Novel Schiff bases–based thiophenes: Design, synthesis and biological evaluation

2‐amino‐5‐(3‐fluoro‐4‐methoxyphenyl)thiophene‐3‐carbonitrile derivatives have been synthesized from 1‐(3‐fluoro‐4‐methoxyphenyl)ethanone, malononitrile, mild base, and sulfur powder using the Gewald method through a multistep reaction sequence. The structures of newly synthesized compounds were established on the basis of their elemental analyses, IR, 1H NMR, 13C NMR, and mass spectral data, and then synthesized compounds were screened for their in vitro antimicrobial activity. Among them, derivatives 3b (thiphene), 3f (pyrazole), and 3d (halogen) showed good activity and remaining derivatives exhibited moderate activity. Literature reports for active derivatives of thiophene hybridized with substituted five, six and fused heterocyclic ring systems.