Aminoalkylation Subject

Substrates containing all the three reactive moieties of Mannich synthesis, that is, substrate, amine, and aldehyde, such as 161 (Fig. 56) also have been subjected to cy-clization. - Two carbonyl functions are present in these molecules, which may produce intramolecular aminoalkylation. 

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. 

Methylpyrrolo[3,4-f]isoxazoles 48, prepared from 3-(l-aminoalkyl)isoxazole-4-carboxylic esters (see Section 4.03.9.1.6), after deprotonation and condensation with aromatic aldehydes afforded compounds 49 that were subjected to N-O bond cleavage the use of Mo(CO)6 gave 3-enoyltetramic acids 50, whereas H2-catalyst allowed further reduction to 3-acyltetramic acids 51 (Scheme 12) <2004SL2815>. 

The possibility of inter-ionic and hydrophobic forces acting together to affect separation in some cases is likely. In a further publication, Shaltiel and Er-El [164] prepared a homologous series of co-aminoalkyl-agarose derivatives of the type, Sepharose-NH(CH2)n-NH2. When an extract of rabbit muscle was subjected to chromatography on these derivatives glycogen synthetase was not bound to n = 3 gels but was retained on 4-... 

On the other hand, this procedure for the self-assembled monolayer formation has a drawback. A monolayer adsorbed on a silica plate surface is subjected to the detachment of CRA-CM molecules more or less in polar solvents such as water and alcohols,since the adsorption stems from the hydrogen bond formation. This problem was overcome by the pretreatment of a silica plate surface with an aminoalkylation silylating reagent to introduce amino residues on the surface. A photoresponsive monolayer of... 

The regioselectivity of the hydrogen abstraction reaction between the photoinitiator and an amine remains an outstanding problem that is the subject of debates and discussions. A recent paper [264] based on ESR and laser flash photolysis clearly shows the presence of the aminoalkyl radical and the significant absence of any aminyl radical in primary and secondary amines such an aminyl radical is, however, readily observed in the same experimental conditions when using tetramethyl piperidine. 

Benzoxazinones of type (12) have been subjected to electrochemical reduction in the presence of strychnine and other optically active bases to give optically active 2-(aminoalkyl)benzoic acids, but the optical yields are generally low <82MI 604-01 >. 

The subjects of reports on radiation-induced polymerization have included the following monomers ethylene,70 tetrafluoroethylene,71 acrylonitrile,72 acrylic acid,78 and methacrylonitrile,74 alkyl acrylates and methacrylates,76 styrene,78 other vinyl monomers,77 78 acrylamide,79 vinylcarbazole,80 maleimide,81 pentenes,82 aminoalkyl monomers,83 isobutyl vinyl ether,84 and buta-1,3-diene.85... 

The synthesis of phosphonic acid derivatives by the direct oxidation of those of the corresponding phosphonous acid has been afforded very little interest (Chapter 2, Section VI.c), unlike the more controllable synthesis of derivatives of the thio- or seleno-phos-phonic acid derivatives (Chapter 5, Section II.B.4). In the present instance, the oxidation of A -protected (fmoc) (l-aminoalkyl)phosphinic esters has been carried out with NaI04 with high yields. Quantitative yields of (aminoalkyl)phosphonic acids were obtained in oxidation reactions with bromine water and with HgCl2-H20. In an alternative approach (Scheme 59), the A -protected (cbz) ethyl(l-aminoalkyl)phosphinate is initially converted into a (l-aminoalkyl)phosphonous acid diester, which is then subjected to the Atherton procedure to achieve change in valence at phosphorus. ... 

The photochemical behavior of the orr/to-(aminoalkyl)slil-benes 92—94 is also dependent upon the polymethylene linker (Scheme II). Irradiation of 93 and 94 results in formation of the benzazepines 96 and 97. These adducts are presumably formed by regioselective N—H transfer to the proximal end of the stilbene double bond in 93 and the distal end in 94, in both cases resulting in the formation of a 1,7-biradical intermediate. Since intramolecular stilbene-amine addition reactions are non-regioselective, the regioselectivily of N-H transfer must be subject to exciplex conformational control. The biradical inter-... 

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