Back to Search Start Over

Synthesis and Transformations of 5-Chloro-2,2′-Dipyrrins and Their Boron Complexes, 8-Chloro-BODIPYs.

Authors :
Wang, Haijun
Vicente, M. Graça H.
Fronczek, Frank R.
Smith, Kevin M.
Source :
Chemistry - A European Journal; Apr2014, Vol. 20 Issue 17, p5064-5074, 11p
Publication Year :
2014

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 the presence of excess alkoxide or Grignard reagent, at room temperature or above, substitution at the boron center also occurred. The 8-chloro-BODIPY was a particularly useful reagent for the preparation of 8-aryl-, 8-alkyl-, and 8-vinyl-substituted BODIPYs in very high yields, using Pd<superscript>0</superscript>-catalyzed Stille cross-coupling reactions. The X-ray structures of eleven BODIPYs and two pyrroles are presented, and the spectroscopic properties of the synthesized BODIPYs are discussed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09476539
Volume :
20
Issue :
17
Database :
Complementary Index
Journal :
Chemistry - A European Journal
Publication Type :
Academic Journal
Accession number :
95626438
Full Text :
https://doi.org/10.1002/chem.201304310