Methyl chloroformate → [3-(3-Methyl-1,2,4-triazolo[4,3-b]pyridazin-6-yl)phenyl]carbamic acid, methyl ester
Reaction equation
[CH3:1][C:2]1[N:6]2[N:7]=[C:8]([C:11]3[CH:16]=[CH:15][CH:14]=[C:13]([NH2:17])[CH:12]=3)[CH:9]=[CH:10][C:5]2=[N:4][N:3]=1.Cl[C:19]([O:21][CH3:22])=[O:20].C(N(C(C)C)CC)(C)C>ClCCl>[CH3:1][C:2]1[N:6]2[N:7]=[C:8]([C:11]3[CH:12]=[C:13]([NH:17][C:19](=[O:20])[O:21][CH3:22])[CH:14]=[CH:15][CH:16]=3)[CH:9]=[CH:10][C:5]2=[N:4][N:3]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 1.0 g of 3-methyl-6-[3-(amino)phenyl]-1,2,4-triazolo[4,3-b]pyridazine in 200 ml of dichloromethane was added 0.36 ml of methyl chloroformate and 0.81 ml of diisopropylethylamine. The mixture was stirred for 3 hours and the solid collected, giving 0.9 g of [3-(3-methyl-1,2,4-triazolo[4,3-b]pyridazin-6-yl)pheny]carbamic acid, methyl ester. A 0.8 g portion of this compound was suspended in 100 ml of dimethylformamide together with 0.15 g of hexane washed sodium hydride (50% in oil). After 30 minutes, 0.22 ml of ethyl iodide was added. This mixture was stirred 2 hours, then poured into saturated aqueous sodium bicarbonate and extracted with dichloromethane. The extracts were combined, dried and evaporated in vacuo. The residue in dichloromethane: methanol (95:5) was filtered through a short pad of silica gel and the filtrate was concentrated. The resulting solid was recrystallized from dichloromethane-hexane, giving 0.32 g of the desired product as off-white crystals, mp 176°-178° C.
Workup
- customthe solid collected
Sources & evidence
- ORD record
- ord-6fc14598221141b39afafe63ab098905
- Source dataset
- uspto-grants-1990_01
- Patent number
- US04892873
Reaction notes
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