A compound of formula I ** Formula ** or a stereoisomer, geometric isomer or tautomeric form thereof, or a pharmaceutically acceptable salt of the compound of formula I or stereoisomer, geometric isomer of tautomeric form thereof, wherein R1 and R2 is selected each independently of the group consisting of hydrogen, C1-C8 alkyl optionally substituted with 1 to 4 halogens； a C1-C4 alkyl group optionally substituted with a substituent selected from the group consisting of OH, from one to four C1-C4 alkyl, C3-C7 cycloalkyl, C1-C4 dialkylamino, C6-C14 aryl optionally substituted with a halogen and optionally substituted conaryloxy C6-C10 optionally substituted with one to two halogens, and 5-10 membered heteroaryl optionally substituted with a C6-C10 aryl group and optionally substituted with one to three C1-C4 alkyl groups； C3-C7 cycloalkyl； C6-C14 aryl； alkyl - (C0-C3) -O-(C1-C3) alkyl optionally substituted with (C1-C3) alkyl； -C1-C3 alkyl-C (>； = O) O-C1-C3 alkyl； 3-8 membered heterocycloalkyl optionally substituted with one or more C1-C4 alkylcarbonyl groups； C6-C10 arylsulfonyl optionally substituted with one or more C1-C2 alkyl； 5-10 membered heteroaryl； and C6-C14-alkylene-C0-C4-alkyl-O-C0-C4 aryl, wherein each C0-C4 alkyl group and each C0-C4 alkylene is optionally substituted with one to four C1-C4alkyl； or, optionally, R1 and R2, together with the nitrogen to which they are attached, form an aliphatic ring of 4-, 5-, 6-, or 7- saturated or unsaturated members, in which one of the carbons in said aliphatic ring is optionally substituted by O, S, NR3 or CO, and wherein said ring is optionally fused to C6-C10 unarylene and is optionally substituted on a ring carbon with a substituent selected from the group consisting of -OH, 5-10 membered heteroaryl optionally substituted with one or more halogens and optionally substituted with one or more C1-C2 alkyl, C1-C4 alkoxy optionally substituted with one or more C1-C2 alkoxy and optionally substituted with one or mor
