Hydrazine → 3-Chloro-6-hydrazinyl-4-(trimethylsilyl)pyridazine

Participants

Reaction Conditions

Reaction Steps

A round-bottom flask under N2 was charged with 20 (13.6 g, 61.4 mmol) and anhydrous hydrazine (1M in THF, 184 mL, 184 mmol) followed by diisopropylethyl amine (11 mL, 61.4 mmol). The reaction was heated to a gentle reflux (70-75° C., external temperature) monitoring the reaction by LCMS. After 4 days the dark mixture was cooled, silica gel (20 g) was added and the mixture was concentrated. The crude mixture was combined with the crude material from a second reaction (16 mmol) and purified on a silica column (120 g, 0-5% MeOH/dichloromethane) to provide 7.5 g (45%) of 21 as a reddish oil/solid mix. Some trace impurities and residual diisopropylethyl amine remained. The product was used ‘as is’ in the next step.

Provenance & Evidence