water, dried, and recrystallized form ethyl acetate to give 8-chloro-1,4-dihydro-[1]-benzopyrano[4,3-c]pyrazole (0.95 g).

Workup

  1. customevaporated in vacuo
  2. washThe residual solid was washed with water
  3. customdried
  4. customrecrystallized
  5. customform ethyl acetate

Sources & evidence

ORD record
ord-6df3fd9e350645cdbf2382edb4c0dc75
Source dataset
uspto-grants-1988_08
Patent number
US04767780

Reaction notes

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