Antimicrobial compositions containing β-amino acid oligomers

• US 6,683,154 B1
• Filed: 02/11/2000
• Issued: 01/27/2004
• Est. Priority Date: 03/04/1997
• Status: Expired due to Term

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Gellman, Samuel Helmer, Weisblum, Bernard, Wang, Xifang, Porter, Emilie Ann
• Primary Examiner(s): Baker, Maurie Garcia
• Application Number:
  US09/502,829
• Time in Patent Office: 1,446 Days
• Field of Search: 514/17-20, 530/350, 530/328, 530/324, 530/323, 530/331, 530/332, 530/333
• US Class Current: 530/323
• CPC Class Codes: C07B 2200/11 Compounds covalently bound to a solid support
• CPC Class Codes: C07C 237/24 having the carbon atom of at least one of the carboxamide groups bound to a carbon atom of a ring other than a six-membered aromatic ring of the carbon skeleton
• CPC Class Codes: C07C 2601/14 The ring being saturated

Abstract

Disclosed are antimicrobial compositions containing β-peptides and methods of inhibiting microbial growth in mammals using the compositions. The β-peptides present in the compositions contain ring structures in the peptide backbone which limit the conformational flexibility of the peptide backbone.

Claims

1. A pharmaceutical composition comprising an antimicrobial-effective amount of a β

-amino acid oligomer or polymer wherein each residue of the oligomer or polymer is a β

-amino acid residue comprising formula;

wherein p is an integer greater than 6;

wherein X is independently selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n+1—

OR, —

(CH)_n+1—

SR, —

(CH₂)_n+1—

S(═

O)—

CH₂—

R, —

(CH₂)_n+1—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

NRR, —

(CH₂)_n+1—

NHC(═

O)R, —

(CH₂)_n+1—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

O—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

N—

{(CH₂)_m—

R¹}₂, —

(CH₂)_n+1—

NHC(═

O)—

(CH₂)_n+1—

R¹, and —

(CH₂)_n+1—

NHS(═

O)₂—

(CH₂)_m—

R¹;

wherein R is independently selected from the group consisting of hydrogen, C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteraryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl; and

wherein R¹ is independently selected from the group consisting of hydroxy, C₁-C₆-alkyloxy, aryloxy, heteroaryloxy, thio, C₁-C₆-alkylthio, C₁-C₆-alkylsulfinyl, C₁-C₆-alkylsulfonyl, arylthio, arylsulfinyl, arylsulfonyl, heteroarylthio, heteroarylsulfinyl, heteroarylsulfonyl, amino, mono- or di-C₁-C₆-alkylamino, mono- or diarylamino, mono- or diheteroarylamino, N-alkyl-N-arylamino, N-alkyl-N-heteroarylamino, N-aryl-N-heteroarylamino, aryl-C₁-C₆-alkylamino, carboxylic acid, carboxamide, mono- or di-C₁-C₆-alkylcarboxamide, mono- or diarylcarboxamide, mono- or diheteroarylcarboxamide, N-alkyl-N-arylcarboxamide, N-alkyl-N-heteroarylcarboxamide, N-aryl-N-heteroarylcarboxamide, sulfonic acid, sulfonamide, mono- or di-C₁-C₆-alkylsulfonamide, mono- or diarylsulfonamide, mono- or diheteroarylsulfonamide, N-alkyl-N-arylsulfonamide, N-alkyl-N-heteroarylsulfonamide, N-aryl-N-heteroarylsulfonamide, urea;

mono- di- or tri-substituted urea, wherein the subsitutent(s) is selected from the group consisting of C₁-C₆-alkyl, aryl, heteroaryl;

O-alkylurethane, O-arylurethane, and O-heteroarylurethane;

wherein Y is independently selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n—

OR, —

(CH₂)_n—

SR, —

(CH₂)_n—

S(═

O)—

CH₂—

R, —

(CH₂)_n—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n—

NRR, —

(CH₂)_n—

NHC(═

O)R, —

(CH₂)_n—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n—

O—

(CH₂)_m—

R¹, —

(CH₂)_n—

S—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n—

N—

{(CH₂)_m—

R¹}₂—

(CH₂)_n—

NHC(═

O)—

(CH₂)_m—

R¹, and —

(CH₂)_n—

NHS(═

O)₂—

(CH₂)_m—

R¹;

wherein R and R¹ are as defined hereinabove;

or

X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubstituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s);

the substituents on carbon atoms of the rings being independently selected from the group consisting of linear or branched C₁-C₆-alkyl, alkenyl, alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteraryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, and the substituents listed above for X and Y when X and Y are not combined;

the substituents on nitrogen heteroatoms of the rings being independently selected from the group consisting of —

S(═

O)₂—

CH₂—

R, —

C(═

O)—

R, —

S(═

O)₂—

(CH₂)_m—

R¹, —

C(═

O)—

(CH₂)_n+1—

R¹;

wherein R and R¹ are as defined hereinabove;

m is an integer of from 2-6 and n is an integer of from 0-6;

W is hydrogen or an amino-terminal capping group;

Z is hydroxy or a carboxy-terminal capping group;

and further wherein in at least one residue, X and Y are combined in a cyclic moiety; and

pharmaceutically-suitable salts thereof;

in combination with a pharmaceutically-suitable carrier.

2. The composition according to claim 1, wherein in each residue:

X is selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n+1—

OR, —

(CH₂)_n+1—

SR, —

(CH₂)_n+1—

S(═

O)—

CH₂—

R, —

(CH₂)_n+1—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

NRR, —

(CH₂)_n+1—

NHC(═

O)R, —

(CH₂)_n+1—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

O—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

N—

{(CH₂)_m—

R¹}₂, —

(CH₂)_n+1—

NHC(═

O)—

(CH₂)_n+1—

R¹, and —

(CH₂)_n+1—

NHS(═

O)₂—

(CH₂)_m—

R¹;

Y is selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n—

OR, —

(CH₂)_n—

SR, —

(CH₂)_n—

S(═

O)—

CH₂—

R, —

(CH₂)_n—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n—

NRR, —

(CH₂)_n—

NHC(═

O)R, —

(CH₂)_n—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n—

O—

(CH₂)_m—

R¹, —

(CH₂)_n—

S—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n—

N—

{(CH₂)_m—

R¹}₂—

(CH₂)_n—

NHC(═

O)—

(CH₂)_m—

R¹, and —

(CH₂)_n—

NHS(═

O)₂—

(CH₂)_m—

R¹; and

when X and Y are combined to define a cyclic moiety, X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).

3. The composition according to claim 1, wherein in each residue:

X and Y are independently selected from the group consisting of linear or branched C₁-C₆-alkyl, hydroxy-C₁-C₆-alkyl, amino-C₁-C₆-alkyl, aryl-C₁-C₆-alkyl, heteroaryl-C₁-C₆-alkyl, and carboxyl-C₁-C₆-alkyl; and

when X and Y are combined to define a cyclic moiety, X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).

4. The composition according to claim 1, wherein in each residue X and Y are combined and X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).

5. The composition according to claim 1, wherein in each residue X and Y are combined and X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubstituted C₅-C₆ cycloalkyl, cycloalkenyl, or heterocyclic ring having one nitrogen atom as the sole heteroatom.

6. The composition according to claim 1, wherein in each residue X and Y are combined and X and Y, together with the carbons to which they are bonded, independently define a substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, unsubstituted or N-substituted piperidinyl, or unsubstituted or N-substituted pyrrolidinyl.

7. The composition according to claim 1, wherein in each residue X and Y are combined and X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted cyclopentyl, cyclohexyl, pyrrolidinyl, or piperidinyl ring, wherein the substituent is selected from the group consisting of amino, mono- or di-C₁-C₆-alkylamino, carboxamido, sulfonamido, urea, thio, and C₁-C₆-alkylthio.

8. The composition according to claim 1, wherein in each residue X and Y are combined and X and Y combined, together with the carbon atoms to which they are bonded, independently define an amino-substituted cyclopentyl, amino-substituted cyclohexyl, N-substituted pyrrolidinyl, or N-substituted piperidinyl ring.

9. The composition according to claim 1, wherein W is selected from the group consisting of hydrogen, formyl, acetyl, tBoc, and Fmoc;

and Z is selected from the group consisting of hydroxy, NH₂, NH(alkyl), and N(alkyl)₂.

10. A method of inhibiting microbial growth in mammals, including humans, the method comprising administering an antimicrobial amount of a composition as recited in claim 1 to a patient in need thereof.

11. The method of claim 10, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 μ

M to 10 mM is administered.

12. The method of claim 10, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 μ

M to 100 μ

M is administered.

13. A method of inhibiting microbial growth in mammals, including humans, the method comprising administering an antimicrobial amount of a composition as recited in claim 2 to a patient in need thereof.

14. The method of claim 13, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 μ

M to 10 mM is administered.

15. The method of claim 13, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 μ

M to 100 μ

M is administered.

16. A method of inhibiting microbial growth in mammals, including humans, the method comprising administering an antimicrobial amount of a composition as recited in claim 4 to a patient in need thereof.

17. The method of claim 16, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 nM to 10 mM is administered.

18. The method of claim 16, wherein an amount of composition sufficient to provide a concentration of β

-amino acid oligomer or polymer at point of contact with a microbial cell of from 1 nM to 1 mM is administered.

19. A β

-amino acid oligomer or polymer comprising residues of formula I;

wherein p is an integer greater than 6, and wherein at least two of the residues of formula I are different;

wherein X is independently selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n+1—

OR, —

(CH)_n+1—

SR, —

(CH₂)_n+1—

S(═

O)—

CH₂—

R, —

(CH₂)_n+1—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

NRR, —

(CH₂)_n+1—

NHC(═

O)R, —

(CH₂)_n+1—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

O—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

N—

{(CH₂)_m—

R¹}₂, —

(CH₂)_n+1—

NHC(═

O)—

(CH₂)_n+1—

R¹, and —

(CH₂)_n+1—

NHS(═

O)₂—

(CH₂)_m—

R¹;

wherein R is independently selected from the group consisting of hydrogen, C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteraryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl; and

wherein R¹ is independently selected from the group consisting of hydroxy, C₁-C₆-alkyloxy, aryloxy, heteroaryloxy, thio, C₁-C₆-alkylthio, C₁-C₆-alkylsulfinyl, C₁-C₆-alkylsulfonyl, arylthio, arylsulfinyl, arylsulfonyl, heteroarylthio, heteroarylsulfinyl, heteroarylsulfonyl, amino, mono- or di-C₁-C₆-alkylamino, mono- or diarylamino, mono- or diheteroarylamino, N-alkyl-N-arylamino, N-alkyl-N-heteroarylamino, N-aryl-N-heteroarylamino, aryl-C₁-C₆-alkylamino, carboxylic acid, carboxamide, mono- or di-C₁-C₆-alkylcarboxamide, mono- or diarylcarboxamide, mono- or diheteroarylcarboxamide, N-alkyl-N-arylcarboxamide, N-alkyl-N-heteroarylcarboxamide, N-aryl-N-heteroarylcarboxamide, sulfonic acid, sulfonamide, mono- or di-C₁-C₆-alkylsulfonamide, mono- or diarylsulfonamide, mono- or diheteroarylsulfonamide, N-alkyl-N-arylsulfonamide, N-alkyl-N-heteroarylsulfonamide, N-aryl-N-heteroarylsulfonamide, urea;

mono- di- or tri-substituted urea, wherein the subsitutent(s) is selected from the group consisting of C₁-C₆-alkyl, aryl, heteroaryl;

O-alkylurethane, O-arylurethane, and O-heteroarylurethane;

wherein Y is independently selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n—

OR, —

(CH₂)_n—

SR, —

(CH₂)_n—

S(═

O)—

CH₂—

R, —

(CH₂)_n—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n—

NRR, —

(CH₂)_n—

NHC(═

O)R, —

(CH₂)_n—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n—

O—

(CH₂)_m—

R¹, —

(CH₂)_n—

S—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n—

N—

{(CH₂)_m—

R¹}₂—

(CH₂)_n—

NHC(═

O)—

(CH₂)_m—

R¹, and —

(CH₂)_n—

NHS(═

O)₂—

(CH₂)_m—

R¹;

wherein R and R¹ are as defined hereinabove;

or

X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s);

the substituents on carbon atoms of the rings being independently selected from the group consisting of linear or branched C₁-C₆-alkyl, alkenyl, alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteraryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, and the substituents listed above for X and Y when X and Y are not combined;

the substituents on nitrogen heteroatoms of the rings being independently selected from the group consisting of —

S(═

O)₂—

CH₂—

R, —

C(═

O)—

R, —

S(═

O)₂—

(CH₂)_m—

R¹, —

C(═

O)—

(CH₂)_n+1—

R¹;

wherein R and R¹ are as defined hereinabove;

m is an integer of from 2-6 and n is an integer of from 0-6;

W is hydrogen or an amino-terminal capping group;

Z is hydroxy or a carboxy-terminal capping group;

and further wherein in at least one residue, X and Y are combined in a cyclic moiety, and salts thereof.

20. The β

-amino acid oligomer or polymer according to claim 19, wherein in each residue;

X is selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n+1—

OR, —

(CH₂)_n+1—

SR, —

(CH₂)_n+1—

S(═

O)—

CH₂—

R, —

(CH₂)_n+1—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

NRR, —

(CH₂)_n+1—

NHC(═

O)R, —

(CH₂)_n+1—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n+1—

O—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n+1—

N—

{(CH₂)_m—

R¹}₂, —

(CH₂)_n+1—

NHC(═

O)—

(CH₂)_n+1—

R¹, and —

(CH₂)_n+1—

NHS(═

O)₂—

(CH₂)_m—

R¹; and

Y is selected from the group consisting of hydrogen, linear or branched C₁-C₆-alkyl, alkenyl, or alkynyl;

mono- or bicyclic aryl, mono- or bicyclic heteroaryl having up to 5 heteroatoms selected from N, O, and S;

mono- or bicyclic aryl-C₁-C₆-alkyl, mono- or bicyclic heteroaryl-C₁-C₆-alkyl, —

(CH₂)_n—

OR, —

(CH₂)_n—

SR, —

(CH₂)_n—

S(═

O)—

CH₂—

R, —

(CH₂)_n—

S(═

O)₂—

CH₂—

R, —

(CH₂)_n—

NRR, —

(CH₂)_n—

NHC(═

O)R, —

(CH₂)_n—

NHS(═

O)₂—

CH₂—

R, —

(CH₂)_n—

O—

(CH₂)_m—

R¹, —

(CH₂)_n—

S—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)—

(CH₂)_m—

R¹, —

(CH₂)_n—

S(═

O)₂—

(CH₂)_m—

R¹, —

(CH₂)_n—

NH—

(CH₂)_m—

R¹, —

(CH₂)_n—

N—

{(CH₂)_m—

R¹}₂—

(CH₂)_n—

NHC(═

O)—

(CH₂)_m—

R¹, and —

(CH₂)_n—

NHS(═

O)₂—

(CH₂)_m—

R¹; and

when X and Y are combined to define a cyclic moiety, X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).

21. The β

-amino acid oligomer or polymer according to claim 19, wherein in each residue;

X and Y are independently selected from the group consisting of linear or branched C₁-C₆-alkyl, hydroxy-C₁-C₆-alkyl, amino-C₁-C₆-alkyl, aryl-C₁-C₆-alkyl, heteroaryl-C₁-C₆-alkyl, and carboxyl-C₁-C₆-alkyl; and

when X and Y are combined to define a cyclic moiety, X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).

22. The β

-amino acid oligomer or polymer according to claim 19, wherein in each residue X and Y are combined, and wherein X and Y combined, together with the carbon atoms to which they are bonded, independently define a substituted or unsubsituted C₃-C₈ cycloalkyl, cycloalkenyl or heterocyclic ring having one or more N, O or S atom(s) as the heteroatom(s).