Patent ID: 8552021

Claim:
A compound the formula I: or a stereoisomeric form thereof, wherein: R 1 is hydrogen, —C(═O)R 6 or —C(═O)CHR 7 —NH 2 ; R 2 is hydrogen; or C 1 -C 6 alkyl or phenyl, the latter being optionally substituted with 1, 2 or 3 substituents each independently selected from halo, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 1 -C 6 alkoxy, hydroxy and amino; or R 2 is naphtyl; or R 2 is indolyl; R 3 is hydrogen, C 1 -C 6 alkyl, benzyl; R 4 is hydrogen, C 1 -C 6 alkyl, benzyl; or R 3 and R 4 together with the carbon atom to which they are attached form C 3 -C 7 cycloalkyl; R 5 is C 1 -C 10 alkyl, optionally substituted with C 1 -C 6 alkoxy; or R 5 is C 3 -C 7 cycloalkyl; benzyl; or phenyl, optionally substituted with 1, 2 or 3 substituents each independently selected from hydroxy, C 1 -C 6 alkoxy, amino, mono- and diC 1 -C 6 alkylamino; R 6 is C 1 -C 6 alkyl; R 7 is C 1 -C 6 alkyl; R 8 is hydrogen or halogen; or a pharmaceutically acceptable salt thereof.