Synthesis of 3-Alkyl-2,5-dimethylfuran Derivatives by Indirect Alkylation of 2,5-Dimethylfuran with Aliphatic Nitrocompounds

Abstract

I n d i r e c t A l k y l a t i o n o f 2 , 5-D i m e t h y l f u r a n w i t h A l i p h a t i c N i t r o c o m p o u n d s

Vinylogous Reactivity of Enol Diazoacetates with Donor–Acceptor Substituted Hydrazones. Synthesis of Substituted Pyrazole Derivatives

“…13 Numerous methodologies have been reported for pyrazole syntheses, 14 and the Knorr condensation reaction of dicarbonyl compounds is the most prevalent approach for pyrazole synthesis. 15 However, this classic condensation between α,γ-diketoesters and hydrazines is hampered by low regioselectivity 16 and general synthetic processes for functionalized pyrazoles having structural diversity and complexity continue to be needed. With the process that is described in Scheme 3 we present a versatile cascade reaction to produce multi-functionalized pyrazoles by a dirhodium(II)-catalyzed vinylogous umpolung reaction followed by Lewis acid catalyzed cyclization and aromatization.…”

Complete Assignment ofH1andC13NMR Spectra of 1,2,4-Trisubstituted Pyrroles

“…Multiplicities are described as: s (singlet), bs (broad singlet), d (doublet), t (triplet), q (quartet), and m (multiplet); coupling constants (J) are reported in Hertz (Hz). 13 C NMR spectra were recorded with total proton decoupling. e complete assignment of each 1 H and 13 C NMR chemical shi for these pyrroles was achieved by 1D and 2D NMR techniques, including APT experiments, 1 H-1 H COSY, 1 H-13 C Hetcor exp, and HMBC spectra.…”

“…Pyrroles are key structural motifs in various classes of natural products [1,2], synthetic pharmaceuticals, and electrical conducting polymers [3][4][5][6] and are also valuable synthetic intermediates [7,8]. In addition to a number of traditionally employed approaches, such as Paal-Knorr synthesis [9][10][11][12][13][14][15], several transition metal-catalyzed methods [16][17][18][19][20][21] and catalytic multicomponent coupling approaches [22][23][24] have recently emerged for the synthesis of pyrroles. Nevertheless, and despite recent advances in domino reactions [25][26][27][28], there is still a need for very �exible and general approaches with wide functional group tolerance.…”

Synthesis of new N-alkyl(aryl)-2,4-diaryl-1H-pyrrol-3-ols via aldol Paal–Knorr reactions

“…One of the most common approaches to pyrrole synthesis is the PaalKnorr reaction in which 1,4-dicarbonyl compounds are converted to pyrroles via acid-mediated dehydrative cyclization in the presence of a primary amine [18][19][20][21][22][23][24][25][26][27][28][29][30]. In this reaction, the 1,4-dicarbonyl compound provides the four carbons of the pyrrole with their substituents, whereas the amine provides the nitrogen with its substituent.…”

“…Pyrroles can be found in a large range of natural products [9] and bioactive molecules [10][11][12][13][14], including the blockbuster drug Atorvastatin calcium [10], as well as important anti-inflammatory agents [11], antitumor agents [12], and immunosuppressants [13]. Accordingly, substantial attention has been paid to develop efficient methods for the synthesis of pyrroles [1][2][3][4][5][6][7][8][15][16][17].One of the most common approaches to pyrrole synthesis is the PaalKnorr reaction in which 1,4-dicarbonyl compounds are converted to pyrroles via acid-mediated dehydrative cyclization in the presence of a primary amine [18][19][20][21][22][23][24][25][26][27][28][29][30]. In this reaction, the 1,4-dicarbonyl compound provides the four carbons of the pyrrole with their substituents, whereas the amine provides the nitrogen with its substituent.…”