Ethylamine, 31 Table

The logical consequence of using chiral acids as CDAs for amines, as outlined in Figure 6, is that (.R)- and (S)-l-(aryl)ethylamines (Table 1, entries 39 to 43) almost ideally fulfill the requirements of CDAs for separating chiral acids due to the difference in bulkiness of the substituents on the stereogenic centers. Amino acid derivatives such as L-leucinamide also serve well as CDAs. Both types have been highly appreciated as can be seen from the number of applications listed in Table 2. The condensation reactions between the chiral carboxylic acids and amines (CDAs) can be performed in several ways. However, the mildest but quantitative ones will be most appropriate in order to minimize the potential risks of racemization of any stereogenic center. Otherwise, erroneous analytical data or optically impure diaslereomers could be obtained in the course of the preparative separation. 

The classical histamine receptor antagonists are stmcturaHy very similar, all being substituted ethylamines (2). Table 1 presents a member of each stmctural subclass. Presumably, the ethylamine core is needed to accomplish nonfmitfiil binding to the high affinity conformation of the receptor. 

TABLE 2. Reductive cleavage reactions of sulphones induced by lithium in methylamine or ethylamine... 

As already reported in Table 6, the solubility of phosphazene polymers is strongly influenced by the nature of the substituent groups attached at the phosphorus atoms along the -P=N- skeleton. Water-solubility, for instance, can be induced in polyphosphazenes by using strongly polar substituents (e.g. methylamine [84], glucosyl [495], glyceryl [496], polyoxyethylene mono-methylether [273] or sulfonic acid [497,498] derivatives), or may be promoted by acids or bases when basic (amino substituents like ethylamine [499]) or acid (e.g. aryloxy carboxylate [499] or aryloxy hydroxylate [295]) substituents are exploited. 

It is difTicult to choose between groups when using the Hass table the substance can belong to group 4 (ethylamine) or 7 (ethylene glycol) or even 8 (ethanol). 

Potassium borohydride reduction of runanine (17) yielded dihydro-runanine (24), the H-NMR spectrum of which (Table II) exhibited a triplet (64.25), the proton bearing the hydroxyl group coupling with those of C-5 (35). The optical activity of runanine (17), [a]D —400°, was similar to that of hasubanonine (5), [a]D —214° (3) therefore, it was concluded that the ethylamine linkage must have the same configuration as hasubanonine [C-13 (R) and C-14 (S)]. From these results, structure 17 was proposed for runanine (35) however, no application of mass spectral data to the structure elucidation was presented (35). 

The degradation of ethylamine (36 ppm) was carried out in different experimental conditions for 1 h through an interval of 15 min. The percentage degradation is given in Table 12.1 and shown graphically in Fig. 12.1. 

As can be seen from the data in Table 35.1, the maximum reaction rate is achieved at the 5 2 formic acid triethylamine ratio that is the commonly used azeotropic mixture known as TEAF. When more acid is present, the catalyst may be less active, but equally there may be less formate anion (i.e., the active reagent). The concentration of the latter also depends upon the solvent being used. When there is more triethylamine present the reaction rate also decreases, and there are some indications that triethylamine may deactivate the catalyst. However, the use of formic acid mixtures with ammonia, ethylamine or diethy-lamine is less effective than triethylamine. 

While mescaline is a simple 2-phenethylamine derivative, the addition of an alpha-methyl group to the side chain yields Structure 8 (TMA). This simple hybrid of the structures of mescaline and amphetamine retains the hallucinogenic effects of mescaline but possesses about twice the potency of the latter (174,200). Addition of the alpha-methyl to other 3,4,5-substituted compounds generally brings about an approximately twofold increase in potency. The addition of an alpha-methyl to 2,4,5-substituted compounds, however, may dramatically increase activity. For example, 2-(2,4,5-trimethoxyphenyl) ethylamine apparently is clinically inactive (195). Addition of an alpha-methyl gives TMA-2 (Table 1), with 20 times the potency of mescaline. However, the addition of an alpha-methyl does not significantly increase in vitro receptor affinity in either 3,4,5-or 2,4,5-series (72,78). Thus it is probable that the alpha-methyl may confer metabolic stability in vivo. It could also be speculated that this protection is more important in the 2,4,5-substituted series than in 3,4,5-substituted compounds. 

Table 5. Oxidation potentials (half peak potentials, Epl/2) of fluoro-ethylamines and related amines...

Fig. 9. Spinning. Four A yV-dimethyl-a-bromophenethylamines ligands were aligned by their ethylamines (tail) as denoted in Alignment 7 of Table 5. Alignments that do not take into consideration the substituted regions of interest can lead to poor alignments providing dis-informative 3D-QSAR models. It is for this reason that many alignment schemes are tested to elucidate the one that will render the most useful model.

There is much less difference in the abstraction rate constants, k4, between ethylamine and n-butylamine (Table III) than that found between methylamine and ethylamine. This is expected if the hydrogen... 

On the other hand, quantitative yields of bicyclo[3.1.1]heptanes were observed when tricy-clo[4.1.0.02,7]heptanes were reduced with lithium in refluxing ethylamine or ethylcncdiamine (see Table 3).17,18 The mechanism of this chemical reduction can be rationalized as follows ... 

Table 54 Dinuclear Complexes of (2-Pyridyl)methylamine, l-(2-Pyridyl)ethylamine and Related Open Chain...

Korenman et al. [45] studied the solvent-water partition coefficients Ksv/ of ethylamine, n-propylamine, and n-butylamine at 20°C. Based on the data for these amines with a short, linear alkyl chain, the contributions to the logarithm of the solvent-water partition coefficients were found to be constant among particular solvent classes. The contribution values are shown in Table 13.4.1. Accordingly, A log K0VI for CH2 is 0.50. 

Using here the more restrictive definition ofa cracking reaction as a process in which there is rupture of at least one carbon-carbon bond in a hydrocarbon (74, 93a, 127,148, 150, 210-213), ethylamine 156), or ether 214), the compensation trend Table II, D was found. Data reported by Tetenyi et al. 215) were represented by the different line Table II, E. Exchange reactions were more satisfactorily considered in two groups ... 

Data for the common compensation line on this metal for cracking of hydrocarbons (74,151,212,213) and ethylamine (156), also including methane exchange (39,219) and oxidation reactions (207,209a) are reported in Table II, K. 

The hydrogenation activity of W2C/Zeolite Y was evaluated in the synthesis of amines. The standard conditions reported earlier were followed. Although traditionally a Ni catalyst is used for hydrogenation, there is a need for a hydrogenation catalyst that is more sulfur resistant than Ni. It was found that the W2C/Zeolite Y may act as a hydrogenation catalyst for acetonitrile. Acetonitrile conversion was found to be high at 573-723 K, but the selectivity was low. A mixture of ethylamine, diethylamine and hydrocarbons was formed, Table 22.2. In this reaction, about 15% of the products could not be accounted for and further work is needed to investigate this reaction. 

The available evidence supports the demethylation scheme and the identity of the initial red product as that of the basic tautomer of trimethylthionine (Azure B), as shown in eqs. 33 and 34. Addition of acid or other weak proton donor protonates the red dye to give the blue form. We have reexamined the reaction of MB or New methylene blue (NMB) in dry acetonitrile with tri-ethylamine (TEA). We have also found that a comparable reaction of NMB occurs with trimethylbenzylstannane (TMBS). Figure 8 shows changes in the visible spectrum of NMB which occur in addition of TEA. Table 12 lists quantitative data. The spectra... 

It can be seen from this table that a-(p-tolyl)ethylamine is judged as the most promising resolving agent for the acid. 

Figure 5. Inhibition of anti-lacto-N-tetraose (R31) by oligosaccharides. Inhibition assays are performed as described in the legend to Figure 2. Abbreviations of oligosaccharides are given in Table I. An abbreviation followed by -OH or etNH, refers to the reduced form or the f3-(p-aminophenyl) ethylamine derivative of the oligosaccharide, respectively.

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