Synthesis of amino-terminated

Hagihara, H. Tsuchihara, K. Sugiyama, J. Takeuchi, K. Shiono, T. Copolymerization of propylene and polar allyl monomer with zirconocene/ methylaluminoxane catalyst catalytic synthesis of amino-terminated isotactic polypropylene. Macromolecules 2004, 37, 5145. 

Derivatization of the hydroxy-terminated telechelics yields a large variety of new telechelics. A few examples are shown in Scheme 46. An improved Gabriel synthesis has been used successfully for the synthesis of amino-terminated telechelics. ... 

Ren L, Zhao G, Qiang T, Wang X, Wang N (2013) Synthesis of amino-terminated hyperbranched polymers and their application in microfiber synthetic leather base dyeing. 

General Procedure for the synthesis of amino-terminated tridendrons. To a solution of LiAlH4 (2 equiv. per CN function) in dry THF was added dropwise under vigorous stirring a solution of THF containing the appropriate... 

The most general methods for the syntheses of 1,2-difunctional molecules are based on the oxidation of carbon-carbon multiple bonds (p. 117) and the opening of oxiranes by hetero atoms (p. 123fl.). There exist, however, also a few useful reactions in which an a - and a d -synthon or two r -synthons are combined. The classical polar reaction is the addition of cyanide anion to carbonyl groups, which leads to a-hydroxynitriles (cyanohydrins). It is used, for example, in Strecker s synthesis of amino acids and in the homologization of monosaccharides. The ff-hydroxy group of a nitrile can be easily substituted by various nucleophiles, the nitrile can be solvolyzed or reduced. Therefore a large variety of terminal difunctional molecules with one additional carbon atom can be made. Equally versatile are a-methylsulfinyl ketones (H.G. Hauthal, 1971 T. Durst, 1979 O. DeLucchi, 1991), which are available from acid chlorides or esters and the dimsyl anion. Carbanions of these compounds can also be used for the synthesis of 1,4-dicarbonyl compounds (p. 65f.). 

Different solid-phase techniques for the synthesis of C-terminal peptide aldehydes have gained much attention and allowed greater accessibility to such compounds. Solid-phase techniques have been used to synthesize peptide aldehydes from semicarbazones, Weinreb amides, phenyl esters, acetals, and a, 3-unsaturated y-amino acids)47-50,60 63 The examples presented below use unique linkers to enhance the automated efficiency of C-terminal peptide aldehyde synthesis)47 For instance, the reduction of phenyl esters led to the aldehyde as the major product, but also a small amount of alcohol)50 The cleavage of u,p-unsaturated y-amino acids via ozonolysis yielded enantiomeric pure C-terminal peptides)49,61 The semicarbazone from reduction of peptide esters technique laid the initial foundation for solid-phase synthesis. Overall, Weinreb reduction is an ideal choice due to its high yields, optical purity, and its adaptability to a solid-phase platform)47 ... 

Reduction of acid halides with lithium tri-tert-butoxyaluminum hydride is an effective method for synthesis of amino aldehydes. Nonfunctionalized amino aldehydes 22 are readily prepared from respective reduction of the N-terminal Fmoc, Boc, or Z acid chlorides or fluorides 21 (Scheme 8, Table 9). This method afforded these aldehydes in about 60% yield with small differences in optical rotation as compared to literature values 11,33 48 54 55 ... 

Commonly used resins in Fmoc/tBu strategy for the synthesis of C-terminal peptide acid are reported in Fig. 5 (11-14). Anchoring reactions must be performed in an anhydrous medium and amino acids containing water should be dried before use. 

Guillaumie, L., Kappel, J. C., Kelly, N. M., Barany, G., and Jensen, K. J. (2000) Solid-phase synthesis of C-terminal peptide aldehydes from amino acetals anchored to a backbone amide linker (BAL) handle. Tetrahedron Lett. 41, 6131-6135. 

Changing the transition-metal from palladium to rhodium (equation 62) makes possible, in addition to the straight-chain alkylation product (243), the regio- and stereoselective synthesis of amino acid derivatives with a terminal double bond (242), starting from optically active branched allylic substrates 241 (Table 21)" . Remarkably, the substitution products were obtained with high enantiomeric excesses, what might result from a slow isomerization of the intermediary formed allyl rhodium complexes ". 

The thiol group of an Fmoc-protected Cys unit can be attached to a XAL handle 26, which then becomes attached to amino-functionalized supports.h l This method circumvents the racemization in the synthesis of C-terminal Cys peptide acids. The peptides are released by treatment with TEA. 

Figure 9.3 General schematic of the synthesis of amino-propyl-terminated poly(dimethylsiloxane) (Elsbernd et al., 1987).

J. Peptide Protein Res. 15, 73 (1980) R. Colombo, Experien -tia 38, 773 (1982). Isoln of chicken VIP A. Nilsson, FEES Letters 47, 284 (1974). Amino acid sequence idem, ibid. 60, 322 (1975). Synthesis of C -terminal fragment M. Bodan-szky et aL, Bioorg. Chem. 5, 339 (1976). Solid -phase synthesis R. Colombo, Int. J. Peptide Protein Res. 19, 71 (1982). Multiple immuuoreactive forms of VIP have also been found in human colonic mucosa R. Dimalinc, G. J. Dockray,... 

The oxime resin 5z [255,256], which forms an acid-stable anchor for the carboxyl group of amino acids, has been used for some time for the synthesis of C-terminal modified peptides and homodetic cyclic peptides. The key step in lactam formation is intramolecular nucleophilic attack of the A-terminus at the anchoring group. The resin also reacts with isocyanates and the products undergo nucleophilic attack by amines resulting in the release of ureas [257], Resin-bound Boc-tryptophan has been used in the acid-catalyzed Pictet-Spengler synthesis with final products cleaved as primary amides by... 

Ohno, H., Toda, A., Oishi, S., Tanaka, T., Takemoto, Y, Fujii, N. and Ibuka, T. 2000. Novel synthesis of chiral terminal aUenes viapaUadium(0)-catalyzed reduction of mesylates of 2-bromoalk-2-en-l-ols bearing a protected amino group, using diethylzinc. Tetrahedron Lett. 41 5131-5134. 

A broad variety of difunctional allylic olefins have been used for the synthesis of amino-, carboxyl-, and halide-terminated polybutadienes by means of the Grubbs catalyst I (396-398). With the same catalyst, commercially interesting hydroxy telechelic polybutadienes could be obtained by the cleavage of the acetyl end-capped polymer or the copolymer, as depicted in Figure 14 (399,400). 

Figure 7.4. (a) Synthesis of end-modified poly(beta-amino ester)s begins with the synthesis of acrylate-terminated polymer (Ex C32-Ac) by using an excess of diacrylate monomer for the reaction, (b) The acrylate-terminated polymer is end-capped by reacting it with (c) various amine-containing monomers, (d) Various acrylate-terminated PBAEs can also be similarly modified for improved efficacy. 

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