A Modular Synthesis of Unsymmetrical Tetraarylazadipyrromethenes
摘要:
A stepwise route to unsymmetrical tetraarylazadipyrromethenes by a condensation of 2,4-diaryl-5-nitroso-pyrroles with 2,4-diarylpyrroles is described. This modular building-block approach allows for the introduction of up to four different aryl substituents on the azadipyrromethene and is tolerant of a varied substituent set. An efficient synthesis of the 2,4-diarylpyrroles building blocks from 1,3-diaryl-4-nitro-butan-1-ones by nitro hydrolysis to a keto-aldehyde and subsequent ammonia condensation reaction has been achieved. The facile conversion of 2,4-diarylpyrroles into their alpha-nitroso analogues by their reaction with sodium nitrite generated the second building block required for the synthesis.
A Modular Synthesis of Unsymmetrical Tetraarylazadipyrromethenes
摘要:
A stepwise route to unsymmetrical tetraarylazadipyrromethenes by a condensation of 2,4-diaryl-5-nitroso-pyrroles with 2,4-diarylpyrroles is described. This modular building-block approach allows for the introduction of up to four different aryl substituents on the azadipyrromethene and is tolerant of a varied substituent set. An efficient synthesis of the 2,4-diarylpyrroles building blocks from 1,3-diaryl-4-nitro-butan-1-ones by nitro hydrolysis to a keto-aldehyde and subsequent ammonia condensation reaction has been achieved. The facile conversion of 2,4-diarylpyrroles into their alpha-nitroso analogues by their reaction with sodium nitrite generated the second building block required for the synthesis.
Base-promoted ring-closing carbonyl–allene metathesis for the synthesis of 2,4-disubstituted pyrroles
作者:Guolin Cheng、Weiwei Lv、Lulu Xue
DOI:10.1039/c8gc01675e
日期:——
A base-promoted ring-closing carbonyl–allene metathesis reaction of N-allenyl β-enaminones (generated in situ from N-propargyl β-enaminones) gives 2,4-disubstituted pyrroles with cleavage of the C(sp)–C(sp3) bond. This transition metal-free procedure generates 1 equiv. of acetic acid as the sole byproduct. A preliminary mechanistic study supports a stepwise [2 + 2] cycloaddition/retro [2 + 2] reaction
Reaction between 4-Nitro-1,3-diarylbutan-1-ones and Ammonium Acetate in the Presence of Morpholine and Sulfur: An Efficient Synthesis of 2,4-Diarylpyrroles
An efficient synthesis of 2,4-diarylpyrroles is described. Heating a mixture of a 4-nitro-1,3-diarylbutan-1-one and ammoniumacetate in the presence of morpholine and sulfur afforded the corresponding 2,4-diarylpyrroles in excellent yields.
2,4- vs 3,4-Disubsituted Pyrrole Synthesis Switched by Copper and Nickel Catalysts
作者:Feng Chen、Tao Shen、Yuxin Cui、Ning Jiao
DOI:10.1021/ol302270z
日期:2012.9.21
A novel and efficient copper or nickel catalyzed highly selective denitrogenative annulation of vinyl azides with aryl acetaldehydes has been developed. 2,4- and 3,4-diaryl substituted pyrroles, which are difficult to synthesize by the reported methods, can be highly regioselectively prepared by this protocol simply switched by the selection of the transition metal catalysts. Compared with the reported acidic or basic conditions for polysubstituted pyrrole synthesis, the present reaction conditions are mild, neutral, and very simple without any additives.
A Modular Synthesis of Unsymmetrical Tetraarylazadipyrromethenes
作者:Michael J. Hall、Shane O. McDonnell、John Killoran、Donal F. O'Shea
DOI:10.1021/jo050696k
日期:2005.7.1
A stepwise route to unsymmetrical tetraarylazadipyrromethenes by a condensation of 2,4-diaryl-5-nitroso-pyrroles with 2,4-diarylpyrroles is described. This modular building-block approach allows for the introduction of up to four different aryl substituents on the azadipyrromethene and is tolerant of a varied substituent set. An efficient synthesis of the 2,4-diarylpyrroles building blocks from 1,3-diaryl-4-nitro-butan-1-ones by nitro hydrolysis to a keto-aldehyde and subsequent ammonia condensation reaction has been achieved. The facile conversion of 2,4-diarylpyrroles into their alpha-nitroso analogues by their reaction with sodium nitrite generated the second building block required for the synthesis.