Isoquinolinium Ylides Research Articles

ChemInform Abstract: Reversible C↔N Migration of the Ethoxycarbonyl Group in the Reactions of Pyridinium and Isoquinolinium Ylides Derived from Malonic Ester with Isocyanates.

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.

ChemInform Abstract: Reactions of N‐Benzyl‐pyridinium or ‐isoquinolinium Ylides with Ethyl 3‐Fluoro‐3‐(fluoroalkyl)acrylates to Give Fluoroalkyl‐Substituted Indolizine and Pyrrolo[2.1‐a]isoquinoline 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.

Reversible C ⇆ N migration of the ethoxycarbonyl group in the reactions of pyridinium and isoquinolinium ylides derived from malonic ester with isocyanates

AbstractPyridinium and isoquinolinium ylides (7 and 12) derived from malonic ester react in an unusual manner with isocyanates giving the new pyridinium ylide (9) and the new isoquinolinium ylide (14). C → N Migration of the COOEt group takes place at room temperature, but, at an elevated temperature, reverse N → C migration of the COOEt group proceeds and ylides 9 and 14 are reconverted into the starting ylides 7 and 12, respectively. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:36–45, 2002; DOI 10.1002/hc.1104

Reactions of N-benzyl-pyridinium or -isoquinolinium ylides with ethyl 3-fluoro-3-(fluoroalkyl)acrylates to give fluoroalkyl-substituted indolizine and pyrrolo[2,1-a]isoquinoline derivatives

In the presence of base, N-benzylpyridinium and N-benzylisoquinolinium ylides generated in situ from the N-benzyl-pyridinium or -isoquinolinium bromides react with ethyl 3-fluoro-3-fluoroalkyl(except bromodifluoromethyl)acrylates to give one or two fluoroalkylated indolizine and pyrrolo[2,1-a]isoquinoline derivatives through 1,3-dipolar cycloaddition followed by an oxidative aromatization or 1,3-H-shift aromatization process. While ethyl 3-bromodifluoromethyl-3-fluoroacrylate reacts with 4-nitrobenzylpyridinium ylide, a trifluoromethylated indolizine derivative was obtained unexpectedly. It is more remarkable that the reaction of ethyl 3-bromodifluoromethyl-3-fluoroacrylate with N-benzylisoquinolinium ylide produces a fluorocarbonyl-substituted pyrrolo[2,1-a]isoquinoline derivative, which is fully characterized by spectroscopic methods and X-ray diffraction analysis, in addition to the 1,3-H-shift aromatization product.

Cycloaddition reactions of N-(cyanomethyl)pyridinium ylides with 2,2-dihydropolyfluoroalkanoates

In the presence of base, 2,2-dihydropolyfluoroalkanoates of type R FCF 2CH 2CO 2Et ( 2) react with N-(cyanomethyl)pyridinium and N-(cyanomethyl)-isoquinolinium ylides ( 1) to give the corresponding indolizine derivatives carrying both a fluoroalkyl and a cyano group ( 3).

Two directions in the heterocyclization of thiocarbamoylpyridinium(isoquinolinium)ylides in their interaction with esters of acetylenecarboxylic acids

It has been found that pyridinium- and isoquinoliniumthiocarbamoylazomethinylides react with esters of acetylenedicarboxylic and propiolic acids in two directions. The first direction is heterocyclization of the thioamide fragment of the ylide; under the influence of dimethyl acetylenedicarboxylate, a thiazolyl-4-one ring is formed, and by the interaction of the pyridiniumylide with methyl propiolate, a thiazin-4-one ring is formed. The second direction consists of annelation of the imidazole ring to the isoquinoline system upon reaction with methyl propiolate.

Regio- and stereodirectivity in the reactions of isoquinolinium ylides with unsaturated nitriles

Reactions of isoquinolinium ylides with arylmethylenemalonitriles involve 1,3-dipolar cycloaddition, with the highly regio- and stereoselective formation of 2-aryl-3-benzoyl(or carbamoyl)1,1-dicyano-2,3-trans-1,2,3,10b-tetrahydropyrrolo[2, 1-a]isoquinolines. In contrast, N-phenacylisoquinolinium ylide reacts with aryl-methylenecyanothioacetamides differently, proceeding regio- and stereoselectively to give 4-aryl-2-hydroxy-3-(1-isoquinolinio)-2-phenyl-3-cyano-3,4-trans-1,2,3,4-tetrahydropyridine-6-thiolates.

Reaktionen unter Beteiligung von Ylid‐Zwischenstufen. III. Zur Darstellung und Konfigurationsanalyse spirokondensierter Tetrahydroindolizine

Reactions by Participating of Ylide‐Intermediates. III. On Preparation and Structural Elucidation of Spiro‐condensed TetrahydroindolizinesN‐(Fluroen‐9‐yl)‐pyridinium‐ and ‐isoquinolinium ylides (5) to (8) react with electrondeficit olefinic dipolarophiles under mild conditiones to give satisfactory to good yields of the corresponding spirocondensated tetrahydroindolizines (10) to (13). The structure and configuration of all isolated products were elucidated by spectroscopical methods, especially by 1 D‐ and 2 D 1H‐n.m.r. The 1.3‐dipolar cycloaddition produced regiospecific cycloadducts. From the observed regiospecifity of unsymmetrically substituted olefines (9) can be concluded that the cycloaddition is HOMO(1.3‐dipole) — LUMO(dipolarophile) controlled. The olefines (9) add stereospecifically under retention of their configuration via exo as well as endo transition states. The nitrosubstituted ylides (6) and (8) produced always mixtures of diastereomeric cycloadducts (11) and (13).

Electron ionization and chemical ionization mass spectra of pyridinium and isoquinolinium ylides

AbstractElectron ionization (EI) spectra and both positive and negative chemical ionization (CI) spectra have been obtained for four isoquinolinium ylides and two pyridinium ylides. Electron transfer reactions dominate the CI mass specra. The base peak in negative chemical ionization is the [M]−· ion, formed by electron capture. In the positive methane CI spectra the molecular ion, [M]+·, is relatively more intense than [MH]+ showing electron transfer to be the main positive ionization process. In the positive ammonia CI spectra, proton transfer to give [MH]+ is the main ionization process, but electron transfer is also observed. The EI spectra show fragmentations in which the aromatic nitrogen moiety retains the charge and fragmentation is by loss of radicals or small neutral molecules from the side‐chains. Radical driven reactions are proposed to explain these spectra.

Preparation of tetrahydroindolizines from pyridinium and isoquinolinium ylides

Carbonyl- and nitrile-stabilised pyridinium and cyclic azonium methylides condense with chalcones to form tetrahydroindolizines and analogous fused pyrrolidines. The stereochemistry is illuminated by 13C and 1H n.m.r. spectroscopy. Several incorrect literature structures are rectified.

Studies on cycloimmonium ylides. Synthesis of some 2,4,6-triaryl-substituted pyridines via isoquinolinium ylides

Studies on cycloimmonium ylides. Synthesis of some 2,4,6-triaryl-substituted pyridines via isoquinolinium ylides

Studies on the reactions of heterocyclic compounds. XIV. 1,3-Dipolar cycloaddition of some isoquinolinium ylides with methyl propiolate.

In the cycloaddition reaction of isoquinolinium bis (methoxycarbonyl) methylide (VI) and isoquinolinium cyano (methoxycarbonyl) methylide (VIII) with methyl propiolate (II), the primary adducts, trimethyl-3, 10b-dihydropyrrolo [2, 1-α] isoquinoline-1, 3, 3-tricarboxylate (VII) and dimethyl 3-cyano 3, 10b-dihydropyrrolo [2, 1-α] isoquinoline-1, 3-dicarboxylate (IX), were isolated. The stability of the primary adduct was found to be affected by the kind of substituent at 3-position.

Studies on the Reactions of Heterocyclic Compounds. X. 1, 3-Dipolar Cycloaddition Reaction of Isoquinolinium Ylides and Dicyanoacetylene

The 1, 3-dipolar cycloaddition of dicyanoacetylene (IIb) to isoquinolinium ylides did not give the primary adduct but the aromatized and/or isomerized products. Further, in the reaction of isoquinolinium bis(methoxycarbonyl)methylide (Ia), possibly a rearranged addition product, 1, 10b-dihydropyrrolo[2, 1-α]isoquinoline (VII), was obtained beside 2, 3-dihydropyrrolo[2, 1-α]isoquinoline (Va) and pyrrolo[2, 1-α]isoquinoline (VIa). In the reaction of isoquinolinium cyano(methoxycarbonyl)methylide (Ib), 2, 3-dihydropyrrolo[2, 1-α]isoquinoline (VIII), formed by the liberation of a methoxycarbonyl group, was obtained in addition to VIa and pyrrolo[2, 1-α]isoquinoline-1, 2, 3-tricarbonitrile (VIb).

Formation of 3,10b-dihydropyrrolo[2,1- [formula omitted]]isoquinolines as a key compound for 1,3-dipolar cycloaddition of some isoquinolinium ylides

Formation of 3,10b-dihydropyrrolo[2,1- [formula omitted]]isoquinolines as a key compound for 1,3-dipolar cycloaddition of some isoquinolinium ylides

Some 1,3-dipolar addition reactions of isoquinolinium ylides : formation of 2,3-dihydrobenzo[g]indolizines and benzoindolizines

Isoquinolinium ylides react with dimethyl acetylenedicarboxylate to yield 2,3-dihydrobenzo[g]-indolizines and the corresponding benzo[g]indolizines, whilst with methyl propiolate only the latter are obtained.