Rational Synthesis of Trans-Substituted Porphyrin Building Blocks Containing One Sulfur or Oxygen Atom in Place of Nitrogen at a Designated Site
摘要:
The use of heteroatom-substituted porphyrins in bioorganic and materials chemistry requires the ability to position a variety of substituents in a controlled manner about the porphyrin periphery. We describe a rational route to trans-AB(2)C-type porphyrins bearing one oxygen atom (N3O) or one sulfur atom (NBS) in a designated location in the porphyrin core. The synthesis involved four stages: (1) Acid-catalyzed condensation of a furyl- or thienylcarbinol in excess pyrrole afforded the aryl-substituted furyl- or thienylpyrromethane in high yield. (2) Treatment of the furyl- or thienylpyrromethane with an acid chloride catalyzed by SnCl4 or AlCl3 afforded the corresponding diketo product. (3) Reduction with NaBH4 in alcoholic solvents gave the furyl- or thienylpyrromethanediols. (4) Reaction of a furylpyrromethanediol, thienylpyrromethanediol, or dipyrromethanediol with a dipyrromethane in a one-flask process of condensation followed by oxidation gave the corresponding porphyrin. Reaction conditions previously identified to minimize scrambling in a dipyrromethane-aldehyde condensation were found to be effective in this application. Thus, reaction with 10 mM reactants in acetonitrile at 0 degrees C containing BF3 . Et2O and NH4Cl followed by oxidation with DDQ resulted in the desired porphyrin(10-20% yields) without acidolysis. In this manner, N3O-, N3S-, or Na-porphyrins bearing 5-(p-iodophenyl), 15-[4-(2-(trimethylsilyl)ethynyl)phenyl], and 10,20-di-p-tolyl groups have been made. This set of trans-substituted porphyrin building blacks is expected to be useful in the synthesis of biomimetic energy transduction systems.
Preparation of Polyfunctional Arylmagnesium Reagents Bearing a Triazene Moiety. A New Carbazole Synthesis
摘要:
The reaction of iodo- or bromo-substituted aryltriazenes with i-PrMgCI-LiCl generates the corresponding magnesiated derivatives which react with various electrophiles (acid chlorides, 3-iodoenones, allylic halides, aidehydes) affording polyfunctional triazenes. They can be readily converted to the corresponding polyfunctional aryl iodides. This new synthetic strategy was applied to prepare functionalized carbazoles.
Preparation of Polyfunctional Arylmagnesium Reagents Bearing a Triazene Moiety. A New Carbazole Synthesis
作者:Ching-Yuan Liu、Paul Knochel
DOI:10.1021/ol0505454
日期:2005.6.1
The reaction of iodo- or bromo-substituted aryltriazenes with i-PrMgCI-LiCl generates the corresponding magnesiated derivatives which react with various electrophiles (acid chlorides, 3-iodoenones, allylic halides, aidehydes) affording polyfunctional triazenes. They can be readily converted to the corresponding polyfunctional aryl iodides. This new synthetic strategy was applied to prepare functionalized carbazoles.
Rational Synthesis of Trans-Substituted Porphyrin Building Blocks Containing One Sulfur or Oxygen Atom in Place of Nitrogen at a Designated Site
作者:Won-Seob Cho、Han-Je Kim、Benjamin J. Littler、Mark A. Miller、Chang-Hee Lee、Jonathan S. Lindsey
DOI:10.1021/jo9909305
日期:1999.10.1
The use of heteroatom-substituted porphyrins in bioorganic and materials chemistry requires the ability to position a variety of substituents in a controlled manner about the porphyrin periphery. We describe a rational route to trans-AB(2)C-type porphyrins bearing one oxygen atom (N3O) or one sulfur atom (NBS) in a designated location in the porphyrin core. The synthesis involved four stages: (1) Acid-catalyzed condensation of a furyl- or thienylcarbinol in excess pyrrole afforded the aryl-substituted furyl- or thienylpyrromethane in high yield. (2) Treatment of the furyl- or thienylpyrromethane with an acid chloride catalyzed by SnCl4 or AlCl3 afforded the corresponding diketo product. (3) Reduction with NaBH4 in alcoholic solvents gave the furyl- or thienylpyrromethanediols. (4) Reaction of a furylpyrromethanediol, thienylpyrromethanediol, or dipyrromethanediol with a dipyrromethane in a one-flask process of condensation followed by oxidation gave the corresponding porphyrin. Reaction conditions previously identified to minimize scrambling in a dipyrromethane-aldehyde condensation were found to be effective in this application. Thus, reaction with 10 mM reactants in acetonitrile at 0 degrees C containing BF3 . Et2O and NH4Cl followed by oxidation with DDQ resulted in the desired porphyrin(10-20% yields) without acidolysis. In this manner, N3O-, N3S-, or Na-porphyrins bearing 5-(p-iodophenyl), 15-[4-(2-(trimethylsilyl)ethynyl)phenyl], and 10,20-di-p-tolyl groups have been made. This set of trans-substituted porphyrin building blacks is expected to be useful in the synthesis of biomimetic energy transduction systems.