Diethylaniline, reactions

Among all the pyridine derivatives, 2-amino-3,5-dicyano-6-sulfanyl pyridines are even more interesting because of their potential therapeutic applications. In synthetic chemistry, the cyclocondensation of aldehydes, malononitrile, and thiols is the most straightforward pathway. In general, this transformation can be realized under basic conditions. The bases reported included EtsN, DABCO, piperidine, morpholine, thiomorpholine, pyrrolidine, N,N-DIPEA, pyridine, 2,4,6-collidine, DMAP, aniline, iV-methylaniline, A,A-dimethylaniline and N,N-diethylaniline. Reactions under neutral conditions have been explored as well. In these cases, Cul nanoparticles [75], ZnCl2 [76], and nanocrystalline magnesium oxide [77] have been applied as the catalysts. 

Diethylaniline. Use 28 g. of pure aniline and 36 g. (34 ml.) of purified ethyl phosphate, and proceed exactly as described for dimethylaniline. The reaction is not so vigorous initially. Separation into two layers occurs after 30 to 90 minutes. The yield of diethylaniline, b.p. 215-216°, is 41-5 g. 

A mixture of 0.30 mol of the tertiairy acetylenic alcohol, 0.35 mol of acetyl chloride (freshly distilled) and 0.35 mol of /V/V-diethylaniline was gradually heated with manual swirling. At 40-50°C an exothermic reaction started and the temperature rose in a few minutes to 120°C. It was kept at that level by occasional cooling. After the exothermic reaction had subsided, the mixture was heated for an additional 10 min at 125-130°C, during which the mixture was swirled by hand so that the salt that had been deposited on the glass wall was redissolved. After cooling to below 50°C a mixture of 5 ml of 36% HCl and 200 ml of ice-water was added and the obtained solution was extracted with small portions of diethyl ether. The ethereal solutions were washed with water and subsequently dried over magnesium sulfate. The solvent was removed by evaporation in a water-pump vacuum... 

V-Alkylation can also be carried out with the appropriate alkyl haUde or alkyl sulfate. Reaction of aniline with ethylene, in the presence of metallic sodium supported on an inert carrier such as carbon or alumina, at high temperature and pressure yields V/-ethyl- or /V,/V-diethylaniline (11). At pressures below 10 MPa (100 atm), the monosubstituted product predominates. 

In contrast to electrophilic reagents, the highly -tt-deficient character of the pteridine nucleus is responsible for its vulnerability towards nucleophilic attack by a wide variety of reagents. The direct nucleophilic substitution of pteridine itself in a Chichibabin-type reaction with sodamide in diethylaniline, however, was unsuccessful (51JCS474). Pteridin-6-one, on the other hand, yielded pteridine-6,7-dione under the same conditions, via a still unknown reaction mechanism. 

On the other hand, Davies5 , studying the reaction of adipic add with 1,5-pentanediol in diphenyl oxide or diethylaniline found an order increasing slowly from two with conversion. From this result he concluded that Flory s1,252-254> and Hinshelwood s240,241 interpretations are erroneous. Two remarks must be made about the works of Davies5 experimental errors relative to titrations are rather high and kinetic laws are established for conversions below 50%. Under such conditions the accuracy of experimental determinations of orders is rather poor. 

Reaction is brought about thermally usually at around 200 °C either in an inert solvent (diphenyl ether, cyclohexane and diethylaniline have been used) or in the absence of a solvent. If the ortho positions in the aromatic ether are blocked (as in LXXVII) then rearrangement to the para position LXXVIII occurs, viz. 

On the other hand, numerous examples are already known in which monomeric metaphosphoric esters are generated by thermolysis reactions. Most worthy of mention in this context is the gas phase pyrolysis of the cyclic phosphonate 150 which leads via a retro-Diels-Alder reaction to butadiene and monomeric methyl metaphosphate (151) 108,109, no). While most of the phosphorus appears as pyrophosphate and trimeric and polymeric metaphosphate, a low percentage (<5%) of products 152 and 153 is also found on condensation of the pyrolyzate in a cold trap containing diethylaniline or N,N,N, N,-tetraethyl-m-phenylene-diamine. The... 

The reaction of 151 with methanol to give dimethyl phosphate (154) or with N-methylaniline to form the phosphoramidate 155 and (presumably) the pyrophosphate 156 complies with expectations. The formation of dimethyl phosphate does not constitute, however, reliable evidence for the formation of intermediate 151 since methanol can also react with polymeric metaphosphates to give dimethyl phosphate. On the other hand, reaction of polyphosphates with N-methylaniline to give 156 can be ruled out (control experiments). The formation of 156 might encourage speculations whether the reaction with N,N-diethylaniline might involve initial preferential reaction of monomeric methyl metaphosphate via interaction with the nitrogen lone pair to form a phosphoric ester amide which is cleaved to phosphates or pyrophosphates on subsequent work-up (water, methanol). Such a reaction route would at least explain the low extent of electrophilic aromatic substitution by methyl metaphosphate. 

The formation of 151 from the phosphonate 171 could be proved only by indirect means. Electron-rich aromatic compounds such as N,N-diethylaniline and N,N,N, N -tetraethyl-m-phenylenediamine U0 1I9> and N-methylaniline 120> are phosphorylated in the para- and in the ortho- plus para-positions by 151. Furthermore, 151 also adds to the nitrogen lone pair of aniline to form the corresponding phosphor-amidate. Considerable competition between nucleophiles of various strengths for the monomeric methyl metaphosphate 151 — e.g. aromatic substitution of N,N-diethylaniline and reaction with methanol or aromatic substitution and reaction with the nitrogen lone pair in N-methylaniline — again underline its extraordinary non-selectivity. 

A. Weller and K. Zachariasse 157-160) thoroughly investigated this radical-ion reaction, starting from the observation that the fluorescence of aromatic hydrocarbons is quenched very efficiently by electron donors such as N,N diethylaniline which results in a new, red-shifted emission in nonpolar solvents This emission was ascribed to an excited charge-transfer complex 1(ArDD(H )), designated heteroexcimer, with a dipole moment of 10D. In polar solvents, however, quenching of aromatic hydrocarbon fluorescence by diethylaniline is not accompanied by hetero-excimer emission in this case the free radical anions Ar<7> and cations D were formed. 

Other aromatic nitramines have not found use as practical explosives. Ethyltetryl (232) is prepared from the nitration of 2,4-dinitro-A-ethylaniline, A,A-diethylaniline or N-ethylaniline. Butyltetryl (233) can be synthesized from the nitration of 2,4-dinitro-A-butylaniline, which is attainable from the reaction of n-butylamine with 2,4-dinitrochlorobenzene. 

Condensed derivatives have also been prepared. Reaction of 2-aminothi-azoles with 2,3-dichloro-l,4-naphthoquinone yields naphth[2,3-h]im-idazo[2,l-h]thiazole-5,10-dienones 62 via thiazolylaminoquinones 61. Cycli-zation can be effected either with diethylaniline (method a) [77IJC(B)356] or with sodium hydroxide and tetrabutylammonium bromide (TBAB) catalyst (method b) (82H333). Following route b, compound 62 (R = Et) can be isolated in 92% yield. Reactions between 2-aminothiazoles and chloranil leading to dithiazolobenzobisimidazolediones have also been reported [79IJC(B)523]. 

Analysis of rate constants for the bimolecular attack of substituted anilines at 308 K clearly indicated that steric effects on the nucleophile play a role. 2,6-Dimethyl- and 2,6-diethylaniline react more than an order of magnitude slower than 3,5-dimethylaniline at the same temperature (Table 7) 9 90. A comparison of the rate constants for reaction of aniline and A-methylaniline at 278 K and A-methylaniline with A-phenylaniline at 298 K provides further evidence of steric effects although the very small rate constant for the diphenylamine could, in part, also be attributed to reduced nucleophihcity due to resonance into the additional phenyl ring. 

A mixture of 152.4ml (193,2g) of absolute ethanol and 583.1ml (627g) n, n-diethylaniline are placed in a dropping funnel and added dropwise with stirring to the mixture from step 1. During this addition maintain the reaction temperature at 20° to 30° C by use of an i9e bath, and flush dry nitrogen through the system. The exit gas line from the condenser is connected, to a mercury bubbler. 

Trifluoromethylation of 1-morpholinocycloalkene or /V,/V-diethylaniline with (CF3)3Bi was mediated by Cu(OAc)2 (Scheme 13) [29]. The reaction of 1-morpholi-nocycloalkene afforded 2-trifhioromethylcycloalkanones in moderate to good yields, after acid hydrolysis of the intermediate products. In the reaction of N,N-diethylaniline, equimolar amounts of trifhioromethylanilines and CF3H were produced. The reaction was believed to proceed through CF3 radical, which was produced from intermediate Cu(CF3)(OAc). 

The liquid phase reaction of aniline with ethanol produces wanted mono-ethylaniline and unwanted diethylaniline... 

Monoethylaniline can also be produced in the vapor phase in a fluidized bed using natural bauxite as the solid catalyst. The elementary reactions are shown in the previous problem. Using an equimolar feed of aniline and ethanol, the fluidized bed produces 3 parts monoethylaniline to 2 parts diethylaniline for a 40% conversion of aniline. Assuming mixed flow of gas in the fluidized bed, find k2lk and the concentration ratio of reactants and products at the exit of the reactor. 

W.A -Diethylaniline (0.70 mol) and redistilled acetyl chloride (0.37 mol) arc placed in the flask. The acetylenic alcohol (0.30 mol) is added over a few min while heating the mixture at ca. 40"C. An exothermic reaction starts and the temperature rises to 120 C in a few min. Occasional cooling is necessary to keep the temperature at that level. After the exothermic reaction has subsided, the mixture is heated for an additional 15 min at 130"C (immersion of the flask in the heating bath is necessary to prevent solidification of the reaction mixture on the glass wall). After cooling to 50 C (stirring has been stopped), a mixture of 300 ml of ice... 

Tangible evidence was found for the in situ production of perfluoro(2,3,4,5-tetrahydro-pyridines) 2, 3, and 4 during the transfer of F- from perfluoro-l-fluoropiperidine (1) to carbanionic sources.22 23 Perfluoro-l-fluoropiperidine (1) was employed to convert triphenyl-phosphane, -arsane, and -stilbane to the difluorides, triphenylphosphorus difluoride, triphenyl-arsenic difluoride, and triphenylantimony difluoride, respectively,24 and sodium phenoxide to 2- and 4-fluorophenol.25 Perfluoro-l-fluoropiperidine (1) reacts with 7V,/V-dimethylaniline, substituting the 0/7/m-hydrogen by fluorine. A similar reaction proceeds with /V,/V-diethylaniline.26... 

A closely related reaction involves that between a saturated acyl halide and a phenol or phenolic ether. A necessary feature of the acid chloride is that it contains a bromine atom at C-2 which allows formation of a double bond during the reaction by loss of bromide. Normal Friedel-Crafts conditions are employed in the first step which leads to an o-hydroxyphenyl 2-bromoalkyl ketone (589). In boiling diethylaniline, hydrogen bromide is lost and the resulting acrylophenone spontaneously cyclizes to the chromanone <24LA(439)132). 

Once again, it is important to realize that cyclization to a coumaranone is a feasible alternative reaction. Indeed, in the above example treatment of the initial ketone (589) with sodium hydroxide instead of diethylaniline gave 2,2-diethyl-5-methylcoumaran-3-one together with hydrolyzed but uncyclized ketone (590). 

Ketone Method. In the ketone method, die central carbon atom is derived from phosgene. A diarylketone is prepared from phosgene and a tertiary arylamine and then condenses with another mole of a tertiary arylamine (same or different) in the presence of phosphorus oxychloride or zinc chloride. The dye is produced directly without an oxidation step. Thus, ethyl violet CT Basic Violet 4, is prepared from 4.4 -bis(diethy]amino)benzophenone with diethylaniline in the presence of phosphorus oxychloride. This reaction is very useful for the preparation of unsymmetrical dyes. 

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