title: [Synthesis and antibacterial activity of imidazothiadiazoles and heterocyclic-amine Mannich-base hydrochloride].
abstract: To optimize the synthetic method and antibacterial activity of fused heterocyclic thiadiazole compounds, cyclocondensation of 2-(4-methoxyphenyl)-5-amino-1,3,4-thiadiazole (2) with alpha-chloro-4-chloro acetophenone (3) resulted in a key intermediate (4), 6 -(4-chlorophenyl)-2-(4-methoxyphenyl)-imidazo-[2,1-b][1,3,4]thiadiazole, which was carried out an nucleophilic substitution with substituted piperazine to give the corresponding free bases of piperazine (5a-5c), then followed by Mannich reaction with heterocyclicamines and formaldehyde to yield the corresponding Mannich bases, (1a-11) as respective hydrochloride salts. The structures were confirmed by IR, 1H NMR, MS and elemental analysis and the antibacterial activities in vitro of fifteen newly synthesized compounds were also tested against Gram positive bacteria and Gram negative bacteria with the standard 2-fold agar dilution method. The antibacterial results showed that the introduction of a polar group resulted in the enhancement of antibacterial activity in vitro. Thus, the structures of these fused compounds could further be investigated.
authors.affiliation: Institute of Pharmacy, Henan University, Kaifeng 475001, China. hgqxy@sina.com.cn
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Hu
authors.forename: Li-li
authors.initials: LL
authors.lastname: Hou
authors.forename: Song-qiang
authors.initials: SQ
authors.lastname: Xie
authors.forename: Wen-long
authors.initials: WL
authors.lastname: Huang
authors.forename: Hui-bin
authors.initials: HB
authors.lastname: Zhang
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D008352:Mannich Bases / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013830:Thiadiazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D007093:Imidazoles; D008352:Mannich Bases; D013830:Thiadiazoles