Stereoselective preparation of highly functionalized (Z)-3-magnesiated enoates by an iodine-magnesium exchange reaction

3-Iodoenoates are converted into the corresponding alkenylmagnesium species with complete retention of configuration of the double bond; both direct reaction and copper(I)-mediated reactions with various electrophiles provide polyfunctional enoates.     

A regioselective and convenient one-pot multicomponent synthesis of 9-amino-3,5-diaryl-4,9-dihydro-5H-[1,2,4]triazolo[5,1-c][1,2,4]triazepine-8-thiol

An efficient and environment-friendly procedure for the synthesis of a new series of nitrogen bridge-head [1,2,4]triazolo[5,1-c][1,2,4]triazepine derivatives through one-pot three-component reaction of polyfunctional triazole with aromatic aldehydes and acetophenone derivatives using alcoholic sodium hydroxide solution. The same new products were prepared in classical route through reaction of triazole with the corresponding chalcones under the same conditions.     

Sulfuryl Fluoride Mediated Conversion of Aldehydes to Nitriles

Aliphatic, aromatic, and heteroaromatic aldehydes were readily converted to corresponding nitriles in a one-pot reaction sequence with hydroxylamine and sulfuryl fluoride. The reaction proceeds at room temperature, does not require metal catalysts and special precautions, and produces nitriles in excellent yields. It is compatible with a variety of functional groups, can be performed in aqueous and organic solvents, and is readily scalable to multigram quantities. Mild conditions and high selectivity of the reaction enabled the construction of polyfunctional probes containing nitrile, alkyne, azide, and fluorosulfate groups for further orthogonal derivatization.     

Synthesis and properties of strongly basic acrylate polyfunctional anion-exchange resin for uranium extraction

Some studies on the synthesis of strongly basic acrylate polyfunctional anion-exchange resins designed for the extraction of uranium from uranium ore leaching solutions were performed. The alkylation reaction conditions providing the synthesis of a polyfunctional anion-exchange resin with 55% of strongly basic groups were determined. Its sorption properties were studied using model solutions. The capacity of the alkylated polyfunctional anion-exchange resin with respect to uranium was shown to be highly competitive with foreign analogues using the comparative analysis of its ion-exchange characteristics with the parameters of known ion-exchange resins.     

New polyfunctional magnesium reagents for organic synthesis

The iodine-magnesium exchange reaction allows the preparation of polyfunctional aryl, heteroaryl, or alkenyl magnesium reagents at low temperature. These reagents display the typical reactivity of Grignard compounds and undergo various copper-catalyzed reactions such as allylation or 1,4-addition. Using this halogen-metal exchange reaction, it was possible to generate polyfunctional magnesium reagents on the solid phase.     

Polyhalogenoheterocyclic compounds: Part 54: [1] Suzuki reactions of 2,4,6-tribromo-3,5-difluoropyridine

Palladium catalysed Suzuki cross-coupling reactions between 2,4,6-tribromo-3,5-difluoropyridine and a short series of aromatic boronic acid derivatives gave 4-bromo-3,5-difluoro-2,6-diphenylpyridine derivatives arising from displacement of bromine atoms attached to positions ortho to ring nitrogen or the corresponding triaryl systems depending on the reaction conditions. Consequently, the use of polybromofluoropyridine scaffolds for the synthesis of polyfunctional heteroaromatic derivatives is expanded further.     

Sulfur dioxide mediated one-pot, three- and four-component syntheses of polyfunctional sulfonamides and sulfonic esters: study of the stereoselectivity of the ene reaction of sulfur dioxide

The ene reaction of sulfur dioxide with enoxysilanes or with allylsilanes generates silyl sulfinates that can be brominated (Br(2) or NBS) or chlorinated (NCS or Cl(2)) to produce the corresponding sulfonyl halides. They react with primary and secondary amines or alcohols to give the corresponding sulfonamides and sulfonic esters, respectively. The hetero-Diels-Alder addition of sulfur dioxide to 1-oxy- or 1,3-dioxy-1,3-dienes generates zwitterions that add to enoxysilanes or allylsilanes giving silyl sulfinates that can be converted in situ into polyfunctional sulfonamides or sulfonic esters. This realizes quick access to libraries of complicated sulfonamides and sulfonic esters applying one-pot, three- and four-component methods.     

Synthesis of a Novel Polyfunctional Anionic Macroinitiator from a Polyfunctional 1,1‐Diphenylethylene Agent

Summary: A polyfunctional 1,1‐diphenylethylene (DPE) agent was prepared by ring‐opening metathesis polymerization of a DPE‐functionalized norbornene monomer. Its reaction with sec‐butyllithium gave a novel polyfunctional anionic macroinitiator with one 1,1‐diarylalkyllithium initiation functionality per repeating unit. The significant applicability of this polyfunctional anionic macroinitiator was demonstrated by its excellent initiation efficiencies in anionic polymerization and a preparation of a graft copolymer with well‐controlled long and dense diblock grafts.

Preparation of a polyfunctional anionic macroinitiator based on ROMP and DPE chemistry.     

Preparation of highly functionalized arylmagnesium reagents by the addition of magnesium phenylselenide to arynes

The described polyfunctional arylmagnesium reagents, resulting from the highly regioselective addition of magnesium phenylselenide to functionalized arynes, can be trapped by a range of electrophiles, yielding polyfunctional selenoethers in 45-85% yields. Furthermore, these Grignard reagents can be used in Negishi cross-coupling reactions with iodoarenes after transmetalation to the corresponding arylzinc compounds, furnishing functionalized biaryl products in 55-73% yields.     

Tetrahydropyrido[3,4-b]pyrazine scaffolds from pentafluoropyridine

[reaction: see text] Representative polyfunctional tetrahydropyrido[3,4-b]pyrazine scaffolds have been synthesized very readily by a one-pot annelation reaction of pentafluoropyridine with appropriate diamines. The trifluorinated pyridopyrazine products react sequentially with various nucleophiles to give poly-substituted tetrahydropyridopyrazines, demonstrating the potential of the polyfluorinated ring fused pyridine system as a scaffold for the synthesis of previously inaccessible poly-substituted pyridopyrazine derivatives. This general approach has special relevance to the development of new chemical entities for the life science industries and particularly in the drug discovery arena, in which low molecular weight, polyfunctional heterocyclic derivatives are playing an increasingly important role.     

Photogeneration of polyfunctional amines and novel thermal curing reactions of epoxy resin and polyurethane oligomer using these amines

Photochemical reactions of various blocked polyfunctional amines such as bis(4-formylaminophenyl)methane (FAPM), bis(4-acetylaminophenyl)methane (AAPM), bis(4-benzoylaminophenyl)methane (BAPM), 2,4-diformylaminotoluene (DFAT), m-xylene diformamide, and bis[[(2-nitrobenzyl)oxy]carbonyl]hexane-1.6-diamine were carried out to give the corresponding free amines in THF solution, in epoxy resin, or in polyurethane oligomer with terminal isocyanate groups. Photolysis of FAPM and DFAT to produce the corresponding polyfunctional amines such as 4,4'-methylenedianiline and 2,4-diaminotoluene proceeded with 80 and 75% conversions, respectively, in THF solution under UV irradiation at 5 h. AAPM and BAPM also produced the corresponding photo-Fries rearrangement products with 32 and 38% conversions, respectively, under the same irradiation conditions. The photolysis of those compounds also occurred with similar conversions in the epoxy resin and in the polyurethane oligomer under UV irradiation; and the thermal curing reactions of the epoxy resin and the polyurethane oligomer with photogenerated polyfunctional amines proceeded smoothly after heating at 140°C for 2 hrs. © 1993 John Wiley & Sons, Inc.     

Nazarov Reagent: New Role for the [4+2] Domino Benzannulation Reaction to Construct Polysubstituted Benzenes

A new role for the Nazarov reagent was revealed in the [4+2] benzannulation reaction, and delivered a series of polyfunctional benzenes in high yields under mild conditions. This metal‐free process not only expanded the application of the Nazarov reagent in organic synthesis, but also provided a new, efficient way to construct polyfunctional benzenes.     

Triphenylphosphine-2,4,4,6-tetrabromo-2,5-cyclohexadienone complex as a reagent for preparation of carboxylic acid bromides

Triphenylphosphine-2,4,4,6-tetrabromo-2,5-cyclohexadienone complex was successfully used as a new reagent for the synthesis of carboxylic acid bromides which were isolated as individual substances or were identified by conversion into the corresponding anilides. The reaction is chemoselective, and it can be applied to polyfunctional compounds, e.g., hydroxy acids.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1517–1521.Original Russian Text Copyright © 2004 by Matveeva, Podrugina, Sandakova, Zefirov.     

Polyfunctional tetrazolic thioethers through electrooxidative/Michael-type sequential reactions of 1,2- and 1,4-dihydroxybenzenes with 1-phenyl-5-mercaptotetrazole

In the presence of 1-phenyl-5-mercaptotetrazole as a nucleophile, electrochemical oxidations of 1,2- and 1,4-dihydroxybenzenes have been investigated in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The voltammetric results indicate that an electrooxidative/Michael-type sequential reaction occurs between the mercaptide anion and the electrochemically generated benzoquinones leading to the corresponding polyfunctional tetrazolic thioethers. The mechanism of electrochemical reaction is proved as an EC pathway using controlled-potential coulometry. In addition, the electrosyntheses of tetrazolic thioethers have been successfully performed in ambient conditions in an undivided cell using an environmentally friendly method with high atom economy.     

Decisive role of water in efficient noncatalyzed synthesis of polyfunctional 1H-1,2,3-triazoles proceeding from γ-hydroxypropynals

A highly efficient method was developed for the synthesis of new polyfunctional 1H-1,2,3-triazoles by the reaction of γ-hydroxypropynals with trimethylsilyl azide in water at room temperature without catalyst. The addition of trimethylsilyl azide to γ-hydroxypropynals occurs regioselectively: Previously unknown hydroxyalkyl-1H-1,2,3-triazolecarbaldehydes have been isolated in 69-96% yields with the prevalence of 1,5-isomers and the content of minor 1,4-isomers equal 9-21%. In the reaction of γ-hydroxypropynals with sodium azide in DMSO the formation of 4-hydroxyalkyl-1H-1,2,3-triazole-5-carbaldehydes is accompanied by the dimerization of initial aldehydes into the corresponding 1,3-dioxolanes.     

Diallylacylhydrazines as monomers for polyfunctional water-soluble polymers

Allylation of acetohydrazide afforded the corresponding diallylacylhydrazine, which can be used for syntheses of water-soluble polyfunctional polymers.     

(Chloromethyl)alkoxyhalogenosilanes in Reaction with N-Trimethylsilyl-N-methylacetamide

Russian Journal of General Chemistry - The reaction of N-trimethylsilyl-N-methylacetamide with polyfunctional silanes, namely methyl(chloromethyl)alkoxychlorosilanes and...     

Reaction of sabinene with aldehydes in the presence of montmorillonite K10 clay

Transformations of sabinene catalyzed by montmorillonite K10 clay were studied. The main reaction paths were found to be oligomerization and isomerization. The reaction of sabinene with crotonaldehyde gave rise to several polyfunctional heterocyclic compounds.     

The Annelation for Enaminoureides of 3,3-Dimethyl-1,2,3,4-tetrahydroisoquinoline Series by Action of Oxalyl Chloride and Ninhydrin

By reaction of Ritter cyclization of cyanoacetylureas with dimethylbenzylcarbinoles the corresponding enaminoureides were obtained, derivatives of 3,3-dimethyl-1,2,3,4-tetrahydroisoquinoline. The polyfunctional character of obtained compounds is confirmed by the structure of products of reaction with some electrophiles: phenyl isocyanate reacts at the γ-C atom of enamine and CONH₂ group of urea, under the action of oxalyl chloride annelation of a pyrrole cycle occurs with the formation of a derivative of 2,3-dioxopyrrolo[2,1-a]isoquinoline. Reaction with ninhydrin occurs similary with enaminoamides having hydrogen atoms at the amide nitrogen: a pyrrole ring is fused with the formation of a system of indeno[1,2-b]pyrrole.     

Preparation of new polyfunctional magnesiated heterocycles using a chlorine-, bromine-, or iodine-magnesium exchange

The reaction of heteroaryl iodides with i-PrMgBr (ca. 1.0 equiv) in THF provides the corresponding magnesiated heterocycles. Functional groups such as an ester, cyano, or chloride functions are tolerated in these new Grignard reagents if the exchange can be performed below -20 degrees C. This is the case for all heterocycles bearing electron-withdrawing groups or chelating functions facilitating the iodine-magnesium exchange. In many cases, the exchange can be extended to heteroaryl bromides, and a case of a chlorine-magnesium exchange is described with tetrachlorothiophene. This new preparation of functionalized heteroarylmagnesium compounds provides after reaction with various electrophiles a new entry to a broad range of polyfunctional pyridines, imidazoles, furanes, thiophenes, pyrroles, antipyrines, and uracil derivatives. The application of the halogen-magnesium exchange in the solid phase allows the performance of solid-phase synthesis, with potential applications for combinatorial chemistry.