الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This thesis comprises four chapters: the first one is an introduction which consists of a brief survey about different routes to synthesize 2-substituted benzothiazoles and 2-substituted benzoxazoles in addition to an account on their cytotoxic activities.
The second chapter deals with the aim of the work and the Schemes for the preparation of starting materials and the target benzothiazole, benzoxazole, pyrazole, pyrimidine, quinazoline and benzotriazine containing compounds.
The third chapter clarifies the theoretical discussion of the experimental work for the preparation of the starting materials Ia&b and Va&b.
Reaction of Ia&b with triethyl orthoformate and malononitrile afforded the key intermediates IIa&b which upon cyclization with hydrazine hydrate yielded IIIa&b. In addition, compound IIa was cyclised to give IVa&b through treatment with certain isothiocyanates.
Moreover, substitution of iodide in Va&b by a cyanide anion gave VIa&b from which VIIa&b, VIII and IXa&b were obtained using different acylating agents such as acetic anhydride, p-chlorobenzoyl chloride and chloroacetyl chloride, sequentially. As an extension, nucleophilic substitution of chloro derivatives of IXa&b with different primary and/or secondary amines yielded Xa-d. Furthermore, hydrolysis of the cyano compounds VIa&b either in basic or acidic medium afforded the carboxylic acids XIa&b and the carboxamides XIIa&b, respectively.
Formation of quinazoline ring was constructed by reacting VIa&b with different reagents like phenyl isothiocyanate, formamide and formic acid
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to obtain XIIIa&b, XIVa&b and XVa&b, in the same order. Reaction of XVa&b with phosphorous oxychloride formed the chloro derivatives XVIa&b, which was subjected to nucleophilic substitution reaction by treatment with aromatic amines affording XVIIa-c. On the other hand, alkylation on pyrimidine nitrogen of XVa&b with different alkyl halides achieved XVIIIa&b.
A variety of quinazoline derivatives XIXa&b, XXa-d and XXIa-d were formed via reacting XIIa&b with carbon disulfide, aromatic aldehydes and certain isothiocyanates, respectively. Additionally, refluxing compounds XIIa&b in acetic anhydride led to preparation of both oxazinone derivatives XXIIa&b and pyrimidinone derivatives XXIIIa&b. Moreover, reacting compounds XIIa&b with cyclopentanone and cyclohexanone afforded XXIVa-d. Finally, formation of benzotriazine derivatives XXVa&b was obtained by subjecting XIIa&b to a diazotization condition.
The structure elucidation of the new compounds was supported by element analysis, IR, 1H NMR in addition to mass spectra.
Additionally, a brief account on the docking study was explained through the binding conformations in comparison with the cytotoxic activity.
The fourth chapter consists of the experimental part of this work which contains the detailed procedures used for the synthesis of the starting materials Ia&b and Va&b, the intermedtiates IIa&b,VIa&b, IXa&b, XIIa&b, XVa&b and XVIa&b, in addition to the target final compounds IIIa&b, IVa&b, VIIa&b, VIII, Xa-d, XIa&b, XIIIa&b, XIVa&b, XVIIa-c, XVIIIa&b, XIXa&b, XXa-d, XXIa-d, XXIIa&b, XXIIIa&b, XXIVa-d and XXVa&b.
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This chapter also includes the in-vitro anticancer activity of twenty-six compounds of newly synthesized derivatives compared to Ib as a standard and demonstrates the correlation between the results of the molecular docking study and anticancer evaluation. There was some sort of constancy between the docking study prediction and the in-vitro biological cytotoxic evaluation. Compound XVIIc showed the highest energy score (-21.34 Kcal/mol) and exhibited the most potent in-vitro cytotoxic activity with IC50 equal to 0.009 μM, while compounds XIa and XXIVa showed intermediate energy scores (-16.79 to -15.75 Kcal/mol) and exhibited moderate in-vitro cytotoxic activity with IC50 0.066 and 0.067 μM, respectively. On the other hand, XXVa showed a weak energy score -15.46 and exhibited the least in-vitro cytotoxic activity with IC50 0.074 μM.