Hydrochloric Acid → 3-tert-butyl-1,4-dihydro-1,2,4-triazol-5-one

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Reaction Steps

Semicarbazide hydrochloride (25.0 g, 224 mmol) was dissolved in water (200 mL). NaHCO3 (40.0 g, 476 mmol) was slowly added to the solution over 30 min at RT followed by the addition of trimethylacetyl chloride (30.0 g, 249 mmol). The mixture was stirred at RT for 12 h. Solids were collected by filtration, washed with cold water, and dried in vacuo. A solution of NaOH (20.0 g, 500 mmol) in water (200 mL) was added. The mixture was stirred at 100° C. for 2 h, cooled with an ice-bath, and neutralized by the drop-wise addition of concentrated HCl. The solids were collected by filtration, washed with water, and dried in vacuo to afford 3-(tert-butyl)-1H-1,2,4-triazol-5(4H)-one (19.6 g, 61.9%) as a white solid. 1H NMR (400 MHz, DMSO-d6): δ 11.26 (s, 1H), 11.04 (s, 1H), 1.16 (s, 9H); MS (ESI) m/z: 142.1 (M+H+).

Provenance & Evidence