Synthesis of thiazolyltriazole substituted azetidinones as antimicrobial agents

321-325The reaction of ethyl 2-amino-4-methylthiazole-5-carboxylate 1 with acetic anhydride followed by reaction with hydrazine hydrate yields the ethyl 2-acetamido-4-methylthiazole-5-carboxylate 2 and N-[5-(hydrazinecarbonyl)-4-methylthiazol-2-yl]acetamide 3, respectively. The compound 3 on further reaction with alcoholic potassium hydroxide-carbon disulphide followed by cyclization with hydrazine hydrate gives N-[5-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)-4-methylthiazol-2-yl]acetamide 5. The compound 5 is then condensed with different aromatic aldehydes to offer Schiff bases 6a-h. The Schiff bases on cyclization with chloroacetyl chloride in presence of triethylamine as catalyst furnish the azetidin-2-one 7a-h. The compounds are synthesized in good yield and the chemical structures of the compounds are elucidated from their IR, 1H NMR, and elemental analysis. All the synthesized compounds have been screened for their antimicrobial activity

Experimental investigation on the seismic performance of masonry buildings using shaking table testing

Masonry buildings worldwide exhibited severe damage and collapse in recent strong earthquake events. It is known that their brittle behavior, which is mainly due to the combination of lowtensile strength, largemass and insufficient connection between structural elements, is the main limitation for their structural implementation in residential buildings. A new construction system for masonry buildings using concrete blocks units and trussed reinforcement is presented here and its seismic behavior is validated through shaking table tests. Dynamic tests of two geometrically identical two-story reduced scale (1:2) models have been carried out, considering artificial accelerograms compatible with the elastic response spectrum defined by the Eurocode 8. The first model was reinforced with the new proposed system while the second modelwas built with unreinforced masonry. The experimental analysis encompasses local and global parameters such as cracking patterns, failure mechanisms, and in-plane and out-of-plane behavior in terms of displacements and lateral drifts from where the global dynamic behavior of the two buildings is analyzed comparatively. Finally, behavior factors for the design recommendations in case of unreinforced masonry are alsoevaluated.QREN (POFC) - ADI - Agência de Inovaçã