Deuterated cftr potentiators

Abstract

This invention relates to compounds of Formula I:and pharmaceutically acceptable salts thereof. This invention also provides compositions comprising a compound of this invention and the use of such compositions in methods of treating diseases and conditions that are beneficially treated by administering a CFTR potentiator.

1 .- 19 . (canceled) 
     
     
         20 . A compound represented by the following structural formula: 
       
         
           
           
               
               
           
         
       
     
     
         21 . The compound of  claim 20 , wherein any atom not designated as deuterium is present at its natural isotopic abundance. 
     
     
         22 . The compound of  claim 20 , wherein the isotopic enrichment coefficient for each designated deuterium is at least 3500, wherein the isotopic enrichment coefficient refers to the ratio between the isotopic abundance and the natural abundance of a specified isotope. 
     
     
         23 . A pharmaceutically acceptable salt of a compound represented by the following structural formula: 
       
         
           
           
               
               
           
         
       
     
     
         24 . The salt of  claim 23 , wherein any atom not designated as deuterium is present at its natural isotopic abundance. 
     
     
         25 . The salt of  claim 23 , wherein the isotopic enrichment coefficient for each designated deuterium is at least 3500, wherein the isotopic enrichment coefficient refers to the ratio between the isotopic abundance and the natural abundance of a specified isotope.