2. Synthesis and X-Ray Crystal Structure of Pyrrolo[1,2-a]benzimidazoles By Prof. Adel M. Awadallah Islamic University of Gaza e-mail: awada@iugaza.edu.ps

3. Contents * Introduction * Reaction of Nitrilimines with 2- Cyanomethylbenzimidazole * Reaction of Nitrilimines with 2- aminobenzimidazole * Reaction of Nitrilimines with 2- Aminopyrimidine

4. Introduction * Nitriles in 1,3-Dipolar Cycloaddition – Synthesis of Heterocycles General Equation

5. Examples Y. Al-Soud, N. Al-Masoudi, A. R. S. Ferwanah, Bioorganic & Medicinal Chemistry, 2003, 11, 1701 – 1708.

6. Reaction of Nitrilimines with 2- Cyanomethylbenzimidazole (Expecting to get a triazole derivative)

7. Results M. Wt = 333 (351 – 18) → H 2 O is lost IR (CN is present, but no C=O)

8. Suggested Structure Elwan, N. Tetrahedron, 2004, 60, 1161-1166.

9. Which is the correct structure ???? Mass Spectra IR Spectra 1 H-NMR 13 C-NMR 2D-NMR Can not Help X-Ray Will Help

10. X-Ray Crystal Structure of the Product

11. Another Example of Structure Determination Problems

12. Which is the correct structure???? Mass Spectra IR Spectra 1 H-NMR 13 C-NMR Can not Help X-Ray Will Help

13. Lit 1: L. A. Vlasova, I. Ya. Postovskii, Khim. Geterotsikl. Soedin. 1971, 7, 700 Lit 2: A. Awadallah, P. Rademacher, R. Boese, J. Prakt. Chem. 1995, 337, 636 - 640

14. Reaction of Nitrilimines with 2-aminobenzimidazole

15. Spectral Data MS m/z (327/329 M +., chlorine isotopes). IR(KBr) υ 3416,3310,3297(3NH), 1683(C=O) cm -1 1 H-NMR(DMSO-D6) δ 2.5 (s, 3H, CH 3 ), 6.4 (s, 2H, NH 2 ), 6.6 (1H, d, 7.0 Hz, ArC-H), 6.8 (1H, t, 7.0 Hz, ArC-H), 7.0 (1H, t, 7.0 Hz, ArC-H), 7.2 (1H, d, 7.0 Hz, ArC-H), 7.4 (4H, 2d, 9.0 Hz, 4-ClC 6 H 4 ), 11.0 (s, 1H, NH); 13 C-NMR(DMSO-D6) δ 191.2 (C=O), 155.1, 144.7 (2C=N), 142.6, 134.1, 128.8, 126.7 (4ArC), 129.6, 121.7, 118.9, 117.0, 115.4, 108.1 (6ArC-H), 25.6 (CH 3 )

16. Reaction of Nitrilimines with 2-Aminopyrimidine

17. Spectral Data MS m/z (287 / 289 M +., chlorine isotopes). IR(KBr) υ No NH(s), No C=O 1 H-NMR (DMSO-D6) δ 2.51 (s, 3H, CH 3 ), 5.51 (1H, t, 11.0 Hz, ArC-H), 7.55 (2H, d, 9.0 Hz, ArC-H), 7.65 (1H, d, 11.0 Hz, CH), 7.92 (2H, d, 9.0 Hz, ArC-H), 8.66 (1H, d, 11.0 Hz, C-H), 13 C-NMR (DMSO-D6) δ 191.66 (C=O), 169.44, 160.96, 129.42, 124.99, 101.55 (5 Ar C-H), 161.44, 157.62, 136.82, 132.00 (4Ar C), 27.29 (CH 3 )

20. شكرا لكم لحسن استماعكم والشكر موصول لجامعة الأقصى والسلام عليكم ورحمة الله وبركاته