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Basicity, alkylamines amines

The range of amines involved may be expanded to more basic alkylamines (Eq. 11.5) [16]. Compound 10 was obtained in moderate yield and enantioselectivity utilizing the R,R) Et FerroTANE ligand. Note that almost stoichiometric amounts of a strong Bronsted acid are required to afford the Markovnikov hydroamination product of the vinyl arene. [Pg.344]

Sulfonamides are prepared from an amine and a sulfonyl chloride in the presence of pyridine or aqueous base. The sulfonamide is one of the most stable nitrogen protective groups. Most arylsulfonamides are stable to alkaline hydrolysis and to catalytic reduction they are cleaved by Na/NH3, Na/butanol, sodium naphthalenide, or sodium anthracenide, as well as by refluxing in acid (48% HBr/cat. phenol). Sulfonamides of less basic amines such as pyrroles and indoles are much easier to cleave than those of the more basic alkylamines. In fact, sulfonamides of the less basic amines (pyrroles, indoles, and imidazoles) can be cleaved by basic hydrolysis, which is almost impossible for the alkyl amines. Because of the inherent differences between the aromatic—NH group and simple aliphatic amines, the protection of these compounds (pyrroles, indoles, and imidazoles) will be described in a separate section. One appealing property of sulfonamides is that the derivatives are more crystalline than amides or carbamates. [Pg.851]

The preferred alkaline compounds for carrying out my invention are the alkali metal and alkaline earth metal oxides, hydroxides and carbonates, and these compounds are utilized in just sufficient amount to displace the desired amine or amines. It is obvious, of course, that if the mixture of amine salts also contains free mineral acid or an ammonium salt, an additional amoimt of alkali stoichiometrically equivalent to these substances must be added. I have also found that as alkaline reagents for accomplishing this separation it is possible to use other alkylamines or methylamines of different basicity. These amines may be used for displacement together with or in place of the alkalies above mentioned. For example, dimethylamine being more basic than trim-ethylamine may be utilized to displace triethylamine from its hydrohalide salts, when utilized in stoichiometrical proportions. Similarly, diethylamine may be utilized to displace mono and triethylamine from their hydrohalide combinations. [Pg.197]

Intriguingly, the scope of amines is complementary in the former case, strongly basic alkylamines are applicable whereas the latter conditions accommodate less basic arylamines and amides. [Pg.56]

The chemistry of amines is dominated by the lone-pair electrons on nitrogen, which makes amines both basic and nucleophilic. The basicity of arylamines is generally lower than that of alkylamines because the nitrogen lone-pair electrons are delocalized by interaction with the aromatic v system. Electron-withdrawing substituents on the aromatic ring further weaken the basicity of a substituted aniline, while electron-donating substituents increase basicity. Alkylamines are sufficiently basic that they exist almost entirely in their protonated form at the physiological pH of 7.3 inside cells. [Pg.984]

ALkylamines are corrosive to copper, copper-containing alloys (brass), aluminum, 2inc, 2inc alloy, and galvani2ed surfaces. Aqueous solutions of aLkylamines slowly etch glass as a consequence of the basic properties of the amines in water. Carbon or stainless steel vessels and piping have been used satisfactorily for handling aLkylamines and, as noted above, some aLkylamines can act as corrosion inhibitors in boiler appHcations. [Pg.199]

Amines. Although the chlorination of aqueous aLkylamines is analogous to that of ammonia, mono- and diaLkylarnines generally chlorinate faster because of their higher basicities (13). Bromination rates are significantly faster than chlorination rates, and in some cases, eg, (CH2)2NH... [Pg.455]

Table 24.1 lists pXa values of some ammonium ions and indicates that there is a substantial range of amine basicities. Most simple alkylainines are similar in their base strength, with p/q/s for their ammonium ions in the narrow range 10 to 11. Aiylctmines, however, are considerably less basic than alkylamines, as are the heterocyclic amines pyridine and pyurole. [Pg.922]

As noted previously, arylamines are generally less basic than alkylamines. Anilinium ion has pKa = 4.63, for instance, whereas methylammonium ion has pfCa = 10.64. Arylamines are less basic than alkylamines because the nitrogen lone-pair electrons are delocalized by interaction with the aromatic ring tt electron system and are less available for bonding to H+. In resonance terms, aryl-amines are stabilized relative to alkylamines because of their five resonance forms. [Pg.924]

Evans and co-workers demonstrated that rhodium-catalyzed allylic amination of enantiomerically enriched acyclic unsymmetrical allylic carbonates occurs with excellent regio- and enantiospedfidty (Tab. 10.5) [35]. Interestingly, while the classical nitrogen nucleophiles furnished allylic amination products in poor yield and with modest regioselectivity, the lithium anion of N-toluenesulfonyl-N-alkylamines proved optimal, in terms of nucleophilicity and basicity. [Pg.202]

The existence of the alkylamines was predicted by J. von Liebig,1 1837 in 1849, A. Wurtz obtained the primary alkylamines and in 1851, A. W. Hofmann prepared the primary, secondary, and tertiary alkylamines, and also the alkylammonium bases or the quarternary ammonium bases in which all four atoms of the ammonium group are replaced by the alkyl radicles. The basic character of ammonia is retained by the amines, and since the alkyl radicles are themselves basic, the aliphatic amines are even more basic than ammonia itself. W. Ostwald made an estimate of the basicity of the ethyl ammonias, and found the relative strengths of these bases ... [Pg.252]

The nitrogen that reacts is the one that is a tertiary alkylamine. Of the other two nitrogens, is attached to an aromatic ring and is much less basic and less nucleophilic. The third nitrogen, , is an amide nitrogen amides are less nucleophilic than amines. [Pg.620]

The pathway of the Kabachnik-Fields reaction depends on the nature of the substrates. The amine and hydrophosphoryl compound form a complex in which either one of the partners may react with the carbonyl compound. Often, the basicity of the amine determines the reaction pathway. Weakly basic amines such as anilines, which can act as proton donors, favour the formation cf an imine, whereas alkylamines such as cyclohexylamines do not form imines ... [Pg.140]

The most conspicuous property of aliphatic amines, apart from their fishy smell, is their high basicity, which usually precludes N-alkylations under acidic reaction conditions (last reaction, Scheme 6.3). Hence, alkylation of amines with tertiary alkyl groups is not usually possible without the use of highly stabilized carbocations which can be formed under basic reaction conditions. Rare exceptions are N-alkyla-tions of amines via radicals (Scheme 4.2), copper-catalyzed propargylations (Scheme 6.3), and the addition of amines to some Michael acceptors and allyl palladium or iridium complexes. Better strategies for the preparation of tert-alkylamines include the addition of Grignard reagents to ketone-derived imines [13] or the reduction of tert-alkyl nitro compounds. [Pg.231]

Amines are weak bases. Alkylamines and ammonia are of comparable basicity, but aromatic amines are much weaker as a result of delocalization of the unshared electron pair on nitrogen to the ortho and para carbons of the aromatic ring. Amides are much weaker bases than amines because of delocalization of the unshared electron pair on nitrogen to the adjacent carbonyl oxygen. Amides are stronger Bronsted acids than amines because of the partial positive charge on the amide nitrogen and resonance in the amidate anion. [Pg.211]

As soon as the first SMA was prepared, the question arose as to the structure and consequently of the basicity of this new type of amine. As is true for N-alkylamines, it could be expected that the silylmethyl group would make MSMA more basic than ammonia through its +1 effect. Conversely, the ability of a silicon atom to accept electrons from a nucleophile, as is the case with silatranes and o-silylbenzylamines,20... [Pg.178]


See other pages where Basicity, alkylamines amines is mentioned: [Pg.958]    [Pg.1287]    [Pg.419]    [Pg.958]    [Pg.958]    [Pg.328]    [Pg.677]    [Pg.336]    [Pg.778]    [Pg.955]    [Pg.190]    [Pg.955]    [Pg.196]    [Pg.341]    [Pg.144]    [Pg.167]    [Pg.206]    [Pg.212]    [Pg.401]    [Pg.86]    [Pg.130]    [Pg.221]    [Pg.24]    [Pg.962]    [Pg.131]    [Pg.42]   
See also in sourсe #XX -- [ Pg.921 , Pg.922 ]

See also in sourсe #XX -- [ Pg.754 , Pg.755 ]

See also in sourсe #XX -- [ Pg.948 , Pg.949 ]




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Alkylamine

Alkylamine basicity

Alkylamines

Alkylamines basicity

Amination alkylamination

Amines alkylamines

Amines basicity

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