نتایج جستجو برای: pyrroles
تعداد نتایج: 1881 فیلتر نتایج به سال:
One-pot synthesis of substituted pyrroles by a cascade reaction of azides with Morita-Baylis-Hillman acetates of acetylenic aldehydes is described and the reaction is efficiently mediated by triphenyl phosphine at room temperature. Sodium azide is successfully used to provide N-unsubstituted pyrroles, while alkyl azides afforded the corresponding N-alkylated pyrroles through a sequence of allyl...
A highly enantioselective Friedel-Crafts alkylation of pyrroles with 2-enoylpyridine N-oxides catalyzed by chiral PYBOX-DIPH-Zn(II) complexes has been developed. The catalyst offers substantial substrate scope and furnished alkylated pyrroles in excellent yields (up to 99%) and enantioselectivities (up to >99% ee).
We herein describe a palladium-catalyzed formal aromaticity transfer coupling reaction between phenols and pyrrolidines or indolines to generate the corresponding N-cyclohexyl pyrroles or indoles. In this transformation, the aromaticity of phenols is formally passed on to the pyrrolidine or indoline units. Substituted phenols thus can serve as latent cyclohexyl equivalents for the fast construc...
A nucleophilic catalysis method providing a concise synthesis of di-, tri-, and tetrasubstituted pyrroles is described. This regioselective one-pot method relies on nucleophilic catalysis of the intermolecular addition of oximes to activated alkynes and thermal rearrangement of the in situ generated O-vinyl oximes to form pyrroles that contain a functional group handle at the C3/C4 position.
A Cu-catalyzed [3+2]-type condensation reaction of oxime acetates and dialkyl acetylenedicarboxylates that provides highly substituted pyrroles under aerobic conditions is described. The newly formed pyrroles are easily employed for further transformations to prepare pyrrolo[2,1-a]isoquinoline skeletons.
Because of their interesting biological properties various methods for the synthesis of substituted pyrroles are described in the literature. However, synthesis of pyrroles fused with a beta-lactam ring has not been reported. Our group has demonstrated synthesis and biological evaluation of various beta-lactams as anticancer agents. The anticancer activities of these compounds have prompted us ...
We have developed an organocatalyzed three-component reaction of 1,2-diones, aldehydes and arylamines, which provides an efficient approach to access polysubstituted pyrroles. In the catalysis of 4-methylbenzenesulfonic acid monohydrate, the reactions of a wide range of 1,2-diones, arylamines and aldehydes took place smoothly to generate the corresponding polysubstituted pyrroles in acceptable ...
An effective gold-catalyzed intermolecular nitrene transfer by the reaction of 2H-azirines and ynamides is reported, which provides highly substituted pyrroles in a straightforward manner. This transformation proceeds under mild conditions and gives the polysubstituted pyrroles in good-to-excellent yields. Preliminary results indicate that a nongold carbenoid pathway is preferred for current py...
A facile and efficient protocol is reported for the synthesis of calix[4]pyrroles and N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl or cycloalkyl ketones with pyrrole catalyzed by reusable Amberlyst(TM)-15 under eco-friendly conditions.
A ruthenium-catalyzed intermolecular [3 + 2] cycloaddition of 2H-azirines and activated alkynes is reported, which provides polysubstituted pyrroles in moderate to good yields. This approach features a C-N bond cleavage of 2H-azirines by a ruthenium catalyst. The results of this study would provide a complementary method to synthesize polysubstituted pyrroles from the known 2H-azirine approache...
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