Synthesis of Guanosine-3'-(5-bromo-4-chloroindol-3-yl)p-hosphate (G-3'-BCIP)

N -2-Benzoyl-5'- O -dimethoxytrityl-2'- O -tetrahydropyranylguanosine ( 5 ) and 1-acetyl-5-bromo-4-chloroindol-3-yl-3-phosphorodichloridate ( 7 ) were synthesized and coupled to give the title compound 9 .