Heterocycles derived from 5-(2-aminothiazol-4-yl)-8-hydroxyquinoline: Synthesis and antimicrobial activity

5-(2-Aminothiazol-4-yl)-8-hydroxyquinoline 2 has been synthesized by treating thiourea with 5-chloro-acetyl-8-hydroxyquinoline 1. The amine 2 was treated with aromatic aldehydes to furnish schiff bases 6a-c which on treatment with phenyl isothiocyanate gave the corresponding thiazolo-s-triazines 7a-c. Reaction of 2 with phenyl isothiocyanate gave the corresponding aminocarbothiamide derivative 8 which on reaction with malonic acid in acetyl chloride afforded thiobarbituric acid derivative 9. Coupling of 9 with diazonium salt gave the phenyl hydrazono derivative 10. However, reaction of 2 with carbon disulphide and methyl iodide afforded dithiocarbamidate 12 which on treatment with ethylenediamine, o-aminophenol and/or phenylenediamine gave the aminoazolo derivatives 13-15, respectively. Other substituted fused thiazolopyrimidines 16-20 have been also prepared by the reaction of 2 with some selected dicarbonyl reagents. The characterisation of synthesized compounds has been done on the basis of elemental analysis, IR, H-1-NMR and mass spectral data. All the newly synthesized compounds have been screened for their antimicrobial activities.