الفهرس 
Synthesis of phthalazine derivativesOnly 14 pages are availabe for public view
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Abstract
Synthesis and Biological Evaluation of some Novel Phthalazine Derivatives
In this thesis the synthesis of 2-(4-(3,4-dimethylphenyl)-1- oxophthalazin-2(1H)-yl)acetohydrazide (4), 4-(3,4-dimethylphenyl)-2-((5-
thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)methyl)phthalazin-1(2H)-one (23), ammonium 2-(2-(4-(3,4-dimethylphenyl)-1-oxophthalazin-2(1H)- yl)acetyl)hydrazine-1-carbodithioate (28), and 4-(3,4-dimethylphenyl)-1- oxophthalazine-2(1H)-carbothiohydrazide (37) were utilized as precursors to construct a novel series of phthalazinones bearing various valuable function groups in excellent yields via several simple and promising approaches.
Synthesis and reactions of 2-(4-(3,4-Dimethylphenyl)-1- oxophthalazin-2(1H)-yl)acetohydrazide (4)
The reaction of acetohydrazide derivative 4 with acrylonitrile in pyridine gave rise to a new 2,3-dihydro-1H-pyrazole derivative 5. In another attempt to build up more heterocycles attached to phthalazine acetohydrazide derivative 4, it was allowed to reflux with ethyl acetoacetate in dioxane. Surprisingly, and after 10 h, only the acyclic derivative 6 was isolated. Additionally, compound 6 was chemically proven when a subsequent cyclization was accomplished and 4-(3,4-dimethylphenyl)-2-(2-(3-methyl-5- oxo-2,5-dihydro-1H-pyrazol-1-yl)-2-oxoethyl)phthalazin-1(2H)-one (7) was attained via refluxing the acyclic isolated intermediate 6 in dioxane for an extra
30 h. Likewise, another 5-exo-trig ring closure was observed, and a new dihydropyrazolone ring was attained through the reaction of phthalazine acetohydrazide derivative 4 with ethyl benzoylacetate in boiling dioxane for 30h . In many attempts to develop better reaction profiles, various reaction conditions were explored to synthesize pyrazole derivative 10. Phthalazine acetohydrazide derivative 4 was allowed to reflux with acetylacetone in dioxane for 10 h to have access to 2-(4-(3,4-dimethylphenyl)-1-oxophthalazin- 2(1H)-yl)-N’-(4-oxopentan-2-ylidene)acetohydrazide (9). An alternative pathway to assemble compound 9 was also developed by the fusion of acetohydrazide 4 with acetylacetone and few drops of piperidine at 200 oC for
only 30 min. The cyclization of the isolated intermediate 9 to the target pyrazole derivative 10 took place through the prolonged heating of 9 in dioxane or via grinding of acetohydrazide derivative 4 with acetylacetone in the presence of a few drops of acetic acid at room temperature for only 30 min (Scheme1).