1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → methyl 2-(4-(((1R,3S)-3-((tert-butoxycarbonyl)amino)-2,2,3-trimethylcyclopentyl)amino)-3-carbamoylpyrrolo[1,2-b]pyridazine-6-carbonyl)hydrazinecarbodithioate

Participants

Reaction Steps

To a solution of 4-((1R,3S)-3-(tert-butoxycarbonylamino)-2,2,3-trimethylcyclopentylamino)-3-carbamoylpyrrolo[1,2-b]pyridazine-6-carboxylic acid (500 mg, 1.122 mmol, from Step 3 of Example 346). HOBT (206 mg, 1.347 mmol) and DIEA (0.490 mL, 2.81 mmol) in DMF (4 mL) were added EDCI (280 mg, 1.459 mmol) and methyl hydrazinecarbodithioate (144 mg, 1.178 mmol) at 23° C. The reaction mixture was stirred for 1.5 hrs followed by the addition of 25 mL of water. The solids were removed. The water phase was extracted with EtOAc (2×30 mL). The combined organic phase was washed with 10% LiCl solution (2×20 mL), 20 mL of brine and dried over Na2SO4. Filtration and concentration gave methyl 2-(4-(((1R,3S)-3-((tert-butoxycarbonyl)amino)-2,2,3-trimethylcyclopentyl)amino)-3-carbamoylpyrrolo[1,2-b]pyridazine-6-carbonyl)hydrazinecarbodithioate (466.5 mg, 76% yield). MS (ES+) m/z: 550.08 (M+H); HPLC retention time: 3.168 min (analytical HPLC Method F).

Provenance & Evidence