Dimethylformamide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

[3S-[3α(Z),4β]]-3-[[(2-Amino-4-thiazolyl)-[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-4-methyl-2-oxo-1-azetidinesulfonic acid (0.66 g), 0.3 g of tributylamine, 0.26 g of N-hydroxybenzotriazole and 0.01 g of dimethylaminopyridine were dissolved in 10 ml of dimethylformamide and a solution of 0.33 g of N,N-dicyclohexylcarbodiimide in 5 ml of dimethylformamide was added. After stirring for 20 minutes at room temperature, a solution of 0.28 g of (aminothioxomethyl)-hydrazine in 10 ml of dimethylformamide was also added. Stirring was continued for 24 hours, formed dicyclohexylurea was filtered off and the dimethylformamide of the filtrate was distilled off. The residue was dissolved in 20 ml tetrahydrofuran/methanol (1.1), filtered and a solution of 0.51 g of potassium perfluorobutanesulfonate in 5 ml of methanol was added followed by 20 ml of ether. The resultant precipitate of crude product was purified by column chromatography on HP-20 using water as an eluent and yielding 0.8 g of the title compound, melting point 218° C., (dec).

Provenance & Evidence