Patent ID: 7928264

Claim:
A compound of formula [I] or salt thereof: wherein R 1 is hydrogen, halogen, nitro, or amino, R 2 is hydrogen or lower alkyl, R 3 is hydrogen, —X— is in which —Y— is a bond, —O—, —NH—, or —CH 2 —, and R 4 , R 5 , and R 6 are each hydrogen, R 7 is lower alkyl, cyclo(lower)alkyl, —Z—R 9 , or in which —Z— is —O— or —S—, and each R 9 is independently lower alkyl or cyclo(lower)alkyl, and R 8 is -D-E-R 10 , in which -D- is —CONHSO 2 —, E is lower alkylene selected from the group consisting of ethylene, trimethylene, 2,2-dimethyltrimethylene, 3,3-dimethyltrimethylene, tetramethylene, pentamethylene, hexamethylene and propylene, and R 10 is —OH.