| abstract |
PROBLEM TO BE SOLVED: To provide a novel compound effective for the onset of delayed reaction such as allergic dermatitis and rhinitis. SOLUTION: Formula (1) (Wherein X is O or S; R 1 is H, lower alkyl, aryl, etc .; R 2 is H, lower alkyl, aryl, etc .; Y 1 , Y 2 are single bonds, lower alkylene, etc .; R 3 is aryl, R 4 is H, lower alkanoyl, etc .; R 5 is H, lower alkyl, etc., provided that when R 2 is aryl, R 3 is not aryl) or a salt thereof I will provide a. [Selection figure] None |