Dipolar Trimethylenemethane Research Articles

ChemInform Abstract: Cycloaddition of Dipolar Trimethylenemethane to C70 Promoted by a Trace Amount of Water.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

3+2] Cycloaddition of Trimethylenemethane and Its Synthetic Equivalents

AbstractFor Abstract see ChemInform Abstract in Full Text.

Thermal Reactions of Dipolar Trimethylenemethane Species.

AbstractFor Abstract see ChemInform Abstract in Full Text.

ChemInform Abstract: Carbozincation of Dipolar Trimethylenemethane. A New Route to Functionalized Organozinc Reagents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Carbozincation of Dipolar Trimethylenemethane. A New Route to Functionalized Organozinc Reagents

Abstract Dipolar trimethylenemethane species, thermally generated from 2,2-dialkoxy-1-methylenecyclopropane, reacts with a dialkylzinc reagent to generate an allylic zinc reagent, which then reacts in situ with a carbonyl compound to give a hydroxy acetal product as the result of coupling of the three reactants.

ChemInform Abstract: [3 + 3] Cycloaddition Reaction of Dipolar Trimethylenemethane with Active Methylene Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

3 + 3] Cycloaddition Reaction of Dipolar Trimethylenemethane with Active Methylene Compound

3 + 3] Cycloaddition Reaction of Dipolar Trimethylenemethane with Active Methylene Compound

Intramolecular [3 + 2]Cycloaddition Reaction of Dipolar Trimethylenemethane

Abstract A variety of alkylidenecyclopropanone acetals possessing a terminal diylophile were allowed to undergo an intramolecular [3 + 2]cycloaddition via a dipolar trimethylenemethane to obtain bicyclo[4.3.0] and [3.3.0] carbo- and heterocycles in good yields. The product selectivities were rigorously controlled by the concerted or stepwise nature of the cycloaddition reaction.

ChemInform Abstract: Thermal Hetero [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to N‐Sulfonyl and N‐Acyl Imines. Synthesis of γ‐Amino Acid Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thermal Hetero [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to N-Sulfonyl and N-Acyl Imines. Synthesis of γ-Amino Acid Derivatives

Abstract Thermal hetero [3 + 2] cycloaddition reaction of a dipolar trimethylenemethane 2 with an N-acyl or N-tosyl imine gives an α-methylene-γ-pyrrolidone acetal 4 in high yield, which upon hydrolysis affords a γ-amino acid derivative.

ChemInform Abstract: Thermal Hetero [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to O‐Alkyloximes. Straightforward Synthetic Routes to Substituted Pyrrolidines and Prolines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thermal Hetero [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to O-Alkyloximes. Straightforward Synthetic Routes to Substituted Pyrrolidines and Prolines

Thermal hetero [3 + 2] cycloaddition reaction of a dipolar trimethylenemethane 2 with an O-alkyloxime produces a substituted pyrrolidine. Thus, heating of a mixture of an alkylidenecyclopropane 1 an anti-O-alkyloxime 3 proceeds smoothly in good yield to give a substituted pyrrolidine 4 bearing a ketene acetal group in its 3-position, which upon hydrolysis under mild conditions gives a 3-alkoxycarbonylpyrrolidine 5 in quantitative yield. On the other hand, the cycloaddition to a syn-oxime is extremely slow. The cycloaddition reaction can be achieved by starting with nearly equimolar quantities of the two starting materials, and the reaction is quite insensitive to the choice of solvent and to the presence of oxygen and water. In the reaction of a substituted methylenecyclopropane 1 (R ≠ H), the reaction may take place with high regio- and stereoselectivity, which is in consonance with the concerted nature of the cycloaddition reaction. The present synthesis represents one of the rare examples of the imine-based route to pyrrolidines, which have been much less explored than the 1,3-dipolar cycloaddition route using olefin and azomethine ylide.

Cycloaddition of Dipolar Trimethylenemethane to C70 Promoted by a Trace Amount of Water

Abstract Thermal cycloaddition of a dipolar TMM to C70 at 80–90 °C in a “wet” solvent affords a mixture of the acetal 2 and the C70-carboxylic acid ester 3. The former (as well as its C60 analog) undergoes isomerization to the latter at 120-160 °C.

ChemInform Abstract: A Concise Synthetic Route to Cyclopentenes by (3 + 2) Cycloaddition of Dipolar Trimethylenemethane to Alkynes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Concise Synthetic Route to Cyclopentenes by [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to Alkynes

A Concise Synthetic Route to Cyclopentenes by [3 + 2] Cycloaddition of Dipolar Trimethylenemethane to Alkynes

In vivo biological behavior of a water-miscible fullerene: 14C labeling, absorption, distribution, excretion and acute toxicity.

Water-soluble fullerenes have recently been shown to exhibit considerable in vitro biological activity including cytotoxicity, site-selective DNA cleavage and inhibition of HIV protease. To assess the potential of these compounds as drugs, studies on the in vivo behavior of fullerenes are needed. We therefore set out to synthesize a radiolabeled, water-soluble fullerene, in order to obtain data on the oral absorption, distribution and excretion of this class of compounds. We synthesized a 14C-labeled water-soluble [60]fullerene using dipolar trimethylenemethane, which undergoes cycloaddition to [60]fullerene. When administered orally to rats, this compound was not efficiently absorbed and was excreted primarily in the feces. When injected intravenously, however, it was distributed rapidly to various tissues, and most of the material was retained in the body after one week. The compound was also able to penetrate the blood-brain barrier. Acute toxicity of the water-miscible fullerene was found to be quite low. Although the water-soluble fullerenes (and possibly their simple metabolites) are not acutely toxic, they are retained in the body for long periods, raising concerns about chronic toxic effects. The fact that fullerenes distribute rapidly to many tissues suggests that they may eventually be useful to deliver highly polar drugs through membranes to a target tissue, however, and they may even have applications in the delivery of drugs to the brain. Recent advances in fullerene synthetic chemistry may also make it possible to control fullerene absorption/excretion profiles in the future.

Synthetic Chemistry of Cyclopropenone Acetals. Penitricin and Buckminsterfullerene.

A variety of substituted cyclopropenone acetals have been prepared and studied for the purpose of gaining further insights into their organometallic and thermal chemistry. Acidic hydrolysis of the acetals gave the corresponding cyclopropenones, among these are a naturally occurring cyclopropenone antibiotic, penitricin. A new class of cysteine protease inhibitor can be realized if the penitricin moiety is contrived as a dipeptide-like binding site. Thermolysisbf substituted cyclopropenone acetals generates vinyl carbene species that undergo [1 + 2] and [3 + 2] cycloadditions to electrondeficient olefins. The cyclopropenone acetal also serves as a precursor to a dipolar trimethylenemethane. The vinyl carbene and the trimethylenemethane species undergo cycloaddition to give buckminsterfullerenes, with which the various organic derivatives of fullerenes generated have been shown to exhibit photo-induced cytotoxicity, DNA cutting activity and enzyme inhibition.

A single electron transfer pathway in the [3+2] cycloaddition of dipolar trimethylenemethane with olefins

A single electron transfer pathway in the [3+2] cycloaddition of dipolar trimethylenemethane with olefins

Regioselective and endo-stereoselective [3 + 2] cycloaddition of dipolar trimethylenemethane to electron-deficient olefin

Regioselective and endo-stereoselective [3 + 2] cycloaddition of dipolar trimethylenemethane to electron-deficient olefin