Patent ID: 8501744

Claim:
A compound of formula (I), or a pharmaceutically acceptable salt, or hydrate thereof, wherein: one of R 1 and R 2 is H, and the other is selected from C 1-8 -alkyl, C 2-8 -alkynyl, C 3-6 -cycloalkyl and C 1-8 -alkyl-C 5-10 -aryl; R 3 is selected from tert-butylmethyl, iso-propylmethyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl and 1-methylcyclopentyl; R 9 is selected from the following: wherein: R 4 is selected from C 1-8 -alkyl and C 3-8 -cycloalkyl.