2-Hydrazinoethanol → 2-[(2E)-2-[(3,5-dibromo-4-pyridinyl)methylidene]hydrazinyl]ethanol

Participants

Reaction Conditions

Reaction Steps

In analogy to GP1, 468 mg of 3,5-dibromo-pyridine-4-carbaldehyde (1.77 mmol, 1 eq; commercially available or prepared as described in U.S. Pat. No. 6,232,320 or WO2005110410) were dissolved in 8 mL 1-propyl alkohol, treated with 0.36 mL 2-hydrazino-ethanol (5.3 mmol, 3 eq.) and heated to 120° C. for 30 min (employing a Biotage Initiator® microwave oven). The reaction mixture was concentrated, the residue partitioned between water and ethyl acetate, the aqueous layer reextracted with ethyl acetate, the combined organic layers dried and concentrated in vacuo to yield 530 mg of the desired product (1.64 mmol, 93% yield), which was used in the subsequent cyclization without further purification steps.

Provenance & Evidence