A Novel Synthetic Route to 2-Aryl-2H-Benzotriazole 1-Oxides

Niclas, H.‐J.; Göhrmann, B.

doi:10.1080/00397918908052609

Cited by 19 publications

(2 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…172°C (lit. 172-174.5°C [20][21][22][23][24][25][26][27][28][29][30][31]48,58 ). All the hydroxy-and methoxysubstituted benzenes (1a-1e) were commercial products (Aldrich or Acros) which were purified prior to use.…”

Section: Discussionmentioning

confidence: 99%

“…In recent years a body of evidence has been accumulated showing that 4,6-dinitrobenzofuroxan (DNBF) is a neutral 10-p-electron heteroaromatic substrate which in many processes exhibits an extremely high electrophilic character. [17][18][19][20][21][22][23][24][25][26][27][28][29] In fact, recent studies have shown that DNBF is a stronger electrophile than both the p-nitrobenzenediazonium ion and the H cation. 30,31 In the present study we have investigated the reactions of DNBF with a series of hydroxy-and methoxysubstituted benzenes 1a-1e (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy‐substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

Terrier

Pouet

Hallé

et al. 1998

J. Phys. Org. Chem.

View full text Add to dashboard Cite

Rate constants have been determined in aqueous Me 2 SO mixtures for the reaction of super-electrophilic 4,6-dinitrobenzofuroxan (DNBF) with a series of hydroxy-and methoxy-substituted benzenes whose pK a values range between -3 and -9. The study extends the reactivity range of weakly basic aromatics with DNBF, from the family of indoles previously studied with pK a values ranging from -1 to -6. The overall rate constants for the reactions of DNBF as the electrophile are at least one order of magnitude greater than for the reactions of H 3 O with the same series of aromatics. This lends further credence to the notion that DNBF possesses super-electrophilic properties. An LFER is observed between logk DNBF 50%Me 2 SO and pK H 2 O a with slope 0.54. In the case of 1,3,5-trimethoxybenzene a significant kinetic isotope effect (KIE) is observed (k H /k D = 3.71 in 50% Me 2 SO). This system hence affords one of the few instances in which a KIE has been observed in S E Ar reactions. It follows from the observed KIE that the addition of DNBF to the aromatic is not rate-limiting and that reversion to reactants and proton loss from the arenonium intermediate occur at comparable rates. Structures of the products of electrophilic substitution have been confirmed by 1 H NMR. In all cases the regiochemistry of the reactions was identical to that observed in protonation studies of the starting aromatics.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy‐substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

Terrier

Pouet

Hallé

et al. 1998

J. Phys. Org. Chem.

View full text Add to dashboard Cite

show abstract

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy-substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

Terrier

Pouet

Hallé

et al. 1998

J. Phys. Org. Chem.

View full text Add to dashboard Cite

Rate constants have been determined in aqueous Me2SO mixtures for the reaction of super‐electrophilic 4,6‐dinitrobenzofuroxan (DNBF) with a series of hydroxy‐ and methoxy‐substituted benzenes whose pKa values range between ‐3 and ‐9. The study extends the reactivity range of weakly basic aromatics with DNBF, from the family of indoles previously studied with pKa values ranging from ‐1 to ‐6. The overall rate constants for the reactions of DNBF as the electrophile are at least one order of magnitude greater than for the reactions of H3O+ with the same series of aromatics. This lends further credence to the notion that DNBF possesses super‐electrophilic properties. An LFER is observed between logk 50%Me 2SODNBF and pK aH 2O with slope 0.54. In the case of 1,3,5‐trimethoxybenzene a significant kinetic isotope effect (KIE) is observed (kH/kD = 3.71 in 50% Me2SO). This system hence affords one of the few instances in which a KIE has been observed in SEAr reactions. It follows from the observed KIE that the addition of DNBF to the aromatic is not rate‐limiting and that reversion to reactants and proton loss from the arenonium intermediate occur at comparable rates. Structures of the products of electrophilic substitution have been confirmed by 1H NMR. In all cases the regiochemistry of the reactions was identical to that observed in protonation studies of the starting aromatics. © 1998 John Wiley & Sons, Ltd.

show abstract

ChemInform Abstract: A Novel Synthetic Route to 2‐Aryl‐2H‐benzotriazole 1‐Oxides.

Niclas¹,

Goehrmann²

1990

ChemInform

View full text Add to dashboard Cite

show abstract

A Novel Synthetic Route to 2-Aryl-2H-Benzotriazole 1-Oxides

Cited by 19 publications

References 11 publications

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy‐substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy‐substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

Electrophilic aromatic substitutions: reactions of hydroxy- and methoxy-substituted benzenes with 4,6-dinitrobenzofuroxan: kinetics and mechanism

ChemInform Abstract: A Novel Synthetic Route to 2‐Aryl‐2H‐benzotriazole 1‐Oxides.

Contact Info

Product

Resources

About