Triethyloxonium tetrafluoroborate → 7-[(2,4-Dichloro-3-fluorophenyl)carbonyl]-3-(5-methyl-1,3-thiazol-4-yl)-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazine

Participants

Reaction Conditions

Reaction Steps

A solution of 4-[(2,4-dichloro-3-fluorophenyl)carbonyl]-2-piperazinone (I37)(250 mg, 0.859 mmol) in dry dichloromethane (DCM) (2147 μl) was stirred at room temperature under an atmosphere of argon. Triethyloxonium tetrafluoroborate (179 mg, 0.945 mmol) was added to the stirred solution and the solution was stirred for 2 hours. 5-methyl-1,3-thiazole-4-carbohydrazide (I123) (162 mg, 1.031 mmol) was then added and the resulting solution was stirred for 65 hours (over the weekend), during which time the solvent evaporated. The residue was redissolved in 1-butanol (2147 p1) and the resulting mixture was heated to 110° C. for 3 hours. The solution was allowed to cool to room temperature before being concentrated under reduced pressure to give a yellow coloured oil. The oil was redissolved in DCM (approx. 30 ml) and the organics were subsequently washed with NaHCO3 (sat. aqueous solution approx. 20 ml) and brine (approx. 20 ml). The organics were dried over MgSO4, filtered and concentrated under reduced pressure to give a yellow coloured oil. The oil was chromatographed [SiO2, 0-10% MeOH in DCM] to give a pale yellow coloured oil. The oil was subsequently further purified using MDAP (formic acid method) to give a white coloured solid of desired material in 68 mg.

Provenance & Evidence