SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME NEW PYRROLE DERIVATIVES

New pyrrole derivatives were synthesized and structures were confirmed by IR, H NMR, C NMR, mass spectra, and elemental analyses data. The reaction was performed by using ordinary condensation type, which enabled to easy work-up and good yield. Synthesized compounds were screened for antimicrobial activity.


INTRODUCTION
Pyrrole derivatives are of considerable synthetic importance due to their extensive used in drug discovery [1] which is linked to their pharmacological activity such as anti-inflammatory [2], cytotoxicity [3][4][5][6], treatment of hyperlipidemias [7] and antitumour agents [8].The pyrrole containing other heterocyclic compounds has been reported previously for biological studies [9].Oxadiazole linked with pyrrole derivatives are display a broad spectrum of biological activity such as antimicrobial activity [10], antitubercular agents [11].Triazole linked with pyrrole derivatives have importance of biological and pharmaceutical importance activity such as anti-inflammation [12,13], antitumor [14] and antimicrobial [15][16][17].These references will serve as the main rationales for the synthesis of new pyrrole connecting oxadiazole and triazole derivatives (Scheme 1) and evaluate them for antimicrobial activity.

Antibacterial activity
The compounds 1-4 were screened for antibacterial activity.Compound 3 is highly active than standard (Ciprofloxacin) against P. mirabilis and compound 4 is highly active than standard against M. luteus at concentration 100 µg/mL.Figure 1 shows that antibacterial activity of the compound 1-4.The bacterial zones of inhibition (mm) values are summarized in Table 1.
Zone of inhibition was measured at (mm) at concentration of 100 µg/mL, ciprofloxacin is used as the standard.Figure 1.Antibacterial activity of the compound (1-4) and standard.

Antifungal activity
The compounds 1-4 were screened for the antifungal activity.Compound 3 is highly active compared with standard (Clotrimazole) against A. niger, the compound 4 is highly compared with standard against C. albicans at concentration 100 µg/mL.Figure 2 shows that antifungal activity of the compound 1-4.The fungal zones of inhibition (mm) values are summarized in Table 2.
Zone of inhibition was measured at (mm) at concentration of 100 µg/mL, clotrizaole is used as the standard.

Structure activity relationship
Scheme 4 shows that significance of antibacterial activity in compounds 3 and antifungal activity in compounds 4. From the results of antimicrobial activity of the pyrrole derivatives, the following structure activity relationships can be derived Antibacterial activity of compound 3 shows that highly active against P. mirabilis and antifungal activity of compound 3 shows highly active against A. niger at concentration 100 µg/mL due to presence of triazole moiety connected with pyrrole derivative.Antibacterial activity of compound 4 shows that highly active against M. luteus and antifungal activity of compound 4 shows highly active against C. albicans at concentration 100 µg/mL due to presence of oxadiazole moiety connected with pyrrole derivative.).The ¹H NMR and 13 C NMR spectra were recorded on a Bruker DRX-300 MHZ.The elemental analysis (C, H, and N,) were recorded using an Elementer analyzer model (Varian EL III).The purity of the compounds was checked by thin layer chromatography (TLC) with silica gel plates.
The mixture of compound 2 (2.97 g, 0.1 mol) in 2N-NaOH solution (20 mL), the reaction mixture was heated and refluxed for 5 h.After cooling, the solution was made acidic with conc.
In vitro antifungal screening.The compounds 1-4 were evaluated for their in vitro antifungal activity such as Aspergillus niger, Candia albicans, Microsporum audouinii and Cryptococcus neoformans (recultured) using disc diffusion method [24] with sabouraud's dextrose agar (Hi-Media).Clotrimazole was used as a standard.Each compound was tested at a concentration of 100 µg/mL in DMSO.The zone of inhibition (mm) was measured incubated at 37 °C.