abstract |
Disclosed are compounds of formula (I) and (II) and pharmaceutically acceptable salts thereof, wherein the variables R, R 1 , R 2 , R 3 , R 21 , R 22 , R 23 , R 34 , R 37 , R 33 , R 39 , D, Q, Y, X, X 1 , X 3 , and X 4 are defined herein. These compounds are useful for treating gram-negative bacterial infections. |