Primary hydrogen atoms

This parameter correlates well with the rate constant for abstraction of the different kinds of hydrogen atoms, primary, secondary and tertiary in hydrocarbons and in alkyl fluorides. It works, both for a relatively neutral radical like methyl, and for electrophilic radicals like trifluoromethyl, because it takes into consideration both SOMO/OMO and SOMO/UMO interactions.979... 

For aliphatic alcohols, the rate of oxidation is related to the ease of abstraction of hydrogen atoms. Primary alcohols, in general, are more easily oxidized than isomeric secondary or tertiary alcohols. Benzyl alcohol is oxidized fastest of all. 

Chlorine is relatively unselective, it does not discriminate greatly among the different types of hydrogen atoms (primary, secondary, and tertiary) in an alkane. 

The cyclic carbonate of benzoin (4,5-diphenyl-l,3-dioxol-2-one, prepared from benzoin and phosgene) blocks both hydrogen atoms of primary amines after dehydration acid stable, easily crystallizable Sheehan oxazolinones are formed, which are also called Ox derivatives. The amine is quantitatively deblocked by catalytic hydrogenation in the presence of 1 equiv. of aqueous acid (J.C Sheehan, 1972, 1973 M.J. Miller, 1983). An intelligent application to syntheses of acid labile -lactams is given in the previous section (p. 161). 

A secondary alkyl radical is more stable than a primary radical Bromine therefore adds to C 1 of 1 butene faster than it adds to C 2 Once the bromine atom has added to the double bond the regioselectivity of addition is set The alkyl radical then abstracts a hydrogen atom from hydrogen bromide to give the alkyl bromide product as shown m... 

Breaking a bond to a primary hydrogen atom m propene requires less energy by 42 kJ/mol (10 kcal/mol) than m propane The free radical produced from propene is allylic and stabilized by electron delocalization the one from propane is not... 

Between 6 and 30% of the radical attack on butane may occur at the primary hydrogen atoms (213). Since ca 6% of the butane goes to or through butyric acid (22), the middle of this range does not seem unreasonable. Because it is much more resistant to oxidation than its precursors or coproducts, acetic acid (qv) is the main product of butane LPO. 

Mannich reaction is the condensation between formaldehyde, ammonia, or a primary or secondary amine (preferably as the hydrochloride), and a compound containing at least one active hydrogen atom... 

Autocatalysis may arise when the nucleophilic atom of the reagent is bound to a hydrogen atom which is eventually eliminated during the reaction. This occurs with neutral reagents such as primary or secondary amines, thiols, and alcohols. If the displaced group (usually an anion) is a sufficiently weak base, the proton is effectively transferred to any basic reactant. Hence, the best known examples of autocatalysis involve chloro-A-heteroaromatic compounds as the substrates. 

The competitive method employed for determining relative rates of substitution in homolytic phenylation cannot be applied for methylation because of the high reactivity of the primary reaction products toward free methyl radicals. Szwarc and his co-workers, however, developed a technique for measuring the relative rates of addition of methyl radicals to aromatic and heteroaromatic systems. - In the decomposition of acetyl peroxide in isooctane the most important reaction is the formation of methane by the abstraction of hydrogen atoms from the solvent by methyl radicals. When an aromatic compound is added to this system it competes with the solvent for methyl radicals, Eqs, (28) and (29). Reaction (28) results in a decrease in the amount... 

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