Alkylamines, synthesis

Ammonia and other amines are good nucleophiles in SN2 reactions. As a result, the simplest method of alkylamine synthesis is by Sn2 alkylation of ammonia or an alkylamine with an alky) halide. If ammonia is used, a primary amine results if a primary amine is used, a secondary amine results and so on. Even tertiary amines react rapidly with alkyl halides to yield quaternary ammonium salts, R4N+ X-... 

Silylation of Amines. While there are several effective methods for preparation of Af-(trimethylsilyl)amines, only a few successful procedures for Af,Af-bis(trimethylsilyl)alkylamines synthesis have been reported. If silylation of ethylamine is attempted with trimethylsilyl chloride, only 13% of NJ -bis(trimethylsilyl)ethylamine is obtained in addition to the major product iV-(trimethylsilyl)ethylamine. However, N,N-bis(trimethylsilyl)amines can be prepared by silylation of monosi-lylamines with trimethylsilyldiethylamine in the presence of catal3Tic ammonium sulfate or ammonium chloride. Another convenient method for the preparation of Af,A-bis(tri-methylsilyl)alkylamines has recently been reported. There trimethylsilyldiethylamine has been found to be effective in the conversion of primary amines, especially aromatic systems, and their monotrimethylsilyl derivatives into the corresponding bistrimethylsilyl products in high yields. For example, when isopropyl amine (or aniline) is refluxed with 1.1 equiv of trimethylsilyldiethylamine and 1.15 equiv of methyl iodide in toluene for 4 h, bis(trimethylsilyl)isopropylamine [or bis(trimethylsilyl)aniline] can be obtained in 99% yield (or 88% yield based on GC) (eqs 16 and 17). 

A method that achieves the same end result as that desired by alkylation of ammonia but which avoids the formation of secondary and tertiary amines as byproducts is the Gabriel synthesis Alkyl halides are converted to primary alkylamines without contam mation by secondary or tertiary amines The key reagent is the potassium salt of phthal imide prepared by the reaction... 

Alkylation of phthalimide The Gabriel synthesis (Section 22 8) The potassium salt of phthalimide reacts with alkyl hal ides to give N alkylphthalimide deriva fives Hydrolysis or hydrazinolysis of this derivative yields a primary alkylamine... 

Gabriel synthesis (Section 22 8) Method for the synthesis of primary alkylamines in which a key step is the formation of a carbon-nitrogen bond by alkylation of the potassium salt of phthalimide... 

The reactions of chloramine are not generally successful with N-chloroalkylamines. Therefore it was surprising that the diaziridine synthesis occurred smoothly from aliphatic Schiff s bases and V-chloro-alkylamines [Eq. (33), Table VII]. As can be seen from examples... 

Fig. 11. Dendron 23 of 3rd generation containing 87 nucleotides. Two key intermediates in the synthesis of dendra such as 23. The box represents long-chain alkylamine controlled-pore glass [53]...

Another method for the synthesis of stable metal nanoparticles involves first mixing the metal hydrosols and an ethanol solution of dodecylamine and then extracting the dodecylamine-stabilized metal nanoparticles into toluene. The ethanol, a water miscible and good solvent for dodecylamine, was used as an intermediate solvent to improve the interfacial contact between citrate-stabilized metal nanoparticles and alkylamine. The extraction of dodecylamine-stabilized metal... 

O-Alkylation of 4-hydroxy-3-morpholino-l,2,5-thiadiazole 132 has been achieved with the chiral cyclic chloro-methyl sulfite 133 which subsequently suffers ring opening on treatment with simple alcohols <2001RCB436> or alkylamines <2002RJ0213> to afford the timolol analogues 134 with very little racemization (Scheme 20). This indicated an almost exclusive attack of the oxy anion on the exocyclic carbon atom and is a significant improvement on the previous oxirane method, which suffers from racemization. An alternative biocatalytic asymmetric synthesis of (A)- and (R)-timolol has also appeared <2004S1625>. 

The reactions used for synthesis of II-VI (CdSe, CdTe), III-V (InP, InAs), and IV-VI (PbS, PbSe, PbTe) semiconductor nanocrystals are outlined by Schemes 3-5.4,17,30-32 The syntheses are carried out at high temperatures, and in the presence of long-chain alkylphosphines (trioctylphosphine,TOP), alkyl-phosphine oxides (trioctylphosphine oxide, TOPO), alkylamines (hexadecyl-amine, HD A), and alkylphosphonic acids as the stabilizing agents. 

FIGURE 8.15 Alkylamines encountered in peptide synthesis. 1, pyridine 2, 2,4,6-trimethylpy-ridine 3, 2,6-di-ferf-butyl-4-methylpyridine 4, 4-dimethylaminopyridine 5, A-methyl-morpholine, 6, fV-methylpiperidine 7, triethylamine 8, diisopropylethylamine 9, l-diethylaminopropane-2-ol 10, dicyclohexylamine 11, diethylamine 12, piperidine 13, piperazine 14, morpholine 15, l,8-diazabicyclo[5.4.0]undec-7-ene 16, 4-(aminoethyl)piperidine 17, frw(2-aminoethyl)amine 18, 3-dimethylaminopropylamine 19, methylamine 20, dimethy-laminoethane-2-ol 21, 1,2,2,6,6-pentamethylpiperidine 22, l,4-diazabicyclo[2,2,2]octane 23, 7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5 -ene. 

This disilaborane was an unexpected co-product in the synthesis of decaborane-alkylamine polymers. The Si2Bio cluster core consists of a distorted icosahedron in which the two silicon atoms occupy adjacent positions. The Si-Si interatomic distance is 2.308(2) A, which is slightly less than the Si-Si distance in organodisilanes (2.35 A) and the Si-B distances [2.017(3) to 2.116(3) A] are very close to the sum of the covalent radii of the two atoms (2.07 A). Further derivatives with disilaborane cluster geometry are known for the phenyl substituted compounds l,2-Ph2-doso-l,2-Si2B1oH1o and l-Me-2-Ph-doso-l,2-Si2BioHi0 [6, 7]. In addition to these disila-doso-dodecaborane clusters one example with two different group 14 elements as a part of the cluster core is known. In Scheme 3.3-2 the synthesis of this sila-stanna-doso-dodecaborate is shown. The structure of this heteroborate was determined in the solid state and the Si-Sn distance is 2.608(4) A (Scheme 3.3-2) [8]. 

As the latter were not easily accessible by chemical synthesis at that time, new methods of preparing these ferrocene derivatives were developed and introduced in 1969. It was then proved that the U-4CRs of chiral a-ferrocenyl-alkylamines can form diastereomeric a-aminoacid derivatives stereo-selectively, and it was further shown that after the reaction the a-ferrocenyl groups of the products can be replaced by protons, thus resynthesizing the chiral a-ferrocenyl-alkylamines simultaneously." Later, the development of this ferrocene chemistry was given up since such syntheses cannot form the products in sufficient quantity and stereoselective purity. ... 

A particularly useful synthesis of primary nitramines involves the nitration of the appropriate carbamate ester followed by ammonolysis with gaseous ammonia in diethyl ether. The ammonium salt of the nitramine precipitates in pure form and is carefully acidified to give the free nitramine. The corresponding carbamate esters are readily synthesized from the action of chlorocarboxylic acid esters on alkylamines in the presence of alkali hydroxides. 

The first synthesis of a cyclodiphosph(III)azane (13) (Scheme 4) was reported by Michaelis and Schroeter who correctly identified (13) as a dimer by molecular weight determinations. These results have been confirmed by more recent work which also shows that the reaction proceeds via an acyclic diphosphinoamine, CljPNPhPClj. The synthesis of cyclodiphosph(IH)azanes by the reaction of phosphorus trichloride with relatively bulky primary alkylamines and related routes has been widely studied. Examples of this work, leading to (14)... 

JAP624149) and a wide variety of l-lV-alkylperhydro-l,7-naphthyridines (207) have been obtained by reaction of the ether (208) with various alkylamines (66KGS427). A convenient synthesis of 5-hydroxy-2-oxo-l,2,3,4-tetrahydro-l,7-naphthyridine (211) starts from the 3-substituted amino isonicotinaldehyde (209) which undergoes a Wittig reaction followed by reduction to give (210), a compound that cyclizes readily in acid solution to (211) (82CPB1257). 

S. Stoszek, Chemik 40,270-278 (1987) C1-C4 Alkylamines as Intermediates for the Synthesis of Special Chemicals". 

Group II The activity drops more than the Ni surface concentration (Fig. 13), i.e., at least about 20 times. However, for several reactions this drop is two or more orders of magnitude. The reactions included in this group are methanation and Fischer-Tropsch synthesis, isomerization, de-hydrocyclization or hydrogenolysis of alkanes, ether formation from alcohols, metathesis of alkylamines, and possibly other reactions. 

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