Alcohols in Basic Media

This same reducing agent has been successfully employed in the synthesis of 2-amino-l-phenyl-l-propanol (70%). The formation of amino alcohols by catalytic hydrogenation over Raney nickel catalyst has been accomplished. However, because of the instability of the nitro alcohols in basic media, lower amines are also formed. 

Formation of Bonds between Hydrogen and Transition Metals 227 1.10.8 by Hydrogen Transfer to the Metal 1.10.8.1. from Alcohols in Basic Media. 

Birnessite has also been synthesized from amorphous manganese oxides prepared from the reduction of Mn04 by alcohols in basic media (reduction method) [21,25,26]. The reaction process starts with the formation of an amorphous manganese oxide, followed by the crystallization of birnessite from amorphous manganese oxide. Increasing the aging temperature can accelerate the crystallization rate. This reduction reaction process is similar to the redox reaction process. 

Vinyl chloride reacts with sulfides, thiols, alcohols, and oximes in basic media. Reaction with hydrated sodium sulfide [1313-82-2] in a mixture of dimethyl sulfoxide [67-68-5] (DMSO) and potassium hydroxide [1310-58-3], KOH, yields divinyl sulfide [627-51-0] and sulfur-containing heterocycles (27). Various vinyl sulfides can be obtained by reacting vinyl chloride with thiols in the presence of base (28). Vinyl ethers are produced in similar fashion, from the reaction of vinyl chloride with alcohols in the presence of a strong base (29,30). A variety of pyrroles and indoles have also been prepared by reacting vinyl chloride with different ketoximes or oximes in a mixture of DMSO and KOH (31). 

Because of the presence of alkali in Raney nickel, ketones are hydrogenated over this catalyst to yield the more stable, equatorial alcohol e.g. 59) as the predominant product, Similar results can be expected with platinum in basic media or with platinum oxide in an alcoholic solvent since this catalyst also contains basic impurities. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Hydrogenation of carbonyls, or incipient carbonyls such as phenols (86), in lower alcohol solvents may result in the formation of ethers. The ether arises through formation of acetals or ketals with subsequent hydrogenolysis. The reaction has been made the basis of certain ether syntheses (45,97). Reaction of alcohols with carbonyls may be promoted by trace contamination, such as iron in platinum oxide (22,53), but it is also a property of the hydrogenation catalyst itself. So strong is the tendency of palladium-hydrogen to promote acetal formation that acetals may form even in basic media (61). 

The reaction of 3,4-bis(benzenesulfonyl)furoxan with alcohols and thiols in basic media affords a variety of alkoxy-and alkylthio-substituted (benzenesulfonyl)furoxans. For these derivatives a paramount problem is to determine the position (3- or 4-) of the substitution in the furoxan ring. The structures of these derivatives were assigned on the basis of both chemical and NMR evidence. In particular, 13C NMR substituent constants were obtained by NMR study of suitable furoxan models. By assuming a complete additivity of the substituent effects at the furoxan ring, these values were used for structural determination <1997FES405>. 

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. 

The reaction between an alcohol and the halide of a non-metal (usually phosphorus) is well known in the synthesis of alkyl halides. Usually the reaction is conducted with an excess of alcohol and/or in basic media thus... 

Aldehydes have been formed from alcohols by the use of other oxidizing agents. Dihydroxyacetone has been oxidized with excess cupric acetate to hydroxypyruvic aldehyde in 87% yield. p-Cyanobenzyl alcohol treated at 0° with a chloroform solution of nitrogen tetroxide gives practically pure p-cyanobenzaldehyde (90%). Aromatic alcohols containing nitro groups have been oxidized to the corresponding nitro aldehydes with concentrated nitric acid, e.g., o- and p-nitrobenzaldehydes (80-85%). m-Nitrobenzenesulfonic acid in basic media has been used for the oxidation of substituted benzyl alcohols, most satisfactorily for the water-soluble phenolic benzyl alcohols. Selenium dioxide, or less effectively tellurium dioxide, oxidizes benzyl alcohol slowly to benzaldehyde. ... 

Besides, it has been shown that palladium is promising for direct alcohol fuel cells applications as it is very active for ethanol electro-oxidation in basic media and that its electroactivity is even higher than that of platinum. Recently, Pd nanoballs and nanowires synthesized by radiolysis in hexagonal mesophases have shown an important elec-trocatalytic activity for ethanol electro-oxidation. ... 

Hydrogenations of cyclohexanones in basic media leads to the formation of the more stable, equatorial alcohol, 18, as the primary product (Eqns. 18.18-19). With basic Raney nickel catalysts, the predominance of equatorial alcohol has been shown to arise from the isomerization of the initially produced axial alcohol under hydrogenation conditions. The use of platinum oxide with its alkaline impurity also leads to extensive equatorial alcohol formation unless acetic acid is used as the solvent. This basic impurity was shown to be... 

---