Synthesis of 8-substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene dyes (BODIPY)

4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (bodipy) dyes are important in synthetic and applied chemistry. the reaction of pyrrolomethane 1 with acetyl chloride and boron trifluoride etherate in the presence of triethylamine afforded the 4,4-difluoro-3,5,8-trimethyl-4-bora-3a,4adiaza- s-indacene 2a. when benzoylchloride and chloroacetyl chloride were used,phenyl 2b and chloromethyl 2c derivatives formed. the treatment of pyrrolomethane 1 with 3- (phenylthio)propanal 3 in the presence of ytterbium (iii) trifluoromethanesulfonate hydrate in catalitic amount yielded the 5-(2-thiophenyl ethane)-1,9-dimethyldipyrromethane 4,which was reacted with ddq and boron trifluoride etherate in the presence of triethylamine formed 8-(2-thiophenylethan) 4,4-difluoro- 3,5dimethyl-4-bora-3a,4a-diaza-3-indacene 5. the oxidation of 8-(thiomethyl) 4,4-difluoro-3,5- dimethyl-4-bora-3a,4a-diaza- s-indacene 6 with m-cpba gave methylsulfonyl product 7. bromination of 4,4-difluoro-3,5,8-trimethyl-4-bora-3a,4a-diaza-s-indacene 2a yielded 1,2,6,7- tetrabromo-4,4-difluoro-3,5,8-trimethyl-4-bora-3a,4a-diaza-s-indacene 8.