Preparation of Diethylamine

I was one of the workers in the preparation of diethylamine some weeks ago and should be very glad to hear of any further help I could give. I can put all my time and energy at your service for the next 6 weeks, and am anxious to know whether the few helpers down here could not be allowed to contribute further to the needs of the country I should be much obliged if you would inform me whether there is any other preparations we can make, as I, for one, am willing and eager to give up all ideas of holiday while there remains so much to be done.23... 

Preparation of Diethylamine from Ethanol by Robert Bottoms Louisville, Kentucky June 18,1935... 

As the monoethylamine can be again used for the preparation of diethylamine, about 50 percent of the monoethylamine can be converted into diethylamine. Source Gamer 1916... 

Gamer, W.E. Tyrer, D. Preparation of Diethylamine Journal of the Chemical Society (1916) 109 174-175... 

The experimental details describe the use of a free secondary amine for the preparation of a nitrosainine. Identical results are, of course, obtained by employing solid diethylamine hydrochloride. 

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. 

Uses. There may be some captive use of carbonyl sulfide for production of certain thiocarbamate herbicides (qv). One patent (38) describes the reaction of diethylamine with carbonyl sulfide to form a thiocarbamate salt which is then alkylated with 4-chloroben2yl haUde to produce 3 -(4-chloroben2yl) A[,A/-diethylthiocarbamate [28249-77-6] ie, benthiocarb [28249-77-6]. Carbonyl sulfide is also reported to be useful for the preparation of abphatic polyureas. In these preparations, potassium thiocyanate and sulfuric acid are used to first generate carbonyl sulfide, COS, which then reacts with a diamine ... 

Esterification. Chlorohydrins can react with salts of carboxyUc acids to form esters. For example, 2-hydroxyethyl benzoate [134-11-2] was prepared ia 92% yield by heating sodium benzoate [532-32-1] with an excess of ethylene chlorohydrin ia the presence of a small amount of diethylamine... 

One scheme for preparation of the diamine side chain consists in first reducing the carbonyl group of the haloketone, 73. Displacement of the halogen with diethylamine gives the amino alcohol (74). Treatment of that intermediate with thionyl bromide serves to replace the hydroxyl by bromine (75). The synthesis is completed by displacement of the bromine with ammonia. 

Preparation of 2-( -Diethylaminoethoxy)Ethyl Diethylphenylacetate A mixture of 21 grams of 2-(/3-chloroethoxy)ethyl diethylphenylacetate and 14 grams diethylamine was heated under pressure in a sealed tube at 140°C for 5 hours. After cooling, the mixture was dissolved in dilute hydrochloric acid and extracted with ether to remove traces of neu-... 

Initially it was necessary to devise an improved method for the preparation of 2-hydroxyglycal esters, because the standard procedure (treatment of an acylglycosyl bromide with diethylamine in benzene or chloroform solution) was inconveniently lengthy in time and frequently afforded only a moderate yield of product (5). As a result of their recent thorough investigation of the kinetic features of the dehydrobromination of tetra-O-acetyl-a-D-glucopyranosyl bromide Lemieux and Lineback... 

This reagent is prepared from 3.0 mL of diethylamine in chloroform and 1 mL of carbon disulphide in 9 mL of chloroform. Mix carefully and store in a dark bottle in a refrigerator. 

N-Acetals of aldehydes can be readily prepared by reaction of aldehydes with tri-methylsilylated secondary amines. Thus, formaldehyde is converted by diethylami-notrimethylsilane 146, in 55% yield, into the silylated 0,N-acetal 422, which reacts with a further equivalent of 86 to give 90% of the N,N-acetal 423 and 94% hexa-methyldisiloxane 7 [41, 42]. On heating of diethylamine with formaldehyde and HMDS 2, 22% 422, 70% of the N,N-acetal 423, HMDSO 7, and ammonia are obtained [42] (Scheme 5.10). 

The Sonogashira reaction is of considerable value in heterocyclic synthesis. It has been conducted on the pyrazine ring of quinoxaline and the resulting alkynyl- and dialkynyl-quinoxalines were subsequently utilized to synthesize condensed quinoxalines [52-55], Ames et al. prepared unsymmetrical diynes from 2,3-dichloroquinoxalines. Thus, condensation of 2-chloroquinoxaline (93) with an excess of phenylacetylene furnished 2-phenylethynylquinoxaline (94). Displacement of the chloride with the amine also occurred when the condensation was carried out in the presence of diethylamine. Treatment of 94 with a large excess of aqueous dimethylamine led to ketone 95 that exists predominantly in the intramolecularly hydrogen-bonded enol form 96. 

Roewer et al. have used salene-type ligands for the preparation of neutral penta- and hexacoordinated silane complexes.834-836 Interestingly, the reaction of the acid form of the salene ligand reacts with organotrichlorosilanes in the presence of diethylamine to form pentacoordinated enamine silane complexes 849-851, whereas the disodium salt of the salene ligand reacts with phenyltrichlorosilane providing the hexacoordinated chlorosilane complex 852 (Scheme 119).834 The pentacoordinated complex 849 was also obtained when the hexacoordinated complex 852 was reacted with triethylamine (Scheme 119). 

The reaction was found to be general and was extended to the preparation of a large range of phosphorodiamidic fluorides, e.g-from diethylamine, butylamine, methylaniline, benzylamine, cycfohexylamine, morpholine and piperidine. The method was patented. 

Magnetic amine resins were prepared by a procedure based on that of Sugiyama and Kamogawa. A slurry of 4.25g of PAM graft beads (24.6 mmol) in 30 ml of water was heated to 50 C and 2 ml of 37% H2C0 solution (24.7 mmol) was added. After one hour 1.8g (24.6 mmol) of diethylamine (b.p. 55.5 C) was added and heating at 50 C under reflux continued for a further one hour. 

The use of acid chlorides in the preparation of amides has been reviewed.7 The diethylamine was distilled from calcium hydride prior to use. 

Method A. A slurry of 3.15 g d-lysergic acid monohydrate (monohydrate means dry) and 7.3 g of diethylamine (or 0.1 mole of similar amine) in 150 ml of pure chloroform is heated to reflux. After the lysergic acid is dissolved (a few min) cool the mixture down to where reflux has stopped by removing the heat. Before the mixture cools any further 2 ml of phosphorous oxychloride is added at such a rate as to give reflux (about 2 min). After addition, reflux for 4-5 min further until an amber-colored solution results. Cool to room temp and wash the mixture with 200 ml of 1 M ammonium hydroxide. The chloroform solution was dried with MgSC>4 (this would have to be after separation), filtered, and concentrated by evaporation in vacuo under a temp of 38° (at no time let the temp go over 40°). The last traces of solvent are removed at 2-5 mm. Dissolve the residue in a minimum amount of methanol and acidify with freshly prepared solution of 20% maleic acid in methanol (not aqueous) to precipitate the LSD in its maleate form. Filter the fluffy white needles, wash with cold methanol and air dry to get 2.2 g of LSD that requires no further purification. 

Better reagents than lithium aluminum hydride alone are its alkoxy derivatives, especially di- and triethoxyaluminohydrides prepared in situ from lithium aluminum hydride and ethanol in ethereal solutions. The best of all, lithium triethoxyaluminohydride, gave higher yields than its trimethoxy and tris(/er/-butoxy) analogs. When an equimolar quantity of this reagent was added to an ethereal solution of a tertiary amide derived from dimethylamine, diethylamine, W-methylaniline, piperidine, pyrrolidine, aziridine or pyrrole, and the mixture was allowed to react at 0° for 1-1.5 hours aldehydes were isolated in 46-92% yields [95,1107], The reaction proved unsuccessful for the preparation of crotonaldehyde and cinnamaldehyde from the corresponding dimethyl amides [95]. 

The purest available commercial samples of acetaldehyde, ethyl ether, and amines were purified by fractional distillation, either by conventional means or by using a spinning band column (Biichi). N-Methyl-diethylamine was prepared from diethylamine (4) and N,N-dimethyl-ethylamine from ethylamine (5). 

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. 

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