Thiacalix[4]arene phosphoric acids. Synthesis, structure, and inhibition of glutathione S-transferases

Abstract

Regioselective phosphorylation of tetrahydroxythiacalix[4] arenes by diethyl chlorophosphate in the presence of triethylamine or by the system diethylphosphite/carbon tetrachloride/triethylamine gave ethyl esters of thiacalix[4] arene monophosphoric or thiacalix[4] arene diphosphoric acids, respectively. The obtained esters were converted with quantitative yields into corresponding free acids by sequential treatment with trimethylbromosilane and methanol. The thiacalix[4] arene diphosphoric acids were evaluated in vitro as inhibitors of glutathione S-transferases.

Graphical Abstract

Keywords:

• thiacalix[4]arenes
• phosphoric acid
• synthesis
• X-ray analysis
• inhibitor
• glutathione S-transferase

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Fund for Fundamental Research of Ukraine through grant 2020.02/0031. O.S. thanks the Tallinn University of Technology for a scholarship in the framework of ETAG20049 (COVSG5) research grant.