Amino acid- , peptide- and polypeptide-lipids, isomers, compositions, and uses thereof

A method of delivering an agent to a subject or a cell, the method comprising contacting with the cell or administering to the subject a composition comprising the agent and a compound of formula (III):

• or a salt thereof;
• wherein:
• p is 1;
• each instance of Q is O;
• each instance of R1 is independently hydrogen, alkyl, or a group of formula (iv);
• provided at least one instance of R1 is a group of formula (iv):
• L is alkylene;
• R6 and R7 are each independently hydrogen, alkyl, a nitrogen protecting group, or a group of formula (i), (ii), or (iii);
• each instance of R2 is independently hydrogen, alkyl, a nitrogen protecting group, or a group of formula (i), (ii), or (iii);
• formulae (i), (ii), and (iii) are:
• wherein each instance of formula (i) is independently formula (i-a) or (i-b):
• each instance of R′ is independently hydrogen or alkyl;
• X is O, S, or NRX, wherein RX is hydrogen or a nitrogen protecting group;
• Y is O;
• RP is hydrogen, alkyl, or an oxygen protecting group when attached to an oxygen atom;
• and
• RL is C6-50 alkyl,
• provided that at least one instance of R2, R6, or R7 is a group of the formula (i), (ii), or (iii);
• wherein each alkyl and alkylene is independently unsubstituted or substituted at one or more positions with a group selected from halogen, —CN, —NO2, —OH, —ORaa, —N(Rbb)2, —N(Rbb)3+X−, —N(ORcc)Rbb, —SH, —SRaa, —C(═O)Raa, —CO2H, —CHO, —C(OR)2, —CO2Raa, —OC(═O)Raa, —OCO2Raa, —C(═O)N(Rbb)2, —OC(═O)N(Rbb)2, —NRbbC(═O)Raa, —NRbbCO2Raa, —NRbbC(═O)N(Rbb)2, —C(═NRbb)Raa, —C(═NRbb)ORaa, —OC(═NRbb)Raa, —OC(═NRbb)ORaa, —C(═NRbb)N(Rbb)2, —OC(═NRbb)N(Rbb)2, —NRbbC(═NRbb)N(Rbb)2, C3-14 carbocyclyl, 3-14 membered heterocyclyl, C6-14 aryl, and 5-14 membered heteroaryl, wherein each alkyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 groups selected from halogen, —OH, —ORee, and C1-50 alkyl;
• or two geminal hydrogens on a carbon atom are replaced with the group ═O;
• each instance of Raa is, independently, selected from C1-50 alkyl;
• each instance of Rbb is, independently, selected from hydrogen and C1-50 alkyl;
• each instance of Ree is, independently, selected from C1-50 alkyl and C3-10 carbocyclyl;
• and
• X− is a counterion.