Synthesis, Crystal Structure, and Biological Activity ofcis/transAmide Rotomers of (Z)-N′-(2-Oxoindolin-3-ylidene)formohydrazide

(Z)-N′-(2-Oxoindolin-3-ylidene)formohydrazide (2) was synthesized by the reaction of (Z)-3-hydrazonoindolin-2-one (1) with formic acid under reflux. The structure of2was characterized by IR, Mass,1H NMR, and X-ray crystal structure determination. Interestingly, compound2appeared in DMSO- d6 ascisandtransamide rotomers in 25% and 75%, respectively. The X-ray analysis showed theZgeometrical isomer of2around –C=N– forcisandtransamide rotomers. The crystal of2belongs to monoclinic, space groupP21/c, with a=4.5206 (1) Å, b=22.4747 (7) Å, c=17.3637 (5) Å, β=103.752 (1)°, Z=8 , V=1713.57 (8) Å3, Dc=1.467 Mg m−3, μ=0.11 mm−1, F(000)=784 , R=0.047 , and wR=0.123 for 3798 observed reflections with I>2σ (I) . Compound2exhibited a moderate activity in its antimicrobial evaluation againstE. coliandP. aeruginosaand a good activity againstS. aureusclose to that of the standard drug ciprofloxacin. Thein vitroanticancer activity of2was evaluated against two human tumor cell lines, namely, HepG2 hepatocellular carcinoma and MCF-7 breast cancer. HepG2 cancer cell line was more susceptible to compound2than MCF-7.