Photo-additions of aromatic hydrocarbons—indene and naphthalene with acrylonitrile

1969 ◽  
Vol 47 (5) ◽  
pp. 757-766 ◽  
Author(s):  
John J. McCullough ◽  
C. W. Huang
Keyword(s):  
Butyl Alcohol ◽  
Major Product ◽  
Minor Amount ◽  
Strong Base ◽  
Magnetic Resonance Data ◽  
Cis And Trans Isomers ◽  
Resonance Data ◽  
Ethanol Yields ◽  
A Minor ◽  
Cis And Trans

The photolyses of indene and naphthalene with acrylonitrile have been studied, and the products characterized. Indene reacts with acrylonitrile when the hydrocarbon absorbs light, or when a triplet sensitizer (acetophenone) is absorbing. Photolysis under the former conditions in ethanol yields 2-(1-indenylpropionitrile) (70%), 2-(3-indenylpropionitrile) (10%), and 6-cyano-2,3-benzobicyclo[3,2,0]hept-2-ene (20%). Base-catalyzed isomerizations of the substituted indenes are reported. On sensitization, cis- and trans-isomers of 7-cyano-2,3-benzobicyclo[3,2,0]hept-2-ene are formed, with a minor amount of indene dimer. The former isomers can be equilibrated with strong base. Adducts of 1,1-dimethyl- and 1,1-diphenylindene with acrylonitrile are also described, and nuclear magnetic resonance data reported. Naphthalene adds acrylonitrile on photolysis in t-butyl alcohol (pyrex filter) to afford trans-8-cyano-2,3-benzobicyclo-[4,2,0]-octa-2,4-diene (90%) and 1- and 2-naphthyl-2-propionitrile (10%). Sensitization with acetophenone gave no detectable products. Irradiation of the major product at 253.7 mμ through Vycor gave naphthalene. The preparative value of these reactions is considered and possible mechanisms are proposed.

Multiple Hydrogen Shifts Leading to Ammonia Loss from the Molecular Ions of Cyanocyclohexanes

2002 ◽  
Vol 8 (6) ◽  
pp. 435-445 ◽  
Author(s):  
T.A. Molenaar-Langeveld ◽  
A.M. van der Burg ◽  
S. Ingemann
Keyword(s):  
Molecular Ions ◽  
Minor Importance ◽  
Deuterium Labeling ◽  
Ammonia Loss ◽  
Cis And Trans Isomers ◽  
Metastable Ions ◽  
Cyclohexadienyl Radical ◽  
A Minor ◽  
Cis And Trans ◽  
Distonic Ion

The loss of ammonia from the metastable molecular ions of cyclic cyano compounds has been examined with the use of deuterium labeling and tandem mass spectrometry. Loss of ammonia is significant for ionized cyanocyclohexane, 1-methyl-, 4-methyl-, 4-cyano-and 4-phenyl-cyanocyclohexanes, 4-cyanopiperidine, cyanocycloheptane and 2-cyanonorbornane. By contrast, loss of ammonia is of minor importance (or absent) for the molecular ions of cyanocyclopentane, 2-methyl-cyanocyclohexane, 1-phenyl-cyanocyclohexane, 1-cyanocyclohexene, 4-cyanotetrahydrothiopyran, 2-cyano-5-norbornene and isocyanocyclohexane. Deuterium labeling of cyanocyclohexane reveals the occurrence of an H-shift from the 4-position to the cyano function, followed by a 1,2-H shift from the 1-position to the C-atom of the newly-formed–CNH group. Subsequently, a series of H-shifts leads to a distonic ion that is formulated as an N-protonated methylamine attached to a cyclohexadienyl radical. Loss of ammonia ensues and leads to ionized toluene as indicated by collision-induced dissociation experiments. For 4-phenyl-cyanocyclohexane, the metastable ions of the cis- and trans-isomers display, essentially, the same unimolecular chemistry. Briefly, the labeling of 4-phenyl-cyanocyclohexane indicates the following: (i) the H atom at the 4-position of the cyclohexane ring is incorporated, to a minor extent, in the ammonia molecule, (ii) loss of NHD2 predominates in the reactions of the molecular ions of 2,2,6,6-d4-4-phenyl-cyanocyclohexane and (iii) the ionized 3,3,5-d3-labeled species expels mainly NH2D. In addition, the metastable molecular ions of the 4-[d5-phenyl]-cyanocyclohexane expel NH3 and NH2D in a ratio of 35:65. A mechanistic scheme is proposed that is consistent with the labeling results for 4-phenyl-cyanocyclohexane as well as the indicated formation of ionized 4-methylbiphenyl as the product ion of ammonia loss.

13C magnetic resonance studies. 144. An examination of β-enolization in the bicyclo[3.3.1]- and [3.2.2]nonan-2-one system

1993 ◽  
Vol 71 (8) ◽  
pp. 1099-1105 ◽  
Author(s):  
David J. Muir ◽  
J.B. Stothers
Keyword(s):  
Electron Transfer ◽  
Magnetic Resonance ◽  
Major Product ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Magnetic Resonance Studies ◽  
Unsaturated Ketones ◽  
A Minor ◽  
Cis And Trans ◽  
Magnetic Resonance Spectra

While 3,3-dimethylbicyclo[3.3.1]nonan-2-one (5) is stable under strongly basic conditions (t-BuO−/t-BuOH/185 °C), its isomer, 3,3-dimethylbicyclo[3.2.2]nonan-2-one (6), is slowly transformed to 5. Similarly, 3,3-dimethylbicyclo-[3.2.2]non-6-en-2-one (8b) rearranges to a [3.3.1] isomer but the latter is not stable. Experiments with 3,3-dimethylbicyclo[3.3.1]non-6-en-2-one (7) revealed that it is converted to five compounds, none of which is 8b. The major product, 8,8-dimethylbicyclo[4.3.0]non-1(6),-en-7-one (11) arises from β-enolate rearrangement. Enone 11 undergoes slow reduction to cis- and trans-8,8-dimethylbicyclo[4.3.0]nonan-7-one, presumably by single electron transfer. Experiments with 11 alone showed that β-enolate rearrangement of 7 → 11 is unidirectional. Haller–Bauer cleavage to acidic products occurs as a minor process in the reactions of the unsaturated ketones. The structures of the products were established primarily from their 1H and 13C magnetic resonance spectra.

The conformational preference of methoxyl and acetoxyl groups in 3-oxycyclohexenes, 2-oxymethylenecyclohexanes, and 1-oxytetralins and the generalized anomeric effect

1987 ◽  
Vol 65 (8) ◽  
pp. 1761-1768 ◽  
Author(s):  
Adama Ouédraogo ◽  
Minh Tan Phan Viet ◽  
John K. Saunders ◽  
Jean Lessard
Keyword(s):  
Methoxyl Group ◽  
Equatorial Orientation ◽  
Anomeric Effect ◽  
Conformational Preference ◽  
Magnetic Resonance Data ◽  
Conformational Effect ◽  
Axial Conformer ◽  
Resonance Data ◽  
Cis And Trans ◽  
Derivatives Of

The 13C and 1H nuclear magnetic resonance data of 3-oxycyclohexenes, 2-oxymethylenecyclohexanes, and 1-oxytetralins show (i) that the pseudoaxial preference is larger for the acetoxyl group than for the methoxyl group in 3-oxycyclohexenes, (ii) that the methoxyl and the acetoxyl groups have the same pseudoaxial preference in 1-oxytetralins, and (iii) that in 2-oxymethylenecyclohexanes, the acetoxyl group prefers the equatorial orientation whereas the methoxyl group prefers to be axial. These results are interpreted in terms of the orbital picture (π–σ* stabilization of the axial conformer) of the generalized anomeric effect to which is opposed a conformational effect termed the "unsaturation effect" in 2-acetoxymethylenecyclo-hexane and probably also, but to a much smaller extent, in 1-acetoxytetralin. The results also show that cis and transtert-butyl analogues of 3-oxycyclohexenes do not represent the true limit conformers whereas cis and trans 4-tert-butyl derivatives of 2-oxymethylenecyclohexanes do not differ drastically from the limit conformers.

Cyclopropylcarbinyl-oxo-carbonium Ions. Part V. Synthesis and Chemistry of some Cyclopropyl Glycopyranosides

1972 ◽  
Vol 50 (18) ◽  
pp. 2909-2918 ◽  
Author(s):  
Bruno Radatus ◽  
Bert Fraser-Reid
Keyword(s):  
Ring Current ◽  
Prolonged Exposure ◽  
Cyclopropane Ring ◽  
Complex Mixture ◽  
Major Product ◽  
Ring Closure ◽  
Magnetic Resonance Data ◽  
Carbonium Ions ◽  
Resonance Data ◽  
Judicious Choice

The synthesis of five cyclopropanated glycopyranosides, 6α, 6β, 7α, 7β, and 11 capable of providing access to the title ions has been examined. Simmons–Smith methylenation of methyl 4,6-O-benzylidene-2,3-dideoxy-α-D-eryrtro-hex-2-enopyranoside (8α) under carefully controlled conditions gives an excellent yield of the α-D-allo adduct (6α). A homoallyl iodide, 4,6-O-benzylidene-1,2,3-trideoxy-3-C-iodomethyl-D-ribo-hex-1-enopyranose, (9), is also produced and upon methanolysis undergoes ring closure to an equal mixture of α-D and β-D anomers of 6. Methylene insertion into the aglycon of the starting olefin 8α occurs giving small amounts of the ethyl hex-2-enopyranoside (10), the cyclopropanated glycoside derived therefrom, 11, being also obtained. Methylenation of the β-D-hex-2-enopyranoside, 8β, gives a complex mixture containing at least eight substances, although the expected β-D-manno adduct, 7β, is the major product. There is considerable anomerization of 8β and of the primary product, 7β; thus the anomer 7α is also produced. The 3-epimer (14) of the above-mentioned homoallyl iodide (9) is obtained in small yield.The cyclopronated glycosides are very susceptible to prolonged exposure to the Simmons–Smith medium. Particularly in the case of 8β the yields of the various products can be optimized by judicious choice of the duration of the reaction.Proton magnetic resonance data for the adducts are presented. The value of the spacing J34provides a clear basis for determining the configuration of the ring. However anisotropy due to the cyclopropane ring-current causes the equatorial H-1 in the β-D-manno-anomer (7β) to resonate at higher field than H-1 in the α-D anomer 7α.

scholarly journals Nucleophilic Substitution at Tetracoordinate Phosphorus.Stereochemical Course and Mechanisms of Nucleophilic Displacement Reactions at Phosphorus in Diastereomeric cis- and trans-2-Halogeno-4-methyl-1,3,2-dioxaphosphorinan-2-thiones: Experimental and DFT Studies

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3655
Author(s):  
Marian Mikołajczyk ◽  
Barbara Ziemnicka ◽  
Jan Krzywański ◽  
Marek Cypryk ◽  
Bartłomiej Gostyński
Keyword(s):  
Dft Calculations ◽  
Alkaline Hydrolysis ◽  
Density Functional ◽  
Phosphorus Pentachloride ◽  
Major Product ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Displacement Reactions ◽  
Single Transition ◽  
Cis And Trans

Geometrical cis- and trans- isomers of 2-chloro-, 2-bromo- and 2-fluoro-4-methyl-1,3,2-dioxaphosphorinan-2-thiones were obtained in a diastereoselective way by (a) sulfurization of corresponding cyclic PIII-halogenides, (b) reaction of cyclic phosphorothioic acids with phosphorus pentachloride and (c) halogen–halogen exchange at PIV-halogenide. Their conformation and configuration at the C4-ring carbon and phosphorus stereocentres were studied by NMR (1H, 31P) methods, X-ray analysis and density functional (DFT) calculations. The stereochemistry of displacement reactions (alkaline hydrolysis, methanolysis, aminolysis) at phosphorus and its mechanism were shown to depend on the nature of halogen. Cyclic cis- and trans-isomers of chlorides and bromides react with nucleophiles (HO−, CH3O−, Me2NH) with inversion of configuration at phosphorus. DFT calculations provided evidence that alkaline hydrolysis of cyclic thiophosphoryl chlorides proceeds according to the SN2-P mechanism with a single transition state according to the potential energy surface (PES) observed. The alkaline hydrolysis reaction of cis- and trans-fluorides afforded the same mixture of the corresponding cyclic thiophosphoric acids with the thermodynamically more stable major product. Similar DFT calculations revealed that substitution at phosphorus in fluorides proceeds stepwise according to the A–E mechanism with formation of a pentacoordinate intermediate since a PES with two transition states was observed.

Nitration of 1-chloro-2,3-dimethylbenzene in acetic anhydride. Formation and rearomatization of adducts

1978 ◽  
Vol 56 (8) ◽  
pp. 1063-1068
Author(s):  
Alfred Fischer ◽  
Colin Campbell Greig
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nitrous Acid ◽  
Major Product ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Nitro Derivatives ◽  
Subsequent Elimination ◽  
And Migration ◽  
Cis And Trans

Nitration of l-chloro-2,3-dimethylbenzene in acetic anhydride gives the cis and trans isomers of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl acetate (29%) and l-chloro-2,3-dimethyl-4-nitro- (46%), -5-nitro- (5%), and -6-nitrobenzene (20%). In formic acid and acidified methanol, exchange of acetate for formate and methoxyl, respectively, occurs and the diastereoisomers of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl formate and methyl ether, respectively, are formed. Rearomatization of each isomer of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl acetate in acetic acid results in initial isomerization to form the pair of diastereoisomers and subsequent elimination of nitrous acid to form 3-chloro-4,5-dimethylphenyl acetate. In 25% trifluoroacetic acid in deuteriochloroform elimination of acetic acid and migration of the nitro group to form 1-chloro-2,3-dimethyl-4-nitro-benzene and a lesser amount of its 6-nitro isomer is the dominant reaction. In the presence of mesitylene the formation of the nitro derivatives is suppressed and 3′-chloro-2,4,4′,5′,6-pentamethylbiphenyl is obtained. It is proposed that cyclohexadienyl cations are significant intermediates in ail of the reactions. Pyrolysis of the adducts gives 1-chloro-2,3-dimethylbenzene as the major product.

Preparations of 2,4-Disubstituted Oestradiols

1989 ◽  
Vol 42 (3) ◽  
pp. 421 ◽  
Author(s):  
DJ Pert ◽  
DD Ridley
Keyword(s):  
Sodium Methoxide ◽  
Major Product ◽  
Minor Amount ◽  
Alternative Routes ◽  
A Minor

2,4-Dibromoestra-1,3,S(10)-triene-3,17 β- diol 3-(2'-hydroxyethyl) ether (8) undergoes reaction with copper(11) chloride/sodium methoxide to afford a 4-bromo [2,3]- dioxan derivative (9) as the major product together with a minor amount of a 2-bromo [3,4]- dioxan derivative (10). These compounds were used to prepare a number of 2,4-disubstituted oestradiol derivatives. � Alternative routes to other 2,4-disubstituted oestradiols are described.

Formation of Adducts in the Nitration of p-Xylene. Exchange and Rearomatization Reactions of p-Xylene Adducts

1974 ◽  
Vol 52 (23) ◽  
pp. 3960-3970 ◽  
Author(s):  
Alfred Fischer ◽  
John Neilson Ramsay
Keyword(s):  
Acetic Anhydride ◽  
Sodium Methoxide ◽  
Major Product ◽  
Side Chain ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Acid Catalyzed ◽  
Cis And Trans

Nitration of p-xylene in acetic anhydride gives as the major product cis and trans isomers of the adduct 1,4-dimethyl-4-nitro-1,4-dihydrophenyl acetate (1) as well as 2-nitro-p-xylene. The acetoxynitro adducts 1a and 1b are stereospecifically cleaved to the hydroxynitro adducts 2a and 2b, respectively, by sodium methoxide. Acid-catalyzed exchange of OAc in 1 for OCH3, OCHO, OCH2C6H4CH3-p occurs and is nonstereospecific. Rearomatization of 1 gives 2-nitro-p-xylene, side-chain (benzylic) derivatives, and 2,5-xylyl acetate. The relevance of these reactions to side-chain substitution of arenes under electrophilic conditions is discussed.

Methods to Determine Phytopharmaceuticals in Tobacco and Tobacco Products. 4th Report: A Procedure to Determine Vamidothion and its Metabolites/Methoden zur Bestimmung von Phytopharmaka in Tabak und Tabakerzeugnissen: IV. Mitteilung: Ein Bestimmungsverfahren fuer Vamidothion und seine Metaboliten

1977 ◽  
Vol 9 (2) ◽  
Author(s):  
A.N. Sagredos ◽  
R. Moser
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Acetic Acid ◽  
Magnetic Resonance ◽  
Aluminium Oxide ◽  
Nuclear Magnetic Resonance Data ◽  
Gas Chromatograph ◽  
Tobacco Products ◽  
Magnetic Resonance Data ◽  
Resonance Data

AbstractBased on previous work (7) a method to simultaneously determine vamidothion [I], vamidothion-sulfoxide [II] and vamidothion sulfone [III] in tobacco has been developed. The compounds are extracted with water/acetone/acetic acid from the tobacco, cleansed over an aluminium oxide column and then determined on the gas chromatograph with the specific sulphur detector. Rates of recovery are 70 % - 92 %, the determination level is 0.1 ppm. Mass spectrometry and nuclear magnetic resonance data of vamidothion [I], vamidothion-sulfoxide [ II ] and vamidothion-sulfone [III] are given.

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