Synthesis and Characterization of 2‐Pyridylsulfur Pentafluorides

Structure-Activity Study of Bioisosteric Trifluoromethyl and Pentafluorosulfanyl Indole Inhibitors of the AAA ATPase p97

Exploratory SAR studies of a new phenyl indole chemotype for p97 inhibition revealed C-5 indole substituent effects in the ADPGlo assay that did not fully correlate with either electronic or steric factors. A focused series of methoxy-, trifluoromethoxy-, methyl-, trifluoromethyl-, pentafluorosulfanyl-, and nitro-analogues was found to exhibit IC50s from low nanomolar to double-digit micromolar. Surprisingly, we found that the trifluoromethoxy-analogue was biochemically a better match of the trifluoromethyl-substituted lead structure than a pentafluorosulfanyl-analogue. Moreover, in spite of their almost equivalent strongly electron-depleting effect on the indole core, pentafluorosulfanyl- and nitro-derivatives were found to exhibit a 430-fold difference in p97 inhibitory activities. Conversely, the electronically divergent C-5 methyl- and nitro-analogues both showed low nanomolar activities.

Synthesis of Phthalocyanines with a Pentafluorosulfanyl Substituent at Peripheral Positions

The pentafluorosulfanyl (SF5) group is more electronegative, lipophilic and sterically bulky relative to the well-explored trifluoromethyl (CF3) group. As such, the SF5 group could offer access to pharmaceuticals, agrochemicals and optoelectronic materials with novel properties. Here, the first synthesis of phthalocyanines (Pcs), a class of compounds used as dyes and with potential as photodynamic therapeutics, with a SF5 group directly attached on their peripheral positions is disclosed. The key for this work is the preparation of a series of SF5-containing phthalonitriles, which was beautifully regio-controlled by a stepwise cyanation via ortho-lithiation/iodination from commercially available pentafluorosulfanyl arenes. The macrocyclization of the SF5-containing phthalonitriles to SF5-substituted Pcs required harsh conditions with the exception of the synthesis of β-SF5-substituted Pc. The regiospecificity of the newly developed SF5-substituted Pcs observed by UV/Vis spectra and fluorescence quantum yields depend on the peripheral positon of the SF5 group.

Synthesis of Diaryliodonium Salts Having Pentafluorosulfanylarenes and Their Application to Electrophilic Pentafluorosulfanylarylation of C-, O-, N-, and S-Nucleophiles

Novel reagents for the electrophilic introduction of pentafluorosulfanyl (SF5) arenes into target molecules are disclosed. Unsymmetrical diaryliodonium salts 1 having SF5-arenes were synthesized by a one-pot process from iodo-SF5-benzenes 2 in good yields. The SF5-aryliodonium salts 1 were found to be efficient for the electrophilic SF5-arylation of carbon and heterocentered nucleophiles to furnish the corresponding substituted SF5-arenes in good to high yields.

Evaluation of tert-butyl isosteres: case studies of physicochemical and pharmacokinetic properties, efficacies, and activities

The tert-butyl group is a common motif in medicinal chemistry. Its incorporation into bioactive compounds is often accompanied by unwanted property modulation, such as increased lipophilicity and decreased metabolic stability. Several alternative substituents are available for the drug discovery process. Herein, physicochemical data of two series of drug analogues of bosentan and vercirnon are documented as part of a comparative study of tert-butyl, pentafluorosulfanyl, trifluoromethyl, bicyclo[1.1.1]pentanyl, and cyclopropyl-trifluoromethyl substituents.