Synthesis of novel 3-[5-ethyl-2-(2-phenoxy-ethyl)-pyridin]-5-substituted isoxazoline libraries via 1,3-dipolar cycloaddition and evaluation of antimicrobial activities

Abstract

A series of novel 3-[5-ethyl-2-(2-phenoxy-ethyl)-pyridin]-5-substituted isoxazolines were synthesized via 1,3-dipolar cycloaddition of in situ generated nitrile oxide from 4-[2-(5-ethylpyridyl)-ethoxy]-benzaldoxime with alkenes to obtain new heterocyclic libraries containing a pyridine moiety in addition to the isoxazoline ring. The newly synthesized compounds were screened for their antimicrobial activity and were compared with standard drugs. The compounds demonstrated potent to weak antimicrobial activity. Of the compounds studied, compounds 3c and 3f showed significant antibacterial as well as antifungal activity. Compounds 3e and 3g showed moderate activity. The title compounds represent a novel class of potent antimicrobial agents.

Microwave-Assisted Solution Phase Synthesis of Novel 2-{4-[2-(N-Methyl-2-pyridylamino)ethoxy]phenyl}-5-Substituted 1,3,4-Oxadiazole Library

“…Recently, we have reported microwave-assisted synthesis of the antihyperglycemic drug rosiglitazone [16]. In continuation to our work on the synthesis of biologically active heterocycles [17,18], herewith, we are reporting as an efficient …”

Applications of Azoalkenes in the Synthesis of Fused Ring Pyridazine Derivatives

“…H-NMR, 13 C-NMR, MS studies, and elemental analysis provided the structure proof of the pyridazine derivatives. As expected, the cycloaddition was regioselective.…”

“…13 C-NMR spectra were measured on Bruker Avance (100 MHz) instrument. The chemical shifts are expressed in δ and following abbreviations were used.…”

“…In our laboratory, we have used chloramine-T for the generation of α-nitroso olefins [11], azoalkenes [1], nitrile oxides [12], nitrile imines [13] etc., which are the intermediates for the synthesis of biologically active six-membered and five-membered heterocycles. During the course of these studies, we have observed that treatment of cyclohexanone oxime with chloramine-T produced a blue color suggestive of formation of 1-chloro-1-nitroso cyclohexane.…”

Synthesis of novel isoxazolines via 1,3-dipolar cycloaddition and evaluation of anti-stress activity

“…Previous studies showed that several isoxazoline moieties possessed a wide spectrum of activities like PTP1B inhibitory activity (Ahmad et al, 2006), antimicrobial (Gaonkar et al, 2007), anti-influenza virus (Kai et al, 2001), antifungal (Basappa et al, 2003), glycoprotein IIb/ IIIa receptor antagonists (Sielecki et al, 2001), anti-HIV (Ichiba et al, 1993), spermicidal and anti-HIV (Srivastava et al, 1999), analgesic and anti-inflammatory (Habeeb et al, 2001), and b-adrenergic receptor antagonist properties (Conti et al, 1998). However, their role during stressful condition is unknown.…”