Macrocyclic compounds which stabilize G-Quadruplex DNA and RNA

1. A compound of formula I:

wherein:

each B and E is independently —C(═O)NH—CH(R a )— or —C(═O)—NH—C(═O)—, and each A and D is independently a group of the formula:

each R 1 , R 2 , R 3 , R 4 , and R 5 is independently H, (C 1 -C 6 )alkyl, or (C 1 -C 6 )alkoxy, wherein each (C 1 -C 6 )alkyl and (C 1 -C 6 )alkoxy is optionally substituted with OH, (C 1 -C 6 )alkoxy, (C 1 -C 6 )alkylthio, aryl, NR c R d , or —C(═O)NR c R d ;

each X is independently NH, S, or O;

each Z is independently N or CH;

the bond represented by ----- is a single or a double bond;

each R a is independently H, aryl, or (C 1 -C 6 )alkyl that is optionally substituted with OH, (C 1 -C 6 )alkoxy, (C 1 -C 6 )alkylthio, aryl, NR e R f , or —C(═O)NR e R f ;

each R c and R d is independently H or (C 1 -C 6 )alkyl; or R c and R d together with the nitrogen to which they are attached form a pyrrolidino, piperidino, piperazino, morpholino, thiomorpholino, or azepino ring; and

each R e and R f is independently H or (C 1 -C 6 )alkyl; or R e and R f together with the nitrogen to which they are attached form a pyrrolidino, piperidino, piperazino, morpholino, thiomorpholino, or azepino ring;

or a salt thereof;

provided the compound of formula I is not telomestatin or dehydrotelomestatin.

2. The compound of claim 1 which is a compound of formula (II):

or a pharmaceutically acceptable salt thereof.

3. A pharmaceutical composition comprising a compound of formula I as described in claim 1 ; or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier.

4. A method to stabilize G-quadruplex DNA comprising contacting the G-quadruplex DNA with a compound of formula I as described in claim 1 , or a salt thereof.

5. The compound of claim 1 which is a compound of the following formula:

or a salt thereof.

6. A compound of the following formula 15, 16, 17, or 50:

or a salt thereof.

7. The compound of claim 1 which is a compound of the following formula:

or a salt thereof.

8. The compound of claim 1 which is a compound of the following formula 219 or 220:

or a salt thereof.