Benzo[b]furan dimers

A compound of the formula I

• wherein
• L is selected from —(CH2)a—, and a group of the formula
• —B—A—B—
• wherein a is selected from 2-20,
• B is —(CH2)b—, —(CH2)c—O—(CH2)d—, or
• and
• A is selected from a group of the formula
• wherein R4 is selected from halogen, lower alkyl, lower alkoxy, NO2, and —NRR,
• D and E are independently selected from O, S, Se, CRR and NR,
• b is selected from 1-10,
• c is selected from 1-8,
• d is selected from 1-8,
• e is selected from 0-4;
• f is selected from 0-3, and
• R is selected from H, lower alkyl, aralkyl and aryl;
• X is selected from O, or —NH—;
• R1 is selected from
• a C1-C20 alkyl which may be unsubstituted or substituted with one or more substituents selected from CN, halogen, lower alkoxy, thio-lower alkyl, nitro, phosphinos, phosphates, and protected amino;
• a C1-C20 alkenyl which may be unsubstituted or substituted with one or more substituents selected from CN, halogen, lower alkoxy, thio-lower alkyl, nitro, phosphinos, phosphates, and protected amino;
• an aromatic group which may be unsubstituted or substituted with one or more substituents
• selected from halogen, lower alkyl, lower alkoxy, thio-lower alkyl, nitro, phosphinos, phosphates, and protected amino;
• and
• an aralkyl which may be unsubstituted or substituted with one or more substituents selected
• from halogen, lower alkyl, lower alkoxy, thio-lower alkyl, nitro, phosphinos, phosphates, and protected amino;
• R2 is selected from halogen, hydroxy, CN, nitro, lower alkyl, lower alkoxy, thio-lower alkyl, lower alkenyl, cycloalkyl, C2-C8 acyl, lower alkyl ester, and lower alkyl amide;
• R3 is a group of the formula
• —(CH2)p—Yq—(CH2)r—Zs—(CH2)t—R5
• wherein Y and Z are independently selected from O, S, —OCH2CH2O—,
• p, r and t are independently selected from values from 0 to 10;
• q and s are independently selected from 0 and 1, provided that when t=0 then s=0, and when r=0 then q=0;
• and
• R5 is selected from OH, CO2H,
• n is selected from 0-4;
• and
• m is 0 or 1, with the proviso that the sum of n plus m does not exceed 4.