Diphenylnitrile Imine Research Articles

Ultrafast Dynamics of Photochemical Nitrile Imine Formation

AbstractThe chemical reactivity of nitrile imines is of great utility in organic synthesis with applications rapidly expanding into the materials and life sciences. Yet, our understanding of the electronic and molecular structures of nitrile imines remains incomplete and the elementary mechanism of their photoinduced generation is entirely unknown. Here, femtosecond infrared spectroscopy after 266 nm‐excitation of 2,5‐diphenyltetrazole has been carried out to temporally resolve the formation and structural relaxation dynamics of the nascent diphenylnitrile imine in liquid solution under ambient conditions. The infrared‐spectroscopic evolution is interpreted by an initial sequence of intersystem crossings within 250 fs followed by the cleavage of N2 with formation of a structurally relaxed nitrile imine on the adiabatic ground‐state singlet surface within a few tens of picoseconds. The infrared spectrum supports the notion of a “floppy” nitrile imine molecule whose equilibrium character ranges from fully propargylic to fully allenic in the room temperature liquid solution.

Ultrafast Dynamics of Photochemical Nitrile Imine Formation.

The chemical reactivity of nitrile imines is of great utility in organic synthesis with applications rapidly expanding into the materials and life sciences. Yet, our understanding of the electronic and molecular structures of nitrile imines remains incomplete and the elementary mechanism of their photoinduced generation is entirely unknown. Here, femtosecond infrared spectroscopy after 266 nm‐excitation of 2,5‐diphenyltetrazole has been carried out to temporally resolve the formation and structural relaxation dynamics of the nascent diphenylnitrile imine in liquid solution under ambient conditions. The infrared‐spectroscopic evolution is interpreted by an initial sequence of intersystem crossings within 250 fs followed by the cleavage of N2 with formation of a structurally relaxed nitrile imine on the adiabatic ground‐state singlet surface within a few tens of picoseconds. The infrared spectrum supports the notion of a “floppy” nitrile imine molecule whose equilibrium character ranges from fully propargylic to fully allenic in the room temperature liquid solution.

Sydnone Photochemistry: Direct Observation of Earl's Bicyclic Lactone Valence Isomers (Oxadiazabicyclo[2.1.0]pentanones), Formation of Carbodiimides, Reaction Mechanism, and Photochromism

The matrix photolyses of 3-phenyl-, 3-pyridyl, and 3,4-diphenylsydnones 16, 19, and 22 were investigated by matrix-isolation infrared spectroscopy. The formation of the neutral, bicyclic lactone valence isomers postulated by Earl – the oxadiazabicyclo[2.1.0]pentanones exo-17 and exo-20 – was clearly observed in the first two cases and is also likely in the case of exo-23 (C=O absorptions in the IR at 1881, 1886, and 1874 cm–1, respectively). The efficient photodecomposition of sydnones to carbodiimides RN=C=NR′ (18, 21, and 24) and CO2 was established in all three cases. The formation of benzonitrile 27 and azacycloheptatetraene 29 in the matrix photolysis of diphenylsydnone 22 is indicative of diphenylnitrile imine PhCNNPh 26 as an intermediate (2340 cm–1). Neither bicyclic lactones nor carbodiimides have been observed previously in sydnone photochemistry. A general reaction mechanism for the formation of carbodiimides, nitrile imines, and photochromism is put forward.

A rhodanine derivative and its cycloadduct with diphenyl nitrile imine

The phenylmethylene substituent at the C5 position of 5-benzylidene-3-phenyl-2-thioxo-1,3-thiazolidin-4-one, CI6HIINOS2, (I), is virtually coplanar with the planar five-membered ring, whereas the phenyl group at N3 is almost orthogonal to this plane. The crystals of the chiral cycloadduct, 7-benzylidene-2,4,9-triphenyl-1,6-dithia-3,4,9-triazaspiro[4.4]non-2-en-8-one, C29H21N3OS2, (III), are racemic. Both five-membered rings have an envelope conformation with the spiro-C atom as the envelope flap, although this envelope is quite flattened for the 1,3-thiazolidine ring. In both compounds, short intramolecular C-H...S contacts cause visible steric strain. The known starting material, (I), has been prepared by condensation of 3-phenyl-2-thioxothiazolidin-4-one and benzaldehyde. Its reaction with N-phenylbenzohydrazonoyl chloride, (II), in the presence of triethylamine yielded (III) via 1,3-dipolar cycloaddition of the intermediate nitrile imine.

Highly selective 1,3-dipolar cycloadditions of captodative olefins 1-acetylvinyl carboxylates to diverse dipoles

Regioselective 1,3-dipolar cycloadditions of captodative 1-acetylvinyl p-nitrobenzoyloxy ( 1a) with propionitrile oxide, diphenylnitrile imine and diazoalkanes provided the corresponding 5-acetyl- isoxazoles and pyrazoles. Evidence to support the formation of the initial cycloadducts was obtained. The addition of nitrones also proved to be highly regio- and stereoselective.

A Pericyclic Cascade in the Addition of Diphenyl Nitrile Imine to Pyridine

A Pericyclic Cascade in the Addition of Diphenyl Nitrile Imine to Pyridine

1,3-Dipolar Cycloaddition of Diphenyl Nitrile Imine with 4-Arylmethylene-2,4-dihydro-5-methyl-2-phenyl/phenylmethyl-3H-pyrazol-3-ones

1,3-Dipolar Cycloaddition of Diphenyl Nitrile Imine with 4-Arylmethylene-2,4-dihydro-5-methyl-2-phenyl/phenylmethyl-3H-pyrazol-3-ones

ChemInform Abstract: Cycloaddition Reactions of 2,3‐Dihydro‐1H‐1,4‐diazepines with Nitrile Oxides and Imines. Synthesis of Bis(1,2,4)oxadiazolo‐ and Bis(1,2,4)triazolo(1,4)diazepine Derivatives.

New heterotricyclic systems, 6,10a,11,11a-tetrahydro-5H-bis[1,2,4]oxadiazolo[4,5-d:5′,4′-g][1,4]diazepines 6,7,9-11 and 5,6,10,10a,11,11a-hexahydro-1H-bis[1,2,4]triazolo[4,3-d:3′,4′-g][1,4]diazepines 8,12 have been obtained by double site- and regie-specific 1,3-dipolar cycloaddition of mesitylnitrile oxide (1) or diphenylnitrile imine (2) to 5,7-disubstituted 2,3-dihydro-1H-1,4-diazepines 3-5. The structure of the synthesized bis-adducts 6-12 shows that the hetero double bonds are much more reactive than the olefinic ones in the dipolarophiles under study. No evidence for the formation of mono-adducts was obtained.

Cycloaddition reactions of 2,3‐dihydro‐1H‐1,4‐diazepines with nitrile oxides and imines. Synthesis of bis[1,2,4]oxadiazolo‐and bis[1,2,4]triazolo[1,4]diazepine derivatives

AbstractNew heterotricyclic systems, 6,10a,11,11a‐tetrahydro‐5H‐bis[1,2,4]oxadiazolo[4,5‐d:5′,4′‐g][1,4]diazepines 6,7,9‐11 and 5,6,10,10a,11,11a‐hexahydro‐1H‐bis[1,2,4]triazolo[4,3‐d:3′,4′‐g][1,4]diazepines 8,12 have been obtained by double site‐ and regie‐specific 1,3‐dipolar cycloaddition of mesitylnitrile oxide (1) or diphenylnitrile imine (2) to 5,7‐disubstituted 2,3‐dihydro‐1H‐1,4‐diazepines 3‐5. The structure of the synthesized bis‐adducts 6‐12 shows that the hetero double bonds are much more reactive than the olefinic ones in the dipolarophiles under study. No evidence for the formation of mono‐adducts was obtained.

The synthesis and unimolecular decomposition of four novel Δ1-1,2,4-triazolines

Treatment of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ1-1,2,4-triazoline (3) with benzonitrile oxide (9), diphenylnitrile imine (10), phenyl azide, and p-nitrophenyl azide led, in each case, to 1,3-dipolar cycloaddition. The products, Δ1-1,2,4-tri-azolines that are spiro-fused to another 5-membered ring, could be isolated in pure form in three of the four cases. All four are thermally unstable and decompose by loss of N2 from the Δ1-1,2,4-triazoline moiety to form an azomethine ylide. Subsequent reactions of those ylides are described.

ChemInform Abstract: STUDIES ON CYCLOADDITION REACTIONS: 1,3‐DIPOLAR CYCLOADDITION REACTIONS OF DIPHENYLNITRILE IMINE WITH FURYLACROLEIN ANILS

Chemischer InformationsdienstVolume 15, Issue 27 Heterocyclic Compounds ChemInform Abstract: STUDIES ON CYCLOADDITION REACTIONS: 1,3-DIPOLAR CYCLOADDITION REACTIONS OF DIPHENYLNITRILE IMINE WITH FURYLACROLEIN ANILS D. PRAJAPATI, D. PRAJAPATISearch for more papers by this authorJ. S. SANDHU, J. S. SANDHUSearch for more papers by this authorJ. N. BARUAH, J. N. BARUAHSearch for more papers by this author D. PRAJAPATI, D. PRAJAPATISearch for more papers by this authorJ. S. SANDHU, J. S. SANDHUSearch for more papers by this authorJ. N. BARUAH, J. N. BARUAHSearch for more papers by this author First published: July 3, 1984 https://doi.org/10.1002/chin.198427192AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume15, Issue27July 3, 1984 RelatedInformation

Cycloaddition mit ungesättigten Zuckern, I. Die 1,3‐dipolare Cycloaddition von Diphenylnitrilimin an α‐D‐erythro‐Hex‐2‐enopyranosid

Cycloaddition with Unsaturated Carbohydrates, I. — The 1,3‐Dipolar Cycloaddition of Diphenylnitrile Imine to α‐D‐erythro‐Hex‐2‐enopyranosideBy 1,3‐dipolar cycloaddition of diphenylnitrile imine to ethyl 4,6‐di‐O‐acetyl‐2,3‐dideoxy‐α‐D‐erythro‐hex‐2‐enopyranoside (1) ethyl 4,6‐di‐O‐acetyl‐2,3‐dideoxy‐3′,4′‐dihydro‐2′,5′‐diphenyl‐2′H‐α‐D‐menno‐hexopyranosido[3,2‐c]pyrazole (2a) and the [2,3‐c]‐regioisomer (3a; 2a: 3a = 4:1) were prepared.

Dissociation of the diphenylnitrile imine radical cation into benzonitrile and [phenylnitrene]+˙

AbstractThe collision induced dissociation/mass analysed ion kinetic energy mass spectra of 2,5‐diphenyltetrazole demonstrate the decay sequence [diphenyltetrazole]+˙→ [diphenylnitrile imine]+˙→ m/z 91. The m/z 91 ion was shown to be identical to the ion formed by loss of N2 from the phenyl azide radical cation, thus suggesting the phenylnitrene structure for the m/z 91 ion.

Site selectivity in the reactions of 1,3-dipoles with norbornadiene derivatives

The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbotnadiene derivatives 1a–c showed varying degree of site- and stereo-selectivity. With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition. By contrast, 2-diazopropane and C-pnenyl-N-methyl-nitrone react with the sole tetrasubstituted double bond of 1a–c in stereo- and site-specific cycloadditions. The quantitative evaluation of the two possible reaction paths was performed by glc analysis. The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1). The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.

Site specificity in cycloadditions of diphenylnitrile imine with 8-substituted-8-azaheptafulvenes and tricarbonyl (8-azaheptafulvene) iron complexes

The reaction of diphenylnitrile imine with 8-substituted-8-azaheptafulvenes is both site and regiospecific and resulted in a mixture of two [8+4]-adducts in high yield. The mechanism of the reaction was investigated. The [8+4]-adducts underwent easily a reversible thermal 1,7-sigmatropic shift involving an sp 3 nitrogen centre. Diphenylnitrile imine reacted also with tricarbonyl(8-azaheptafutvene)iron complexes lo give adducts to the CN double bond, the degradative oxidation of which with trimethylamine-N-oxide was investigated. The specificity of the cycloadditions is briefly discussed on the basis of a simple perturbation theory approach.

1,3-Dipolar cycloaddition to a 1,4-quinone methide: 2,6-Di-t-butyl-4-methylenecyclohexa-2,5-dienone

The reactive 1,3-dipoles ethoxycarbonylformonitrile oxide, benzonitrile oxide, diphenylnitrile imine and benzonitrilium 4-nitrobenzylid add to the 4-methylenecyclohexa-2,5-dienone (1) to give the respective 1 : 1 cycloadducts (4a-d). The yields are high and the reactions therefore provide ready access to members of the hetero-spiro[4,5]decatrienone system. Diazomethane, phenyldiazomethane and diphenyldiazomethane also add to the exocyclic methylene moiety of (1) to give only the nitrogen deficient spiro[2,5]octa-4,7-dienones (10a-c).

The reaction of benzonitrile oxide and diphenyl nitrile imine with β‐keto sulfoxides. Synthesis of 4‐methylsulfinyl isoxazoles and pyrazoles

The reaction of benzonitrile oxide and diphenyl nitrile imine with β‐keto sulfoxides. Synthesis of 4‐methylsulfinyl isoxazoles and pyrazoles