The title compound 3-(4-hydroxy-3-methoxyphenyl)-7,7-dimethyl-7,8-dihydrocinnolin-5(6H)-one (3) was prepared via one-pot three component reaction of 2-(4-hydroxy-3-methoxyphenyl)-2-oxoacetaldehyde with dimedone in the presence of hydrazine hydrate and studied by the single crystal X-ray diffraction method. Its structure was also confirmed by IR, 1H and 13C NMR spectroscopy. Compound 3 was crystallized in the monoclinic system, space group P21/c, = 7.921(2) Å, b = 11.566(4) Å, c = 16.986(6) Å, β = 107.338(5)°, V = 1485.5(8) Å3, Z = 4, R1 = 0.0559 and wR2 = 0.1253. The crystal structure of 3 also shows a weak interaction between O3 and N2 atoms.

Khalafy, J., Rimaz, M., Ezzati, M & Poursattar Marjani, A. (2013). Crystal structure of 3-(4-hydroxy-3-methoxyphenyl)-7,7-dimethyl-7,8-dihydrocinnolin-5(6H)-one.Current Chemistry Letters, 2(1), 43-48.

(a) Yu, Y., Singh, S. K., Liu, A., Li, T.-K., Liu, L. F., and La Voie, E. J. (2003) Substituted dibenzo[c,h]cinnolines: topoisomerase I-targeting anticancer agents, Bioorg. Med. Chem.,11, 1475-1491; (b) Ruchelman, A. L., Sing, S. K., Ray, A., Wu, X., Yang, J. M., Zhu, N., Liu, A., Liu, L. F., and LaVoie, E. J. (2004) 11H-Isoquino[4,3-]cinnolin-12-ones: novel anticancer agents with potent topoisomerase I-targeting activity and cytotoxicity, Bioorg. Med. Chem., 12, 795-806; (c) Lunniss, C.; Eldred, C., Aston, N., Craven, A., Gohil, K., Judkins, B., Keeling, S., Ranshaw, L., Robinson, E., Shipley, T., and Trivedi, N. (2010) Addressing species specific metabolism and solubility issues in a quinoline series of oral PDE4 inhibitors, Bioorg. Med. Chem. Lett., 20, 137-140.

Chapoulaud, V. G., Plé, N., Turck, A., and Queguiner, G. (2000) Synthesis of 4,8-Diarylcinnolines and Quinazolines with Potential Applications in Nonlinear Optics. Diazines. Part 28, Tetrahedron, 56, 5499-5507.

For the review about cinnoline synthesis, see: (a) Haider, N., and Holzer, W. (2004) Product Class 9: Cinnolines. Sci. Synth., 16, 251-313; (b) Vinogradova, O. V., and Balova, I. A. (2008) Methods for the synthesis of cinnolines, Chem. Heterocycl. Comp., 44, 501-522.

Cinnoline synthesis from arenediazonium salts: Vasilevsky, S. F., Tretyakov, E. V., and Verkruijsse, H. D. A (1994) Convenient Synthesis of 4-Chloro- and 4-Bromocinnolines from o-Aminophenylacetylenes, Synth. Commun., 24, 1733-1736.

Cinnoline synthesis from arylhydrazones: (a) Kiselyov, A. S. (1995) Trifluoromethyl group in the synthesis of heterocyclic compounds: New and efficient synthesis of 3-aryl-4-aminocinnolines, Tetrahedron Lett., 36, 1383-1386; (b) Shvartsberg, M. S., and Ivanchikova, I. D. (2000) An unknown route of cyclocondensation of peri-acetylenylquinones with hydrazine, Tetrahedron Lett., 41, 771-773; (c) Gomaa, M. A. -M. (2003) An efficient and facile synthesis of substituted cinnoline and benzo[h]cinnoline derivatives, Tetrahedron Lett., 44, 3493-3496.

Cinnoline synthesis from arylhydrazines: Alford, E. J., and Schofield, K. (1952) Cinnolines. Part XXVIII. The nature of the C(3)-position. Part I. The Neber–Bossel synthesis of 3-hydroxycinnoline, J. Chem. Soc., 2102-2108.

Cinnoline synthesis from nitrile: Chen, D., Yang, C., Xie, Y., and Ding, J. (2009) Novel Process to 4,4-Dialkyl-1,4-dihydro-6-methoxy-3-phenylcinnolines via Grignard Reaction, Heterocycles., 77, 273-277.

(a) Bräse, S., Gil, C., and Knepper, K. (2002) The recent impact of solid-phase synthesis on medicinally relevant benzoannelated nitrogen heterocycles, Bioorg. Med. Chem., 10, 2415-2437; (b) Kimball, D. B., Weakley, T. J. R., Herges, R., and Haley, M. M. (2002) Deciphering the Mechanistic Dichotomy in the Cyclization of 1-(2-Ethynylphenyl)-3,3-dialkyltriazenes:  Competition between Pericyclic and Pseudocoarctate Pathways, J. Am. Chem. Soc., 124, 13463-13473; (c) Kimball, D. B., Weakley, T. J. R., and Haley, M. M. (2002) Cyclization of 1-(2-Alkynylphenyl)-3,3-dialkyltriazenes:  A Convenient, High-Yield Synthesis of Substituted Cinnolines and Isoindazoles, J. Org. Chem., 67, 6395-6405; (d) Vinogradovaa, O. V., Sorokoumova, V. N., and Balova, I. A. (2009) A short route to 3-alkynyl-4-bromo(chloro)cinnolines by Richter-type cyclization of ortho-(dodeca-1,3-diynyl)aryltriaz-1-enes, Tetrahedron Lett., 50, 6358-6360.

(a) Zeni, G., and Larock, R. C. (2006) Synthesis of Heterocycles via Palladium-Catalyzed Oxidative Addition, Chem. Rev., 106, 4644-4680; (b) Zeni, G., and Larock, R. C. (2004) Synthesis of Heterocycles via Palladium π-Olefin and π-Alkyne Chemistry, Chem. Rev., 104, 2285-2310.

Zhu, C., and Yamane, M. (2011) Synthesis of 3,4-disubstituted cinnolines by the Pd-catalyzed annulation of 2-iodophenyltriazenes with an internal alkyne, Tetrahedron., 67, 4933-4938.

Khalafy, J., Rimaz, M., Ezzati, M., and Prager, R. H. (2012) A Green One-Pot Protocol for Regioselective Synthesis of New Substituted 7,8-Dihydrocinnoline-5(6H)-ones, Bull. Korean Chem. Soc., 33, 2890-2896.

Khalafy, J., Rimaz, M., Panahi, L., and Rabiei, H. (2011). A regiospecific one-pot, three component synthesis of 4-aryl-6,8-dimethylpyrimido[4,5-]pyridazine-5,7(6H,8H)-diones as new potential monoamine oxidase inhibitors, Bull. Korean Chem. Soc., 32, 2428-2432.

Rimaz, M., and Khalafy, J. (2010) Novel one-pot, three component synthesis of alkyl 6-aryl-3-methylpyridazine-4-carboxylates in water. Arkivoc, ii, 110-117.

Rimaz, M., Khalafy, J., and Najafi Moghadam, P. (2010) A regioselective one-pot, three component synthesis of 6-aryl-4-cyano-3(2H)-pyridazinones in water. Aust. J. Chem., 63, 1396-1401.

Rimaz, M., Noroozi Pesyan, N., and Khalafy, J. (2010) Tautomerism and isotopic multiplets in the 13C NMR spectra of partially deuterated 3-arylpyrimido[4,5-]pyridazine-5,7(6H,8H)-diones and their sulfur analogs-evidence for elucidation of the structure backbone and tautomeric forms, Magn. Reson. Chem., 48, 276-285.

Rimaz M., Khalafy J., Noroozi Pesyan N., and Prager R. H. (2010) A simple one-pot, three component synthesis of 3-arylpyrimido[4,5-]pyridazine-5,7(6H,8H)-diones and their sulfur analogues as potential monoamine oxidase inhibitors. Aust. J. Chem., 63, 507-510.

Khalafy, J., Rimaz, M., and Ezzati, M. (2012) Regioselective one-pot, three component synthesis of ethyl 6-aryl-3-propylpyridazine-4-carboxylates in water, Curr. Chem. Lett., 1, 115-122.

Khalafy, J., Parsa Habashi, B., Poursattar Marjani, A., and Najafi Moghadam, P. (2012) The synthesis of 2-arylquinoxaline derivatives, Curr. Chem. Lett., 1, 139–146.

Bruker, SMART. Bruker AXS Inc., Madison, Wisconsin, USA 2002.

Bruker SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA, 2008.

Sheldrick, G. M. (2008) A short history of SHELX, Acta Cryst., A64, 112–122.