Synthesis and Characterization of Two Novel Oxazol-5-ones Derivatives and Their Multifunctional Properties; pH Sensitivity, Electropolymerizability and Antiproliferative Activity.

The aim of this study is to synthesize oxazol-5-one derivatives, which have multi-functional properties. Nomenclatures of newly synthesized molecules are 4-(4-N,N-diethylaminophenylmethylene)-2-(3-thienyl)oxazol-5-one (4a) and 4-(4-(1,4,7,10-tetraoxa-13-azacyclopentadecyl)phenylmethylene)-2-(3-thienyl)oxazol-5-one (4b). These two novel derivatives contain pH sensitive and polymerizable groups. 3-Thienyl group was attached to position-2 of the oxazol-5-one ring to provide electrochemical polymerization capability. pH sensing properties were provided by attaching p-N,N-diethylaminophenylmethylene and p-aza-15-crown-5-phenylmethylene groups to the arylmethylene moiety at position-4 of the ring. Target molecules were synthesized by classical process known as Erlenmeyer-Plöchl Azlactone Synthesis Erlenmeyer (Justus Liebigs Ann Chem 275:1-12, 1893), Rodrigues et al. (J Chem Educ 92:1543-1546, 2015) . After structural characterization of 4a and 4b, absorption and emission characteristics were determined in solvents that have different polarities. Difference in maximum absorption and emission wavelengths of the molecules related to solvent polarities were observed at around 6-7 nm and 35-36 nm respectively. In pH studies of the target derivatives in PVC polymer matrix, ratiometric changes were observed at isosbestic point around 398 nm. Polymeric depositions of the molecules (4a, 4b) were proved by using cyclic voltammetry, electrochemical impedance spectrometry studies and scanning electron microscope images. MTT assay studies showed significant results like, 4b derivative's strong cytotoxic activity on PC-3 (cancerous cell line) with IC value of 12.57 ± 0.41 µg/ml without exhibiting any cytotoxic effect on HEK293 (healthy cell line).