Amines structures

Hydrolysis of an enamine yields a carbonyl compound and a secondary amine. Only a few rate constants are mentioned in the literature. The rate of hydrolysis of l-(jS-styryl)piperidine and l-(l-hexenyl)piperidine have been determined in 95% ethanol at 20°C 13). The values for the first-order rate constants are 4 x 10 sec and approximately 10 sec , respectively. Apart from steric effects the difference in rate may be interpreted in terms of resonance stabilization by the phenyl group on the vinyl amine structure, thus lowering the nucleophilic reactivity of the /3-carbon atom of that enamine. 

Hies 4 02a Determine whether the vinyl amine structure we considered in the last chapter is a... 

Recently, Li et al. [30], Yu et al. [31] reinvestigated the mechanism of graft copolymerization of vinyl monomers onto carbohydrates such as starch and cellulose initiated by the Ce(IV) ion with some new results as mentioned in Section II. Furthermore, they investigated the mechanism of model graft copolymerization of vinyl monomers onto chitosan [51]. They chose the compounds containing adjacent hydroxyl-amine structures, such as D-glucosamine, /mn5-2-amino-cyclohexanol, 2-... 

Interactive to use a web-based palette to draw amine structures based on their IUPAC names. 

III. cyclic amine structures incorporated into the polymer chain... 

The earliest structure-activity relationships indicated that the transplatinum geometry is inactive— significantly higher doses must be given before any therapeutic effect is seen. In 1991, it was reported that alteration of amine structure and the introduction of sterically hindered amines produced cytotoxicity similar to that of cisplatin.162 The first examples used planar amines and a variety of tra s-[PtCl2(L)(L )] compounds have been synthesized and evaluated ((21)-(26), Figure 12).163... 

The products from the cyclopropenium immonium cations 153 and primary and secondary amines88 vary with amine structure and basicity of the amino function... 

The major metabolites of lidocaine formed from this part of the molecule are the amine (16), which is further oxidized to the para-phenol, N-dealkylation of the parent drug with loss of acetaldehyde to form the secondary amine, and a second N-dealkylation to form the primary amine (structure not shown). Although there are only a few major metabolites of lidocaine, with sensitive analytical methods it is likely that hundreds of minor metabolites could be detected. 

The compounds are obtained by coupling diazotized 1-aminoanthraquinone onto 2-hydroxy-3-naphthoic acid, followed by separation, drying, and conversion into the azo dye acid chloride. Condensation with amines (structure 81) is achieved in an aprotic organic solvent. 

Unlike the MM2 force field, there is no explicit treatment of the nitrogen (or oxygen) lone pair in MM3. This allows one to calculate planar amine structures, as a model to... 

The most active rodenticidal compound turned out to be our initial lead, 2,4,6-trichloro-2, 4, 6 -trinitrodiphenyl amine (Structure 5). This was tested under a variety of conditions with white laboratory rats and mice. We were able to determine from these tests that, even given a choice, laboratory rats and mice would consume enough of the toxicant to cause 80% lethality. 

Mechanism of Action A sympathomimetic amine structurally similar to dextroamphetamine and is most likely mediated via norepinephrine and dopamine metabolism. Causes stimulation of the hypothalamus. Therapeutic Effect Decreased appetite. 

Nearly all peptide-bond-forming reactions employ tertiary amines in some manner, most commonly for neutralization of amine salts and/or as an adjunct to the activating agent. Table 2 shows the effect of tertiary amine structure on the rate of racemization of two UNCAs in toluene solvent. 

In amine-imine systems (75 76) the mobile proton can in principle be located at either of the two basic nitrogen sites in the anion (77). Since the canonical form with aromatic (benzenoid) structure is polar in the imine (76b) and non-polar in the amine (75a), the amine structure should be favoured, particularly in non-polar solvents. This seems generally to be the case, although solvent and medium effects do not appear to have been investigated the results available at the present time refer mainly to aqueous and other polar solvents. 

Additional information about the effect of amine structure and solvent on the steric course of the reaction of amines with acetylenecarboxylic esters has recently been reported by Huisgen [93]. 

The extent of racemization of peptide aldehydes exposed to silica gel has been determined as a function of time (Table 3).b0 The amount of racemization increases in the order Z-Cys(Bzl)-H > Z-Phe-H > Z-Leu-H > Z-Arg(N02)-HJ5 The unusually small amount of racemization observed with Z-Arg(N02)-H is probably due to its cyclic carbinol amine structure, which prevents racemization through a keto-enol mechanism. More racemization is seen in aldehydes possessing side chains such as Z-Cys(Bzl)-H that favor enolsJ15 ... 

Increasing the solvent polarity results in a red shift in the -t -amine exciplex fluorescence and a decrease in its lifetime and intensity (113), no fluorescence being detected in solvents more polar than tetrahydrofuran (e = 7.6). The decrease in fluorescence intensity is accompanied by ionic dissociation to yield the t-17 and the R3N" free radical ions (116) and proton transfer leading to product formation (see Section IV-B). The formation and decay of t-17 have been investigated by means of time resolved resonance Raman (TR ) spectroscopy (116). Both the TR spectrum and its excitation spectrum are similar to those obtained under steady state conditions. The initial yield of t-1 is dependent upon the amine structure due to competition between ionic dissociation and other radical ion pair processes (proton transfer, intersystem crossing, and quenching by ground state amine), which are dependent upon amine structure. However, the second order decay of t-1" is independent of amine structure... 

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