Diisopropylethylamine → HCID 69182632, compound

Participants

Reaction Steps

To a solution of 73.9 mg (0.281 mmol) of 8-methyl-5,6,7,8-tetrahydropyrido[3,4-c]pyridazine, trifluoroacetate salt (Intermediate 34), 93.6 mg (0.281 mmol) of (3R)-3-[(tert-butoxycarbonyl)amino]4-(2,4,5-trifluorophenyl)butanoic acid (Intermediate 3) and 0.150 mL (0.843 mmol) of N,N-diisopropylethylamine in 2.5 ml of DMF were added O-(7-azabenzotriazol-yl)-N,N,N′,N′-tetra-methyluronium hexafluorophosphate (HATU; 128 mg, 0.337 mmol), 1-hydroxy-7-azabenzotriazole (HOAt; 45.9 mg, 0.337 mmol). The reaction was stirred at room temperature for 18 h. Then the reaction mixture was partitioned between ethyl acetate and 0.5M aqueous sodium bicarbonate solution. The aqueous phase was extracted with three portions of ethyl acetate. The combined organic phase was washed with brine, dried over magnesium sulfate and concentrated in vacuo. The mixture was purified by preparative TLC (100% ethyl acetate), then by chiral HPLC (ChiralCell OJ column, 14% ethanol/hexanes) to afford the title compound as a solid. The slower eluting isomer was used in Step B below. LC/MS: 409 (M+1-56).

Provenance & Evidence