Phenyl Ketene Research Articles

Synthesis of New Nitro-Furan and Nitro-Thiophene Derivatives from (Chlorocarbonyl) Phenyl Ketene

Nitro-aromatic compounds are used in many human enteropathogenic bacterial infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram-negative intestial Enterobacteriaceae. The interesting properties of these compounds encourage us to synthesis some new of these compounds by a simple route, starting from (Chlorocarbonyl) phenyl ketene.

A simple and an efficient approach to the synthesis of a special tautomer of 1,3-thiazinones and 1,3-oxazinones

A specific tautomer of 1,3-thiazinone and 1,3-oxazinone derivatives were prepared in a one step procedure from condensation of chlorocarbonyl ketenes (CCKs) such as (chlorocarbonyl)phenyl ketene and (chlorocarbonyl)benzyl ketene with thiobenzamide, thioacetamide , cinnamide , benzamide, 2-phenylacetamide and acetamide . This method provides an easy route to prepare 2,5-disubstituted 4-hydroxy-1,3-thiaizin-6-ones and 2, 5-disubstituted 4-hydroxy 1, 3-oxazin-6ones in good to excellent yields in a short experimental time.

Double C—H Activation During Functionalization of Phenyl(methyl)ketene on Iridium(I) Using Alkynes. Synthesis of 1,4‐Dien‐3‐ones.

Under the influence of an Ir(I) metal fragment, the methyl group of phenyl(methyl)ketene undergoes two C-H activations in reacting with internal alkynes, giving metallacycles 3 in 86-94% yield. Treatment of 3 with CO liberates 1,4-dien-3-ones 5 in 81-93% yield, along with CO complex 4. A possible mechanism for the very selective double C-H activation-alkyne coupling is discussed.

A Convenient One‐Pot Synthesis of Substituted 2‐Pyrone Derivatives.

Abstract 2-Pyrone derivatives were prepared in a one step procedure from readily available (chlorocarbonyl)phenyl ketene and 1,3-diketones such as 2,4-pentanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dimethyl-pyrimidine-2,4,6-trione and ethyl 2,4-dioxopentanoate. A mechanism is presented to account for the formation of the products. This method provides an easy route to prepare 3,4,5,6-tetrasubstituted 2-pyrones in good to excellent yields and in a short experimental time.

Ruthenium‐Catalyzed Cyclization of Epoxide with a Tethered Alkyne: Formation of Ketene Intermediates via Oxygen Transfer from Epoxides to Terminal Alkynes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Double C−H Activation during Functionalization of Phenyl(methyl)ketene on Iridium(I) Using Alkynes. Synthesis of 1,4-Dien-3-ones

Under the influence of an Ir(I) metal fragment, the methyl group of phenyl(methyl)ketene undergoes two C-H activations in reacting with internal alkynes, giving metallacycles 3 in 86-94% yield. Treatment of 3 with CO liberates 1,4-dien-3-ones 5 in 81-93% yield, along with CO complex 4. A possible mechanism for the very selective double C-H activation-alkyne coupling is discussed.

A convenient one-pot synthesis of substituted 2-pyrone derivatives

2-Pyrone derivatives were prepared in a one step procedure from readily available (chlorocarbonyl)phenyl ketene and 1,3-diketones such as 2,4-pentanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dimethyl-pyrimidine-2,4,6-trione and ethyl 2,4-dioxopentanoate. A mechanism is presented to account for the formation of the products. This method provides an easy route to prepare 3,4,5,6-tetrasubstituted 2-pyrones in good to excellent yields and in a short experimental time.

Ruthenium-catalyzed cyclization of epoxide with a tethered alkyne: formation of ketene intermediates via oxygen transfer from epoxides to terminal alkynes.

Treatment of (o-ethynyl)phenyl epoxides with TpRuPPh(3)(CH(3)CN)(2)PF(6) (10 mol %) in hot toluene (100 degrees C, 3-6 h) gave 2-naphthols or 1-alkylidene-2-indanones very selectively with isolated yields exceeding 72%, depending on the nature of the epoxide substituents. Surprisingly, the reaction intermediate proved to be a ruthenium-pi-ketene species that can be trapped efficiently by alcohol to give an ester compound. This phenomenon indicates a novel oxygen transfer from epoxide to its terminal alkyne catalyzed by a ruthenium complex. A plausible mechanism is proposed on the basis of reaction products and the deuterium-labeling experiment. The 2-naphthol products are thought to derive from 6-endo-dig cyclization of (o-alkenyl)phenyl ketene intermediates, whereas 1-alkylidene-2-indanones are given from the 5-endo-dig cyclization pathway.

Five-Membered 2,3-Dioxo Heterocycles: XLV. Thermolysis of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the Absence of Other Partners and in the Presence of Carbonyl Compounds

Aroyl(phenyl)ketenes generated by thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones undergo [4+2]-cyclodimerization to 3-aroyl-6-aryl-3,5-diphenyl-3,4-dihydro-2H-pyran-2,4-diones. Heating of the latter leads to rearrangement with formation of 4-aroyloxy-6-aryl-3,5-diphenyl-2H-pyran-2-ones. Thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the presence of carbonyl compounds yields 6-aryl-5-phenyl-4H-1,3-dioxin-4-ones.

Synthesis of 2-arylmethylidene-5-oxo-1,4-diphenyl-2,5-dihydro-1H-pyrazol-2-ium-3-olates

Condensation of several arylhydrazones with chlorocarbonyl phenyl ketene gave 2-(arylmethylidene)-5-oxo-1,4-diphenyl-2,5-dihydro-1H-pyrazol-2-ium-3-olates in high yields.

Quinolizine-2,4-diones by reversible dimerisation 2-pyridylketenesElectronic supplementary information (ESI) available: figure of experimental (Ar matrix, 10 K) IR spectrum of 10b and calculated (B3LYP/6-31G*) IR spectra of s-cis- and s-trans-10b, and tables of Cartesian coordinates and calculated IR spectra of s-cis- and s-trans-10a,b, 2-(2-pyridyl)benzocyclobutenone, and hypothetical ylides 3 (Me and Ph in place of H). See http://www.rsc.org/suppdata/p1/b2/b202523j/

Quinolizine-2,4-diones 11 are obtained by flash vacuum thermolysis (FVT) of 3-acyl-1,2,3-triazolo[1,5-a]pyridines 7. The reaction takes place via methyl- and phenyl(2-pyridyl)ketenes 10, which are directly observable by infrared spectroscopy in low temperature matrices. FVT of 11 regenerates the ketenes 10.

SYNTHESIS OF CROSS-CONJUGATED HETEROCYCLIC MESOMERIC BETAINES

Reaction of (chlorocarbonyl)phenyl ketene with several oximes such as p-chlorobenzaldehyde oxime, 2,4-dichlorobenzaldehyde oxime, p-N,N-dimethylbenzaldehyde oxime, 9-anthracene carboxaldehyde oxime and benzophenone oxime resulted in a series of cross-conjugated heterocyclic mesomeric betaines CCMB.

ChemInform Abstract: A One-Pot Synthesis of 5-Phenyl-1,3-dioxane-4,6-dione Derivatives.

Abstract A general procedure for synthesis of 5-phenyl-1,3-dioxane-4,6-dione derivatives is described. The synthesis involves the cycloaddition of (α-chlorocarbonyl)phenyl ketene with carbonyl compounds to generate the corresponding substituted 2-oxetanone's which is readily transformed to the final products in one step. The 1,3-dioxane-4,6-dione is a rigid cyclic structure, and can undergo easy hydrolysis.

A One Pot Synthesis of 5-Phenyl-1,3-Dioxane-4,6-Dione Derivatives

A general procedure for synthesis of 5-phenyl-1,3-dioxane-4,6-dione derivatives is described. The synthesis involves the cycloaddition of (α-chlorocarbonyl)phenyl ketene with carbonyl compounds to generate the corresponding substituted 2-oxetanone's which is readily transformed to the final products in one step. The 1,3-dioxane-4,6-dione is a rigid cyclic structure, and can undergo easy hydrolysis.

Synthesis, structure and reactivity of highly functionalized η1-stibaallyliron complexes [(OC)2(η5-C5Me5)Fe–Sb(Cl)C(OSiMe3)CPhR] (R = Ph, Me or c-C6H11)

Insertion of one equivalent of methyl(phenyl)ketene or cyclohexyl(phenyl)ketene into the Sb–Si bond of [FeCp*(CO)2{Sb(SiMe3)2}] afforded η1-stibaallyliron complexes [(OC)2(η5-C5Me5)Fe–Sb(SiMe3)C(OSiMe3) CR1Ph] (R1 = c-C6H11 or Me). The remaining Sb–Si bond was readily cleaved by C2Cl6 to give complexes [(OC)2Cp*Fe–Sb(Cl)C(OSiMe3)CR1Ph]. Treatment of the latter where R1 = Ph with LiSb(SiMe3)2·2.8thf, LiCCPh, or LiC(N2)SiMe3 resulted in the formation of compounds [(OC)2Cp*Fe–Sb(R)C(OSiMe3)CPh2 [R = Sb(SiMe3)2, CCPh or C(N2)SiMe3]. The new compounds were characterized by elemental analyses and spectra (IR, 1H, 13C, 29Si NMR). The molecular structure of [(OC)2Cp*Fe–Sb(Cl)C(OSiMe3)CPh2] was elucidated by a single crystal X-ray diffraction analysis.

Solvent isotope effect on the hydroxide-ioncatalyzed hydration of ketenes in aqueous solution

Five ketenes, phenyl(ethyl)ketene, phenyl(methylthio)ketene, diphenylketene, pentafluorophenylketene, and 1-naphthylketene, were generated flash photolytically and solvent isotope effects (H2O vs. D2O) on their hydroxide-ion-catalyzed hydration in aqueous solution were determined. The values obtained are all weakly inverse and closely similar (kHO/kDO = 0.76-0.97), as expected for these fast, hydroxide-ion-consuming reactions, known to proceed by nucleophilic attack of hydroxide on the ketene carbonyl group. The characteristic magnitude of these isotope effects should prove useful in identifying new examples of this reaction.Key words: ketenes, flash photolysis, photo-Wolff reaction, solvent isotope effects on hydroxide ion consumption.

Solvent isotope effect on the hydroxide-ion-catalyzed hydration of ketenes in aqueous solution

Five ketenes, phenyl(ethyl)ketene, phenyl(methylthio)ketene, diphenylketene, pentafluorophenylketene, and 1-naphthylketene, were generated flash photolytically and solvent isotope effects (H 2O vs. D2O) on their hydroxide-ion- catalyzed hydration in aqueous solution were determined. The values obtained are all weakly inverse and closely similar (kHO/kDO = 0.76-0.97), as expected for these fast, hydroxide-ion-consuming reactions, known to proceed by nucleophilic attack of hydroxide on the ketene carbonyl group. The characteristic magnitude of these isotope effects should prove useful in identifying new examples of this reaction.

Spectroscopy and Absolute Reactivity of Ketenes in Acetonitrile Studied by Laser Flash Photolysis with Time-Resolved Infrared Detection

Laser flash photolysis with time-resolved infrared detection of transients (LFP-TRIR) has been used to study the IR spectroscopy and reactivity of a number of substituted ketenes, prepared by the 308-nm photolysis of α-diazocarbonyl precursors in acetonitrile solution at room temperature. The correlation of the experimental ketene asymmetric stretching frequency to the Swain−Lupton field (F) and resonance (R) effect substituent parameters was unsatisfactory, whereas the correlation to the inductive substituent parameter (σI) of Charton gave excellent results. This suggests that the asymmetric stretching frequency of substituted ketenes depends mainly on the inductive (i.e., field) effect of the substituents. The mechanism and kinetics of the reactions of these ketenes with various amines in acetonitrile were also studied. An intermediate species identified as either zwitterionic ylide or amide enol formed in the nucleophilic addition of the secondary amine to the Cα of the ketene is observed by TRIR. The decay of this species is assisted by the amine and is concomitant with the formation of an amide, the final product of the reaction. Our kinetic data on ketene amine reactions show a general trend, indicating a much higher reactivity (ca. 3 orders of magnitude difference in the corresponding rate constants) of secondary amines compared with that of tertiary amines. Secondary diethylamine shows reactivity similar to those observed for primary amines, while secondary piperidine seems to be, in general, somewhat more reactive. The observed trend is rationalized in terms of the steric effects exerted by both amine and ketene substituents. Our data on para-substituted phenyl ketenes provide support for the negative charge development on the ketene moiety in the transition state, with electron-withdrawing substituents accelerating and electron-releasing substituents slowing down the addition reaction.

Iminium carbonic acid derivative salts. XII. electrophilic reactions of 2‐methylthio‐4,5‐dihydrothiazolium iodides, 5‐methyl‐2‐methylthiothiazolium iodides and 2‐methylthio‐5,6‐dihydro‐1,3‐thiazinium iodides. part III. With Vinylogous and Phenylogous Active Methylene Compounds

Abstract3‐Benzyl‐2‐memyltmo‐4,5‐dmydrothiazolium iodide (1), 5‐metlyl‐2‐methylthio‐3‐phenethylthiazolium iodide (4) and 3‐methyl and 3‐benzyl‐2‐methylthio‐5,6‐dihydro‐1,3‐thiazinium iodides 7a, b were reacted with the vinylogous doubly activated CH‐acidic compounds 2a‐d and the phenylogous doubly activated components 8, 11, 16, 19 and 21 to yield new types of S, N‐heterocycles 3, 5, 6, 9, 10, 12, 13, 14, 15 with the partial structure of push‐pull substituted butadienes and 17, 18, 20, 22, 23 and 24 with the character of push‐pull substituted phenyl ketene S, N‐acetals.

A thermal rearrangement of ethylene acetal of bicyclo[4.2.0]octa‐4,7‐diene‐2,3‐dione

AbstractPyrolysis of the title compound 3 at 400 °C gave α‐(2‐hydroxyphenyl)‐γ‐butyrolactone (4) whose structure was confirmed by an alternative synthesis. A reaction mechanism via a phenyl ketene acetal is proposed.