u2014 cl u2014 co 2 r u2032 u2014 c o linker linker u2014 nr 1 linker or u2014 s linker wherein the linker when present is a linker to a first amino acid or a lipophilic group x 3 is u2014 h u2014 f u2014 cl or u2014 or 1 in certain embodiments the invention relates to any one of the aforementioned compounds wherein x 1 is u2014 h in certain embodiments the invention relates to any one of the aforementioned compounds wherein x 1 is u2014 cl in certain embodiments the invention relates to any one of the aforementioned compounds wherein q is 1 and x 2 is u2014 c o linker in certain embodiments the invention relates to any one of the aforementioned compounds wherein r is alkyl in certain embodiments the invention relates to any one of the aforementioned compounds wherein r is methyl ethyl propyl or butyl in certain embodiments the invention relates to any one of the aforementioned compounds wherein r is methyl in certain embodiments the invention relates to any one of the aforementioned compounds wherein the compound is in certain embodiments the invention relates to any one of the aforementioned compounds wherein the compound is in certain embodiments the invention relates to any one of the aforementioned compounds wherein the first amino acid is a natural u03b1 amino acid or a non natural u03b1 amino acid in certain embodiments the invention relates to any one of the aforementioned compounds wherein the first amino acid is a natural u03b1 amino acid in certain embodiments the invention relates to any one of the aforementioned compounds wherein the first amino acid is a non natural u03b1 amino acid in certain embodiments.