Patent ID: 8680300

Claim:
A compound having the formula (I): or an isomer, salt, or solvate thereof, wherein R 1 is selected from hydrogen, alkyl, acyl, aryl and heteroaryl; R 2 is selected from hydrogen, alkyl and aryl; R 3 is selected from hydrogen, alkyl and aryl; R 4 is selected from hydrogen, alkyl, aryl, alkoxy, acyloxy, amine and amide; and R 5 is selected from hydrogen, alkyl and acyl; or R 4 and R 5 do not exist and an ether linkage is formed between the carbon atom in position 6 and the oxygen atom joined to the carbob atom in position 3; R 6 is selected from alkyl, aryl and alkoxy; R 7 is selected from alkoxy, alkyl, aryl, —CH 2 —COR 8 and heterocycle; R 8 is selected from alkyl and aryl.