Toluene → [1-(5-Tert-butyl-isoxazol-3-ylcarbamoyl)butyl]-carbamic acid tert-butyl ester

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Reaction Steps

To a solution of 5-tert-butyl-isoxazol-3-ylamine hydrochloride (1.22 g, 8.69 mmol) in THF was added 2 M AIMe3 in toluene (4.3 ml, 8.6 mmol) at room temperature and stirred for 1 hr. A solution of 2-tert-butoxycarbonylamino-pentanoic acid methyl ester (1.005 g, 4.34 mmol) in THF was added and the resulting mixture was stirred at room temperature over the weekend. The mixture was quenched with Rochelle salt and extracted with ethyl acetate. The organic layer was separated, dried and concentrated to give 2.08 g of the title compound as a crude oil. The oil was purified by silica gel column chromatography using 1% methanl in methylenechloride as eluent to give the title compound as a white solid (0.554 g). 1H NMR (CDCl3) □ 8.8 (brs, 1H), 6.7 (s, 1H), 4.85 (brs, 1H), 4.22 (m, 1H), 1.9 (m, 1H), 1.4-1.7 (m, 3H), 1.45 (s, 9H), 1.44 (s, 9H), 0.97 (t, 3H) ppm. LC-MS M+1=340.3.

Provenance & Evidence