Patent ID: 8058431

Claim:
A fluorescent dye having the formula wherein all of A 1 , A 2 , A 3 , and A 4 are H or one of A 1 , A 2 , A 3 , and A 4 is a halogen and the others are H; B is selected from the group consisting of S, O, Nâ€”R, and Câ€”(R) 2 wherein R is C 1 -C 6 alkyl; D is an unsubstituted C 1 -C 6 alkyl; X is H or a methoxy group; Y is Z1-Câ•Câ€”Z2 wherein Z1 and Z2 independently are H or a methoxy group; L is CH 3 or phenyl; and M is phenyl or an unsubstituted C 1 -C 18 amino-alkyl.