Tetrahydrofuran → Ethyl 2-chloro-2-(hydroxyimino)acetate

Ethyl chloroximidoacetate is prepared starting from glycine ethyl ester hydrochloride according to a literature procedure (G. S. Skinner, J. Am. Chem. Soc. 46 (1924), 731). 14.55 g (0.096 mol) of this product are added dropwise, dissolved in 100 ml of tetrahydrofuran, at room temperature to a solution of 17.07 g (0.11 mol) of the protected propargylamine from a) and 11.14 g (0.11 mol) of triethylamine in 400 ml of diethyl ether during the course of 5 hours. The mixture is stirred overnight, washed with dil. ammonium chloride solution and water, dried and concentrated in vacuo. Yield: 25 g. The product ethyl 5-tert.-butoxycarbonyaminomethylisoxazole-3-carboxylate can be further purified by crystallization from ethyl acetate/petroleum ether, resulting in a melting point of 72° C.

1. washwashed with dil. ammonium chloride solution and water
2. customdried
3. concentrationconcentrated in vacuo
4. custom-butoxycarbonyaminomethylisoxazole-3-carboxylate can be further purified by crystallization from ethyl acetate/petroleum ether
5. customresulting in a melting point of 72° C.

ORD record

ord-a11ff1ee0983424298aa28df5a5eff34

Source dataset

uspto-grants-1993_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05273989