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

HRID 1036850Notes

Reaction equation

HRID 1036850 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>[N:1]1[NH:2][C:3](=[O:16])[CH:4]=[C: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

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 6,7-dihydro-2H-benzo[6,7]cyclohepta[1,2-c]pyridazin-3(5H)-one 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-60767e185fda46ce9131caec617d8bfc
Source dataset
uspto-grants-2013_10
Patent number
US08546433B2

Reaction notes

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