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

HRID 452377Notes

Reaction equation

HRID 452377 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-9111fbc79c1a4c408d41d605e93b0d7f
Source dataset
uspto-grants-2013_07
Patent number
US08492373B2

Reaction notes

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