Oxidation Dakin

Ethers of benzenepentol have been obtained by Dakin oxidation of the appropriately substituted acetophenone. Thus, the oxidation of 2-hydroxy-3,4,6-ttimethoxyacetophenone and 2-hydroxy-3,4,5-ttimethoxyacetophenone with hydrogen peroxide ia the presence of alkali gives l,2-dihydroxy-3,4,6-ttimethoxybenzene and l,2-dihydroxy-3,4,5-ttimethoxybenzene, respectively further methylation of these ethers yields the pentamethyl ether of benzenepentol (mp 58—59 degC) (253). The one-step aromatization of myoinositol to produce esters of pentahydroxybenzene is achieved by treatment with carboxylic acid anhydrides ia DMSO and ia the presence of pyridine (254) (see Vitamins). 6-Alkyl- or... 

Peroxysulfuric acid, PBA and MPPA, common reagents of the past, appear less frequently in the current literature. Basic 30% hydrogen peroxide or r-butylhydroperoxide have special utility for oxidation of cyclobutanones and strained, bridged cycloalkanones to lactones. Basic 3- % hydrogen peroxide is used in the Dakin oxidation of aryl aldehydes to phenols, while peroxymonophosphoric acid oxidizes aryl ketones to phenolic acetates. ... 

M.E. Jung and co-workers have developed a synthesis of selectively protected L-Dopa derivatives from L-tyrosine via a Reimer-Tiemann reaction followed by the modified Dakin oxidation. The formyl group introduced by the Reimer-Tlemann reaction had to be converted to the corresponding phenol. After trying many sets of conditions, the Syper process was chosen, which uses arylselenium compounds as activators for the oxidation. Treatment of the aromatic aldehyde with 2.5 equivalents of 30% hydrogen peroxide in the presence of 4% diphenyl diselenide in dichloromethane for 18h gave the aryl formate in excellent yield. This ester was cleaved by treatment with methanolic ammonia for 1h to afford the desired phenol in good yield. 

Carboxy-functionalized fluorescein dyes are important as conjugated fluorescent markers of biologically active compounds. M.H. Lyttle et al. have used the Dakin oxidation on 4-methoxy-3-hydroxy-2-chloro-benzaldehyde to obtain the desired resorcinol derivative that served as an intermediate in their improved synthesis. ... 

The total synthesis of (-)-(R)-MEM-protected arthrographol was accomplished by G.L.D. Krupadanam et al." authors used sequential Viismeier reaction/Dakin oxidation to prepare a 1,2,4-trihydroxybenzene derivative. 

Dakin oxidation Conversion of aromatic aldehydes and ketones to the corresponding phenols. 118... 

Hocking, M. B. Dakin oxidation of o-hydroxyacetophenone and some benzophenones. Rate enhancement and mechanistic aspects. Can. 

The references at the end of the book are listed in alphabetical order, and the named reaction for which the references are listed is typed in blue and with boldface (see Dakin oxidation). Important the references are listed in chronological order when they appear as superscript numbers in the text (e g., reference 10 is a more recent paper than reference 12, but it received a smaller reference number because it was cited in the text earlier). 

The mechanism of the Dakin oxidation is very similar to the mechanism of the Baeyer-Viiiiger oxidation. 

For the Dakin oxidation example, the references at the end of the book will be printed in the order they have been cited, but within a group of references (e.g., 15-17) they appear in chronological order. 

Dakin oxidation 419, 420 Dakin rearrangement 799, 800 Dehalogenation 1098-1100 Dehydrodiconiferyl alcohol, mass spectrum of... 

M8 Hocking, K 8handari, 8 Shell, TA Smyth. Steric and pH effects on the rate of Dakin oxidation of acylphenols. J Org Chem 47 4208-4215, 1982. 

There is no doubt that hydroquinones and hence their oxidation products, quinones, are formed by the Dakin oxidation when mechanical pulps are treated with... 

MB Hocking, M Ko, and TA Smith. Detection of intermediates and isolation of hydro-quinone monoacetate in the Dakin oxidation of p-hydroxyacetophenone. Can. J. Chem. 56 2646-2649, 1978. 

DAKIN Oxidation 84 DAKIN WEST Acylation 84 DANHEISER Annutation 85 DANISHEFSKY Sitytoxydenes 66 DARAPSKI Ammoacid synthesis 87 DARZENS - NENITZESCU Acylation 67 DARZENS Epoxide synthesis 88 DAVIDSON Oxazola synthase 89 OELEPINE Aldehyde oxidation 89 DAVIS Oxidumg reagent 90 Decker 127... 

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