Hydrochloric Acid → 6,7-dihydro-2H-benzo[6,7]cyclohepta[1,2-c]pyridazin-3(5H)-one

HRID 2406125Notes

Reaction equation

HRID 2406125 reaction equation
[N:1]1[NH:2][C:3](=[O:16])[CH2:4][CH:5]2[CH2:11][CH2:10][CH2:9][C:8]3[CH:12]=[CH:13][CH:14]=[CH:15][C:7]=3[C:6]=12.[N+](C1C=C(S([O-])(=O)=O)C=CC=1)([O-])=O.[Na+].[OH-].[Na+].Cl>O>[O:16]=[C:3]1[NH:2][N:1]=[C:6]2[C:7]3[CH:15]=[CH:14][CH:13]=[CH:12][C:8]=3[CH2:9][CH2:10][CH2:11][C:5]2=[CH:4]1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 31389Sodium 3-nitrobenzenesulfonateHCID 147375392,4,4A,5,6,7-Hexahydro-benzo[6,7]cyclohepta[1,2-C]pyridazin-3-one

Product 1

HCID 141261586,7-dihydro-2H-benzo[6,7]cyclohepta[1,2-c]pyridazin-3(5H)-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

Alternatively, a solution of 4a,5,6,7-tetrahydro-2H-benzo[6,7]cyclohepta[c]pyridazin-3(4H)-one (2.31 g, 10.74 mmol), sodium m-nitrobenzenesulfonate (2.48 g, 11 mmol), sodium hydroxide (1.86 g, 46.5 mmol) in water (80 mL) was heated under reflux for 1.5 h. The solution was cooled to ambient temperature, and then acidified with concentrated hydrochloric acid. The solid which precipitated was filtered off, washed with water and crystallized from ethanol to give 3-oxo-6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-c]pyridazine as tan crystals, 1.46 g; 1H NMR (DMSO-d6, 300 MHz) 13.04 (s, 1H), 7.25-7.45 (m, 4H), 6.78 (s, 1H), 2.49 (m, 2H), 2.35 (m, 2H), 2.04 (m, 2H) ppm; MS (ES) 213 (M+H).

Workup

  1. temperatureunder reflux for 1.5 h
  2. customThe solid which precipitated
  3. filtrationwas filtered off
  4. washwashed with water
  5. customcrystallized from ethanol

Sources & evidence

ORD record
ord-9171be772b0842b59e710058c1869bcb
Source dataset
uspto-grants-2014_08
Patent number
US08809347B2

Reaction notes

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