Syntheses and anti-allergic activity of 2-((bis(trimethylsilyl)methylthio/methylsulfonyl)methyl)-5-aryl-1,3,4-oxadiazoles

A new class of sila-substituted 1,3,4-oxadiazoles was synthesized by a convenient synthetic method. Both silathio/silasulfonyl acetic acids were efficiently condensed with benzohydrazides in the presence of phosphorus oxychloride to give sila-substituted 1,3,4-oxadiazoles in high yields. The compounds displayed variable extent of anti-allergic activity on IgE/Ag-stimulated RBL-2H3 cells at 50 and 100 μM concentrations. Compounds having sulfonyl moiety with bis(trimethylsilyl)-1,3,4-oxadiazoles (5a–c), exhibited better anti-allergic activities than those of compounds having sulphur moiety with bis(trimethylsilyl)-1,3,4-oxadiazoles (4a–c).

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► We synthesized a new class of bis(trimethylsilyl)-1,3,4-oxadiazoles.
► These compounds significantly inhibit β-hexosaminidase release stimulated by IgE/Ag at 50 and 100 μM concentrations.
► Compounds 5a, 5b and 5c were most potent anti-allergic candidates in this series.