tert-Butanol → tert-butyl N-(pent-4-yn-1-yl)carbamate

Beteiligte Stoffe

Reaktionsschritte

To a magnetically stirred solution of 9.13 grams hex-5-ynoic acid (0.081 mol), 7.12 mL triethylamine (0.051 mol), 30 mL tert-butanol, was added 17.7 mL diphenylphosphoryl azide (0.082 mol) and the mixture heated to reflux for 3 hours. The reaction mixture was allowed to cool to room temperature and poured over a biphasic mixture of 200 mL water and 200 mL ether. The layers were separated and the organic layer was washed 1×50 mL 5% ethylene-diaminetetraacetic acid disodium salt, 1×50 mL 10% sodium bicarbonate, 1×50 mL brine, dried over magnesium sulfate and activated carbon, filtered and concentrated in vacuo. The resulting residue was further purified by column chromatography, using silica gel, eluting with 1:1 ether/hexane (TLC, SiO2, 1:3 ethyl acetate/hexane, Rf =0.18, ninhydrin char) to yield 3.8 grams (25%) N-boc-5-amino-1-pentyne. 1H NMR (CDCl3, dTMS) 4.65 (1H, bs, NH), 3.22 (2H, q, 3JHH=6 Hz, NCH2), 2.23 (2H, dt, 3JHH=6 Hz, 4JHH=3 Hz, CH2C∫C), 1.98 (1H, t, 4JHH=3 Hz, C∫CH), 1.73 (2H, p, 3JHH=6 Hz, CH2), 1.42 (9H, s, t-Bu)

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