The compound 2 (0.21g, 0.25mmol) was dissolved in 1ml of pyridine and 1ml of acetic anhydride1,2. The mixture was heated at reflux during 1h with magnetic stirring, and then evaporated under reduced pressure. The residue was purified on silica gel column using hexane: ethyl acetate (80:20) as eluent led to 2 (91.04 mg, 0.16 mmol) in 64 % yield.
Melting point: 185-186 °C (Hexane)
MS (EI, 70eV): 569 (M+.).
1H NMR (300 MHz, CDCl3) d(ppm): 8.75 (NH, s); 2.21, 2.25 (COCH3, 2s); 0.74 (3H-18, s); 1.15 (3H-19, s); 0.87 (3H-21, d, J = 6 Hz); 0.84 (3H-26, d, J = 2 Hz ); 0.85 (3H-27, d, J = 2 Hz ); 0.87 (3H-28, s); 1.10 (3H-29, d, J = 6 Hz ).
13C NMR (75 MHz, CDCl3) d(ppm): 36.42 (C-1); 37.36 (C-2); 100.04 (C-3); 51.29 (C-4); 50.74 (C-5); 21.80 (C-6); 28.30 (C-7); 129.05 (C-8); 131.13 (C-9); 36.31 (C-10); 22.00 (C-11); 25.50 (C-12); 44.89 (C-13); 49.53 (C-14); 30.84 (C-15); 29.85 (C-16); 46.46 (C-17); 15.80 (C-18); 18.20 (C-19); 36.01 (C-20); 18.71 (C-21); 35.86 (C-22); 24.32 (C-23); 32.45 (C-24); 34.60 (C-25); 21.75 (C-26); 21.85 (C-27); 24.25 (C-28); 14.25 (C-29); 143.17 (C=N); 170.15, 171.00 (COCH3); 22.50, 24.25 (COCH3).
MS (m/z): 569 (10%), 428 (42%), 315 (85%).
Supplementary materials
Supplementary File 1Supplementary File 2Supplementary File 3Acknowledgments
We would like to thank Pr. A. Idmessaaoud for helpful discussions.
References
- Daoubi, M.; Benharref, A.; Pierrot, M. Acta Cryst. 2001, E57, o1187–1188.
- Mazoir, N.; Auhmani, A.; Ait Itto, My. Y.; Benharref, A. Molbank 2004, M365.
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