Coumarin functionalized dimeric mesogens for promising anticoagulant activity: Tuning of liquid crystalline property

Abstract

This paper demonstrates the synthesis of novel bi-substituted coumarin-based symmetrical compounds (A1-A6)via a simple two-step reaction by conversion of coumarin (I) to dicoumarol (II) followed by the alkylation using different alkyl bromides. The chemical proposed structure was confirmed by IR, NMR, Mass, and CHN analysis. These dimeric materials were further investigated for liquid crystalline properties. The thermal behavior and liquid crystalline properties were evaluated using TGA, DSC, POM, and high temperature XRD. The substitution of various alkyl chains on coumarin core presented a broad scope to achieve different types of liquid crystalline properties. These symmetrical dimers of coumarin derivatives exhibited enantiotropic type mesophase with a broad temperature range and wide thermal stability. The compound with a hexadecyloxy tail exhibited mesogenic properties at room temperature. The lower alkoxy side chain substituted materials presented only nematic phase while higher alkoxy side chain substituted materials displayed smectic type mesogenic properties. The present coumarin-based dimeric mesogens were easily fabricated by simple two-step method as compared to other coumarin-based mesogens. In addition, one of the dicoumarol derivatives showed promising anticoagulant activity. Compound A5 at 10.0 mg/5.0 mL of blood concentration revealed good efficacy as an anticoagulant agent to prevent blood clotting.