Lipophilic enantiomers of desacetylglucosamine muramyl dipeptide with anti-inflammatory and growth promoting activity

An oligopeptide of the following formula:

• or a pharmaceutically acceptable acid or salt thereof, wherein:
• R1 is C1-C18 linear alkyl or substituted or unsubstituted aryl;
• R2, R3, and R4 are each independently selected from H, substituted or unsubstituted alkyl and substituted or unsubstituted aryl;
• R5 is H, unsubstituted alkyl, or substituted or unsubstituted aryl;
• and
• X is O or NR6, wherein R6 is hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted aryl.