Hydrazine hydrate (1:1) → 6-(4-Hydroxyphenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one
Reaction equation
[OH:1][C:2]1[CH:15]=[CH:14][C:5]([C:6]([CH:8]([CH3:13])[CH2:9][C:10](O)=[O:11])=O)=[CH:4][CH:3]=1.O.[NH2:17][NH2:18]>CC(O)C>[OH:1][C:2]1[CH:15]=[CH:14][C:5]([C:6]2[CH:8]([CH3:13])[CH2:9][C:10](=[O:11])[NH:17][N:18]=2)=[CH:4][CH:3]=1Participants
Conditions
- Temperature
- 65 °C
Procedure
1 l three-necked round-bottomed flask equipped with a condenser connected to a gas inlet, a glass rod air driven stirrer and a thermometer was charged with 63.8 g, (306 mmol) of (±)-3-(4'-hydroxybenzoyl)-3-methylpropanoic acid from Example H and 2-propanol (400 ml) at 40° C. The solution was placed under an atmosphere of nitrogen and heated to 65° C. Then hydrazine monohydrate (45 ml, 2.2 mol) was added dropwise over 10 min. The reaction mixture was heated to 80°-81° C. (reflux), stirred for 1 hour then slowly cooled to 3° C. over 1 hour with gentle stirring. The formed precipitate was collected by suction filtration, triturated in a 1 L beaker with deionized water (300 ml) at 23° C. for 2 hrs and collected by suction filtration. The solids were dried to constant weight in an air oven (90° C.) to provide 51.9 g (83.5%) of pure (±}-4,5-dihydro-6-(4'-hydroxyphenyl)-5-methyl-3(2H)-pyridazinone, m.p. 268°-273° C.
Workup
- custom1 l three-necked round-bottomed flask equipped with a condenser
- customconnected to a gas inlet
- temperatureThe reaction mixture was heated to 80°-81° C.
- temperature(reflux)
- temperaturethen slowly cooled to 3° C. over 1 hour with gentle stirring
- filtrationThe formed precipitate was collected by suction filtration
- customtriturated in a 1 L beaker with deionized water (300 ml) at 23° C. for 2 hrs
- filtrationcollected by suction filtration
- customThe solids were dried to constant weight in an air oven (90° C.)
Sources & evidence
- ORD record
- ord-25b7cc7f2c164efea3222ebcd849dccf
- Source dataset
- uspto-grants-1993_04
- Patent number
- US05204463
Reaction notes
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