I. A. M. Saraireh / Tetrahedron Letters 53 (2012) 2023–2025
2025
additional 2 h. AcOH (12 lL, 17.2 mmol) in dry THF (5 ml) was
References and notes
added. The mixture was allowed to warm to room temperature
and H2O (20 ml) was added. The product was extracted with Et2O
(3 ꢂ 50 ml) and the combined organic extracts washed with satu-
rated aqueous NaHCO3 (50 ml) and brine (50 ml), dried over anhy-
drous Na2SO4, and concentrated under reduced pressure to give a
brown oil. Purification by column chromatography using EtOAc/n-
hexane (3:7) as eluent furnished the title compound 10 (2.996 g,
77%) as a yellow oil. Anal. Calcd C23H24N4O6 C 61.06, H 5.35, N
1. (a) Myers, A. G.; Gleason, J. L.; Yoon, T.; Kung, D. W. J. Am. Chem. Soc. 1997, 119,
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12.38. Found: C, 60.99; H, 5.21; N, 12.24. mmax(KBr) 3315 (NH);
2099 (CN2); 1705 (CO2CH2); 1631 (COCN2); 1520 cmꢀ1 (Ph). 1H
NMR (300 MHz, CDCl3): d = 1.21 (6H, d, J = 7 Hz, CH3CH), 4.48 (2H,
m, 2 N–CH–CO), 5.11 (4H, s, 2 OCH2Ph), 5.41 (2H, br s, 2NH), 7.2–
7.40 (10 H, m, 2 Ph), 13C NMR (75 MHz, CDCl3): d = 18.4, 51.7,
55.1, 67.1, 128.2, 128.3, 128.6, 136.4, 155.9, 194.
Supplementary data
11. Bonini, B. F.; Comes-Franchini, M.; Fochi, M.; Mazzanti, G.; Ricci, A.; Varchi, G.
Polyhedron 2000, 19, 529.
Supplementary data associated with this article can be found, in