A new pyrrole alkaloid from Selaginella moellendorfii Hieron

One new pyrrole alkaloid,N-（2E）-3-（3,4-dihydrophenyl）prop-N₁-（4-aminoburyl）-3-pyrrole formaldehyde （1）,was isolated from the whole herbs of Selaginella moellendorfii Hieron.The structure was elucidated by spectroscopic analyses including UV,1R,1D NMR,2D NMR and MS methods.Additionally, compound 1 exhibited potent protective effect against the injury of human umbilical vein endothelial cell（HUVECs） induced by high concentrations of glucose in vitro.     

A new route for the synthesis of 1,3-diketones

A simple route for the synthesis of 1,3-diketones by the reaction of acetylenic ketones with amines followed by hydrolysis of the resulting aminovinylketons is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 710–714, April, 1995.     

Annulation of pyrrole: application to the synthesis of indolizidine alkaloids

The nucleophilicity of pyrrole has been exploited to rapidly assemble the bicyclic skeleton of the indolizidine alkaloids. The key sequence is the annulation of a second ring onto pyrrole from a γ-lactone and has been exploited in the synthesis of the natural products (±)-monomorine and (±)-indolizidine 209D.     

Microwave-assisted ring-closing metathesis of diallylamines: a rapid synthesis of pyrrole and pyrroline derivatives

The ring-closing metathesis (RCM) reactions of diallylamines occurred under controlled microwave irradiation. In addition to the high reaction rate, the key features of the reaction are that it can be carried out without deactivation of the substrates and without the use of Lewis acids.     

TiO2-coated graphene oxide-molybdate complex as a new separable nanocatalyst for the synthesis of pyrrole derivatives by Paal-Knorr reaction

The preparation of chemical and pharmaceutical compounds through organic reactions has always been associated with the production of environmental waste. Growth population and concerns about ecological pollution increase the interest in using heterogeneous solid catalysts with capabilities such as increasing reaction efficiency and reducing the production of by-products, as well as the ability to separate and reuse. To develop and benefit such catalysts as much as possible, in this study, using graphene oxide (GO) as a support, we succeeded in preparing a heterogeneous catalyst with a high contact surface, excellent performance, and recyclability. Graphene oxide nanosheets were synthesized according to Hummer’s method. hexamolybdate anions ([n-Bu₄N]₂[Mo₆O₁₉]) were placed on this support as a catalytically active site using linkers. The structure of this catalyst was confirmed by XRD, FT-IR, EDS, SEM, TEM, TGA, Raman, and nitrogen adsorption–desorption analyses, and it was used to produce pyrroles by the Paal-Knorr method. The performance of the synthesized nanocatalyst was satisfactory for all the derivatives studied. Recovery and reuse of GO@TiO₂@(CH₂)₃N = Mo[Mo₅O₁₈] after catalytic reactions were examined. This catalyst could be quickly recovered by simple filtration and recycled ten times without significant loss of its catalytic activity.     

The application of vinylogous iminium salt derivatives to an efficient relay synthesis of the pyrrole containing alkaloids polycitone A and B

A new and efficient relay synthesis of the marine natural products polycitone A and B is described. The new strategy relies on the formation of 2,4-disubstituted pyrroles from a vinamidinium salt followed by electrophilic substitution at the 5-position of the pyrrole and Suzuki coupling at the 4-position to produce the tetrasubstituted heterocycle efficiently and with complete control of regiochemistry.     

Polygodial: A viable natural product scaffold for the rapid synthesis of novel polycyclic pyrrole and pyrrolidine derivatives

The dialdehyde polygodial was utilised as a chiral scaffold for the unified synthesis of novel polycyclic pyrrole and pyrrolidine derivatives. Mechanistic insight into the reaction of primary amines with this dialdehyde was obtained. In addition, one of these polycyclic pyrroles was transformed further to prepare novel pentacyclic frameworks.     

Daminin, a bioactive pyrrole alkaloid from the Mediterranean sponge Axinella damicornis

The isolation and characterization of the known pyrrole alkaloid agelongine (6) and of the new natural product daminin (7), the bromine-free analogue of 6, from a specimen of the marine sponge Axinella damicornis is described. Compound 7 showed significant neuroprotective properties. Moreover, for the supply of sufficient material for future medicinal investigations, a short total synthesis of 7 was developed.     

New routes for the synthesis of fused pyrrole scaffolds through transition metal-free tandem reactions

A series of transition metal-free tandem reactions for the synthesis of indolizines and 6,7-dihydroindolizin-8(5H)-ones by 4-bromobut-2-enoate ramifications reacted with 2-acetyl pyrrole derivatives are described. As the α-carbon changed from CH₃, CH₂Cl, CHCl₂, to CCl₃, different kinds of tandem reactions were observed. These tandem reactions could be used to synthesize fused indolizine and indolizidine scaffolds under mild and green conditions.     

Development of novel pyrrole synthesis for the preparation of intermediates of bioactive pyrrole alkaloids

We have developed a novel method for the synthesis of 3,4-diarylpyrrole-2,5-dicarboxylates via α-diazo esters, which are easily obtained from phenylalanine derivatives. Utilizing this method, intermediates of bioactive compounds having the structure of 3,4-diarylpyrrole-2,5-dicarboxylates were synthesized.     

Copper catalyzed synthesis of highly substituted pyrrole and isoindole derivatives

We have developed an efficient synthesis of highly substituted pyrrole and isoindole derivatives using copper(I) catalyst. This methodology is helpful for the synthesis of some quinones bearing annealed N-heterocyclic natural products.     

Pyrrole synthesis using a tandem Grubbs’ carbene-RuCl3 catalytic system

A straightforward pyrrole synthesis from diallylamines is developed by using a tandem catalyst system leading to ring-closing metathesis with the second generation Grubbs’ catalyst (10%) followed by dehydrogenation in the presence of RuCl₃ × H₂O (2%).     

Convenient synthesis of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives

Optimization details and limitations of a novel synthetic method of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives are herein disclosed. This synthesis consists of four steps that include a highly selective cyclization, and can be carried out from starting materials to target compounds without column chromatography purification. The high selectivity is controlled by lithium coordination and steric hindrance caused by tert-butyl ester.     

Phosphole, pyrrole, and their tetrahydro derivatives: A theoretical study of their properties

A theoretical analysis of four molecules (phosphole, phospholane, pyrrole, and pyrrolidine) in their ground and transition states has been carried out. The transition state of phosphole is highly aromatic and a partition of its energy into atomic contributions reveals that it is the phosphorus atom that is responsible for this observation.     

The synthesis of pyrrole bis-coumarins, new structures for fluorescent probes

Pyrrole bis-coumarins as fluorescent probes have been synthesized from 1,4-dicoumarinyl-1,4-diones, themselves prepared in moderate to high yields in one step from the corresponding α-bromo-3-acetylcoumarins using Zn-I₂. The mechanism of the reaction can be explained through a Wurtz-like self-condensation of α-bromo-3-acetylcoumarins.     

A novel one-pot synthesis of some new interesting pyrrole derivatives

[reaction: see text] 11-(1H-Pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline and 3-(1H-pyrrol-1-yl)indolin-2-one derivatives have been synthesized in good yields in a novel, one-pot, and efficient process by condensation of 11H-indeno[1,2-b]quinoxalin-11-one or isatin derivatives with 4-hydroxyproline on solid-support montmorillonite K10 under microwave irradiation.     

A convenient semicarbazide resin for the solid-phase synthesis of peptide ketones and aldehydes

Use of a semicarbazide resin for the solid-phase preparation of peptide ketones and aldehyde led to optimal results in terms of both purity of the final product and overall yield. This resin was prepared without complication by activation of the commercial available aminomethyl polystyrene with CDI at room temperature, followed by treatment with tert-butyl carbazate. Furthermore, the TNBSA colorimetric assay has been adapted for checking the incorporation of the carbonyl moiety onto hydrazine-based resins.     

Synthesis of new 3-cyanoacetamide pyrrole and 3-acetonitrile pyrrole derivatives

A new fused heterocyclic derivatives of pyrrole containing acetonitrile or cyanoacetonitrile moiety at 3-position is described by a one-pot multicomponent reaction. The reaction of dimedone, various aniline, aryl glyoxal with malononitrile/ethyl cyanoacetate/methyl cyanoacetate under mild conditions. The present method does not involve any hazardous organic solvents or catalysts. The significant features of this method are readily available starting materials, good yields, and easy purification.     

A new synthetic route to oxazole and pyrrole 2-deoxy-C-ribosides

The synthesis of oxazole and pyrrole 3-carbethoxy/3-arylsulfonyl d and l-2-deoxyribosides by TosMIC addition/cyclization on d and l-2-deoxyribo-1-carboxaldehyde and unsaturated esters in moderate to good yields is reported.