Patent ID: 7115601

Claim:
A compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R 1 is selected from hydrogen, alkenyl, alkoxyalkyl, alkyl, and arylalkyl; R 2 is a 3- to 8-membered saturated or partially unsaturated ring containing one to three heteroatoms selected from N, O, and S(O) n , wherein n is 0, 1, or 2; wherein said ring is attached through a nitrogen atom, and wherein said ring is substituted by a 3- to 10-membered monocyclic or bicyclic spirocycle containing from zero to three heteroatoms selected from N, O, and S(O) n , wherein n is 0, 1, or 2; and wherein said ring and said spirocycle are each optionally substituted with one to three substituents independently selected from alkoxy, alkyl, alkylcarbonyl, aryl, halo, heteroaryl, heterocyclyl, —NR a R b , oxo, thiooxo, and trialkylsilyl; R 3 and R 4 are independently selected from hydrogen, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocyclyl, and heterocyclylalkyl; and R a and R b are independently selected from hydrogen, alkyl, aryl, and arylalkyl.