Small molecules that bind MR1

A method of treating a respiratory infection of Mycobacterium tuberculosis or Streptococcus pyogenes in a human subject, the method comprising administering to the human subject in need thereof a pharmaceutically effective amount of a compound selected from Formula 1b, Formula 2b, and Formula 3b, or a pharmaceutically acceptable salt thereof:

• wherein, in each appearance:
• R1 is independently selected from H, OH, C1-C3 alkyl, and —CH═O;
• R2 is independently selected from H, a 5-10-membered carbocycle, a 5-10-membered heterocycle, and
• C1-C3 alkyl, wherein the C1-C3 alkyl can be substituted by 1 or 2 substituents selected from OH and CO2H;
• R3 is selected from OH and —O(C═O)—C1-C3 alkyl;
• R4 is independently selected from H, OH, C1-C3 alkyl, and —CH═O;
• R5 is independently selected from H, a 5-10-membered carbocycle, a 5-10-membered heterocycle, and
• C1-C3 alkyl, wherein the C1-C3 alkyl can be substituted by 1 or 2 substituents selected from OH and CO2H;
• R6 is selected from OH and —O(C═O)-C1-C3 alkyl;
• and
• R7 is H or OH.