Vanilloid analogues containing resinferatoxin pharmacophores as potent vanilloid receptor agonists and analgesics, compositions and uses thereof

A compound represented by the following formula (I):

• wherein,
• X is an oxygen or sulfur atom;
• A is —NHCH2— or —CH2—;
• R1 is a substituted or unsubstituted C1-4alkaryl group, or the group of the formula:
• R4CO— wherein R4 is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms;
• R2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms or a halogen atom;
• R3 is a hydrogen atom, an alkyl grouip having 1 to 4 carbon atoms, an aminoalkyl, a diacid monoester, α-alkyl acid;
• n is an integer of 1 to 2;
• and
• the asterisk mark * indicates a chiral carbon atom, and its pharmaceutically accepatable salts.