The reactions of trans-[PtCl₄(RCN)₂] (R= Me, Et, CH₂Ph, Ph) with the diamines and the triamine NH₂{spacer}NH₂ (spacer = CH₂CH₂, CH(Me)CH₂, CH₂CH₂CH₂, CH₂CH₂CH₂CH₂, CH₂CH₂NHCH₂CH₂) in a molar ratio 1 : 2 produce trans-[PtCl₄{NH=C(R)NH{spacer}NH₂}₂] (spacer/R = CH₂CH₂/Et 1, CH₂CHMe/Et 2 (a mixture of regioisomers), CH₂CH₂CH₂/Et 3, CH₂CH₂CH₂CH₂/Et 4, CH₂CH₂/Me 5, CH₂CH₂/CH₂Ph 6, CH₂CH₂/Ph 7, CH₂CH₂NHCH₂CH₂/Et 8) with the monodentately coordinated amidine ligands having the pendant NH₂ groups. The complexes have been characterised by C, H, and N elemental analyses, ¹³C CP-MAS NMR and IR spectroscopy, (TOF)-ESI-MS, and [1·H₂](Pic)₂·EtOH also by X-ray diffraction.
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http://dx.doi.org/10.1039/c001103g | DOI Listing |
Disulfide bridging, also known as disulfide stapling, is a powerful strategy for the construction of site-selective protein bioconjugates. Here we describe the first examples of a new class of such reagents, containing a 'stable-labile' design. These dual-reactive reagents are designed to form a stable bond to one cysteine and a labile bond to the second; resulting in a robust attachment to the protein with one end of the bridge, whilst the other end serves as a reactive handle for subsequent bioconjugation.
View Article and Find Full Text PDFIn the most general practice of asymmetric catalysis, a chiral catalyst, typically bearing a center or an axis of chirality, is employed as the chiral source for imparting enantiocontrol over the developing product. Given the current interest toward optically pure compounds, various forms of chiral induction enabled by diverse chiral sources as well as the use of multiple catalysts under one-pot conditions have been in focus. In one such promising development, an achiral -sulfonamide protected 1,6-amino allyl alcohol (NaphSONHCHC(Ph)CHCH[double bond, length as m-dash]CHCHOH) was subjected to Tsuji-Trost activation and an intramolecular amination to form important chiral pyrrolidine frameworks.
View Article and Find Full Text PDFBiosens Bioelectron
April 2021
Department of Chemistry, Shanghai Stomatological Hospital, State Key Laboratory of Molecular Engineering of Polymers and Institute of Biomedical Sciences, Fudan University, Shanghai, 200433, PR China. Electronic address:
Chempluschem
November 2020
Department of Chemistry, Yonsei University, Seoul, 03722, Republic of Korea.
Two indolocarbazole-naphthyridine foldamers 2 and 3 that fold into helical conformations were prepared. The 4-(N,N-dimethylamino)pyridine (DMAP) moiety was introduced at one end of the foldamer strands to develop foldamer-based catalysts for the site-selective acylation of polyols. These foldamers adopt helical conformations containing internal cavities capable of binding octyl β-d-glucopyranoside.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2017
Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California, Irvine, CA 92697;
Product template (PT) domains from fungal nonreducing polyketide synthases (NR-PKSs) are responsible for controlling the aldol cyclizations of poly-β-ketone intermediates assembled during the catalytic cycle. Our ability to understand the high regioselective control that PT domains exert is hindered by the inaccessibility of intrinsically unstable poly-β-ketones for in vitro studies. We describe here the crystallographic application of "atom replacement" mimetics in which isoxazole rings linked by thioethers mimic the alternating sites of carbonyls in the poly-β-ketone intermediates.
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