Aminoalkyl Types

In further work on nylon [145], this trifunctional reactant was applied simultaneously with various nucleophilic dyes of the aminoalkyl type (Scheme 7.71). As in the case of the Basazol system on cellulose (Scheme 7.60), the intended formation of covalent dye-fibre linkages has to compete with side reactions, such as partial hydrolysis (Scheme 7.70), di- or trimerisation that may lead to less than optimum fastness, or substrate crosslinking that may adversely influence desirable fibre characteristics. 

The addition of compounds of type 3 to C=N double bond systems leads to O-alkyl(aminoalkyl) O-silylphosphonates 9. Monoalkyl esters of aminoalkyl phosphonous acids 10 are formed in excellent yield by solvolysis of 9 [3]. 

Nucleophilic aminoalkyl dyes of the types described above can be fixed on cotton that has... 

Interest in Fixing Agent P (7.123) has been revived in the context of nucleophilic aminoalkyl dyes of the 7.129 and 7.131 types. Nylon pretreated with this symmetrical trifunctional reactant contains residual acryloyl sites that will undergo an addition reaction with nucleophilic dye molecules [145]. Although in theory each N-terminal amino group in the fibre can give rise to two acryloyl sites (Scheme 7.73), crosslinking between two N-... 

In 1960 HeUmann and Opitz introduced their a-Aminoalkyliemng book, wherein they mentioned that the majority of the name reactions by MCRs belong together since they have in common their essential features. This collection of 3CRs can be considered as Hellmann-Opitz 3-component reactions, (HO-3CRs). They are either a-aminoalkylations of nucleophiles of MCR type I, or they form intermediate products that react with further bifunctional educts into heterocycles by 4CRs of type II. Their last step is always a ring closure that proceeds irreversibly. 

The MCRs of type II forming heterocycles begin with a-aminoalkylations of nucleophilic compounds, and subsequently these products react further with bifunctional educts whose last step is always an irreversible ring formation. Such... 

Although the intramolecular aminocarbonylation described above is an extension of the standard amide-forming reaction, a different type of intramolecular aminocarbonylation has been studied, wherein the amine moiety adds across the olefin moiety activated by a Pd catalyst to generate /3-aminoalkyl-Pd species, followed by CO insertion and alcoholysis, forming a lactone or an ester. ... 

The PET systems of the aminoalkyl aromatic type discussed so far display a very simple behavior in that luminescence intensity (or quantum yield) is the only variable. Such systems are very user-friendly as a result and tolerate a wide variety of communication wavelengths. However these simple systems could be adapted to include an additional absorptiometric sensing channel which can confirm the results of ion density (pH say) obtained via luminescence. Of course, such increased user-confidence is only attained with a proportionate reduction in simplicity. Now excitation needs to be done at the isosbestic wavelength. These systems, e.g. 11 and 12, use a push-pull fluorophore with electron donor and acceptor substituents which give rise to internal charge transfer (ICT) excited states. In contrast, the simple PET systems employed aromatic hydrocarbon fluorophores with essentially pure nn excited states. The charge separation in ICT states can cause electrostatic... 

Given the success of PET switches and sensors of the off-on type (Section 5), there is no fundamental reason why on-off systems cannot grow to be similarly useful. However there is little doubt that off-on systems are more visually appealing. Besides this aesthetic factor, off-on systems and especially the aminoalkyl aromatic family tend to be synthetically more accessible since amine synthons are available in great variety. 

Few examples of Mannich-type aminoalkylations of ketones on solid phase have been reported [54]. The resulting 3-amino ketones are generally acid-sensitive and highly reactive, and mild cleavage conditions must be employed for the release of the... 

The methodology of the catalytic asymmetric aldol reaction has been further extended to the aldol-type condensation of (isocyanomethyl)phosphonates (12) with aldehydes, providing a useful method for the synthesis of optically active (l-aminoalkyl)phosphonic acids, which are a class of biologically interesting phosphorous analogs of a-amino acids (Scheme 8B1.6) [21,22], Higher enantioselectivity and reactivity are obtained with diphenyl ester 12b than with diethyl ester 12a (Table 8B1.6). 

Chatgilialoglu C, Castelhano AL, Griller D (1985) Structures and optical absorption spectra of some sulfuranyl radicals in solution. J Org Chem 50 2516-2518 D Alessandro N, Bianchi G, Fang X, Jin F, Schuchmann H-P, von Sonntag C (2000) Reaction of superoxide with phenoxyl-type radicals. J Chem Soc Perkin Trans 2 1862-1867 Das S, von Sonntag C (1986) Oxidation of trimethylamine by OH radicals in aqueous solution, as studied by pulse radiolysis, ESR and product analysis. The reactions of the alkylamine radical cation, the aminoalkyl radical and the protonated aminoalkyl radical. Z Naturforsch 41b 505-513 Das S, Schuchmann MN, Schuchmann H-P, von Sonntag C (1987) The production of the superoxide radical anion by the OH radical-induced oxidation of trimethylamine in oxygenated aqueous solution. The kinetics of the hydrolysis of (hydroxymethyl)dimethylamine. Chem Ber 120 319-323... 

However, it could be shown that in principle simple imines can be used successfully as well for asymmetric aminoalkylation reactions catalyzed by chiral Lewis acids. The asymmetric allylation of simple imines 16 with allyltributylstannane (Scheme 6) catalyzed by the / -pinene derivative 17 [32a], for example furnished comparatively good results (for related asymmetric catalytic allylations of simple imines, see [32b-d]). Moreover, it was demonstrated on the basis of several Strecker-type syntheses [33-35] that catalysts such as the chiral aluminum complex 18 (Scheme 6) [33a—b] are also well suited for enantioselective aminoalkylations with simple imines. The mechanism indicated in Scheme 6 shows that the... 

For two recent examples of asymmetric catalytic aminoalkylations of Reformatsky-type reagents, see a) Y. Ukaji, Y. Yoshida, K. Inomata, Tetrahedron ... 

The use of amides as source of carbamoyl and a-aminoalkyl radicals has also been widely employed since the 1970s [11]. Fenton-type systems utilizing tert-butyl hydroperoxide or hydrogen peroxide in the presence of Fe(II) salts and the S2Os2 / Ag+ system have been applied in the functionalization of aromatic bases with amides (Equation 14.7). 

A separate vein of examples worthy of investigation can be found in a surprising location - pharmaceutical chemistry. In fact, this field abounds with aminoalkyl aromatic systems of varied structure. At least one reason for this wealth is that biogenic amines are of this structural type and serve as a continuing inspiration for the drug discovery effort. An early example is (43), first described in 1951 as a prospective antimalarial [101]. (43) has been found in our laboratory to display pH sensitive fluorescence [102] as expected of a PET sensor. The spacer of three carbon atoms limits the PET rate in the proton-free form which leads to a modest but useful proton-induced fluorescence enhancement. The fluorescence properties of another antimalarial (44) with structural features required of a PET sensor have been recently reported in a different context [103] and deserves sensory evaluation. 

There are two major groups of synthetic compounds which have cannabin-oid activity, but which differ chemically from the tricyclic THC-like canna-binoids the bicyclic cannabinoids, exemplified by compound CP55940 (23), and the (aminoalkyl)indoles exemplified by pravadoline (24a). A detailed SAR analysis of these groups of compounds is beyond the scope of this review. The bicyclic cannabinoids and derivatives have been reviewed previously [105] recent publications deal mainly with related tricyclic non-classical cannabinoids [106] and with the (aminoalkyl)indoles [92, 107]. It is of interest to note that while the bicyclic cannabinoids were originally prepared as simplified cannabinoids, the cannabinoid-type activity of the (ami-noalkyl)indoles was discovered by serendipity. These compounds were synthesized in a project aimed at the discovery of novel nonsteroidal anti-inflammatory agents presumably based on the indomethacin structure. However, while they did not possess anti-inflammatory properties, they were found to be antinociceptive, and to inhibit the electrically evoked contractions in a mouse vas deferens muscle preparation. This led to binding experi-... 

As ensues from the above discussions, the type of amine influences, in various ways, the availability of ketone-amine photoinitiator systems during the PET, during the proton transfer, and during the addition of the a-aminoalkyl radical at the C=C double bond. For practical purposes, the compounds VI-XI possess the most favorable properties. 

The aminoalkylation reactions applied to the synthesis of alkaloids arc mostly cycliyui-tions of the type described in Chap, I, C.4, usually involving CH substrates such as alkyl ketones. The analogous reactions on alkcncs arc frequently accompanied by more or less relevant modiheations of the substrate molecule (Chap. I, C.5). Activated aromatic substrates, particularly phenols and their alkylether derivatives, arc also subjected to Mannich reaction. 

The N-aminoalkylation of pyrazole and triazole (88, Fig. 34), also, can take place regioselectively in a fashion similar to the abovementioned N-aminoalkylations that occur on 5-phenyl idantoin 69. This is related to the tautomeric equilibrium present in the heteroaromatic ring, with the prevailing site of the reaction of type A (see also Fig. 79, below). -252.3io.432... 

Catecholamines degrade rapidly via oxidative reactions and are catalyzed by oxygen, pH s >6, heavy metal ions, heat, and UV-VIS radiation. UV-VIS radiation is more deleterious than temperature, and UV is 15 times more deleterious than VIS radiation. The degradation rates, of individual catecholamines, vary and are dependent on the position of their phenolic groups and the type of N-substituents in the aminoalkyl side chain. For instance, norepinephrine is more stable than epinephrine, and epinephrine is more stable than isoprenaline. 

A novel Mannich-type reaction of N-(y3-aminoalkyl)benzotriazoles with silyl enolates has also been developed [11]. 

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