2-(3,4-Dimethylphenyl)-2,4-dihydro-5-methyl-3H-pyrazol-3-one

3, 4-dimethylphenylhydrazine hydrochloride (8.7g, 50m mol), was dissolved in 100mlof glacial acetic acid, ethyl acetoacetate (6.5g, 50m mol) and sodium acetate (4.1g, 50m mol) , 120 reflux reaction 7h, TLC detection of raw materials reaction completely.Evaporated under reduced pressureglacial acetic acid, was added 100ml of water, 100ml of ethyl acetate 4 times the combined ethyl acetatelayer was not over anhydrous sodium sulfate, and concentrated under reduced pressure to give 1- (3, 4-dimethylphenyl) - 3- methyl-1hydrogen - pyrazol-5 (4 hydrogen) -one (8.3g, 82percent yield)A solution of 3, 4-dimethylphenylhydrazine (7.3 g; 0.053 mol.) and ethyl acetoacetate (6.9 g; 0.053 mol.) in glacial acetic acid (50.0 mL) was stirred and heated at 100 for 24 h. The solvent was evaporated and the product purified by chromatography (silica gel, 50percent ethyl acetate/hexanes) to afford the title compound (16.8 g; 64percent). MS(ES) m/z 203 [M+H].A pyrazole (j) prepared by the method of Scheme II is treated with a sulfonyl azide such as p-toluenesulfonyl azide in the presence of a base typically triethylamine or pyridine in a suitable solvent such as ethanol, methanol or tetrahydrofuran to afford diazopyrazole (k).A solution of 3, 4-dimethylphenylhydrazine (7.3 g; 0.053 mol.) and ethyl acetoacetate (6.9 g; 0.053 mol.) in glacial acetic acid (50.0 mL) was stirred and heated at 100 for 24 h. The solvent was evaporated and the product purified by chromatography (silica gel, 50% ethyl acetate/hexanes) to afford the title compound (16.8 g; 64%). MS(ES) m/z 203 [M+H].3) 190g of intermediate II and 2.86L of hydrochloric acid (2M) were weighed in a 10L four-necked flask, and 61.04g of 0.96 L aqueous solution of sodium nitrite was added to the system at a controlled temperature of 0 C. The starting material II was added at 0 C and stirred for 0.5 hours, 3.78 L of ethanol was added and the pH was adjusted to 7-8 with sodium bicarbonate. After stirring at room temperature for 24 hours, suction filtration was performed. The filter cake was slurried with 4.2 L of water for 0.5 h. The filter cake was acidified and slurried with 4.2 L of concentrated hydrochloric acid for 0.5 h. After the solution was dissolved under reflux, the temperature was lowered to 0 C, and the mixture was continuously stirred for 2 hours, and then filtered by suction. After the solid was put into air drying at 55 C for 12 hours, 128.72 g of a dark red solid was obtained. The yield was 35.1% and the purity was 99.1%

Molecular Weight:202.25
XLogP3:2
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:202.110613074
Monoisotopic Mass:202.110613074
Topological Polar Surface Area:32.7
Heavy Atom Count:15
Complexity:298
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes