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

Temperature

100 °C

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.

1. customcommercially available or prepared
2. dissolution6,232,320 or WO2005110410) were dissolved in 32 mL 1-propyl alkohol
3. concentrationThe reaction mixture was concentrated
4. customthe residue partitioned between conc. aq. sodium bicarbonate solution and ethyl acetate
5. customthe combined organic layers dried
6. concentrationconcentrated in vacuo

ORD record

ord-8d5e6c9f1cca4471b1c8ee247953a65c

Source dataset

uspto-grants-2013_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08481539B2