Synthesis and Antimicrobial Activities of Some Triazole, Thiadiazole, and Oxadiazole Substituted Coumarins

Abstract

Ethyl‐2‐(4‐methyl‐2‐oxo‐2‐coumarin‐7‐yloxy)acetate 1 has been prepared from 7‐hydroxy‐4‐methyl‐2‐coumarin, which on further treatment with hydrazine hydrate in boiling ethanol gave the hydrazide compound 2. The resulting hydrazide was reacted with substituted aryl isothiocyanates to form thiosemicarbazides compounds 3a, 3b, 3c, 3d, 3e. 1‐(2‐(4‐Methyl‐2‐oxo‐2‐coumarin‐7‐yloxy)acetyl)‐4‐aryl thiosemicarbazides 3 underwent cyclization with different reagents under different reaction conditions to furnish coumarin derivatives possessing triazoles 4a, 4b, 4c, 4d, 4e, thiadiazoles 5a, 5b, 5c, 5d, 5e, and oxadiazoles 6a, 6b, 6c, 6d, 6e, respectively. The structures of all the compounds have been assigned by elemental analysis and spectral studies. The synthesized compounds were screened for their antimicrobial analgesic activities. The nonconventional controlled microwave irradiation synthesis is carried out at (200 W) at 70°C. This approach offers a number of advantages in terms of methodology, high‐product yield, short reaction time, mild reaction conditions, environmentally benign, and easy workup.

Synthesis, characterization, biochemical, and molecular modeling studies of carvacrol‐based new thiosemicarbazide and 1,3,4‐thiadiazole derivatives

“…The product was characterized by 1 H and 13 C NMR and high resolution mass spectroscopy (HRMS). [ 60–62 ]…”

Recent advances and perspectives in the synthesis of bioactive coumarins

“…As a result, the preparation of novel compounds that fuse these azoles onto a coumarin structure has been reported by Surendra Babu et al (2014). 62 In this procedure, the key intermediate, ethyl-2-(4-methyl-2-oxo-2-coumarin-7-yloxy)acetate, was prepared via the reaction of 7-hydroxy-4-methyl coumarin in the presence of anhydrous K 2 CO 3 with ethyl chloroacetate in boiling acetone. This compound was readily converted to 2-(4-methyl-2-oxo-2Hchromen-4-yloxy)acetohydrazide via treatment with hydrazine hydrate.…”

5-[Substituted]-1, 3, 4-thiadiazol-2-amines: Synthesis, Spectral Characterization, and Evaluation of their DNA interactions

“…(a)1,2,3-thiadiazole (b)1,2,5-thiadiazole (c) 1,2,4-thiadiazole and (d) 1,3,4-thiadiazole 7 . Among, 1,3,4-thiadiazoles having more applications and exhibiting potential biological activities like insecticidal 8,9 , fungicidal 10,11 ,herbicidal activity 12 , potent anti-cancer 13,14 ,anti-proliferative activity 15,16 , Antiviral 17 , inhibitors of acetyl cholinesterase (AChE) and butyrylcholinesterase (BuChE) 18 , Alzheimer 19,20 , and antimicrobial activities 21 . 1,3,4-thiadiazoles also used in electrical and optical 22 , liquid crystal [24][25][26] , corrosion inhibitors 27 , in dye preparation 28 .…”