Boscalid and both saturated analogues 30, 31 also effectively inhibited the growth of Fusarium oxysporum (Figure ). Moreover, at low concentrations, the oxygen-containing saturated analogue 31 exhibited a potency identical to that of Boscalid. In the inhibition of growth of Fusarium verticillioides, compound 31 was still active but exhibited a lower potency compared to Boscalid (Figure ). Summary. The ortho-substituted phenyl ring (as well as metaand para-isomers) is a basic structural element in chemistry, and children learn about it already at school in a general chemistry class. In this work, we developed water-soluble saturated bioisosteres of ortho-substituted phenyl ring: 2oxabicyclo[2.1.1]hexanes (Figure ). These scaffolds were synthesized from available starting materials on a multigram scale. Crystallographic analysis revealed that these structures and the ortho-substituted phenyl ring indeed have similar geometric properties. Moreover, replacement of the orthosubstituted phenyl ring in bioactive compounds with 2oxabicyclo[2.1.1]hexanes, in most cases, improved water solubility (up to more than ten times), reduced lipophilicity, improved metabolic stability and most importantly -retained bioactivity.