4-METHYL-3(2H)-PYRIDAZINONE

A solution of bromine (27.4 ml, 0.535 mol) in glacial acetic acid (70 ml) was added dropwise to a solution of the product of step b) (25. 8 g, 0.232 mol) in glacial acetic acid (330 ml) whilst maintaining the temperature AT ~50 C. The mixture was then heated at 80 C for 2 h. The mixture was cooled to room temperature and concentrated to dryness. The solid residue was triturated with ether. The solid was then added to saturated NAHCO3 solution and extracted with ethyl acetate. The organic extract was dried over sodium sulphate, filtered and concentrated to dryness to give pale brown solid. (12.2 g, 48percent). 1H NMR (400 MHz, CDCL3) 8 11.50 (1 H, s), 7.71 (1 H, d, J=4. 0HZ), 7.10 (L H, d, J=2. 8HZ), 2. 23 (3 H, d, J= 1.1 Hz) ppm....d at room temperature for 2 hours and worked up in the customary manner and 2-(1, 3-benzodioxol-5-yl)-2-(2, 3-dihydro-4, 6-dimethylpyridazin-3-on-2-yl)N-(4-isopropylphenylsulfonyl)acetamide is obtained, m.p. 105. Analogously, by reaction of methyl benzo[1, 3]dioxol-5-ylbromoacetate with ... 4, 5, 6-trimethyl-2, 3-dihydropyridazin-3-one 4-methyl-2, 3-dihydropyridazin-3-one 5-(4-methoxyphenyl)-2H-3, 6-dihydro-1, 3, 4-thiadiazin-2-one ...The product of step c) (12.2 g, 0.112 mol) in phosphorus oxychloride (125 ML) was heated at 90°C for 3 h. The mixture was cooled to room temperature and concentrated almost to dryness. The residue was poured into ice/water, made basic by careful addition of 4N NAOH and extracted with ether. The aqueous phase was re-extracted with DCM. The organic phases were combined, washed with water, dried over sodium sulphate, filtered and concentrated to dryness. The residue was purified by flash chromatography on silica gel in 2: 1 ethyl acetate- isohexane to give an orange solid (11.2 g, 78percent). LH NMR (400 MHz, CDCIs) 8 8.97 (1 H, d, J = 4. 9 HZ), 7.35 (1 H, d, J = 4. 9 HZ), 2.44 (3 H, s) ppm.

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