Synthesis and Structure-Activity Relationship Studies of 3-(N-Butylethanimidoyl)-4-hydroxy-2H-chromen-2-one (BHC) Analogues for Myosin II Inhibition
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Authors
Brawley, Jhonnathan
Issue Date
2022
Type
Dissertation
Language
Keywords
Alternative Title
Abstract
The objective of current treatments for various myopathies is to interrupt the signal from the brain to the affected muscle group, providing relief. To prevent unwanted side effects and possible poor drug-drug interactions, the downstream cause of myopathies and muscle movement, myosin II, can be targeted. There are many small molecules that are currently being studied to inhibit the various isoforms of muscle myosin II including blebbistatin. Recently a coumarin based Schiff base, 3-(N-butylethanimidoyl)-4-hydroxy-2H-chromen-2-one (BHC), was found to inhibit myosin II. The structure-activity relationship (SAR) study of BHC analogues are performed in this study. To implement the SAR studies of BHC analogues, the synthetic route to complete the Schiff base was developed. The synthesis of 3-acetyl-4-hydroxycoumarin allows for a convenient source to develop a library of BHC analogues. Along with the synthesis of 3-acetyl variants, the formation of 3-acyl moieties of various lengths were also developed for SAR studies. In addition to the coumarin based scaffold, the development of a 2-acetyl-4-hydroxyquinolinone scaffold allowed for further SAR studies. Through the use of in vitro, ex vivo, and ¬in silico studies, the activity of the synthesized BHC analogues were analyzed. The inhibition activity of the analogues determined through ATPase assays found the trend that both longer linear alkyl and methyl-aromatic imino tails are favored. The lead analogues tested containing a hexyl and a benzyl imino tail have a IC50 values of 1.2 ± 1.0 µM and 0.8 ± 0.2 µM, respectively, to skeletal myosin II inhibition. Competitive assays and in silico¬ analysis also suggest that BHC analogues bind in the same pocket as the more thoroughly studied myosin II inhibitor blebbistatin.