Synthesis and antimicrobial studies of new N,N′-[5,5′-{2,2′-(bis-alkoxy) bis(2,1-phenylene)]bis(4-acetyl-4,5-dihydro-1,3,4-thiadiazole-5, 2-diyl)]diacetamide

Abstract

The bisthiadiazolines 4a(a-f) and 4b(a-f) built around the various rigid chains have been synthesized in good yields by refluxing bisthiosemicarbazones 3a(a-f) and 3b(a-f) in acetic anhydride medium. The reaction of bisaldehydes 2a(a-f) and 2b(a-f) with thiosemicarbazide under alcoholic medium yielded 3a(a-f) and 3b(a-f) and the former were obtained from the reaction of 2/4-hydroxybenzaldehyde with suitable alkylating agent in the presence of anhydrous K 2 CO 3 /dry acetone and Bu 4 N + I − (PTC). The intermediates and final compounds have been characterized from the rigorous analysis of their IR, 1 H-NMR, 13 C-NMR, ESI-Mass and elemental analysis. The antibacterial and antifungal activities of the prepared compounds were also evaluated against the Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillius subtilis and Aspergillius janus and Pencillium glabrum strains, respectively. The formation and antimicrobial behaviour of the bisthiadiazolines 4a(a-f) and 4b(a-f) are found to be independent of nature of the internal spacer unit.

Synthesis and characterization of some novel bis‐thiazoles

“…Literature survey reported that compounds having 1,4‐bis(methoxymethyl) linkage are biologically active …”

“…The reactivity of bis‐thiosemicarbazone derivative 3 , which contains 1,4‐bis(methoxymethyl) linkage toward various hydrazonoyl halides in the presence of triethylamine as a basic catalyst was explored.…”

“…Literature survey reported that compounds having 1,4bis(methoxymethyl) linkage are biologically active. [26][27][28][29] The reactivity of bis-thiosemicarbazone derivative 3, which contains 1,4-bis(methoxymethyl) linkage [26] toward various hydrazonoyl halides [30] in the presence of triethylamine as a basic catalyst was explored.…”

“…The desired product precipitated from reaction mixture was filtered, washed with EtOH, and recrystallized from dioxane to give pure product 3 as yellow solid, 78% yield; mp. 240°C to 242°C (Lit mp 236°C‐238°C); IR (KBr): v 3426, 3246, 3158 (2NH, 2NH 2 ), 3024, 2912 (C─H), 1596 (C═N), 1522, 1486, 1449, 1357, 1286, 1246, 1161, 1117, 1080, 1045 cm −1 ; 1 H NMR (DMSO‐ d 6 ): δ 3.56 (s, 4H, 2NH 2 ), 5.21 (s, 4H, 2CH 2 ), 7.25 to 7.65 (m, 12H, Ar─H), 8.55 (s, 2H, 2CH═N), 11.47 (br s, 2H, 2NH); MS m/z (%): 492 (M + , 14). Anal.…”

2‐Bromo‐1‐(1H‐pyrazol‐4‐yl)ethanone: Versatile Precursor for Novel Mono‐ and Bis[pyrazolylthiazoles]

“…2′-(4,4′-(1,4-Phenylenebis(methylene))bis(oxy)bis(4,1-phenylene)) bis(methan-1-yl-1-ylidene)bis(hydrazinecarbothioamide) 22c.Yellow solid, (66% yield), mp. 260-262°C, (Lit [49]…”