Oxidation, Boyland-Sims

Oxidation of aromatic amines to phenols using alkaline persulfate. 

Boyland, E. Manson, D. Sims, P. J. Chem. Soc. 1953, 3623. Eric Boyland and Peter Sims were at the Royal Cancer Hospital in London, UK. 

Name Reactions A Collection of Detailed Mechanisms and Synthetic Applications, DOI 10.1007/978-3-319-03979-4 37, Springer International Publishing Switzerland 2014 

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Another hydroxylation reaction is the Elbs reaction In this method, phenols can be oxidized to p-diphenols with K2S20g in alkaline solution. Primary, secondary, or tertiary aromatic amines give predominant or exclusive ortho substitution unless both ortho positions are blocked, in which case para substitution is found. The reaction with amines is called the Boyland-Sims oxidation. Yields are low with either phenols or amines, generally under 50%. The mechanisms are not clear, but for the Boyland-Sims oxidation there is evidence that the S20 ion attacks at the ipso position, and then a migration follows. ... 

Borohydride reduction, chiral, 52, 2 in reductive amination, 59, 1 Boyland-Sims oxidation, 35, 2 Bucherer reaction, 1, 5... 

Hydroxylation of arylamines with persulfate ion, or Boyland-Sims oxidation, gives ortho-substituted aminophenols in good yields [29]. As with the Elbs oxidation, the procedure is also carried out in two steps - first, treatment with the oxidant to obtain an aminophenyl sulfate ester and, second, hydrolysis to obtain the final product. Primary, secondary and tertiary amines can all be used in this reaction. The ortho product is formed, except when no ortho-positions are available, which leads to para-substitution. Electrophilic attack on the ipso-carbon is believed to be the most likely mechanism, although minor radical pathways also seem to be present. 

The Persulfate Oxidation of Phenols and Arylamines (The Elbs and the Boyland-Sims Oxidations)... 

Oxidation of anilines with alkaline potassium persulfate (K2S2O8) followed by hydrolysis to give ortho-hydroxyl anilines is known as the Boyland-Sims oxidation. ... 

The ortho-isomer is formed predominantly. However, the para-sulfate is formed in small amounts with certain anilines. The intermediate A formed first in the Boyland-Sims oxidation on rearrangement gives both the ortho- and para-amino aryl sulfates B and C (Scheme 7.31). ... 

Bond angles, in mono-/poly-hydroxybenzenes 200, 201, 203, 204 Bond dissociation, O—H 129-143 Bond dissociation energy 5, 224, 895 O-H 139, 140, 982 Bond dissociation enthalpy 3 Bond lengths, in mono-/poly-hydroxybenzenes 200, 201, 203, 204 Bond orbitals, natural 3 Borins—see 1,3,2-Dioxaborins Bovine semm albumin 978 Boyland-Sims oxidation 409 Boyland-Sims rearrangement 801 Bromination 649-651 of calixarenes 1403... 

This reaction is related to the Boyland-Sims Oxidation and Elbs Persulfate Oxidation. 

Other references related to the Boyland-Sims oxidation are cited in the literature. ... 

Also known as the Elbs persulfate oxidation,it is a variant of the Boyland-Sims oxidation except the substrate is phenol rather than aniline. Its mechanism is similar to that of the Boyland-Sims oxidation. 

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