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

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Reaction Steps

A mixture of 4-[(2,4-dichloro-3-fluorophenyl)carbonyl]-2-piperazinone (I37) (170 mg, 0.585 mmol) in dry dichloromethane (DCM) (1.463 ml) was stirred at room temperature under an atmosphere of argon. Triethyloxonium tetrafluoroborate (122 mg, 0.644 mmol) was added and the resulting mixture was stirred for 2½ hours. After this time, 4-methyl-1,3-thiazole-2-carbohydrazide (I121)(115 mg, 0.732 mmol) was added and the solution was stirred for a further 18 hours at room temperature. The solution was concentrated under reduced pressure and then redissolved in 1-butanol (1.463 ml) and the resulting solution was heated at reflux for 4 hours. The solution was cooled to room temperature, diluted with DCM (approx. 50 ml) and washed with water (2× approx. 20 ml). The organics were dried over MgSO4, filtered and concentrated under reduced pressure to give a yellow coloured oil. The residue was purified using MDAP and dried under vacuum for 4 days to give the desired product in 42 mg.

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