Yields primary yield

Alcohol synthesis via the reaction of Grignard reagents with carbonyl com pounds (Section 14 6) This is one of the most useful reactions in synthetic organ ic chemistry Grignard reagents react with formaldehyde to yield primary alco hols with aldehydes to give secondary alcohols and with ketones to form terti ary alcohols... 

The most obvious way to reduce an aldehyde or a ketone to an alcohol is by hydro genation of the carbon-oxygen double bond Like the hydrogenation of alkenes the reac tion IS exothermic but exceedingly slow m the absence of a catalyst Finely divided metals such as platinum palladium nickel and ruthenium are effective catalysts for the hydrogenation of aldehydes and ketones Aldehydes yield primary alcohols... 

Grignard reagents react with ethylene oxide to yield primary alcohols containing two more carbon atoms than the alkyl halide from which the organometallic compound was prepared... 

Linear alpha-olefins are the source of the largest volume of ahphatic amine oxides. The olefin reacts with hydrogen bromide in the presence of peroxide catalyst, to yield primary alkyl bromide, which then reacts with dimethylamine to yield the corresponding alkyl dimethyl amine. Fatty alcohols and fatty acids are also used to produce amine oxides (Fig. 1). 

Hydrogenolysis of propylene oxide yields primary and secondary alcohols as well as the isomeri2ation products of acetone and propionaldehyde. Pd and Pt catalysts favor acetone and 2-propanol formation (83—85). Ni and Cu catalysts favor propionaldehyde and 1-propanol formation (86,87). 

Attempted diazotization in dilute acid sometimes yields primary nitroso compounds. Reactions of 3- and 5-amino-1,2,4-thiadiazoles with sodium nitrite and acid give primary nitrosamines (e.g. 432->433) (65AHC(5)n9) which can be related to the secondary nitrosamines (434) prepared in the normal way. 1-Substituted 5-aminotetrazoles with nitrous acid give stable primary nitrosamines (435). Primary nitrosamines have been isolated in the imidazole series. 

Cl3SiH, Et3N, CH2CI2, 4-48 h, 25-80°, 80-95° yield. Primary, secondary, tertiary, allylic, propargylic, orbenzylic derivatives are cleaved by this method. 

The various Grignard reagents react with a variety of aldehydes and ketones to yield primary alcohols (yield, 27 6%), secondary alcohols (yield, 13 1-71 1%), and tertiary alcohols (yield, 24 9-81 7%) Products of the reactions with acetone are given in Table 4... 

The Cunius degradation of acyl azides prepared either by treatment of acyl halides with sodium azide or trimethylsilyl azide [47] or by treatment of acyl hydrazides with nitrous acid [f J yields pnmarily alkyl isocyanates, which can be isolated when the reaction is earned out in aptotic solvents If alcohols are used as solvents, urethanes are formed Hydrolysis of the isocyanates and the urethanes yields primary amines. 

The type of alcohol produced depends on the carbonyl compound. Substituents present on the car bonyl group of an aldehyde or ketone stay there—they become substituents on the carbon that bears the hydroxyl group in the product. Thus as shown in Table 14.3 (following page), formaldehyde reacts with Grignard reagents to yield primary alcohols, aldehydes yield secondary alcohols, and ketones yield tertiary alcohols. 

N02C6H40C02Bn, Pyr, DMF, 26°, 24 h, 74% yield. Primary amines are selectively protected over secondary amines, but anilines are insufficiently nucleophilic to react with this reagent. ... 

This group was developed for the protection of amino acids. It is formed from 4-ethoxy-l,l,l-trifluoro-3-buten-2-one in aqueous sodium hydroxide (70-94% yield). Primary amino acids form the Z-enamines, whereas secondary amines such as proline form the -enamines. Deprotection is achieved with 1-6 N aqueous HCl in dioxane at rt. ... 

The fonnadoo of C-N bonds can be achieved by using chkmumoe or O-methylhydrosylamine to yield primary amines aiyl diazonium salts yield azo-compounds ... 

Alcohols are among the most versatile of all organic compounds. They occur widely in nature, are important industrial 7, and have an unusually rich chemistry. The most widely used methods of alcohol synthesis start with carbonyl compounds. Aldehydes, ketones, esters, and carboxylic acids are reduced by reaction with LiAlH4. Aldehydes, esters, and carboxylic acids yield primary alcohols (RCH2OH) on reduction ketones yield secondary alcohols (R2CHOH). 

Grignard reagents react with oxetane, a four-membered cyclic ether, to yield primary alcohols, but the reaction is much slower than the corresponding reaction with ethylene oxide. Suggest a reason for the difference in reactivity between oxetane and ethylene oxide. 

Conversion of Acid Chlorides into Alcohols Reduction Acid chlorides are reduced by LiAJH4 to yield primary alcohols. The reaction is of little practical value, however, because the parent carboxylic acids are generally more readily available and can themselves be reduced by L1AIH4 to yield alcohols. Reduction occurs via a typical nucleophilic acyl substitution mechanism in which a hydride ion (H -) adds to the carbonyl group, yielding a tetrahedral intermediate that expels Cl-. The net effect is a substitution of -Cl by -H to yield an aldehyde, which is then immediately reduced by UAIH4 in a second step to yield the primary alcohol. 

Conversion of Esters into Alcohols Reduction Esters are easily reduced by treatment with L1AIH4 to yield primary alcohols (Section 17.4). 

Ammonia, primary amines, and secondary amines can all be used in the reductive amination reaction, yielding primary, secondary, and tertiary amines, respectively. 

Alternatively, secondary and tertiary carboxylic acid methyl or ethyl esters react (6) with two equivalents of trimethylsilylmethy] lithium (prepared in pentane) to give /1-ketosilanesingood (80-96%) yield. Primary esters also give /3-ketosilanes, but in lower (45%) yield. 

Decay of donor-acceptor complex through electron transfer to solvent molecules yielding primary radical ion pairs ... 

Scavenging experiments in hydrocarbon liquids (Rzad et al, 1970 Kimura and Fueki, 1970) tend to give low observed ionization yield, although the primary yield may be greater. The situation is similar for free-ion yield measurement under a relatively large external field. Both processes require large extrapolations to obtain the W value. 

First, we will review the stationary primary yield of the hydrated electron at neutral pH for low-LET radiation at a small dose. The primary species are eh, H30+, H, OH, H2, and H2Or Material balance gives... 

Since charge conservation requires g(eh) = g(H30+), the latter yield will not be considered further. The chemical measurement of g(eh) uses Eq. (6.2) and the measurements of primary yields of H, H2, OH, and H202 in a suitable system. Various systems may be used for this purpose (see Draganic and Draganic , 1971). For example, in methanol solution radiolysis, H2 is produced by the reaction H + CH3OH—H2 + CH2OH. Therefore, in this system, G(H2) = g(H2) + g(H). If, in addition, there is excess oxygen, the H atoms would be removed by the reaction H + 02 H02. Therefore, from these two measurements, both g(H) and g(H2) may be obtained. 

The primary yield of H,02 may be obtained by measuring the H202 yield in a system containing excess oxygen. In this case, hydrated electrons and H atoms are converted into O,- and H02, respectively, with an equilibrium between these species ... 

In this manner, one obtains g(eh) = 2.7 at neutral pH. In the past, considerable controversy existed about these primary yields in view of work at different laboratories using slightly different techniques, under somewhat different conditions, and so forth (see Farhataziz et al, 1966). Table 6.1 illustrates the results and possible reconciliation. The controversies have been basically resolved, and most workers now agree that g(eh) = g(OH) = 2.7 0.1, g(H) = 0.56 0.05,... 

Adapted from Farhataziz et al. (1966). Note that these are observed yields from which the primary yields are calculated and referred to in the text. 

Farhataziz et al. (1974a, b) studied the effect of pressure on eam and found that as the pressure is increased from 9 bar to 6.7 Kbar at 23° (1) the primary yield of e decreases from 3.2 to 2.0 (2) hv increases from 0.67 to 0.91 eV (3) the half-width of the absorption spectrum on the high-energy side increases by 35% and (4) the extinction coefficient decreases by 19%, which is similar to eh. The pressure effects are consistent with the large volume of ean (98 ml/M), whereas the reduction in the observed primary yield at 0.1 ps is attributable to the reaction eam + NH4+. Some of the properties of eam have been discussed by several authors in Solvated Electron (Hart, 1965). 

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