Alkyl amines diethylamine

Mention should also be made of the alkylation of diethylamine by isopropyl bromide, which cannot be effected in absence of a solvent at atmospheric pressure but occurs with astonishingly good yields in glycerol or ethylene glycol.474 Isopropyl bromide (123 g), diethylamine (94.9 g), and glycerol (50 g) are boiled together under reflux for 72 h the mixture is made alkaline and the liberated amine is dried over potassium hydroxide and fractionally distilled this gives A,A-diethylisopropylamine, b.p. 108°, in 60% yield (67 g). 

Aminoalkylpyridines have been prepared by heating thioamides with an alkyl amine and Raney Nickel in an autoclave imder 10 atm of hydrogen at 70° for several hours. Under these conditions, 0-(2-pyridyl)propionic thioamide reacts with diethylamine to give 2-(3-diethylaminopropyl)pyridine (IX-230). °... 

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Inclusion of the carbon atoms of an aromatic ring in the side chain sequence is apparently quite consistent with antlmalarial activity. Thus, reaction of p-acetamidophenol with formaldehyde and diethylamine affords the Mannich product, 79. This is then converted to the diamine (80) by saponification. Alkylation with the chloroquinoline, 70, affords amidoquine (81). The same sequence starting with the Mannich product in which pyrrolidine has been used as the amine (82) gives amopyroquine (83). 

Modification of the synthesis of the side chain by reaction of 73 with isopropyl amine rather than diethylamine gives eventually the haloamine, 94. Alkylation of the aminoquinoline (92)... 

There is evidence from a detailed study of the photolyses of 2-alkyl-substituted aryl azides 40 in diethylamine that A3,7V-diethyl-1 //-azepin-2-amines are formed as oxygen-sensitive, meta-stablc intermediates that can give rise to a variety of byproducts, including 5-acyl- A%V-diethyl-pyridin-2-amines and 6-alkyl-7-(diethylamino)-2//-azepin-2-ones 11 however, formation of these oxidation products can be avoided by refluxing the photolysate mixture with methanol prior to exposure to oxygen, in which case practicable yields of the /V,/V-diethyl-3W-azepin-2-amines 41 result. 

Methyl 3-(2-phenylsulfonylethyl)-2-quinoxalinecarboxylate 1,4-dioxide (66) and diethylamine gave only methyl 3-(2-diethylaminoethyl)-2-quinoxalme-carboxylate 1,4-dioxide (67) (Et2NH, MeCN, 20°C, 2 h 40%) ° when ammonia or a primary amine was used similarly, the analogous (unisolated) product (68, R = H or alkyl) underwent spontaneous cyclization to afford, for... 

FDMR has also been used to detect the transient radical cations formed from secondary amines by pulse radiolysis. As mentioned earlier this technique has been used to study a variety of systems such as the radical cation of triethylamine. The radical cations of diethylamine, n-propyl amine and f-butylamine, have also been studied25. The results have shown that the FDMR signal is enhanced with increasing alkyl substitution of the amine as in the pyrrolidines (18) and the piperidines (19)25. 

Piperidine is a secondary amine pK 11.3 cf. diethylamine, pK 11.0) it is more basic than pyridine pK 5.2). It is also a good nucleophile, and it is A-alkylated by alkyl halides in the presence of potassium carbonate to form first A-alkylpiperidines and then quaternary salts. 

This important synthetic problem has been satisfactorily solved with the introduction of lithium dialkylamide bases. Lithium diisopropylamide (LDA, Creger s base ) has already been mentioned for the a-alkylation of acids by means of their dianions1. This method has been further improved through the use of hexamethylphosphoric triamide (HMPA)2 and then extended to the a-alkylation of esters3. Generally, LDA became the most widely used base for the preparation of lactone enolates. In some cases lithium amides of other secondary amines like cyclo-hexylisopropylamine, diethylamine or hexamethyldisilazane have been used. The sodium or potassium salts of the latter have also been used but only as exceptions (vide infra). Other methods for the preparation of y-Iactone enolates. e.g., in a tetrahydrofuran solution of potassium, containing K anions and K+ cations complexed by 18-crown-6, and their alkylation have been successfully demonstrated (yields 80 95 %)4 but they probably cannot compete with the simplicity and proven reliability of the lithium amide method. 

Rueter et al.62 described an efficient and clean synthesis of diethyl-(2-/ -tolyl-ethyl)amine (30) from 2-p-tolylethanol and diethylamine by making use of the benzenesulfonyl chloride resin (26) to catch the intermediate O-alkylated substrate (31) followed by the release (from the intermediate resin) of the final product (30) upon treatment with diethylamine (Fig. 12). 

On the other side of the scale, very moderate, but not negligible, Lewis acidities are ascribed, according to their a parameters, to C-H acids, such as chloroform and bromoform, primary and secondary acyclic amines, such as -butylamine and diethylamine, and protogenic solvents, such as methyl-alkyl ketones, acetonitrile, and nitromethane. It can be expected that liquid 1 -alkynes (not on the List), having the grouping H-C=C-R, also have non-negligible a values, being C-H Lewis acids. It can be safely concluded, however, that aprotic solvents other than those of the classes noted above have no Lewis acid character, with a 0 for all intents and purposes. 

Quinuclidine and DABCO are 40-60 times more reactive than triethylamine. This is again due to the way the ring structures keep the nitrogen s substituents away from interfering with the lone pair as it attacks the electrophile. You should contrast the effect that the cyclic structure has on the pJCaH of the amines none Triethylamine and quinuclidine are equally basic and, as you can see in the margin, so (more or less) are diethylamine, dibutylamine, and piperidine. A proton is so small that it cares very little whether the alkyl groups are tied back or not. 

Urethanes. Methyl carbamates (1) can be prepared from primary or secondary amines, alkyl halides, and carbon dioxide in a reaction promoted by copper(I) /-butoxide (equation I). The ligand t-butyl isocyanide can be replaced with tri-n-butylphosphine. Copper(I) f-butoxide is more effective than other copper salts. In the case of diethylamine, the intermediates a and b were isolated and b was converted to the methyl carbamate in 86% yield. 

Amino alcohols are commonly made by the amination of halo alcohols or by alkylation of amino alcohols. Thus (S-diethylaminoethyl alcohol is synthesized from diethylamine and ethylene chlorohydrin (70%)/ Higher amino alcohols are made in a similar manner. No isomerization... 

Alkylation of amines by conjugated olefins Addition of isoprene to a solution of sodium naphthalenidc in THP and diethylamine gives diethylisopcntenylamine (I) in 70% yield. 

Pyrrolidine and piperidine are better nncleophiles than diethylamine, principally because the lone pair is less hindered - in the heterocycles the two alkyl snbstitnents , i.e. the ring carbons, are constrained back and away from the nitrogen lone pair, and approach by an electrophile is thus rendered easier than in diethylamine, where rotations of the C-N and C-C bonds interfere. The p/fau values of pyrrolidine (11.27) and piperidine (11.29) are typical of amine bases they are slightly stronger bases than diethylamine (10.98). Morpholine (8.3) is a somewhat weaker base than piperidine. 

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