Hydrochloric Acid → HCID 178445967, compound

Participants

Reaction Steps

To a suspension of 240 mg of N-[2-(1-naphthylmethyl)-3-(piperidinocarbonyl)propionyl]-L-histidine hydrazide in 3 ml of dry N,N-dimethylformamide were added successively 0.32 ml of a dry 5.1N-hydrogen chloride in N,N-dimethylformamide solution and 0.08 ml of isoamyl nitrite at -20° C. with stirring. After disappearance of hydrazide compound, the reaction mixture was cooled to -30° C. and neutralized with 0.23 ml of triethylamine to prepare a solution of N-[2-(1-naphthylmethyl)-3-(piperidinocarbonyl)propionyl]-L-histidine azide. The cold azide solution was added dropwise to a solution of 120 mg of isopropyl (2RS, 3S)-3-amino-2-hydroxy-5-methylhexanoate hydrochloride and 0.07 ml of triethylamine in 2 ml of dry N,N-dimethylformamide under ice-cooling with stirring, and the mixture was stirred for 16 hours. The reaction mixture was evaporated under reduced pressure. A 5% aqueous sodium bicarbonate solution was added to the residue. The mixture was extracted with ethyl acetate, and the ethyl acetate layer was washed with a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate, and evaporated under reduced pressure. The residue was separated by silica gel flash column chromatography (eluent: chloroform/methanol=20/1 by volume), and fraction containing desired product which has Rf1 value of 0.63 was combined and purified to obtain 18 mg of isopropyl (2RS, 3S)-3-{N-[ 2-(1-naphthylmethyl)-3-(piperidinocarbonyl)propionyl]-L-histidyl}amino-2-hydroxy-5-methylhexanoate as a white powder.

Provenance & Evidence