2-Fluorobenzoyl chloride → 3-Chloro-6-(o-fluorobenzoyl)-5,6,7,8-tetrahydro-4-methylpyrido[4,3-c]pyridazine
Reaction equation
[Cl:1][C:2]1[N:7]=[N:6][C:5]2[CH2:8][CH2:9][NH:10][CH2:11][C:4]=2[C:3]=1[CH3:12].C([O-])(=O)/C=C\C([O-])=O.[F:21][C:22]1[CH:30]=[CH:29][CH:28]=[CH:27][C:23]=1[C:24](Cl)=[O:25]>>[Cl:1][C:2]1[N:7]=[N:6][C:5]2[CH2:8][CH2:9][N:10]([C:24](=[O:25])[C:23]3[CH:27]=[CH:28][CH:29]=[CH:30][C:22]=3[F:21])[CH2:11][C:4]=2[C:3]=1[CH3:12]Participants
4
Procedure
A suspension of 14.4 g of 6-carbethoxy-5,6,7,8-tetrahydro-4-methyl-3(2H)pyrido[4,3-c]pyridazinone in 100 cc of concentrated hydrochloric acid is heated to the boil at reflux for 20 hours while stirring. The resulting 5,6,7,8-tetrahydro-4-methyl-3(2H)pyrido[4,3-c]pyridazinone is isolated (M.P. of the hydrochloride 344° to 348°) and is converted in a manner analogous to that described in Example 1(e) into 3-chloro-5,6,7,8-tetrahydro-4-methylpyrido[4,3-c]pyridazine (M.P. of the maleate: 170° to 173°), this is reacted with o-fluorobenzoyl chloride, whereby 3-chloro-6-(o-fluorobenzoyl)-5,6,7,8-tetrahydro-4-methylpyrido[4,3-c]pyridazine is obtained (M.P. 151°-153°).
Sources & evidence
- ORD record
- ord-2efffb293c594128bf082482b3aec66c
- Source dataset
- uspto-grants-1981_04
- Patent number
- US04263298
Reaction notes
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