21870-78-0Relevant articles and documents
C-3 epimers of sugar amino acids as foldameric building blocks: improved synthesis, useful derivatives, coupling strategies
Nagy, Adrienn,Csordás, Barbara,Zsoldos-Mády, Virág,Pintér, István,Farkas, Viktor,Perczel, András
, p. 223 - 240 (2017/02/05)
To obtain key sugar derivatives for making homooligomeric foldamers or α/β-chimera peptides, economic and multigram scale synthetic methods were to be developed. Though described in the literature, the cost-effective making of both 3-amino-3-deoxy-ribofuranuronic acid (H–tX–OH) and its C-3 epimeric stereoisomer, the 3-amino-3-deoxy-xylofuranuronic acid (H–cX–OH) from d-glucose is described here. The present synthetic route elaborated is (1) appropriate for large-scale synthesis; (2) reagent costs reduced (e.g. by a factor of 400); (3) yields optimized are ~80% or higher for all six consecutive steps concluding –tX– or –cX– and (4) reaction times shortened. Thus, a new synthetic route step-by-step optimized for yield, cost, time and purification is given both for d-xylo and d-ribo-amino-furanuronic acids using sustainable chemistry (e.g. less chromatography with organic solvents; using continuous-flow reactor). Our study encompasses necessary building blocks (e.g. –X–OMe, –X–OiPr, –X–NHMe, Fmoc–X–OH) and key coupling reactions making –Aaa–tX–Aaa– or –Aaa–tX–tX–Aaa– type “inserts”. Completed for both stereoisomers of X, including the newly synthesized Fmoc–cX–OH, producing longer oligomers for drug design and discovery is more of a reality than a wish.
Nucleophilic displacement reactions in ionic liquids: Substrate and solvent effect in the reaction of NaN3 and KCN with alkyl halides and tosylates
Chiappe, Cinzia,Pieraccini, Daniela,Saullo, Paola
, p. 6710 - 6715 (2007/10/03)
Room-temperature ionic liquids have been used as environmentally benign solvents for the preparation of primary and secondary alkyl azides and nitriles under solid-RTIL phase-transfer conditions. The reaction of primary, secondary, and tertiary halides or tosylates with KCN and NaN3 has been investigated in three ionic liquids ([bmim][PF6], [bmim][N(Tf) 2], and [hpyr] [N(Tf)2]). The observed nucleofugacity scales for the reaction of NaN3 are similar to those reported for the same process in cyclohexane, indicating that in these solvents it is possible to evidence the intrinsic ability to depart of leaving groups. Changes in the nature of the IL cation or anion determine significant modifications in reactivity of the investigated substrates. Reactivity has been interpreted considering a gradual shift of the mechanism from concerted SN2 (primary substrates) to stepwise SN1 (tertiary substrate, 3), through the nucleophilically assisted formation of an ion pair intermediate, in the case of 2d.
3-Azidotetrahydrofuran-2-carboxylates: Monomers for five-ring templated β-amino acid foldamers?
Watterson, Mark P.,Pickering, Lea,Smith, Martin D.,Hudson, Sarah J.,Marsh, Paul R.,Mordaunt, Jacqueline E.,Watkin, David J.,Newman, Christopher J.,Fleet, George W. J.
, p. 1855 - 1859 (2007/10/03)
Four diastereomeric methyl 3-azidotetrahydrofuran-2-carboxylates were prepared from diacetone glucose as precursors for the synthesis of β-amino acid oligomers with secondary structure.
