Synthesis and transformations of 5-chloro-2,2'-dipyrrins and their boron complexes, 8-chloro-BODIPYs.

ABSTRACT: Symmetric dipyrrylketones 1 a,b were synthesized in two steps from the corresponding α-free pyrroles, by reaction with thiophosgene followed by oxidative hydrolysis under basic conditions. The dipyrrylketones produced the corresponding 5-chloro-dipyrrinium salts or 5-ethoxy-dipyrrins on reaction with phosgene or Meerwein's salt, respectively. Boron complexation of the dipyrrins afforded the corresponding 8-functionalized BODIPYs (borondipyrromethenes) in high yields. The 5-chloro-dipyrrinium salts reacted with methoxide or ethoxide ions to produce monopyrrole esters, presumably via a 5,5-dialkoxy-dipyrromethane intermediate. In contrast, 8-chloro-BODIPYs underwent a variety of nucleophilic substitutions of the chloro group in the presence of alkoxide ions, Grignard reagents, and thiols. In

SUBMITTER: Wang H 

PROVIDER: S-EPMC4012389 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature