Novel (±)-trans-ß-lactam ureas: Synthesis, in silico and in vitro biological profiling.

A diastereomeric mixture of racemic 3-phthalimido-b-lactam 2a/2b was synthesized by the Staudinger reaction of carboxylic acid activated with 2-chloro-1-methylpyridinium iodide and imine 1. The amino group at the C3 position of the b-lactam ring was used for further structural upgrade. trans-b-lactam ureas 4a-t were prepared by the condensation reaction of the amino group of b-lactam ring with various aromatic and aliphatic isocyanates. Antimicrobial activity of compounds 4a-t was evaluated in vitro and neither antibacterial nor antifungal activity were observed. Several of the newly synthesized trans-b-lactam ureas 4a-c, 4f, 4h, 4n, 4o, 4p, and 4s were evaluated for in vitro antiproliferative activity against liver hepatocellular carcinoma (HepG2), ovarian carcinoma (A2780), breast adenocarcinoma (MCF7) and untransformed human fibroblasts (HFF1). The b-lactam urea 4o showed the most potent antiproliferative activity against the ovarian carcinoma (A2780) cell line. Compounds 4o and 4p exhibited strong cytotoxic effects against human non-tumor cell line HFF1. The b-lactam ureas 4a-t were estimated to be soluble and membrane permeable, moderately lipophilic molecules (logP 4.6) with a predisposition to be CYP3A4 and P-glycoprotein substrates. The tools PASS and SwissTargetPrediction could not predict biological targets for compounds 4a-t with high probability, pointing to the novelty of their structure. Considering low toxicity risk, molecules 4a and 4f can be selected as the most promising candidates for further structure modifications.

Diverse coordination of aroylhydrazones toward iron(III) in solid state and in solution: spectrometric, spectroscopic and computational study.

The coordination properties of N'-(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (H2L1), N'-(2-hydroxy-4-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (H2L2) and N'-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (H2L3) toward Fe(III) ions were studied by computational, spectrometric (MS) and spectroscopic methods (UV-Vis, IR and Raman spectroscopy) in solid state and in solution. Free ligands were present in keto-amine form with intramolecular H-bond. In MeOH:H2O 1:1 system, the 1:1 complexes with Fe(III) were formed, characterized by lgK ≥ 6. The coordination to the metal ion was achieved via oxygen and azomethine nitrogen since the hydrolysis of hydrazone bond was suppressed. Unlike the 1:1 stoichiometry in methanolic solution, the composition of the complexes extracted to chloroform was Fe(L)(HL). The release of three protons upon complexation was determined by independent spectrophotometric measurements. The complexes isolated from MeOH/EtOH solution have also stoichiometry 1:2. However, depending on the position of the methoxy substituent, two types of complexes were formed. In Fe(H2L1)2Cl3 and Fe(H2L3)2Cl3, hydrazones acted as neutral ligands, while in Fe(HL2)2Cl the keto-enol tautomeric interconversion and release of one proton per ligand took place. All complexes were analyzed in gas phase as well, using triple quadrupole, ion trap and H/D exchange for determination of labile hydrogens. Based on the fragmentation pathways, the structural isomers were distinguished.