Benzyl prop-2-yn-1-ylcarbamate → Benzyl 3-(6-{3-[(tert-butoxycarbonyl)amino]prop-1-ynyl}pyridin-3-yl)prop-2-ynylcarbamate

Participants

Reaction Steps

A mixture of tert-butyl 3-(5-bromopyridin-2-yl)prop-2-ynylcarbamate (3-1) (1.44 g), N-Cbz propargylamine (1.09 g), Pd(PPh3)2Cl2 (73 mg), and CuI (10 mg) in diisopropylamine (25 mL) was heated under reflux under a nitrogen atmosphere for 3 hours. The mixture was cooled to ambient temperature and diluted with ethyl acetate (70 mL). The precipitates were filtered and rinsed with ethyl acetate (30 mL). The filtrate and washings were combined, concentrated under reduced pressure, and purified by silica gel column chromatography using a mixture of MTBE and hexanes (2:3 to 4:1). The fractions containing the product were combined and concentrated under reduced pressure. The residue was crystallized from MTBE. Crystals were filtered, washed with MTBE, and dried to give 6-1 (1.07 g). An additional 120 mg of 6-1 was isolated from the mother liquors and washings.

Provenance & Evidence