Oxidative cyclizations. VII. Cyclization of 2-substituted anilines with alkaline hypohalite

1984 ◽  
Vol 37 (10) ◽  
pp. 2013 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Oxidative Cyclization ◽  
Azo Compounds ◽  
Substituted Anilines ◽  
Oxidative Cyclizations ◽  
Visible Spectra ◽  
Transient Intermediates ◽  
Ortho Substituent

The Green-Rowe oxidation of 2-nitroanilines with alkaline hypochlorite, to yield benzofuroxans, is demonstrated by studies of the visible spectra of transient intermediates to proceed through N-chlorination and a singlet nitrene. Two variations on the route to the nitrene are possible. The cyclization step is represented as an internal capture of the nitrene by the ortho substituent, and on this basis the Green-Rowe oxidative cyclization is now extended to anilines whose ortho substituent is benzoyl or phenylazo. It is not however successful for ortho phenyl. Azo compounds were observed as byproducts in some of these reactions, and are shown to arise via N,N-dichloroanilines.

Oxidative cyclizations. I. The mechanism of the oxidation of ortho-substituted anilines with phenyliodoso acetate

1967 ◽  
Vol 20 (8) ◽  
pp. 1625 ◽  
Author(s):  
LK Dyall ◽  
JE Kemp
Keyword(s):  
Free Radical ◽  
Cyclic Oxidation ◽  
Reaction Path ◽  
Heterocyclic Ring ◽  
Azo Compounds ◽  
Substituted Anilines ◽  
Aryl Azides ◽  
Oxidative Cyclizations ◽  
Amine Oxidation ◽  
Ortho Substituent

A comparison has been made of the types of ortho substituents which can be incorporated into a new heterocyclic ring by pyrolysis of aryl azides or during oxidation of anilines with phenyliodoso acetate. The results enable a new mechanism to be proposed for the amine oxidation. In its key step, the ortho substituent displaces iodobenzene from an intermediate iodoso ester to form the cyclic oxidation product. A competing reaction path involves homolysis of this iodoso ester to yield the free-radical precursors of azo compounds.

Oxidative Cyclizations. V. The Oxidation of ortho-Substituted Benzenamines with Lead(IV) Tetraacetate

1979 ◽  
Vol 32 (3) ◽  
pp. 643 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Experimental Evidence ◽  
Base Pair ◽  
Reactive Intermediates ◽  
Oxidative Cyclization ◽  
Azo Compounds ◽  
Acid Base ◽  
Oxidative Cyclizations ◽  
Conjugate Acid

Lead(IV) tetraacetate has been used to oxidize 1-aminoanthraquinone, 1-arylazonaphthalen-2-amines and benzenamines whose ortho-substitutents were arylazo, nitro, or benzopl. Only the amines with ortho-arylazo substituents underwent oxidative cyclization, to yield triazoles; the others yielded azo compounds and polymers. Experimental evidence shows that neither nitrenes nor arenamino ('anilenium') cations can be the reactive intermediates in some of these reactions. All the results can be rationalized in terms of the conjugate acid-base pair of intermediates, arenamine cation ArNH2+' and arenamino ArNH.

Oxidative cyclizations. III. Kinetic studies of the oxidation of 2,4-dinitroaniline and 2-benzoylaniline with (diacetoxyiodo)benzene

1973 ◽  
Vol 26 (9) ◽  
pp. 1969 ◽  
Author(s):  
LK Dyall ◽  
JE Kemp
Keyword(s):  
Acetic Acid ◽  
Equilibrium Constants ◽  
Kinetic Studies ◽  
Reaction Rates ◽  
Oxidative Cyclization ◽  
Toluene Solution ◽  
Common Mechanism ◽  
Substituted Anilines ◽  
Oxidative Cyclizations ◽  
Cyclic Product

For the oxidative cyclization of 2,4-dinitroaniline and 2- benzoylaniline with (diacetoxyiodo)benzene in toluene solution, the kinetic orders are unity in amine and oxidant, zero in iodobenzene and cyclic product, and -1 in monomeric acetic acid. These characteristic orders are also those observed for 2-nitroaniline and, together with evidence for a specific solvation effect by acetic acid on the reaction rates of all three amines, indicate that a common mechanism of oxidative cyclization applies to a range of ortho-substituted anilines. For 2-benzoylaniline, there is infrared evidence of an N-H bond in an iodoso intermediate. ��� Equilibrium constants for the monomer ↔ dimer equilibrium of acetic acid in toluene solution have been determined at four temperatures between 25� and 46�.

Oxidative cyclizations. IV. Isokinetic relationship in the oxidation of orthosubstituted anilines with (diacetoxyiodo)benzene

1973 ◽  
Vol 26 (12) ◽  
pp. 2665 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Activation Parameters ◽  
Oxidative Cyclization ◽  
Substituted Anilines ◽  
Isokinetic Relationship ◽  
Oxidative Cyclizations

The rates of oxidative cyclization of 11 ortho-substituted anilines by (diacetoxyiodo)benzene have been measured in toluene-acetic acid solution. The activation parameters give a precise fit to an isokinetic relationship, which indicates that a common reaction mechanism is followed. This mechanism applies to amines from the benzene, naphthalene, and anthraquinone families, with nitro and various carbonyl and arylazo groups as the ortho substituents.

Aromatic amides. V. Intramolecular hydrogen bonding in ortho-substituted anilides

1970 ◽  
Vol 23 (8) ◽  
pp. 1667 ◽  
Author(s):  
JM Appleton ◽  
BD Andrews ◽  
ID Rae ◽  
BE Reichert
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Geometry ◽  
Intramolecular Hydrogen Bonding ◽  
Amide Group ◽  
Amide Proton ◽  
Substituted Anilines ◽  
Real Value ◽  
Intramolecular Hydrogen ◽  
Acyl Derivatives ◽  
Ortho Substituent

The proton magnetic resonance spectra of deuterochloroform solutions of a number of ortho-substituted anilines and their S-acyl derivatives have been measured. Variations in the acylation shifts of the ring protons are explained in terms of intramolecular hydrogen bonding between the amide proton and the ortho-substituent. Calculations of the contribution made to the acylation shifts by the anisotropy of the amide group were found to be too sensitive to the molecular geometry to be of any real value. Acylation shifts for a series of 4'-substituted 2'-nitroacetanilides correlate well with the σp values of the 4'-substituents.

scholarly journals Understanding Selectivities in Ligand-free Oxidative Cyclizations of 1,5- and 1,6-Dienes with RuO4 from Density Functional Theory

2010 ◽  
Vol 65 (3) ◽  
pp. 367-s400 ◽  
Author(s):  
Philipp J. di Dio ◽  
Stefan Zahn ◽  
Christian B.W. Stark ◽  
Barbara Kirchner
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Alkyl Chain ◽  
Energy Gap ◽  
Theoretical Data ◽  
Oxidative Cyclization ◽  
Transition Structure ◽  
Functional Theory ◽  
Oxidative Cyclizations ◽  
Ligand Free

Quantum-chemical calculations using density functional theory were carried out to investigate the mechanism of the oxidative cyclization of 1,5- and 1,6-dienes with ruthenium tetroxide. Current experimental results show different selectivities for the formation of tetrahydrofuran and tetrahydropyran derivatives. Our theoretical data correctly reproduce the experimental selectivities. Transition structures for the first [3+2]-cycloaddition of RuO4 with ethene and for the second [3+2]- cycloaddition with two ethene molecules, 1,5-hexadiene, and 1,6-heptadiene were calculated. For the formation of tetrahydrofuran and tetrahydropyran derivatives we observed two reaction pathways. The transition structure for the formation of cis-tetrahydrofuran derivatives was found to be more stable than the trans-tetrahydrofuran-forming transition structure by about 40 kJ mol−1. By comparison to the reaction with two ethene molecules it was shown that the linking alkyl chain causes the energy gap between stereoisomers by a directing influence. In the tetrahydropyran reaction the transtetrahydropyran- forming transition structure was less than 4 kJ mol−1 more stable than the transition structure leading to the cis-tetrahydropyran. The obtained geometries showed that for tetrahydropyrans the energy gap between stereoisomers is not caused by the linking alkyl chain.

scholarly journals Preparation characterization and biological activity of some new tetra - azo compounds

2008 ◽  
pp. 35-44
Keyword(s):  
Ph Value ◽  
Chemical Properties ◽  
Azo Compounds ◽  
Gram Negative Bacteria ◽  
Gram Positive Bacteria ◽  
Phenol Derivatives ◽  
Visible Spectra ◽  
Physical And Chemical ◽  
And Chemical Properties

In this paper , preparation and characterization of some tetra azo compounds .Azo coupling of 3`,3,4`,4- tetra amino biphenyl with phenol and some phenol derivatives in alkaline solution gave azo dyes. I.R and U.V. visible spectra were recorded to identify the three azo compounds prepared . Some physical and chemical properties such as molar absorption coefficient in different pH value and maximum absorption λ maxwere investigated. The biological effect of these dye against two gram positive Bacteria (S.aureuse) and other two gram negative Bacteria (P.aeruginosa) is presented .

DOUBLE-MINIMUM POTENTIAL FOR INTRAMOLECULARLY HYDROGEN-BONDED PROTONS IN ORTHO-SUBSTITUTED ANILINES

1964 ◽  
Vol 42 (2) ◽  
pp. 201-211 ◽  
Author(s):  
P. J. Krueger
Keyword(s):  
Hydrogen Bonding ◽  
Vibrational Level ◽  
Fundamental Mode ◽  
Intramolecular Hydrogen Bonding ◽  
Antisymmetric Mode ◽  
Substituted Anilines ◽  
Minimum Potential ◽  
Intramolecular Hydrogen ◽  
Ortho Substituent ◽  
Hydrogen Bonded

The concentration and temperature-independent splitting of the first overtone NH2 symmetric stretching band in 31 ortho-substituted anilines in which intramolecular hydrogen bonding is possible is interpreted in terms of a double-minimum potential for the hydrogen bonded proton. The intensity ratio of the doublet and the extent of the splitting is related to the basicity of the ortho-substituent, modified by the rigid geometrical restrictions of the intramolecular system. The absence of band splitting in the corresponding fundamental mode suggests that the secondary minimum lies in the vicinity of the v = 2 vibrational level. The antisymmetric mode appears to be less sensitive to perturbations.Deuteration studies, the spectra of some o-substituted N-methyl anilines, and the first over-tone bands of N-methyl aniline in very basic solvents support these views.

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