Organic compounds

A compound of Formula I:

• wherein
• (i) R1 is H or C1-4 alkyl (e.g., methyl or ethyl);
• (ii) R2 and R3 are independently H or C1-6 alkyl (e.g., methyl or ethyl);
• (iii) R4 is H or C1-4 alkyl (e.g., methyl or ethyl);
• (iv) R5 is aryl (e.g., phenyl) optionally substituted with one or more groups independently selected from —C(═O)—C1-6 alkyl (e.g., —C(═O)—CH3) and C1-6-hydroxyalkyl (e.g., 1-hydroxyethyl);
• (v) R6 and R7 are independently H or aryl (e.g., phenyl) optionally substituted with one or more groups independently selected from C1-6 alkyl (e.g., methyl or ethyl) and halogen (e.g., F or Cl), for example unsubstituted phenyl or phenyl substituted with one or more halogen (e.g., F) or phenyl substituted with one or more C1-6 alkyl and one or more halogen or phenyl substituted with one C1-6 alkyl and one halogen, for example 4-fluorophenyl or 3,4-difluorophenyl or 4-fluoro-3-methylphenyl;
• and
• (vi) n is 1, 2, 3, or 4,
• in free or salt form.