13734-34-4Relevant articles and documents
Synthesis of cyclic peptides through ring-closing metathesis of photolabile protecting groups
Hoffmann, Judith,Kazmaier, Uli
, p. 411 - 420 (2015)
The new photolabile protecting groups 4-allyl-5-methoxy-3-nitrobenzyl (AMNB) and 4-allyl-5-methoxy-3-nitrobenzyloxycarbonyl (AMNBOC) with an allylic side chain can easily be obtained from vanillin. These protecting groups can be introduced on the C- as well as on the N-terminus of peptides, and subsequent ring-closing metatheses provides a straightforward protocol for the synthesis of cyclic peptides. The protecting groups can be removed under UVA irradiation (365 nm).
Reusable resin plug-bound palladium catalysts for organic synthesis
Atrash, Butrus,Reader, John,Bradley, Mark
, p. 4779 - 4782 (2003)
Resin plugs, a unique and conveniently handled form of resin, prepared by sintering high-density polyethylene (HDPE) with pre-functionalised resins, were derivatised and loaded with palladium(0). These 'plugs' were used in the preparation of a Suzuki reaction based library and the removal of allyl ester protecting groups. The 'plugs of catalyst' were easily separated from the reaction mixture and were re-used multiple times with minimal loss of activity.
β-Sheet to Helical-Sheet Evolution Induced by Topochemical Polymerization: Cross-α-Amyloid-like Packing in a Pseudoprotein with Gly-Phe-Gly Repeats
Hema, Kuntrapakam,Sureshan, Kana M.
, p. 8854 - 8859 (2020)
Protein-mimics are of great interest for their structure, stability, and properties. We are interested in the synthesis of protein-mimics containing triazole linkages as peptide-bond surrogate by topochemical azide-alkyne cycloaddition (TAAC) polymerization of azide- and alkyne-modified peptides. The rationally designed dipeptide N3-CH2CO-Phe-NHCH2CCH (1) crystallized in a parallel β-sheet arrangement and are head-to-tail aligned in a direction perpendicular to the β-sheet-direction. Upon heating, crystals of 1 underwent single-crystal-to-single-crystal polymerization forming a triazole-linked pseudoprotein with Gly-Phe-Gly repeats. During TAAC polymerization, the pseudoprotein evolved as helical chains. These helical chains are laterally assembled by backbone hydrogen bonding in a direction perpendicular to the helical axis to form helical sheets. This interesting helical-sheet orientation in the crystal resembles the cross-α-amyloids, where α-helices are arranged laterally as sheets.
Highly Stable Zr(IV)-Based Metal-Organic Frameworks for Chiral Separation in Reversed-Phase Liquid Chromatography
Jiang, Hong,Yang, Kuiwei,Zhao, Xiangxiang,Zhang, Wenqiang,Liu, Yan,Jiang, Jianwen,Cui, Yong
supporting information, p. 390 - 398 (2021/01/13)
Separation of racemic mixtures is of great importance and interest in chemistry and pharmacology. Porous materials including metal-organic frameworks (MOFs) have been widely explored as chiral stationary phases (CSPs) in chiral resolution. However, it remains a challenge to develop new CSPs for reversed-phase high-performance liquid chromatography (RP-HPLC), which is the most popular chromatographic mode and accounts for over 90% of all separations. Here we demonstrated for the first time that highly stable Zr-based MOFs can be efficient CSPs for RP-HPLC. By elaborately designing and synthesizing three tetracarboxylate ligands of enantiopure 1,1′-biphenyl-20-crown-6, we prepared three chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2]. They share the same flu topological structure but channels of different sizes and display excellent tolerance to water, acid, and base. Chiral crown ether moieties are periodically aligned within the framework channels, allowing for stereoselective recognition of guest molecules via supramolecular interactions. Under acidic aqueous eluent conditions, the Zr-MOF-packed HPLC columns provide high resolution, selectivity, and durability for the separation of a variety of model racemates, including unprotected and protected amino acids and N-containing drugs, which are comparable to or even superior to several commercial chiral columns for HPLC separation. DFT calculations suggest that the Zr-MOF provides a confined microenvironment for chiral crown ethers that dictates the separation selectivity.
Topochemical Ene–Azide Cycloaddition Reaction
Khazeber, Ravichandran,Sureshan, Kana M.
supporting information, p. 24875 - 24881 (2021/09/22)
Topochemical reactions, high-yielding solid-state reactions arising from the proximal alignment of reacting partners in the crystal lattice, do not require solvents, catalysts, and additives, are of high demand in the context of green processes and enviro
Crystallization method of Boc-amino acid
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Paragraph 0045-0052, (2021/04/17)
The invention belongs to the technical field of medicinal chemistry, and particularly relates to a crystallization method of Boc amino acid. The preparation method comprises the following steps: (1) reacting free amino acid with di-tert-butyl dicarbonate, carrying out post-treatment to obtain a Boc-protected amino acid reaction solution, and carrying out reduced pressure distillation to remove a solvent until the solvent is dry, thereby obtaining a colorless or light yellow transparent oily substance; (2) adding a seed crystal into the obtained oily substance, standing for a period of time at normal temperature, curing the oily substance to be white, and then adding a weak polar solvent for pulping; (3) pulping for a period of time, filtering, washing, and drying under reduced pressure to obtain the product. According to the method, crystallized Boc amino acid cannot be separated out and crystallized by a conventional method, so that the purity of the product is improved, and meanwhile, the product has certain stability and can be stored for a long time without being decomposed.