Amines dialkylamines

Secondary amines (dialkylamines, benzyl tort-butyl amines and cyclic amines) can be oxidized to the nitrones using hydrogen peroxide in the presence of catalysts like Na2W04 or SeOi (equation 74)". ... 

Furthermore, [Pd(Triphos)](CF3 803)2 has been used as an effective catalyst for the addition of amine to alkyne, and the vinyl carbamate derivatives can be prepared in one step from acetylene, CO2, and one of the following amines dialkylamine, morpholine, piperidine, and pyrrolidine, using RuCl3 3H20 or [RuCl2(norbornadiene)]n as the catalyst. In addition, the preparation of vinyl phenyl ethers has been modified using tributyl(vinyl)tin or 2,4,6-trivinylcyclotriboroxane-pyridine complex as the vinyl source. 

There are two major differences between the reduction of imines and aldehydes by 2-tol imines are reduced more rapidly than aldehydes and give amine complexes as stable products (Scheme 10) [57]. Substituents on the imine affect the rate of reduction and the stability of the amine complex product. PhCH=NPh reacts with 2-lol in THF at —40°C at a rate about 150 times faster than benzaldehyde. The more basic imine PhCH=NCH2Ph reacts with 2-lol in THF at —57°C at a rate about 15 times faster than PhCH=NPh. The stability of the amine complexes depends on the basicity and steric requirements of the complexed amine. Dialkylamine complex 10 is stable to 80°C, while the less basic aryl(alkyl)amine complex 9 is stable to only 50 C. The complex of the very bulky t-Bu(PhCH2)NH complex 11 decomposed above O C. In general, amine complexes with greater number of substituents are less stable. Beller has isolated the NH3 complex 12 from catalytic systems it is unusually stable and acts as a viable catalyst precursor [58]. 

The cleavage products of several sulfonates are utilized on an industrial scale (Fig. 3). The fusion of aromatic sulfonates with sodium hydroxide [1310-73-2J and other caustic alkalies produces phenohc salts (see Alkylphenols Phenol). Chlorinated aromatics are produced by treatment of an aromatic sulfonate with hydrochloric acid and sodium chlorate [7775-09-9J. Nitriles (qv) (see Supplement) can be produced by reaction of a sulfonate with a cyanide salt. Arenesulfonates can be converted to amines with the use of ammonia. This transformation is also rather facile using mono- and dialkylamines. 

Amine Boranes. Trialkylamine and dialkylamine boranes, such as tri-Z-butylamine borane and dimethylamine borane, are mainly used in... 

A diazonium salt is a weak electrophile, and thus reacts only with highly electron-rich species such as amino and hydroxy compounds. Even hydroxy compounds must be ionized for reaction to occur. Consequendy, hydroxy compounds such as phenols and naphthols are coupled in an alkaline medium (pH > of phenol or naphthol typically pH 7—11), whereas aromatic amines such as N,N diaLkylamines are coupled in a slightly acid medium, typically pH 1—5. This provides optimum stabiUty for the dia2onium salt (stable in acid) without deactivating the nucleophile (protonation of the amine). 

The secondary amines used in the preparation of enamines have been primarily simple dialkylamines or cyclic amines of five- or higher-membered rings. Azetidine (4) yields a stable enamine with cyclopentanone (28). No simple enamines formed by condensation of ethylenimine (5) or a substituted ethylenimine with an aldehyde or ketone have been reported. 

Aliphatic tertiary amines have been prepared by the desulfurization of thenyl-dialkylamines obtained from the Leuckart reaction with 2-... 

In addition to their behavior as bases, primary and secondary amines can also act as very weak acids because an N-H proton can be removed by a sufficiently strong base. We ve seen, for example, how diisopropylamine (pK-A 40) reacts with butyilithium to yield lithium diisopropylamide (LDA Section 22.5). Dialkylamine anions like LDA are extremely powerful bases that are often used... 

Diethyl methylphosphonite in refluxing dialkylamine is the favored method for the formation of 37/-azepines from nitroarenes,75,176,207 although tributylphosphane and tri-piperidinophosphane are recommended for the deoxygenation of nitrobenzene in piperidine.79 Deoxygenation of nitrobenzene in diethylamine furnishes Ar,Ar-diethyl-3/f-azepin-2-amine, and a range of 5-substituted 3//-azepines 97 have been prepared in a similar manner from 4-sub-stituted nitroarenes.79,176 Curiously, the corresponding 2-substituted nitroarenes, with the exception of 2-nitrotoluene, yield only tarry products. 

Singlet phenylnitrene, and hence /V,A -diethyl-3//-azcpin-2-amines, e. g. 102, can be generated by the thermolysis of A,-phenyl-Af,<9-bis(trimcthylsi]yl)hydroxylamine (100) in the presence of dialkylamines the reaction fails, however, with arylamines.210 Photofragmentation of the spiro oxaziridine 101 in diethylamine solution also produces the 3//-azepine 102,2,1 and an oxaziridine intermediate is probably involved in the formation, in low yield (1 %), of azepine 102 by the photolysis of A/,A( -diarylbenzoquinonc diimine A/,A/ -dioxides in benzene/die-thylamine solution.212... 

Therefore in this section we will focus first on the reactions of arenediazonium ions with secondary amines such as A-alkylanilines and dialkylamines. Reactions with primary amines will be discussed later in this section. Most diarylamines do not undergo Af-azo coupling to a significant extent, as they are weaker nucleophiles. 

With terminal alkynes, the direction of the reaction depends on the nature of the substituent, the type of amine and the catalyst. Thus, dialkylamines can react with propyne to give 4-dialkylamino-4-methyl-2-pentynes traced from the Hy regioselec-hve formation of 2-dialkylaminopropene, i.e. the Markovnikov hydroaminahon product (Scheme 4-11) [256]. 

Scheme 2.12 shows some representative Mannich reactions. Entries 1 and 2 show the preparation of typical Mannich bases from a ketone, formaldehyde, and a dialkylamine following the classical procedure. Alternatively, formaldehyde equivalents may be used, such as l>is-(di methyl ami no)methane in Entry 3. On treatment with trifluoroacetic acid, this aminal generates the iminium trifluoroacetate as a reactive electrophile. lV,A-(Dimethyl)methylene ammonium iodide is commercially available and is known as Eschenmoser s salt.192 This compound is sufficiently electrophilic to react directly with silyl enol ethers in neutral solution.183 The reagent can be added to a solution of an enolate or enolate precursor, which permits the reaction to be carried out under nonacidic conditions. Entries 4 and 5 illustrate the preparation of Mannich bases using Eschenmoser s salt in reactions with preformed enolates. 

Dialkylamino derivatives of elements located in the periodic table to the left or below those listed above cannot be prepared by the above method due to either the ionic character of some of the inorganic halides or the formation of stable metal halide-amine addition products. Therefore, other methods must be applied. Dialkylamino derivatives of tin7 and antimony8 are conveniently obtained by reaction of the corresponding halides with lithium dialkylamides. Others, such as the dialkylamino derivatives of aluminum,9 are made by the interaction of the hydride with dialkylamines. Dialkylamino derivatives of beryllium10 or lithium11 result from the reaction of the respective alkyl derivative with a dialkylamine. 

In the presence of samarium(II) iodide, A-(2-iodobenzyl)dialkylamines 347 react with electrophiles at an a-carbon atom to yield deiodinated products by way of intermediate samarium compounds 348. Thus TV-(2-iodobenzyl)diethylamine and pentan-3-one afford the hydroxy amine 349 and 7V-(2-iodobenzyl)pyrrolidine and propyl isocyanate give the amide 350390. 

The reaction of [Rh(C(0)Me)(C0)2l3] with various nucleophiles has been studied by IR [17]. Acetate ion gave immediate formation of AC2O. Amines gave amides, the more nucleophilic dialkylamines reacting more rapidly than methyl anilines. The kinetics of these reactions were interpreted as consistent with two pathways, one being elimination of Acl from [Rh(C(0)Me)(CO)l3] and the other direct nucleophilic attack at the acyl (Eq. (22)). 

Entries 1 and 2 in Scheme 2.11 show the preparation of Mannich bases from a ketone, formaldehyde, and a dialkylamine following the classical procedure. Alternatively, formaldehyde equivalents may be used, such as bis(dimethylamino)methane in entry 3. On treatment with trifluoroacetic acid, this aminal generates the iminium trifluoroacetate as a reactive electrophile. 

Reaction with ammonia yields 5-cyanotetrazole, a nitrogen heterocychc ring compound. Reactions with alkyl amine, RNH2, yield dialkyloxalamidines RNHC(=NH)CH(=NH)NR with dialkylamine, R2NH, the product is N,N-diaIkylcyanoformamidine ... 

N-Nitroso-dialkylamine (Nitrosamine) einschliefllich ihrer cyclischen Analogen konnen als N-geschiitzte sekundare Amine fungieren sie konnen z. B. 

Durch eine analoge Reaktion lassen sich aus primaren aliphatischem Amin symmetrische Dialkylamine herstellen2. 

As seen in Tables II-IV, dialkylamines react with the substituted terminal acetylenes to give only trans-aminovinyl products. Primary aliphatic amines react with both ethyl propiolate and 1-ethylsulfonyl-l-propyne to give mixtures of cis and trans products and with p-tolylsulfonylacetylene to give only trans products. Ethylenimine reacts with ethyl propiolate and 1-ethylsulfonyl-l-propyne to give mixtures of cis and trans products. Aniline reacts with p-tolylsulfonylacetylene to give a mixture of cis and trans products. The solvent has a great effect on the cis- and trans ratio when ethylenimine is used. 

Other unsymmetrical ureas are obtained by starting with a dialkylamine and a primary aromatic amine to give 1,1-dialkyl-3-arylureas (Eqs. 42-46) as shown in Table VII. 

Propynyl dialkylamines are produced in low yields (see Table II) when the stoichiometric amount of reagents are used. When an excess of lithium dialkyl-amide is used, partial isomerization of the product to allenyl amines, CH2=C=CHNR2 [13], takes place. 

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