22329-75-5Relevant articles and documents
Unsaturated carbonyl compounds and their preparation method and application
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Paragraph 0223-0230, (2019/07/04)
The invention discloses a unsaturated carbonyl compounds and their preparation method and application. The unsaturated carbonyl compounds of the general formula as the molecular structure of the following formula (I) as shown: The unsaturated carbonyl com
Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- And β-C-H bonds through an Allyl-Iridium Intermediate
Wang, Zhen,He, Zhiqi,Zhang, Linrui,Huang, Yong
supporting information, p. 735 - 740 (2018/01/26)
Direct aerobic α,β-dehydrogenation of γ, δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed a new strategy that overcomes the challenging issue associated with the low α-acidity of amides and acids. Instead of α-C-H metalation, this reaction proceeds by β-C-H activation, which results in enhanced α-acidity. Conjugated dienamides and dienoic acids were synthesized in excellent yield with this reaction, which uses a simple reaction protocol. Mechanistic experiments suggest a catalyst resting state mechanism in which both α-C-H and β-C-H cleavage is accelerated.
Total synthesis and antibacterial testing of the A54556 cyclic acyldepsipeptides isolated from streptomyces hawaiiensis
Goodreid, Jordan D.,Wong, Keith,Leung, Elisa,McCaw, Shannon E.,Gray-Owen, Scott D.,Lough, Alan,Houry, Walid A.,Batey, Robert A.
, p. 2170 - 2181 (2014/12/11)
The first total synthesis of all six known A54556 acyldepsipeptide (ADEP) antibiotics from Streptomyces hawaiiensis is reported. This family of compounds has a unique mechanism of antibacterial action, acting as activators of caseinolytic protease (ClpP). Assembly of the 16-membered depsipeptide core was accomplished via a pentafluorophenyl ester-based macrolactamization strategy. Late stage amine deprotection was carried out under neutral conditions by employing a mild hydrogenolysis strategy, which avoids the formation of undesired ring-opened depsipeptide side products encountered during deprotection of acid-labile protecting groups. The free amines were found to be significantly more reactive toward late stage amide bond formation as compared to the corresponding ammonium salts, giving final products in excellent yields. A thorough NMR spectroscopic analysis of these compounds was carried out to formally assign the structures and to aid with the spectroscopic assignment of ADEP analogues. The identity of two of the structures was confirmed by comparison with biologically produced samples from S. hawaiiensis. An X-ray crystallographic analysis of an ADEP analogue reveals a conformation similar to that found in cocrystal structures of ADEPs with ClpP protease. The degree of antibacterial activity of the different compounds was evaluated in vitro using MIC assays employing both Gram-positive and Gram-negative strains and a fluorescence-based biochemical assay.
Synthesis of polymeric ladders by topochemical polymerization
Hou, Xiaodong,Wang, Zhihan,Lee, Joseph,Wysocki, Erin,Oian, Casey,Schlak, Jennifer,Chu, Qianli R.
supporting information, p. 1218 - 1220 (2014/02/14)
Two polymeric ladders were synthesized by topochemical polymerization. The critical assemblies with multiple reactive centers were characterized by single crystal X-ray diffraction. Approximately 64% and 70% of the mass of the two polymeric ladders can be
Mining the Cinnabaramide Biosynthetic Pathway to Generate Novel Proteasome Inhibitors
Rachid, Shwan,Huo, Liujie,Herrmann, Jennifer,Stadler, Marc,Koepcke, Baerbel,Bitzer, Jens,Mueller, Rolf
, p. 922 - 931 (2012/02/15)
The cinnabaramides and salinosporamides are mixed PKS/NRPS natural products isolated from a terrestrial streptomycete and a marine actinomycete, respectively. They interfere with the proteasome and thus potentially inhibit the growth of cancer cells. The compounds exhibit a γ-lactam-β-lactone bicyclic ring structure attached to a cyclohexenyl unit and a PKS side chain. As a first step towards improving anticancer activity and permitting genetic approaches to novel analogues, we have cloned and characterized the cinnabaramide biosynthetic genes from Streptomyces sp. JS360. In addition to the expected PKS and NRPS genes, the cluster encodes functionalities for the assembly of the hexyl side chain precursor. The corresponding enzymes exhibit relaxed substrate specificities towards a number of synthesized precursors, enabling production of novel chlorinated cinnabaramides. These were isolated and analyzed for activity, revealing that derivatives bearing a chlorine atom in the PKS side chain show higher inhibitory potentials towards the proteasome's proteolytic subunits (especially the trypsin and chymotrypsin units) and higher cytotoxicities towards human tumor cell lines than the parent cinnabaramide A. Although their activities towards the proteasome were weaker than that of salinosporamide A, the cinnabaramides were found to inhibit the growth of various fungi with greater potency. Copyright
Synthesis and preliminary biological characterization of new semisynthetic derivatives of ramoplanin
Ciabatti, Romeo,Maffioli, Sonia I.,Panzone, Gianbattista,Canavesi, Augusto,Michelucci, Elena,Tiseni, Paolo S.,Marzorati, Ettore,Checchia, Anna,Giannone, Matteo,Jabes, Daniela,Romanò, Gabriella,Brunati, Cristina,Candiani, Gianpaolo,Castiglione, Franca
, p. 3077 - 3085 (2008/02/06)
Ramoplanin is a glycolipodepsipeptide antibiotic active against Gram-positive bacteria including vancomycin-resistant enterococci. Ramoplanin inhibits bacterial cell wall biosynthesis by a mechanism different from that of glycopeptides and hence does not show cross-resistance with these antibiotics. The systemic use of ramoplanin has been so far prevented because of its low local tolerability when injected intravenously. To overcome this problem, the fatty acid side chain of ramoplanin was selectively removed and replaced with a variety of different carboxylic acids. Many of the new ramoplanin derivatives showed antimicrobial activity similar to that of the natural precursor coupled with a significantly improved local tolerability. Among them the derivative in which the 2-methylphenylacetic acid has replaced the di-unsaturated fatty acid side chain (48) was selected as the most interesting compound and submitted to further in vitro and in vivo characterization studies.
Reaction principles and crystal structure design for the topochemical polymerization of 1,3-dienes
Matsumoto, Akikazu,Sada, Kazuki,Tashiro, Kohji,Miyata, Mikiji,Tsubouchi, Takashi,Tanaka, Toshihiro,Odani, Toru,Nagahama, Sadamu,Tanaka, Tomoyuki,Inoue, Katsunari,Saragai, Seishi,Nakamoto, Shinsuke
, p. 2502 - 2505 (2007/10/03)
Stacking made to order: Weak intermolecular interactions such as 2D hydrogen-bonding networks, aromatic-ring stacking, and CH/π or halogen-halogen interactions account for the columnar organization of muconic and sorbic acid derivatives in the crystalline state (see picture). When the stacking distance is close to 5 A these 1,3-dienes undergo topochemical polymerization upon irradiation.
Conjugation of biomolecules using Diels-Alder cycloaddition
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, (2008/06/13)
A method is provided for covalently linking carbohydrates, proteins, nucleic acids, and other biomolecules under neutral conditions, using a Diels-Alder cycloaddition reaction. In an example, activated carbon-carbon double bonds were attached to free amino sites of a carrier protein, and a conjugated diene was attached to a carbohydrate hapten. Spontaneous coupling of the carbohydrate and the protein components under very mild conditions provided glycoconjugates containing up to 37 carbohydrate hapten units per carrier protein molecule. The method is also applicable to the immobilization of biomolecules on gel or solid supports. The conjugated products are useful as immunogens and as analytical and diagnostic reagents.
Organoaluminum-promoted cycloaddition of trialkylsilylketene with aldehydes: A new, stereoselectie approach to cis-2-oxetanones and 2(Z)-alkenoic acids
Concepcion,Maruoka,Yamamoto
, p. 4011 - 4020 (2007/10/02)
The exceptionally bulky methylaluminum bis(4-bromo-2,6-di-tert-butylphenoxide) (MABR) can be successfully utilized as a highly efficient Lewis acid for achieving high stereoselectivity in the cycloaddition of trialkylsilylketene with aldehydes. This method serves as a highly effective route to the synthesis of cis-2-oxetanones from saturated aldehydes, and the synthesis of 2(Z)-alkenoic acids from aromatic and α,β-unsaturated aldehydes.
