2-(TERT-BUTYL)-4,5-DICHLORO-2,3-DIHYDROPYRIDAZIN-3-ONE

Synthesis of 2-(i-butyl)-4, 5-dichloropyridazin-3(2H)-one (Compound 11); Solid i-butyl hydrazine hydrochloride (1 equiv) was added to a stirred solution of sodium hydroxide (0.95 equiv) dissolved in 10percent water/toluene mixture (6 vol) at ambient temperature. The resulting white suspension was cooled slightly while mucochloric acid (1 equiv) was slowly added. After completion of the addition, the reaction mixture was stirred at ambient temperature for 20-30 minutes followed by dropwise addition of acetic acid (0.95 equiv). The reaction mixture was heated to 45 - 50 °C and stirred for 18 h, until starting material was consumed, as measured by HPLC. The reaction solution was allowed to cool to ambient temperature and then was diluted with water (~7 vol) and the organic layer separated. The organic layer was cooled to 0 °C and washed with 30percent NaOH (3.6 vol), followed by 35percent HC1 (3.6 vol) and water (2 x 3.6 vol). The organic solution was concentrated under vacuum and restripped with methanol (1.5 vol) to yield compound 11 as a brown solid that was dried under vacuum at 35 °C (65-75percent yield, 100percent purity by HPLC).To a 1, 4-dioxane solution of the compound 3 (2 g, 9 mmol), an aqueous solution (15 mL) of potassium hydroxide (1.5 g, 27 mmol) was added, and the mixture was heated to reflux for 5 hours. The obtained mixture was poured into ice water, concentrated hydrochloric acid was added thereto, and a solid thus precipitated (crude form) was collected by filtration. The crude form was washed with water and heptane in this order, and thus compound 4 (1.6 g, yield 91%) was obtained.A potassium hydroxide (1.5 g, 27 mmol) aqueouscompound 3 (2 g, 9 mmol), and the mixed solution wassolution (15 mE) was added to a 1, 4-dioxane solution of therefluxed for five hours. The resulting mixed solution waspoured into ice water, concentrated hydrochloric acid wasadded thereto, and the precipitated solid (crude product) wascollected by filtration. The crude product was washed withwater and heptane in this order to obtain the compound 4 (1.6g, yield: 9 1%).Example 38 A; Synthesis of 2-(i-butyl)-4-chloro-5-hydroxypyridazin-3(2H)-one (Compound 17); A dry vessel was sequentially charged while stirring with compound 11 (lOOg), potassium hydroxide (76.1 g), and ethylene glycol (1 L). The resulting suspension was heated to 115 C and stirred at this temperature for 5 hrs. The brown solution was cooled to 0 C and 1 M hydrochloric acid solution (1 L) added slowly with stirring over 60 minutes, keeping the temperature below 25 C during the addition, resulting in precipitation of a light brown solid. The slurry was stirred for 2 hrs and filtered, washing the cake with cold water (4 x 500 mL) and ethanol (100 mL). The Crude compound 17 thus obtained was then recrystallized from hot ethanol (1 L), filtered, and dried under vacuum for 34 h at 45 C to yield pure compound 17 (68.3 g, 75% yield).Specific operation: Into a 250 mL three-necked flask, at 20 ± 5 deg. C was added 100 mmol KOH, 70 mL of ethylene glycol, stirred to dissolve KOH, added 20 mmol C, gradually warmed to 130 deg. C, TLC monitored the reaction progress, when the reaction was complete, the reaction solution was poured into 500 ML distilled water, then with 6 mol / L hydrochloric acid solution pH was adjusted to 1, a large amount of white solid precipitated, vacuum filtered, washed with distilled water, the filter cake was dried under infrared light to obtain the crude product D, recrystallized from ethanol, to obtain the target compound D as a pure product.3- (1-hydroxyethyl) -4-phenyl-1-oxaspiro [4.5] dec-3-en-2-one(2.72g, 0.01mol), Potassium carbonate (1.66g, 0.01 2mol), 2-tert-butyl-4, 5-dichloropyridazin-3 (2H) -one (commercially available, 2.42 g, 0.011 mol), Soluble in 20mL N, N-dimethylformamide, The reaction mixture was reacted at 80 C for 1 h.After the reaction was monitored by TLC, ethyl acetate and water were added for extraction. The organic phase was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and desolvated under reduced pressure. The residue was subjected to column chromatography (eluent: ethyl acetate and petroleum ether (Boiling range 60-90 C), volume ratio is 1: 4) to obtain compounds 8-9, 2.87 g, colorless oil, 63% 254 yield.

Pyridazinone, 2-tert-butyl-4,5-dichloro-3(2H)-pyridazinone, is an important intermediate for the synthesis of acaricide pyridazin.

Molecular Weight:221.08
XLogP3:2.1
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:220.0170183
Monoisotopic Mass:220.0170183
Topological Polar Surface Area:32.7
Heavy Atom Count:13
Complexity:302
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes