Patent ID: 8071650

Claim:
A compound of the following formula (I): or a pharmaceutically acceptable salt thereof, wherein: X represents S, O or â€”NCN; Y represents NH; R 1 represents anthracenylmethyl, naphthylmethyl, alkoxycarbonyl or alkylcarbonyloxy (wherein, m is 1, 2, 3 or 4; R 4 and R 5 are independently hydrogen, lower alkyl having 2 to 5 carbon atoms, methanesulfonylamino, lower alkoxy having 2 to 5 carbon atoms, methoxyalkoxy, methoxyalkoxyalkyl, alkoxycarbonyloxy, benzyloxy, acetoxymethyl, propinoyloxymethyl, butoxyalkyl, trimethylacetoxy, or trimethylacetoxymethyl; and R 6 and R 7 are independently hydrogen or lower alkyl having 1 to 5 carbon atoms); R 2 represents R 8 â€”(CH 2 ) n â€” {wherein, n is 1, 2, 3 or 4; R 8 is benzoyl substituted or unsubstituted with lower alkyl having 1 to 5 carbon atoms, nitro, amino, cyano, methanesulfonylamino, formyl or halogen; or (wherein, R 17 R 18 , R 20 and R 21 are independently hydrogen, halogen, lower alkyl having 1 to 5 carbon atoms, alkoxy, methylenedioxy, methanesulfonylaminomethyl, alkoxycarbonyl, sulfamoyl, alkoxycarbonylamino, â€”NHCH 2 CO 2 H, alkoxyalkylcarbonylamino, alkoxycarbonylalkylamino, nitro, formyl, acetyl, formylamino, acetylamino, cyano, â€”OSO 2 CH 3 , thiocarbamoyl, â€”C(â•O)NHNH 2 , â€”PO(â•O)(OCH 3 ) 2 , carboxyl, NHBoc or guanidine; R 19 is alkylsulfonylamino (wherein, alkyl has 1 to 5 carbon atoms); and R 22 and R 23 are independently hydrogen, halogen, alkoxy or hydroxy; or hydroxyphenylalkyl or (methanesulfonylaminophenyl)alkyl}, with the proviso that if both R 4 and R 5 are hydrogen, then R 17 R 18 , R 20 and R 21 are not simultaneously alkyl and halogen; when R 4 or R 5 is alkoxy, then at least one of R 17 R 18 , R 20 and R 21 is alkylsulfonylamino, sulfamoyl, alkoxyalkylcarbonylamino, alkoxycarbonylamino, alkoxycarbonylalkylamino, â€”NHCH 2 CO 2 H, guanidine, acetylamino, trifluorormethylsulfonylamino or formylamino; and when R 17 R 18 , R 20 or R 21 is alkoxy, then at least one of R 4 and R 5 is methanesulfonylamino or alkoxycarbonyloxy.