Of diethylamine

N-Nitrosodiethylamine. Add 36-5 g. (51-5 ml.) of diethylamine slowly to the calculated quantity of carefully standardised 5A-hydra chloric acid cooled in ice (1). Introduce the solution of the hydi ochloride into a solution of 39 g. of sodium nitrite (assumed to be of 90 per cent, purity) in 45 ml. of water contained in a 250 ml. distilling flask. Distil the mixture rapidly to dryness. Separate the yellow upper layer of the nitrosamine from the distillate saturate the aqueous layer with soUd potassium carbonate and remove the nitroso compound which separates and add it to the main product. Dry over anhydrous potassium carbonate and distil. Collect the diethylnitrosamine at 172-173-5°, The yield is 41 g. 

In the above reaction one molecular proportion of sodium ethoxide is employed this is Michael s original method for conducting the reaction, which is reversible and particularly so under these conditions, and in certain circumstances may lead to apparently abnormal results. With smaller amounts of sodium alkoxide (1/5 mol or so the so-called catal3rtic method) or in the presence of secondary amines, the equilibrium is usually more on the side of the adduct, and good yields of adducts are frequently obtained. An example of the Michael addition of the latter type is to be found in the formation of ethyl propane-1 1 3 3 tetracarboxylate (II) from formaldehyde and ethyl malonate in the presence of diethylamine. Ethyl methylene-malonate (I) is formed intermediately by the simple Knoevenagel reaction and this Is followed by the Michael addition. Acid hydrolysis of (II) gives glutaric acid (III). 

Ethyl propane-1 1 3 3-tetracarboxylate. Cool a mixture of 320 g. (302 ml.) of redistilled diethyl malonate and 80 g. of 40 per cent, formaldehyde solution ( formalin ) contained in a 1-htre round-bottomed flask to 5° by immersion in ice, and add 5 g. (7 ml.) of diethylamine. Keep the mixture at room temperature for 15 hours and then heat under a reflux condenser on a boiling water bath for 6 hours. Separate the aqueous layer, dry the organic layer with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ethyl 1 1 3 3-tetracarboxylate at 200-215°/20 mm. The yield is 250 g. 

The following are examples of the above procedure. A mixture of diethylamine and re-butyl alcohol may be separated by adding sufficient dilute sulphuric acid to neutralise the base steam distillation will remove the alcohol. The amine can be recovered by adding sodium hydroxide to the residue and repeating the distillation. A mixture of diethyl ketone and acetic acid may be treated with sufficient dilute sodium hydroxide solution to transform the acid into sodium acetate and distilling the aqueous mixture. The ketone will pass over in the steam and the non-volatile, stable salt will remain in the flask. Acidification with dilute sulphuric acid hberates acetic acid, which can be isolated by steam distillation or by extraction. 

H2C=CH-C=CH-C3h7. All glassware of the distillation apparatus was rinsed AcHi with a dilute solution of diethylamine in diethyl ether. 

Rhoda.mines, Rhodamines are commercially the most important arninoxanthenes. If phthalic anhydride is used in place of formaldehyde in the above condensation reaction with y -dialkylarninophenol, a triphenyknethane analogue, 9-phenylxanthene, is produced. Historically, these have been called rhodamines. Rhodamine B (Basic Violet 10, Cl45170) (17) is usually manufactured by the condensation of two moles of y -diethylaminophenol with phthahc anhydride (24). An alternative route is the reaction of diethylamine with fluorescein dichloride [630-88-6] (3,6-dichlorofluoran) (18) under pressure. 

A variety of substituted alkanolamines (Table 2) can also be made by reaction of oxide with the appropriate amine. Aminoethylethanolamine is made from the reaction of ethylenediamine [107-15-3J and ethylene oxide. Methyldiethanolamine is made from the reaction of ethylene oxide and methylamine [74-89-5J. Diethylethanolamine is made by the reaction of diethylamine [109-87-7] and ethylene oxide. 

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 ... 

A synthesis of optically active citroneUal uses myrcene (7), which is produced from P-piaene. Reaction of diethylamine with myrcene gives A/,A/-diethylgeranyl- and nerylamines. Treatment of the aHyUc amines with a homogeneous chiral rhodium catalyst causes isomerization and also induces asymmetry to give the chiral enamines, which can be readily hydrolyzed to (+)-citroneUal (151). 

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... 

FIG. 15-35 Extraction of diethylamine from water into toluene (dispersed) in towers packed with unglazed porcelain Raschig rings, To convert feet to meters, multiply hy 0,3048 to convert inches to centimeters, multiply hy 2,54, [Leihson and Beckman, Chem, Eng, Prog, 49, 405 (1953), with permission.)... 

To 500 g. (3.85 moles) of freshly distilled ethyl acetoacetate in a i-l. flask set in ice and well cooled, are added 152 g. (2.0 moles) of 40 per cent aqueous formaldehyde solution and 20-25 drops of diethylamine. The flask and contents are kept cold for six hours and are then allowed to stand at room temperature for forty to forty-five hours. At the end of this time two layers are present, a lower oily layer and an upper aqueous layer. The layers are separated, and the aqueous layer is extracted with 50 cc. of ether. The ether solution is added to the oily layer, and the resulting solution is dried over 30 g. of calcium chloride. The ether is then removed by distillation on a steam bath. The residue, amounting to approximately 500 g., is diluted with an equal volume of alcohol and is thoroughly cooled in an ice bath. Ammonia is then passed into the mixture until the solution is saturated. This requires from four to eight hours, and during this time the flask is kept packed in ice. The ammoniacal alcoholic solution is allowed to stand at room temperature for forty to forty-five hours. Most of the alcohol is now evaporated the residue is cooled, and the solid i,4-dihydro-3,5-dicarbethoxy-2,6-dimethylpyridine is removed from the remaining alcohol on a suction filter. The dried ester melts at 175-180 and amounts to 4ro-435 g. (84-89 per cent of the theoretical amount). 

PoIyfluoFohalogenated oxiranes ate usually opened by nucleophilic reagents, for example alkoxides, at the central carbon atom However, an increase in the volume of the attacking agent, as in the case of diethylamine, directs the nucleophile toward the terminal carbon atom [dd] (equation 29)... 

Once formed, 7 and 8 undergo a Michael reaction that gives rise to ketoenamine 9. Ring closure, to form 10, and loss of water then afforded 1,4-dihydropyridine 11. The presence of 9 and 10 could not be detected thus ring closure and dehydration were deduced to proceed faster than the Michael addition. This has the result of making the Michael addition the rate-determining step in this sequence. Conversely, if the reaction is run in the presence of a small amount of diethylamine, compounds related to 10 could be isolated. Diol 20 has been isolated in an unique case (R = CFb). Attempts to dehydrate this compound under a variety of conditions were unsuccessful. Stereoelectronic effects related to the dehydration may be the cause. In related heterocyclic ring formations, it has been determined that dehydration (20 —> 10) is about 10 times slower than diol formation (19 —> 20). Therefore, one would expect 20 to... 

Aminoenyne ketones 350 (90ZOR2508) react with 1,2-diaminoethane and 1-amino-2-hydroxyethane analogously as a twofold nucleophilic attack at the triple bond followed by elimination of diethylamine to afford imidazolines 351 and oxazolines 352, which also contain a strong hydrogen bond and a completely enolyzed vinylacetyl group (92KGS1409 94ZOR51). 

Reaction of pyroc techol with epichlorohydrin in the presence of base affords the benzodioxan derivative, 136, (The reaction may well involve initial displacement of halogen by phenoxide followed by opening of the oxirane by the anion from the second phenolic group.) Treatment of the alcohol with thio-nyl chloride gives the corresponding chloro compound (137). Displacement of halogen by means of diethylamine affords piper-oxan (138), a compound with a-sympathetic blocking activity. 

A mixture consisting of 13.5 g of 4-(4 -hydroxyanilino)-7-chloroquinoline hydrochloride dissolved In absolute ethanol is treated with a solution of 4.3B g of diethylamine and 1. B g of paraformaldehyde in 20 cc of absolute ethanol. The reaction mixture is heated under reflux for 16 hours, evaporated to one-half volume and the warm solution treated with an excess of hydrogen chloride dissolved in absolute ethanol. Acetone is added to the warm solution until it becomes turbid and then the solution is cooled. The crude dihydrochloride which separates is collected and purified by recrystallization from methanol MP 240°-242°C. 

Paraformaldehyde (7.5 g) (0.25 mol) and 18.3 g (0.25 mol) of diethylamine are mixed in 25 cc of alcohol and warmed until a clear solution Is obtained. The solution is cooled and mixed with 26.6 g (0.10 mol) of 3,3 -diallyl-4,4 -biphenol in 25 cc of alcohol. After standing several hours, the solution is warmed for one hour on the steam bath, allowing the alcohol to boil off. The residue is then taken up in ether and water, the ether layer separated and washed with 2% sodium hydroxide solution and finally with water. The washed ether solution is dried over solid potassium carbonate, and filtered. After acidifying with alcoholic hydrogen chloride, the ether is distilled off and the alcoholic residue diluted with an equal volume of acetone. The crystalline hydrochloride is filtered off, triturated with alcohol, diluted with several volumes of acetone, filtered and dried MP 209°-210°C. 

To this solution there is added in about 20 minutes a solution of diethylamine in CHCI3 while the temperature is kept below 35°C. The reacting mixture is heated to boiling, water formed during the reaction being distilled off thereby. After two hours the distillate contains no more water and the reaction is finished. Water is added to dissolve diethylamine hydrochloride formed during the reaction, and the chloroform layer containing the product is separated from the aqueous layer. The product may be purified by distillation it boils at 132°C at 0.2 mm pressure. It is converted to the citrate by reaction with citric acid. 

Calcon may also be used for the titration of calcium in the presence of magnesium (compare Section 10.48). The neutral solution (say, 50 mL)is treated with 5 mL of diethylamine (giving a pH of about 12.5, which is sufficiently high to precipitate the magnesium quantitatively as the hydroxide) and four drops... 

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. 

Irradiation of 2-azidobiphenylene in the presence of diethylamine yields no azepines, whereas 4-azidobenzocyclobutene (75) gives the cyc obut[<7]azepine 76 as the only ring-expanded product.189... 

Photolysis of methyl 4-azidobenzoate in a 1 % solution of diethylamine in methanol affords only /V,iV-dicthyl-3//-azepin-2-amine (50% yield), a result which emphasizes the superior nucleophilic character of diethylamine in these reactions.199... 

Deoxygenations of 2-nitrosobiphenyls with triethyl phosphite in the presence of diethylamine produce mixtures of carbazoles and Ar,Ar-diethyl-3/f-azepin-2-amines.182 The yields, however, are substantially lower (10-51 %) than those obtained by the photolyses of 2-azidobiphenyls in diethylamine. 

N. A-Diethyl-2.3-dihydro-8//-thieno[2,3-r/]azcpin-7-amine (20), which is obtained in 49 % yield by photolysis of 6-azido-2,3-dihydrothiophene in a mixture of diethylamine and tetrahydro-furan. on treatment with bromine yields the fully unsaturated derivative 21.1,4... 

Azidopyrimidines 1 and 2-azidopyrazines 3 containing electron-donating substituents exist largely in the azide rather than the tetrazole form. Such azides are converted into 1,3,5-triazepines 2 and 4, respectively, when irradiated in the presence of a large excess of diethylamine or sodium methoxide.374... 

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