Diisopropylethylamine → HCID 67089528, compound

Participants

Reaction Steps

N-(9H-9-fluorenylmethoxycarbonyl)hydrazine hydrochloride (Compound 40; 500 mg, 1.72 mmol) and L-(+)-tartaric acid (Compound 15; 634 mg, 4.22 mmol) were dissolved by the addition of N,N-dimethylformamide (10 ml) and diisopropylethylamine (300 μl, 1.72 mmol). Next, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (485 mg, 2.53 mmol) was added, and this was followed by overnight stirring at room temperature. This was concentrated under reduced pressure; to the residue obtained, aqueous sodium hydrogen carbonate and diethyl ether were added; two liquid phases were separated. The water phase obtained was acidified with a 2N aqueous solution of potassium hydrogen sulfate under ice cooling, after which it was extracted with ethyl acetate. The organic phase was washed with saturated brine, after which it was dried with sodium sulfate. The solid was filtered and concentrated under reduced pressure, after which it was crystallized from methanol-diethyl ether to yield the desired 4-[N′-(9H-fluoren-9-ylmethoxycarbonyl)-hydrazino]-2,3-dihydroxy-4-oxo-butanoic acid (Compound 41: 413 mg, 63%).

Provenance & Evidence