Synthesis, Crystal Structure, and Biological Activity of cis/trans Amide Rotomers of (Z)- N'-(2-Oxoindolin-3-ylidene)formohydrazide

Abstract

(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 of 2 was characterized by IR, Mass, 1 H NMR, and X-ray crystal structure determination. Interestingly, compound 2 appeared in DMSO- d 6 as cis and trans amide rotomers in 25% and 75%, respectively. The X-ray analysis showed the Z geometrical isomer of 2 around -C=N- for cis and trans amide rotomers. The crystal of 2 belongs to monoclinic, space group P2c, 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) Å 3, D c = 1.467 Mg m -3, = 0.11 mm -1, F (000) = 784, R = 0.047, and w R = 0.123 for 3798 observed reflections with I > 2 σ (I). Compound 2 exhibited a moderate activity in its antimicrobial evaluation against E. coli and P. aeruginosa and a good activity against S. aureus close to that of the standard drug ciprofloxacin. The in vitro anticancer activity of 2 was evaluated against two human tumor cell lines, namely, HepG2 hepatocellular carcinoma and MCF-7 breast cancer. HepG2 cancer cell line was more susceptible to compound 2 than MCF-7.