Ethyl bromoacetate → Tert-butyl 2-(2-ethoxy-2-oxoethyl)hydrazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 500 mL 3-neck round bottom flask was charged with t-butyl carbazate (15.0 g, 113.5 mmol), toluene (120 mL), triethylamine (18.98 mL, 136.2 mmol) and ethyl bromoacetate (15.10 mL, 136.2 mmol). The mixture was heated in an oil bath to about 100° C. for 19 hours. The reaction mixture was allowed to cool to room temperature and was then filtered, washing the solid triethylamine bromide with ethyl acetate/hexanes. The combined organics were washed successively with saturated sodium bicarbonate, water and brine, dried over sodium sulfate, filtered, concentrated and dried in vacuo to give a crude reddish oil (20.78 g). The crude material was absorbed onto Celite® and purified on a 10×20 cm silica gel column eluting with 15% (4 L), 20% (7 L), 30% (2 L), 40% (2 L), 50% (2 L) ethyl acetate/hexanes and finally ethyl acetate (2 L). The desired fractions were combined and concentrated to give an oil (10.85 g) which solidified upon standing. The residue was concentrated with dichloro-methane/toluene and dried in vacuo to give compound A (44%) as an off-white solid. TLC: Rf =0.13, silica gel, 30% ethyl acetate/hexanes, UV and PMA detection.

Provenance & Evidence