الفهرس 
Summary of the original workOnly 14 pages are availabe for public view
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Abstract
The thesis is divided into four parts:
1- Part 1. A convenient and efficient method for the synthesis of
benzo- and naphthothiazoldiones.
2- Part 2. Oxidation of aroylthioureas during their reactions with diphenylcyclopropenone resulting in (E/Z)-3-(aroylthioureido)-2-phenylcinnamic acids.
3- Part 3. Reactions of aroylthioureas with acetylenic esters and dibenzoylethylene. Selectivity of the formation of novel thiazin-4-ones.
4- Part 4. Biological screening of some starting materials and products obtained.
Part 1: A convenient and efficient method for
the synthesis of benzo- and naphthothiazoldiones
In this part we examined the reactions of aroylphenylthioureas 1a-c with 2,3,5,6-tetracholoro-1,4-benzoquinone (2a), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (2b) and 2,3-dichloro-1,4-naphthoquinone (2c). The reactions proceeded to give the corresponding benzo(naphtho)thiazoles as shown in scheme 1.
The reaction mechanism described the reactions of the quinone -acceptors 2a-c with 1a-c, as due to a type of tautomerism occurs in 1a-c between the NH and the C=S into the N=C-SH group. Thereafter, the forming SH adds to the C-2 of the quinone, which accompanied with elimination of HCl molecule to produce 5a-i. Then, another nucleophilic attack of the aromatic NH-amine in 6a-i to the C-3 followed by elimination of another molecule of HCl molecule to give the stable compounds 4a-i. It is believed that attachment by the SH group proceeds more faster compared with the aromatic amine, therefore, the reaction would proceed by the steps shown in Figure 1.
The advantages of this method are the reasonable yields, and the ease with which the reaction can be carried out as one-pot procedure with readily avaliable starting materials. Undoubtly, research future generations of fused thiazoles will continue to contribute to some of the most fascinating developments in the field of heterocyclic chemistry.
Part 2. Oxidation of aroylthioureas during their reactions with diphenylcyclopropenone resulting
in (E/Z)-3-(aroylthioureido)-2-phenylcinnamic acids
In this part, we present our results of the reaction of 2,3-diphenylcyclopropenone with N-substituted-aroylthioureas with emphasis on synthetic and mechanistic implications. Hence, we synthesized the aroylthioureas 1d,e utilized by the methodology which depended on the reaction of the phenyl isothiocyanate with the corresponding amines. The 1H NMR spectrum of 1d and 1e showed the NH proton attached directly to the antipyrinyl or thiazoyl group molecule appeared more deshielded (H = 11.71 and 11.80 in 1d and 1e, respectively) compared with the other NH proton attached to the benzoyl group which might due to the mutual donating resonance between the N1 and the other nitrogen atom in the ring system (Figure 2).
Scheme 2 outlines the formation of E/Z-3-(aroylthioureido)-2-phenylcinnamic acids 8a-e during the reaction of 2,3-diphenylcyclopropenones (7) with N-substituted aroylthioureas 1a-e under refluxing acetic acid. The E- and Z-forms of 8a-e were chromatographically separated. In particular, the spectral data including the IR, NMR and mass spectra as well as the elemental analyses of 8a-e proved the presence of the skeleton structure of Ar-CO-NH-CS-N(R) (Scheme 2).