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

HRID 653130Notes

Reaction equation

HRID 653130 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-77357fd31b994db28c89ffac2771be6e
Source dataset
uspto-grants-1987_06
Patent number
US04675324

Reaction notes

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