- Lewis Acid-Catalyzed Intramolecular [3+2] Cross-Cycloaddition of Aziridine 2,2-Diesters with Conjugated Dienes for Construction of Aza-[n.2.1] Skeletons
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A novel Lewis acid-catalyzed [3+2] intramolecular cross-cycloaddition (IMCC) between aziridine 2,2-diesters and conjugated dienes has been developed. This is the first regiospecific IMCC of intramolecular 1,3-dipolar cycloadditions of azomethine ylides with carbon=carbon double bonds, and supplies a general and efficient strategy for construction of structurally complex and diverse aza-[n.2.1] skeletons. The [3+2]IMCC could be carried out under mild conditions and in gram scale. More importantly, 3-alkyl-substituted aziridines were also successful. The excellent structural diversity, the facile operation and the versatile post-modifications will support the applications of the [3+2]IMCC in natural products synthesis and drugs discovery.
- Zhan, Yizhou,Liu, Tao,Ren, Jun,Wang, Zhongwen
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- Synthetic antibody protein mimics of infliximab by molecular scaffolding on novel CycloTriVeratrilene (CTV) derivatives
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Syntheses of novel semi-orthogonally protected CycloTriVeratrilene (CTV) analogues with enhanced water solubility, that is 3 and 4, derived from the previously described CTV scaffold derivative 2 are described here. These scaffolds 2-4 enabled a sequential introduction of three different complementarity determining region (CDR) mimics via Cu(i)-catalysed azide-alkyne cycloaddition towards medium-sized protein mimics denoted as "synthetic antibodies". The highly optimised sequential introduction enabled selective attachment of three different CDR mimics in a one-pot fashion. This approach of obtaining synthetic antibodies, demonstrated by the synthesis of paratope mimics of monoclonal antibody infliximab (Remicade), provided a facile access to a range of (highly) pre-organised molecules bearing three different (cyclic) peptide segments and may find a wide range of applications in the field of protein-protein interaction disruptors as well as in the development of synthetic vaccines or lectin mimics. The prepared synthetic antibodies were tested for their affinity towards tumour necrosis factor alpha using surface plasmon resonance and synthetic antibodies with micromolar affinities were uncovered.
- Longin, Ond?ej,Hezwani, Mohammed,Van De Langemheen, Helmus,Liskamp, Rob M. J.
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p. 5254 - 5274
(2018/08/04)
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- Synthesis of podands with cyanurate or isocyanurate cores and terminal triple bonds
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The synthesis of podands with cyanuric or isocyanuric acid cores and oligoethyleneoxy pendant arms exhibiting terminal triple bonds or brominated triple bonds is reported. The starting material for cyanuric acid derived podands is commercially available c
- Piron, Flavia,Oprea, Cornelia,Cisma, Crinas,Terec, Anamaria,Roncali, Jean,Grosu, Ion
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experimental part
p. 1639 - 1644
(2010/07/04)
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- Carbocyclization reaction of ω-iodo- and 1,ω-diiodo-1-alkynes without the loss of iodine atoms through a carbenoid-chain process
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(Chemical Equation Presented) Atom-economical carbocyclization reactions of ω-iodo-1-alkynes and 1,ω-diiodo-1-alkynes to give products with incorporation of iodine atoms is described. Cycloisomerization of 2-(2-propynyloxy)ethyl iodides is initiated by a catalytic amount of LDA to give 3-(iodomethylene)tetrahydrofurans in high yields. Upon treatment of with a catalytic amount of 1-hexynyllithium, 1ω-diiodo-1-alkynes efficiently undergo cycloisomerization to give (diiodomethylene)cycloalkanes. The diiodomethylene products are also obtained by iodine atom-transfer-type cyclization of ω-iodo-1-alkynes, using 1-iodo-1-hexyne as an external iodine atom source. Bromine atom-transfer and proton-transfer cyclization proceed as well by employing 1-bromo-1-octyne and 1-octyne, respectively. These reactions are proposed to proceed through a carbenoid-chain process involving exo-cyclization of the lithium acetylide intermediates to give Li,I-alkylidene carbenoids. It is shown that the exo-cyclization proceeded stereospecifically through inversion of the stereochemistry at the electrophilic carbon.
- Harada, Toshiro,Muramatsu, Keiko,Mizunashi, Kenia,Kitano, Chie,Imaoka, Daisuke,Fujiwara, Takayuki,Kataoka, Hiroshi
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p. 249 - 258
(2008/09/17)
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