Tributylamine → 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 (2.18 g), 0.93 g of tributylamine, 0.1 g of N-hydroxybenzotriazole and 0.05 g of 4-dimethylaminopyridine were dissolved in 20 ml of dimethylformamide and a solution of 1.06 g of dicyclohexylcarbodiimide in 5 ml of dimethylformamide was added. After stirring for 15 minutes at room temperature, a solution of 0.94 g Girard Reagent P in 20 ml of dimethylformamide was added. After 3 hours of stirring, formed dicyclohexylurea was filtered off and the dimethylformamide of the filtrate was distilled off. Addition of 50 ml of tetrahydrofuran to the residue yielded 1.8 g of crude product, which was purified by column chromatography on HP-20 using water as an eluent, yielding 0.63 g of product, melting point 235° C.

Provenance & Evidence