Oxidation, alcohols phenols

Sulfation andSulfamation. Sulfamic acid can be regarded as an ammonia—SO. complex and has been used thus commercially, always in anhydrous systems. Sulfation of mono-, ie, primary and secondary, alcohols polyhydric alcohols unsaturated alcohols phenols and phenolethylene oxide condensation products has been performed with sulfamic acid (see Sulfonation and sulfation). The best-known appHcation of sulfamic acid for sulfamation is the preparation of sodium cyclohexylsulfamate [139-05-9] which is a synthetic sweetener (see Sweeteners). 

Equation 20 is the rate-controlling step. The reaction rate of the hydrophobes decreases in the order primary alcohols > phenols > carboxylic acids (84). With alkylphenols and carboxylates, buildup of polyadducts begins after the starting material has been completely converted to the monoadduct, reflecting the increased acid strengths of these hydrophobes over the alcohols. Polymerization continues until all ethylene oxide has reacted. Beyond formation of the monoadduct, reactivity is essentially independent of chain length. The effectiveness of ethoxylation catalysts increases with base strength. In practice, ratios of 0.005—0.05 1 mol of NaOH, KOH, or NaOCH to alcohol are frequendy used. 

With Phenols. The 2-hydroxylethyl aryl ethers are prepared from the reaction of ethylene oxide with phenols at elevated temperatures and pressures (78,79). 2-Phenoxyethyl alcohol is a perfume fixative. The water-soluble alkylphenol ethers of the higher poly(ethylene glycol)s are important surface-active agents. They are made by adding ethylene oxide to the alkylphenol at ca 200°C and 200—250 kPa (>2 atm), using sodium acetate or... 

Muconic acid has been obtained in a variety of ways. The procedures that seem most important from a preparative point of view are by treatment of ethyl o ,5-dibromoadipate with alcoholic potassium hydroxide, by condensation of glyoxal (as the sodium bisulfite addition product) with malonic acid, by heating ethyl l-acetoxy-l,4-dihydromuconate (obtained by condensing ethyl oxalate and ethyl crotonate, acetylating, and reducing),and by oxidation of phenol with peracetic acid. ... 

Oxidative reactions frequently represent a convenient preparative route to synthetic intermediates and end products This chapter includes oxidations of alkanes and cycloalkanes, alkenes and cycloalkenes, dienes, aromatic fluorocarbons, alcohols, phenols, ethers, aldehydes and ketones, carboxylic acids, nitrogen compounds, and organophosphorus, -sulfur, -selenium, -iodine, and -boron compounds... 

Previous studies by Sorokin with iron phthalocyanine catalysts made use of oxone in the oxidation of 2,3,6-trimethylphenol [134]. Here, 4 equiv. KHSO5 were necessary to achieve full conversion. Otherwise, a hexamethyl-biphenol is observed as minor side-product. Covalently supported iron phthalocyanine complexes also showed activity in the oxidation of phenols bearing functional groups (alcohols, double bonds, benzylic, and allylic positions) [135]. Besides, silica-supported iron phthalocyanine catalysts were reported in the synthesis of menadione [136]. 

The oxidation of phenol in alcoholic media by a morpholine complex of Cu(II) (as a model for tyrosinase) to give 4,5-dimorpholino-orr/jo-benzoquinone in 64 %... 

Schemes 6-10 Oxidative addition of alcohol, phenol, and water to cationic iridium phosphine complex 67...

The most characteristic reaction of butadiene catalyzed by palladium catalysts is the dimerization with incorporation of various nucleophiles [Eq. (11)]. The main product of this telomerization reaction is the 8-substituted 1,6-octadiene, 17. Also, 3-substituted 1,7-octadiene, 18, is formed as a minor product. So far, the following nucleophiles are known to react with butadiene to form corresponding telomers water, carboxylic acids, primary and secondary alcohols, phenols, ammonia, primary and secondary amines, enamines, active methylene compounds activated by two electron-attracting groups, and nitroalkanes. Some of these nucleophiles are known to react oxidatively with simple olefins in the presence of Pd2+ salts. Carbon monoxide and hydrosilanes also take part in the telomerization. The telomerization reactions are surveyed based on the classification by the nucleophiles. 

Related (diisopropoxyphosphoryl)- and (diisobutoxyphosphoryl)formonitrile oxides (114), generated in basic media from the corresponding oximes react in situ with alcohols, phenols, alkanethiols, thiophenols, aliphatic and aromatic primary amines, hydrazines and hydrazides as well as 4-aminoantipyryne to give hydroxymates, thiohydroxymates, and amidoximes, respectively. It is important to note that the addition is stereoselective and gives E-adducts with the exception of (i-Pr0)2P(0)C( N0H)0Me, which is formed as a 1 1 mixture of E and Z isomers. 

Aryl and alkyl hydroxylations, epoxide formation, oxidative dealkylation of heteroatoms, reduction, dehalogenation, desulfuration, deamination, aryl N-oxygenation, oxidation of sulfur Oxidation of nucleophilic nitrogen and sulfur, oxidative desulfurization Oxidation of aromatic hydrocarbons, phenols, amines, and sulfides oxidative dealkylation, reduction of N-oxides Alcohol oxidation reduction of ketones Oxidative deamination... 

Abstract The basic principles of the oxidative carbonylation reaction together with its synthetic applications are reviewed. In the first section, an overview of oxidative carbonylation is presented, and the general mechanisms followed by different substrates (alkenes, dienes, allenes, alkynes, ketones, ketenes, aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, phenols, amines) leading to a variety of carbonyl compounds are discussed. The second section is focused on processes catalyzed by Pdl2-based systems, and on their ability to promote different kind of oxidative carbonylations under mild conditions to afford important carbonyl derivatives with high selectivity and efficiency. In particular, the recent developments towards the one-step synthesis of new heterocyclic derivatives are described. 

Chemical instability of medicinal agents may take many forms, because the drugs in use today are of such diverse chemical constitution. Chemically, drug substances are alcohols, phenols, aldehydes, ketones, esters, ethers, acids, salts, alkaloids, glycosides, and others, each with reactive chemical groups having different stability characteristics. Chemically, the most frequently encountered destructive processes involve hydrolysis and oxidation. 

PMMAs are attacked by esters, ethers, ketones, aldehydes, aromatic and halogenated hydrocarbons, certain alcohols, oxidizing agents, phenols Possible for special grades... 

Kinetic studies on the oxidations of cyclohexene, benzyl alcohol, phenol, and trans-stiVoene by [Ru (0)(tpy)(bpy(P03H2)2)] (bpy(P03H2)2) = 2,2 -bipyridine-4,4 -diphosphonic acid adsorbed to thin films of Ti02 nanoparticles on glass have been reported. There is evidence for initial two-electron steps to give Ru intermediates in all four cases. 

Phenols. Phenols are oxidized via hydroxylation to yield a diphenolic molecule. This hydroxylation is either ortho or para to the primary alcohol. Phenols may also be conjugated with either glucuronic acid or sulfuric acid. 

One of the most versatile methods for the preparation of 1,1-disubstituted X -phosphorins 124 was discovered by Stade who found that X -phosphorins 2 can be oxidized (mercuric acetate gives the best results) in the presence of alcohols or phenols in benzene to 1.1-dialkoxy- or l.l-diphenoxy-X -phosphorins 124. The first step is probably a reaction of the soft X -phosphorin- jr-system with the soft acid Hg which by electron transfer leads to the weakly electrophilic radical cation 58. This is then attacked by alcohol or phenol - or as Hettche has found by other nucleophiles such as an amine to form by loss of a proton the neutral X -phosphorin radical 59. This radical is oxidized once again by mercury ions leading to the formation of elemental mercury and the strongly electrophilic, short-lived X -phosphorin cation 127, which is immediately attacked by alcohol, phenol or amine. Loss of a proton then leads to the X -phosphorin 124. It is also conceivable that 59 can couple directly with a radical to form 124 (Method E, p. 82). 

The ready formation of benzylic hydroperoxides is used in industrial oxidations, as in the synthesis of propylene oxide and phenol (see Sections 9.5.2 and 9.5.4, respectively). In contrast with autoxidation of alkenes, where various secondary processes may follow, autoxidation of arenes is less complicated. Chain termination of 99 may lead to an alcohol and aldehyde [Eq. (9.151)], and the rapid autoxidation of the latter may produce the corresponding carboxylic acid [Eq. (9.152)] ... 

Phenols. The condensation of ethylene oxides with phenols ha not been investigated so extensively as that of alcohols, but generally follows a similar course. 

Linear ethoxylates are tine preferred raw materials for production of ether sulfates used in detergent formulations because of uniformity, high purity, and biodegradahility, The alkyl chain is usually in the C y. to Cy range having a molar ethylene oxide alcohol ratio of anywhere from 1 1 to 7 1. Propoxylates, ethoxylates, and mixed alkoxylates of aliphatic alcohols or alkyl phenols are sulfated for use in specialty applications. 

It is possible to oxidize alcohols in the presence of free phenols,217 although many times phenols are protected for solubilizing purposes. 

IBX possesses a great selectivity for the reaction with alcohols and the interaction with other functional groups normally demands more severe experimental conditions. According to Santagostino et al.,83 phenols and anilines react with IBX producing complex and dark colored reaction mixtures. Nevertheless, it is possible to selectively oxidize alcohols in the presence of certain phenols that are not very electron rich.88b... 

It is possible to oxidize alcohols with TPAP in the presence of free phenols.95 Although, there is one instance in which it has been published that, unless a phenol is acetylated, an oxidation with TPAP fails.73 Oxidation-prone heterocycles, such as pyrroles96 and indoles,97 are not affected by TPAP during the oxidation of alcohols. 

Certain dinuclear iron complexes are found to be efficient catalysts for the oxidation of primary and secondary alcohols with hydrogen peroxide.214 Metalloporphyrins are used as peroxidase mimics in the oxidation of phenol with hydrogen peroxide. 

Oxidations of variously-substituted 4-alkyl- and 4-alkoxyphenols with BAIB or BTIB in alcoholic solvents provide ready access to alkoxy(alkyl)- and dialkoxycyclohexadienones (Scheme 23) [70-72]. Dienone formation is generally attributed to the capture of aryloxyiodane and/or aryloxenium ion intermediates with the alcohol [73]. Related C-0 bond forming oxidations of phenols with BAIB and BTIB, including intramolecular cyclizations leading to spiro-dienones, are summarized in several reviews [1 - 3,74]. 

---