10.1080/10426500701340949
The research focuses on the preparation of new tert-butyl substituted coumarins, thiocoumarins, and dithiocoumarins. The study was motivated by the researchers' interest in these compounds for their investigations on the EPR spectra of ester, thioester, and dithiopyrone radical anions. The researchers synthesized various compounds, starting from tert-butylphenols and diketene to prepare 6-tert-butyl-4-methylcoumarin and 6,8-di-tert-butyl-4-methylcoumarin via aryl acetoacetates. Thionation of these coumarins with Lawesson's or Davy's reagent led to the formation of the corresponding thion- and dithiocoumarins. Key chemicals involved in the research include 4-tert-butylphenol, 2,4-di-tert-butylphenol, 4-tert-butylthiophenol, diketene, sulfuric acid, aluminum trichloride, and various reagents for thionation such as Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 1,3-disulfide) and Davy's reagent (2,4-bis(methylthio)-1,3,2,4-dithiadiphosphetane 2,4-disulfide). The structures of the synthesized compounds were confirmed using NMR spectroscopy and X-ray structure analysis.