Oxidation primary and secondary alcohol

Bromine or chlorine dissolved in hexamethylphosphoric triamide [680-31-9] (HMPT) with a base, eg, NaH2PO, present, oxidizes primary and secondary alcohols to carbonyl compounds in high yield (38). 

Compounds containing susceptible C—H bonds can be oxidized to alcohols. " Nearly always, the C—H bond involved is tertiary, so the product is a tertiary alcohol. This is partly because tertiary C—H bonds are more susceptible to free-radical attack than primary and secondary bonds and partly because the reagents involved would oxidize primary and secondary alcohols further. In the best method, the reagent is ozone and the substrate is absorbed on silica gel. Yields as high as 99% have been... 

DiazotriazoIe 28 (R = Ph) reacted with /-butyl alcohol and 2-propanol to give compounds 148 and 149 (Scheme 40) in comparable yields by carbenic C—H insertion and nucleophilic substitution, respectively [81DIS(B)(42)1892]. In the case of 2-propanol, an oxidation-reduction process, to give the parent triazole and acetone, was also observed to a smaller extent. Also, it was previously reported that 3-diazotriazole 28 (R = COOH) oxidizes primary and secondary alcohols to the corresponding aldehydes and ketones (1898LA33). 

Oxidation of alcohols. These reagents react at low temperatures (-78°) in ch2ci2 to form a zwitterionic complex (I), which loses C02 at O 1 to form 2. The complex 1 in the presence of triethylamine oxidizes primary and secondary alcohols to the corresponding carbonyl compounds in 70-90% yield. 

Oxidations. The reagent 1 oxidizes primary and secondary alcohols to carbonyl compounds in fair to good yield. It is not useful for epoxidation of simple alkenes, but it epoxidizes allylic alcohols to form a,/ -epoxy alcohols in 60-70% yield, In general, this epoxidation is more stcreospccific than that observed with r-butyl hydroperoxide in combination with Mo(CO)6 (9, 81-82). 

Nevertheless, normally it is possible to selectively oxidize primary and secondary alcohols with PDC without affecting tertiary allylic alcohols.159... 

Because of steric constrains, the activation of primary and secondary alcohols is quicker than the activation of tertiary alcohols. Therefore, normally, it is possible to oxidize primary and secondary alcohols, with no interference from elimination reactions of tertiary alcohols present in the same molecule.220... 

Oxidation of aUylic and henzylic alcohols. The reagent oxidizes primary and secondary alcohols very slowly, but allylic and benzylic alcohols arc oxidized to the... 

Oxidation of alcohols. In the presence of catalytic amounts of pyridinium dichromate, this peroxide can oxidize primary and secondary alcohols to the corresponding carbonyl compounds in 70-100% yield. Reactions catalyzed by dichloro-tris(triphenylphosphinc)ruthenium are useful for highly selective oxidation of primary allylic and benzylic alcohols m the presence of secondary ones. 

Oxidation. This mild oxidizing reagent can be used for selective oxidation of benzylic and allylic alcohols. Complete conversnm requires 3 equiv. of oxidant. Primary and secondary alcohols are oxidized slowly in refluxing chloroform, but require a large excess of oxidant. An example is the selective oxidation of 1-phenyl-1,3-propanediol to 3-hydroxy-1-phenyl-1-propanone (52% yield). 

Historically, the first supported oxidizing reagent, reported by Fdtizon and Golfier, was silver carbonate on celite (another diatomaceous earth). This was obtained by precipitation of the reagent onto its support. Ag2C03 on celite smoothly oxidizes primary and secondary alcohols, a,(o-diols, hydroquinones and amines. The main practical asset of the reagent is that it avoids the need to filter off finely divided silver salts after reaction. 

One of the best activators for dimethyl sulfoxide is the complex of sulfur trioxide/pyridine, which in the presence of triethylamine rapidly oxidizes primary and secondary alcohols to aldehydes and ketones in very good yields at ambient temperature. This reagent also allows the very use l conversion of allylic alcohols to the conesponding a,p-unsaturated carbonyl compounds. A further advantage of this procedure over many of the others is the ease of work-up, especially over the dimethyl sulfoxide-dicy-clohexylcarbodiimide method. 

This oxidation reagent is obtained by addition of tetra-n-butylammonium chloride to an aqueous solution of chromium trioxide. It oxidizes primary and secondary alcohols to carbonyl compounds in generally good yield. The main advantages are the homogeneous conditions and the requirement for only a small excess of oxidant. ... 

The research that involves the end-of-process treatments to eliminate pollutants is termed green chemistry. As Ronald Breslow (Columbia University) pointed out, concern for the environment is as old as the biblical injunction, hurt not the earth, neither the sea, nor the trees. The following example indicates approaches to the environmentally benign chemistry. The process described is high yielding with water as the by-product. Sato et al. have developed an efficient, environmentally friendly method for oxidizing primary and secondary alcohols (Scheme 8). The Japanese... 

The BH3-Me2S complex is a reagent to reduce carboxylic acids. Dess-Martin periodinane (33) is one of the standard reagents used to oxidize primary and secondary alcohols. 

Aldehydes are oxidized not only by the same reagents that oxidize primary and secondary alcohols—permanganate and dichromate—but also by the very mild oxidizing agent silver ion. Oxidation by silver ion requires an alkaline medium to prevent precipitation of the insoluble silver oxide, a complexing agent is added ammonia... 

Crich, D., Neelamkavil, S. Improved method of oxidizing primary and secondary alcohols by Swern or Corey-Kim oxidation using a recyclable fluorous sulfoxide as the oxidizing agent. WO 2002-US19274 2003002526, 2003 (The Board of Trustees of the University of Illinois, USA). 

Oxidizing agent. Parikh and Doering10 report a novel reagent consisting of sulfur trioxide, conveniently in the form of the pyridine complex, and DMSO in the presence of triethylamine. The reagent oxidizes primary and secondary alcohols to aldehydes and ketones rapidly at room temperature. It oxidizes allylic alcohols to the corresponding a -unsaturated carbonyl compounds. 

Dimethyl sulfoxide-Sulfur trioxide [1, 309, before references]. The combination of DMSO and sulfur trioxide, in the form of the pyridine complex, in the presence of trimethylamine oxidizes primary and secondary alcohols in good yield to aldehydes and ketones, respectively.55 The reaction usually is complete within minutes and the products are isolated by acidification and precipitation with water. The reagent also oxidizes allylic alcohols to the corresponding a,fi-unsaturated carbonyl compounds. One advantage over the DMSO-DCC method is that the elaborate purification required when dicyclohexylurea is a product can be dispensed with. Testosterone, with a 17/3-hydroxyl group, was oxidized toA -androstene-3,17-dione very rapidly the 17-epimer required a period of 35 min. 

Full details for preparation of this tetravalent iodine compound arc now available.1 Since explosions have been reported in the preparation, the directions should be followed with care. Moreover, the reagent is sensitive to moisture, which converts it into iodosylbenzoic acid, also reported as explosive. The periodinane oxidizes primary and secondary alcohols rapidly and efficiently to carbonyl compounds without further oxidation to acids. Bcnzylic and allylic alcohols can be selectively oxidized. It does not react with sulfides or vinyl ethers. The iodine-containing by-product can be removed by hydrolysis to 2-iodosylbcnzoic acid. 

It is mainly on the industrial scale that catalytic dehydration of alcohols becomes important, but it has been used in the laboratory particularly for preparation of the lower alkenes such as ethylene, propene, and butene. The most suitable catalysts are y-alumina, thorium dioxide, and blue tungsten oxide. Primary and secondary alcohols are usually dehydrated in the gas phase at 250-450° high-boiling tertiary alcohols are dehydrated without need for a catalyst when they are heated at 150-200° (see page 814). 

Oxidation. Primary and secondary alcohols are readily oxidized to carbonyl compounds by bromine-hexamethylenetetramine (88-96% yield). 

Oxidation. This compound has been in the literature for some time, but was recognized as a useful oxidation reagent only recently by Corey and Suggs. It oxidizes primary and secondary alcohols in yields equal to or greater than those obtained with Collins reagent (4, 215-216) and has the advantage that a large excess is not necessary. The oxidations are usually conducted in methylene chloride at room temperature (1-2 hr.). With acid-sensitive substrates, the reaction can be buffered with sodium acetate as in the last example. 

Manganese dioxide is capable of oxidizing alcohols to ketones or aldehydes. The reaction proceeds via a radical intermediate (see below), producing MnO (which is Mn +) as the byproduct. Manganese dioxide is an important reagent in organic synthesis since it oxidizes primary and secondary alcohols to the aldehyde or ketone, respectively, in neutral media.This reaction was discovered by Ballet al when they precipitated manganese dioxide and used it to convert vitamin A (94) to retinal (95) in 80% yield. 49... 

Compound L must, therefore be an alcohol. It is indicated that L reacts with chromic acid to give M. This indicates that L must be either a primary or secondary alcohol since chromic acid is a strong oxidizing agent that readily oxidizes primary and secondary alcohols to... 

Chloro-l,3-dimethylimidazolium chloride (DMC) [26] (R =R = Me, L = H in 11, Scheme 4.8a) not only acts as a powerful dehydration agent but also has unique and versatile abilities to chlorinate primary alcohols, to oxidize primary and secondary alcohols and to reduce sulfoxides and so on. In addition, DMC easily reacts with amines to yield the corresponding guanidines. Thus, methods of preparing monocyclic and bicyclic systems by application of DMC chemistry in the key steps have been developed [27] the reaction of DMC-type chloroamidine compounds with amines for trisubstituted mono-cyclic guanidines [27a] (Scheme 4.8a), the intramolecular cyclization of thiourea derivatives after activation with DMC for monosubstituted or disubstituted monocyclic and bicyclic guanidines [27b] (Scheme 4.8b), and the DMC mediated cyclization of... 

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