Ethylhydrazine → N-[(E)-(3,5-dibromo-4-pyridinyl)methylideneamino]ethanamine

Participants

Reaction Conditions

Reaction Steps

In analogy to GP 1, 2.65 g of 3,5-dibromo-pyridine-4-carbaldehyde (10 mmol, 1 eq; commercially available or prepared as described in U.S. Pat. No. 6,232,320 or WO2005110410) were dissolved in 32 mL 1-propyl alkohol, treated with 2.25 g N-ethyl hydrazine (oxalate salt; 15 mmol, 1.5 eq.) and heated to 100° C. for 30 min (employing a Biotage Initiator® microwave oven in batch mode). The reaction mixture was concentrated, the residue partitioned between conc. aq. sodium bicarbonate solution and ethyl acetate, the aqueous layer reextracted with ethyl acetate, the combined organic layers dried and concentrated in vacuo to yield 3.08 g of the desired product (10 mmol, quantitative yield), which was used in the subsequent cyclization without further purification steps.

Provenance & Evidence