4-Ethyl-5-methyl-2H-1,2,4-triazol-3(4H)-one synthesis

Yield:58910-25-1 10%

Reaction Conditions:

Stage #1: ethanamine hydrochloridewith sodium ethanolate in ethanol at 20; for 0.0833333 h;
Stage #2: (E)-ethyl 2-(1-ethoxyethylidene)hydrazine carboxylate in ethanol;Reflux;

Steps:

1 Step 1

Ethanamine hydrochloride (2.0 g, 10 mmol) was dissolved in absolute EtOH (200 mL) to which a suspension of sodium ethoxide (1.33 g, 19.5 mmol) in absolute EtOH (70 mL) was added and reaction was stirred for 5 min at room temperature. A solution of (E) -ethyl 2- (1-ethoxyethylidene) hydrazine carboxylate (1.6 g, 19.5 mmol) in absolute EtOH (50 mL) was added dropwise and reaction refluxed for 4 h. The reaction was then cooled to room temperature and filtered over a celite pad. The eluant was dried under reduced pressure and the resultant residue was recrystallised (through a hot filtration) from EtOAc to give the pure product. Isolated yield: 183 mg (10%) ; White crystals (recrystallised from EtOAc) ; LCMS (ES, m/z) : 128.1 [M+H]⁺.

References:

WO2021/233397,2021,A1 Location in patent:Paragraph 0124