الفهرس 
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Abstract
Thiazole derivatives have gained continuous attention among the researchers and hold a prominent position in drug designing as they exhibit broad range of biological and medicinal properties. Thus, the present thesis deals with the synthesis of some new thiazole-based heterocycles based on the readily available 2-aminothiazole and screening their antibacterial activity against a range of Gram-positive and Gram-negative bacteria. The key of our research paper, 2-amino-5-(4-ethoxycarbonyl-phenylazo)thiazole(3), was prepared by the electrophilic diazo-coupling reaction between 2-aminothiazole and the diazotized ethyl 4-aminobenzoate (Scheme1). Diazotization of ethyl 4-aminobenzoate has been achieved by treatment with sodium nitrite and conc. HCl at 0-5°C. The obtained diazonium chloride was coupled with 2-aminothiazole in ethyl alcohol and sodium acetate at the most reactive site of thiazole, the fifth position of thiazole (C-5) rather than the fourth one (C-4). N-Acetylation of 2-amino-5-(4-ethoxycarbonyl-phenylazo)thiazole(3) proceeded by heating acetic anhydride at the amino group to furnish 2-acetamido-5-(4-ethoxycarbonyl-phenylazo)thiazole(4). the Chloroacetylation of 2-aminothiazole derivative 3 was achieved by stirring with chloroacetyl chloride in dry dimethylformamide and anhydrous K2CO3 to afford 2-chloroacetamido-5-(ethoxycarbonyl-phenylazo)thiazole(5).