2-Formyl-2-arylhydrazonoethanenitriles 6b-d where prepared via reacting enaminonitrile 2b,c with aromatic diazonium salts. These reacted with phenylhydrazine to yield bis hydrazones that were converted to arylazopyrazoles via a novel Vilsmeier-Haack reaction type. Reaction of 6c with hydroxylamine afforded oxime that could be successfully cyclised into arylazoisoxazole. Reaction of 6c with hydrazine hydrate to yield arylazoaminopyrazole that proved to be excellent precursors for synthesis functional substituted pyrazolopyrimidines. 2-Arylhydrazonoketones are readily obtained via condensation of arylhydrazines with 1,2-diketone [1,2] or via the coupling reaction of active methylene ketones with aromatic diazonium salts [3][4][5]. 2-Arylhydrazonals (1a) are prepared via coupling enaminones with aromatic diazonium salts, were shown to be excellent precursors to functionally substituted pyridazines [6][7][8], pyrazoles [9][10][11], and condensed azoles [12][13][14].In conjunction to our interest in chemistry of 2-arylhydrazonals 2b [8][9][10][11][12][13][14] as precursors to arylazoaminoazoles for potential utility in dye industry, we report here on the coupling reaction of the enaminonitriles 2b,c with aromatic diazonium salts and results of our investigation aimed at exploring synthetic potentials of these coupling products. The enaminonitrile derivative 2b needed in this investigation was prepared following literature procedure [15] (Figure 1).The newly required enaminonitrile 2c was prepared in 73 % via reacting cyanoacetic acid with triethylorthoformate and piperidine or in better yield (80 %) via reacting 3-ethoxyacrylonitrile (3) with piperidine. 1 H-NMR indicate that the reaction product exists solely in the trans form as it indicated two olefinic protons at δ 4.0 and 7.1 with J = 13.5 Hz typical for trans olefinic protons. Appearance the olefinic proton of H-2 at δ 4.0 ppm is a result of shielding by electron donation from lone pair and cyano group anisotropy.We have found that coupling of 2b with aromatic diazonium salts affords either only formazanes 7 or mixtures of

Recently reported syntheses of 3(5)-aminopyrazoles, 4-aminopyrazoles, and 1-aminopyrazoles as well as of diaminopyrazoles and their general pattern of reactivity towards mono-and bidentate electrophiles have been surveyed. Emphasis has also been laid on techniques for ascertaining the site selectivity in reactions with electrophiles, including single crystal X-ray structure analysis, 1 H-15 N HMBC, and NOE intensity difference experiments as well as other modern 2D NMR techniques. Some thermally induced cycloadditions have also been treated.

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under the supervision of Associate Professor Trond Vidar Hansen. Financial support from Quota Programme and The Research Council of Norway is gratefully acknowledged. It is a pleasure to thank all of you who made this thesis possible. Firstly, I sincerely thank my supervisor, Associate Professor Trond Vidar Hansen for giving me the opportunity to start on this interesting project, and for his help, availability, advice, and guidance during my stay in his research group. I would like to thank Professor Lars Skattebøl for his useful advice, guidance, helpful discussions, and proofreading my manuscripts throughout these years. Also I would like to thank Professor Arne Jørgen Aasen for sharing his knowledge and proofreading my thesis. I am grateful to all members of Trond Vidar Hansen's group, the Department of Pharmaceutical Chemistry, my colleagues, and especially Alexandra Gade and Øyvind Jacobsen, and also of the technical staff for social and scientific contribution. Lastly, I would like to thank my wife, Sylvia Antoun, for her love, encouragement and patience over these years.