Reverse-turn mimetics and methods relating thereto

A compound having the structure:

• or pharmaceutically acceptable salt or stereoisomer thereof,
• wherein
• A is —(CR2R2a)m— where m is 1, 2 or 3;
• B is —(CR3R3a)n— where n is 1, 2, 3 or 4;
• X is —N(R4)—, —O—, or —S—;
• R2 and R3 are, at each occurrence, the same or different and independently an amino acid side chain moiety or amino acid side chain derivative, a peptide or peptide derivative or a solid support;
• R5 is an amino acid side chain moiety or amino acid side chain derivative;
• R2a and R3a are, at each occurrence, the same or different and independently hydrogen, hydroxy, —COOH, —CONH2, —R6, —OR6, —COOR6, —COR6 or —CONHR6, where R6 is lower alkyl optionally substituted with halogen or hydroxy;
• R1 and R4 are the same or different and chosen from a solid support, amino acid, peptide, protein, amino acid side chain moieties, amino acid side chain derivatives and peptide derivatives;
• and
• wherein R1 and R2 taken together optionally form a fused heterocycle or substituted heterocycle, wherein a substituted moiety has at least one hydrogen atom replaced with at least one substituent chosen from:
• halogen, oxo, hydroxy, haloalkyl, —R, —OR, C(═O)R, —C(═O)OR, C(═O)NRR, —NRR, NRC(═O)R, —NRC(═O)OR, NRC(═O)NRR, —OC(═O)R, OC(═O)OR, OC(═O)NRR, SH, —SR, —SOR, —SO2R, NRSO2R, —Si(R)3, and —OP(OR)3, wherein each occurrence of R is the same or different and independently an amino acid side chain moiety or an amino acid side chain derivative, hydrogen, alkyl, aryl, arylalkyl, heterocycle or heterocyclealkyl, or wherein any two R groups attached to the same nitrogen atom, taken together with the nitrogen atom to which they are attached, form a heterocyclic ring or a substituted heterocyclic ring.