Methods for synthesizing rhodamine dyes

A method of synthesizing a rhodamine dye, the method comprising:

• reacting a compound of formula (I):
• wherein
• R1 and R2 are each independently hydrogen, alkyl, or R1a—CO—, wherein R1a is hydrogen, C1-C4 alkyl, C1-C4 haloalkyl, or C1-C4 alkoxy;
• or R1 and R2, together with the atoms to which they are attached, form a 3-8 membered ring;
• Rc is selected from the group consisting of hydrogen, alkyl, alkoxy, haloalkyl and halogen;
• and
• Ra and Rb are each independently selected from the group consisting of hydrogen, alkyl, alkoxy, haloalkyl and halogen;
• or
• R1 and Ra, together with the atoms to which they are attached, form a 5-8 membered ring, and
• R2 and Rb, together with the atoms to which they are attached, form a 5-8 membered ring;
• with a compound of formula (II),
• wherein
• R is selected from the group consisting of halogen, alkyl, haloalkyl, cyano, carboxy, alkoxy, haloalkoxy, alkoxycarbonyl, (carboxyl)heteroalkyl, alkylcarbonyl, alkoxyalkyl, cycloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, sulfonate, sulfonamide and amide;
• n is 0, 1, 2, 3 or 4;
• X is halogen or OR3;
• and R3 is selected from the group consisting of hydrogen, alkyl, aryl, alkylcarbonyl, alkoxycarbonyl, haloalkyl, haloalkylcarbonyl, haloalkoxycarbonyl, alkylsulfonyl, arylsulfonyl and haloalkylsulfonyl;
• to form the rhodamine dye.