N-Ethyl derivatives

In the case of tertiary N-ethylamine derivatives the N-ethyl group is first selectively oxidized by p-chloranil to an enamino group which then condenses with excess p-chloranil to a blue aminovinylquinone derivative [7]. Secondary N-ethyl derivatives do not yield blue aminovinylquinone derivatives they probably react directly with chloranil by nucleophihc attack at one of the four chlorine atoms to yield aminoquinones of other colors [7], It has also been suggested that some classes of substances react to yield charge transfer complexes [1, 5, 8, 12],... 

The chromatograms are freed from mobile phase in a stream of warm air, then immersed in the dipping solution for 2 s or homogeneously sprayed with the appropriate spray solution. Then, in the case of N-ethyl derivatives, the plate is heated to 105-110 °C for 2 min to accelerate the reaction [7]. Heating (e. g. to 80-105 °C for 15 min) can also lead to color intensification and color change in the case of other alkaloids [5, 6]. 

Ethoxylcarbonyl-2-arylazo-2-nitroe thane derivatives lb 365 Ethoxyquine la 106,108 Ethylamine lb 104,268 N-Ethylamine derivatives, tertiary lb 290 Ethylamphetamines la 45 N-Ethyl-N -benzylthiourea lb 301 N-Ethyl derivatives lb 190 -, secondary lb 190 -, tertiary lb 188, 191 Ethelenediamine la 392 Ethylene glycol dinitrate lb 415 N4-Ethyl-N4-(2-methanesulfonamido-ethyl)-2-methyl-l,4-phenylenediamine, reagent la 368... 

The detection limits (substance per chromatogram zone) are 10 to 20 ng for arom amines [1], 100 ng for phenothiazines [8], 0.5 to 2 pg for secondary amine alkaloids 5 to 50 pg for N-ethyl derivatives [7], 1 to 3 pg for penicillins [10], 1 to 4 pg for dime and 1 to 2 pg for a range of steroids [9]. There have been some repmrts of apprecis lower detection limits of 40-400 ng substance per chromatogram zone and even less alkaloids [6]. 

The Leuckart-Wallach reaction is the oldest method of reductive amination of carbonyl compounds. It makes use of formamide, formic acid or ammonium formate at high temperature. The final product is a formamide derivative, which can be converted to an amine by reduction or hydrolysis. The method has been applied to the preparation of 1,2-diamines with a norbornane framework, which are interesting rigid analogues of 1,2-diaminocyclohexanes. As a matter of fact, starting from N-acetyl-2-oxo-l-norbornylamine 222, the diamide 223 was obtained with excellent diastereoselectivity and then converted to the M-methyl-N -ethyl derivative 224 by reduction with borane [ 104] (Scheme 34). On the other hand, when the reac-... 

Stone, D.M. Johnson, M. Hanson, G.R. and Gibb, J.W. A comparison of the neurotoxic potential of methylenedioxy amphetamine (MDA) and its N-methylated and N-ethylated derivatives. Eur J Pharmacol 134 245-248, 1987a. 

The yield of the cyclization of /V-(3-nitrophenyl)aminomethylenemalo-nate (752, R = H) in polyphosphate did not improve significantly when the N-ethyl derivative (752, R = Et) was applied, but the isomeric ratio was shifted towards the 5-substituted compound (754) (75JHC557). 

Thienylaminomethylenemalonates were ethylated with ethyl p-toluenesulfonate in the presence of potassium carbonate (85EUP161235) and potassium hydroxide (87MI3) in DMF to afford N-ethyl derivatives (711, R = H, Me) in 80% and 41-48% yields, respectively. 

Isoxazolylaminomethylenemalonate (1482, R = H) was ethylated with ethyl iodide in DMF in the presence of potassium carbonate at ambient temperature overnight to afford the N-ethyl derivative (1482, R = Et)... 

Table 1.19. Some aminoglycoside antibiotics which have gained significant therapeutic application. Producer microorganisms are listed in brackets. In addition to naturally produced aminoglycosides, a number of semi-synthetic derivatives have also found medical application. Examples include amikacin, a semi-synthetic derivative of kanamycin and netilmicin, an N-ethyl derivative of sissomicin...

Their stability is comparable with that of disubstituted oxadiazoles. For instance, 5-hydroxy-3-phenyloxadiazole is not decomposed by heating up to 300° and it is stable towards hydrochloric, nitric and sulfuric acid. The hydroxyl group cannot be substituted by chlorine when treated with phosphorus pentachloride or oxychloride at 100° 27, 28). It is reduced to benzamidine with hydroiodic acid and red phosphorus 81). The silver salt treated with ethyl iodide gives an N-ethyl derivative XLVI 28, 58, 59). 

The solvent replacement was necessary because pyrrole complexes lacking a substituent on nitrogen undergo reductive amination to N-ethyl derivatives in CH3CN. 

AM Treston, WD Hooper. Urinary metabolites of phenobarbitone, primidone, and their N-methyl and N-ethyl derivatives in humans. Xenobiotica 22 385, 1992. 

Photoirradiation of the bromobenzyl-enamine 380 (R = H) in a solution of dioxan-acetonitrile containing triethylamine gave the dihy-drophenanthridine 381 (78CC766), which was also obtained when 380 was treated with lithium diethylamide (LDEA) in THF (78JA3598). Under the same conditions, the N-ethyl derivative 380 (R = Et) gave the... 

Reduction of deoxyaspidodispermine with lithium aluminum hydride in tetrahydrofuran (THF) gave the N-ethyl derivative (M+ 298) still showing a base peak at m/e 112, and this eliminated the possibility of a carbinolamine at C-3 or C-21. 

Chemoselective /V-ethylation of Boc-amino acids can be accomplished widiout racemization via the corresponding dianions. Thus, iV-f-butoxycarbonylamino acid (35) was converted into dianion (36) by treatment with 2 equiv. of Bu Li, followed by the reaction with 1 equiv. of triethyloxonium tetrafluoro-borate to give N-ethyl derivative (37) along with a trace of ethyl ester (38). On treatment with 2.2 equiv. of the triethyloxonium salt (36 R = Ph) gave (38 R = Ph) in 95% yield (Scheme 17).2 ... 

Of particular importance is the marked difference between the absorption spectra of the N-methyl and those of N-ethyl derivatives. None of the prevailing theories of color and chemical constitution can explain or predict these distinct differences. 

---