Patent ID: 8575375

Claim:
A compound of structure 4, wherein: R 1 is H or (optionally substituted) C 1-4 alkyl, C 3-6 cycloalkyl, C 2-4 alkynyl, C 2-4 alkenyl, C 6-10 aryl, 2-arylsubstituted ethynyl, arylsubstituted C 1-4 alkyl, arylsubstituted C 2-4 -alkenyl, arylsubstituted C 3-6 cycloalkyl, heterocycle; 2-heterocycle-substituted ethynyl, heterocycle-substituted C 1-4 alkyl, heterocycle-substituted C 2-4 -alkenyl, or heterocycle-substituted C 3-6 cycloalkyl; R 4 is H or Me; and stereoisomers and pharmaceutically acceptable compositions salts thereof.