5-Methyl-3(2H)-pyridazinone

5-Methyl-2H-pyridazin-3-one 5-Hydroxy-4-methyl-5H-furan-2-one (10.0 g, 87.6 mmol) and hydrazine hydrate (4.38 g, 87.6 mmol) were stirred vigorously at room temperature for 1.5 hours in tetrahydrofuran. A solid began to precipitate and the reaction was heated at 60° C. overnight. The crude reaction mixture was concentrated onto silica gel and purified by column chromatography (0 to 10percent methanol in 1:1 EtOAc/dichloromethane) to give 7.7 g (80percent) of the title compound.5-Methyl-2H-pyridazin-3-one γγ°5-Hydroxy-4-methyl-5H-furan-2-one (10.0 g, 87.6 mmol) and hydrazine hydrate (4.38 g, 87.6 mmol) were stirred vigorously at r.t. for 1.5 hours in tetrahydrofuran. A solid began to precipitate and the reaction was heated at 60 °C overnight. The crude reaction mixture was concentrated onto silica gel and purified by column chromatography (0 to 10 percent methanol in 1 :1 EtOAc / dichloromethane) to give 7.7 g (80 percent) of the title compound. 5-Methyl-2H-pyridazin-3-one γγ°5-Hydroxy-4-methyl-5H-furan-2-one (10.0 g, 87.6 mmol) and hydrazine hydrate (4.38 g, 87.6 mmol) were stirred vigorously at r.t. for 1.5 hours in tetrahydrofuran. A solid began to precipitate and the reaction was heated at 60 °C overnight. The crude reaction mixture was concentrated onto silica gel and purified by column chromatography (0 to 10 percent methanol in 1 :1 EtOAc / dichloromethane) to give 7.7 g (80 percent) of the title compound. Example 295-Methyl-2H-pyridazin-3-one The 4, 4-dimethoxy-3-methyl-but-2-enoic acid ethyl ester (Qi-Ying Hu, Pankaj D. Rege, and E. J. Corey, J. Am. Chem. Soc., 2004, 126, 5984) (82 g, 440 mmol) was mixed with hydrazine hydrate (50 g, 999 mmol) at room temperature. The mixture was heated at 60° C. for 4 h. After evaporation of solvents the oil residue was further dried under vacuum. To the resulting residue was added 6 M aq. HCl. The mixture was heated at 60° C. for 5 h. The solvents were removed in vacuo. To the residue was added methanol three times, followed by concentration. To the resulting residue was treated with dry ethanol followed by filtration to removed insoluble solid. The filtrate was concentrated to dryness. To the resulting residue was added dry i-PrOH and 20 g anhydrous KStep 14A: 5-Methyl-2H-pyridazin-3-one; The 4, 4-dimethoxy-3-methyl-but-2-enoic acid ethyl ester (Qi-Ying Hu, Pankaj D. Rege, and E. J. Corey, J. Am. Chem. Soc., (2004), 126, 5984) (82 g, 440 mmol) was mixed with hydrazine hydrate (50 g, 999 mmol) at room temperature. The mixture was heated at 60° C. for 4 h. After evaporation of solvents the oil residue was further dried under vacuum. To the resulting residue was added 6 M aq. HCl. The mixture was heated at 60° C. for 5 h. The solvents were removed in vacuo. To the residue was added MeOH three times, followed by concentration. The resulting residue was treated with dry EtOH followed by filtration to remove insoluble solids. The filtrate was concentrated to dryness. To the resulting residue was added dry IPA and 20 g anhydrous KStep 10A: 5-Methylpyridazin-3(2H)-one; The 4, 4-dimethoxy-3-methyl-but-2-enoic acid ethyl ester (Qi-Ying Au, Pankaj D. Rege, and E. J. Corey, J. Am. Chem. Soc., 2004, 126, 5984) (82 g, 440 mmol) was mixed with hydrazine hydrate (50 g, 999 mmol) at room temperature. The mixture was heated at 60° C. for 4 h. After evaporation of solvents the oil residue was further dried in vacuo. To the resulting residue was added 6 M aq. HCl. The mixture was heated at 60° C. for 5 h. The solvents were removed in vacuo. To the residue was added MeOH three times, followed by concentration in vacuo. The resulting residue was treated with dry EtOH followed by filtration to remove the solids. The filtrate was concentrated in vacuo. To the resulting residue was added dry IPA and 20 g anhydrous KStep 7A: 5-Methylpyridazin-3(2H)-one The 4, 4-dimethoxy-3-methyl-but-2-enoic acid ethyl ester (Qi-Ying Hu, Pankaj D. Rege, and E. J. Corey, J. Am. Chem. Soc., (2004), 126, 5984) (82 g, 440 mmol) was mixed with hydrazine hydrate (50 g, 999 mmol) at room temperature. The mixture was heated at 60° C. for 4 h. After evaporation of solvents the oil residue was further dried under vacuum. To the resulting residue was added 6 M aq. HCl. The mixture was heated at 60° C. for 5 h. The solvents were removed in vacuo. To the residue was added MeOH three times, followed by concentration in vacuo. To the resulting residue was treated with dry ethanol followed by filtration to removed insoluble solid. The filtrate was concentrated to dryness. To the resulting residue was added dry IPA and 20 g anhydrous KStep 13A:

Molecular Weight:110.11
XLogP3:-0.3
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:2
Exact Mass:110.048012819
Monoisotopic Mass:110.048012819
Topological Polar Surface Area:41.5
Heavy Atom Count:8
Complexity:169
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes