Efficient Synthesis of Triazolo[4,5-d]pyrimidine-7-carbonitriles and Imidazole-4,5-dicarbonitriles Using Triethylorthoalkylates and Their Structural Characterisation by Single-Crystal X-Ray Diffraction


  • Amal Al-Azmi Associate professor of organic chemistry - Kuwait University




triethylorthoalkylates, triazole, imidazole, pyrimidine, crystal structure, Hirshfeld surface analysis



Cyclisation of 5-amino-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbimidoyl cyanide and 3-amino-3-((Z)-2-cyano-2-phenylvinylamino) maleonitrile using either triethyl orthoformate or triethyl orthopropionate in dimethylformamide (DMF):1,4-dioxane (1:1 v/v) mixture under reflux conditions afforded 5-alkyl-3-(4-nitrophenyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine-7-carbonitriles and (Z)-1-(2-cyano-2-phenylvinyl)-2-alkyl-1H-imidazole-4,5-dicarbonitriles, respectively, in moderate to good yields. The structures of these novel compounds were confirmed with 1H/13C nuclear resonance (NMR), infrared spectroscopy (IR), and high-resolution mass spectroscopic methods. Two representative compounds from these molecules, namely 5-ethyl-3-(4-nitrophenyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine-7-carbonitrile and (Z)-1-(2-cyano-2-phenylvinyl)-1H-imidazole-4,5-dicarbonitrile, were further analysed by the single-crystal X-ray diffraction method. A comprehensive study of structural features and intermolecular interactions present among these heterocyclic compounds was carried out. The crystal data were further examined by a Hirshfeld surface analysis, which provided both qualitative and quantitative information on various intermolecular interactions experienced within the crystal network.  

Author Biography

Amal Al-Azmi, Associate professor of organic chemistry - Kuwait University



D. W. Woodward, US Patent,1950, 2534331.

S. J. Johnson, Synthesis,1991,75.

M. J. Alves, B. L. Booth, and M. F. Proença, J. Chem. Soc., Perkin Trans.1, 1990, 1705.

B. L. Booth, A. M. Dias, and M. F. Proença, J. Chem. Soc., Perkin Trans. 1, 1992, 2119.

A. Al-Azmi, A. A. Elassar and B. L. Booth, The Chemistry of Diaminomaleonitrile and its Utility in Heterocyclic Synthesis, Tetrahedron, 2003, 2749.

A. Al-Azmi, Recent Developments in the Chemistry of Diaminomaleonitrile.Current Organic Synthesis, 2015, 12(2), 110-135.

A. Al-Azmi, B. L. Booth, R. A. Carpenter, A. Carvalho, E. Marrelec, R. G. Pritchard, and F. J. R. P. Proença, J. Chem. Soc., Perkin Trans. 1, 2001, 2532.

A. Al-Azmi and A. K. Kalarikkal, Reactions of 9-aryl-6-cyanopurines with primary amines, Heterocycles, 2009, 78 (9), 2245.

A. Al-Azmi, Novel 6-substituted pyrimidines and pyrimido[5,4-d]pyrimdines from (2-acetamido-1,2-dicyanovinyl)ammonium chloride, J. Chem. Res., 8, 530, 2005.

A. Al-Azmi and A. K. Kalarikkal, Synthesis of 1,4,5-trisubstituted-1,2,3-triazoles via coupling reaction of diaminomaleonitrile with aromatic diazonium salts, Tetrahedron, 69 (52), 11122-11129, 2013.

A. Al-Azmi, DFT Study on Two Plausible Mechanistic Routes to Pyrazolo[3,4-d]pyrimidine-4-Amines from Pyrazoloformimidate, Current Organic Chemistry, 24 (2), 2020, doi:10.2174/1385272824666200203122450.

A. Al-Azmi, H. Mahmoud, Facile Synthesis and Antimicrobial Activities of Novel 1,4-Bis(3,5-dialkyl-4H-1,2,4-triazol-4-yl)benzene and 5-Aryltriaz-1-en-1-yl-1-phenyl-1H-pyrazole-4-carbonitrile Derivatives, ACS Omega, 2020, doi.org/10.1021/acsomega.0c01001.

A. Al-Azmi and A. K. Kalarikkal, Pyrazoles vs. Pyrazolo[1,5-a]pyrimidines and Pyridones vs. Enamines: Reactions of 2-Aryl-3-oxopropanenitrile with Nitrogen and Carbonyl Compounds, Current Organic Synthesis, 14, 1-16, 2017.

E. Nicolaï, G. Curé, J. Goyard, M. Kirchner, J. M. Teulon, A. Versigny, M. Cazes, F. Caussade, A. Virone-Oddos, A. Cloarec. Synthesis and SAR Studies of Novel Triazolopyrimidine Derivatives as Potent, Orally Active Angiotensin II Receptor Antagonists, J. Med. Chem., 1994, 37(15), 2371-86.

W. A. El‐Sayed, O. M. Ali, M. S. Faheem, I. F. Zied, A. A.‐H. Abdel‐Rahman, Synthesis and Antimicrobial Activity of New 1,2,3‐Triazolopyrimidine Derivatives and Their Glycoside and Acyclic Nucleoside Analogs, J. Heterocycl. Chem., 2012, 49 (3), 607-612.

G. S. Hassan, M. A. El-Sherbeny, M. B. El-Ashmawy, S. M. Bayomi, A. R. Maarouf, F. A. Badria, Synthesis and antitumor testing of certain new fused triazolopyrimidine and triazoloquinazoline derivatives, Arab. J. Chem.,2017, 10 (10),1345-1355.

I. Ali, M. N. Lone, H. Y. Aboul-Enein, Imidazoles as potential anticancer agents, Med. Chem. Comm., 2017, 8(9), 1742–1773.

A. Plaquet, B. Champagne, J. Kulhánek, F. Bureš, E. Bogdan, F.Castet, L.Ducasse, V. T Rodriguez, Effects of the Nature and Length of the π-Conjugated Bridge on the Second-Order Nonlinear Optical Responses of Push-Pull Molecules Including 4,5-dicyanoimidazole and Their Protonated Forms, Chem. Phys. Chem., 2011, 12(17), 3245-52.

Z. Hloušková, F. Bureš, Synthesis and properties of push-pull imidazole derivatives with application as photo-redox catalysts, Arkivoc, 2017, iv, 330-342

Crystal data for compound 6b (ref. CCDC 993548) can be obtained on request from the Director, Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EW, UK. CCDC.

Crystal data for compound 9a (ref. CCDC 2004526) can be obtained on request from the Director, Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EW, UK. CCDC

A. M. Spackman, D. Jayatilaka, Hirshfeld Surface Analysis, Cryst. Eng.Comm.,2009, 11, 19-32.

J. J. McKinnon, M. A. Spackman, A. S. Mitchell, Novel tools for visualizing and exploring intermolecular interactions in molecular crystals. Acta. Cryst. B, 2004 60: 627-66.

J. J. McKinnon, D. Jayatilaka, A. M. Spackman, Towards quantitative analysis of intermolecular interactions with Hirshfeld surfaces. Chem. Commun., 2007, 3814-3816.

M. J. Turner, J. J. McKinnon, S. K. Wolff, D. J. Grimwood, P. R. Spackman, D. Jayatilaka, A. M. Spackman, CrystalExplorer 17, 2017. University of Western Australia. http://hirshfeldsurface.ne