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1.
Judith Cudaj 《Tetrahedron letters》2010,51(23):3092-3094
We present a total synthesis of the fungal natural product graphislactone G, a chlorinated resorcylic lactone. The key step is a Suzuki coupling used for the construction of the central biaryl bond. Graphislactone G was prepared in 13 steps with 22% yield starting with orcinol and phloroglucinic acid, where the longest linear sequence consists of nine steps. 相似文献
2.
First Stereoselective Synthesis of the Cytotoxic Polyketide (4R)‐1‐(3,5‐Dihydroxyphenyl)‐4‐hydroxypentan‐2‐one
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Kothakonda Rajendra Prasad Sudina Purushotham Reddy Katragadda Suresh Babu Janaswamy Madhusudana Rao 《Helvetica chimica acta》2015,98(1):143-147
The first stereoselective synthesis of the cytotoxic polyketide (4R)‐1‐(3,5‐dihydroxyphenyl)‐4‐hydroxypentan‐2‐one ( 1 ) was achieved from readily available propylene oxide and 3,5‐dimethoxybenzyl alcohol. The synthesis involves Jacobsen's hydrolytic kinetic resolution (HKR) and Grignard reaction as key steps. 相似文献
3.
Matthias Schmid Adriana S. Grossmann Peter Mayer Thomas Müller Thomas Magauer 《Tetrahedron》2019,75(24):3195-3215
We describe the evolution of a synthetic strategy for the construction of the marine polyketide salimabromide. Combining a bicyclo[3.1.0]hexan-2-one ring-expansion to build up a functionalized naphthalene and an unprecedented rearrangement/cyclization cascade, enabled synthesis of a dearomatized tricyclic subunit of the target compound. Alternatively, an intramolecular keteniminium [2 + 2]-cycloaddition and subsequent Baeyer–Villiger ring-expansion gave access to the sterically encumbered architecture of salimabromide. Sequential oxidation of the carbon framework finally enabled the total synthesis of this unusual natural product. 相似文献
4.
Syntheses of (+)-altholactone isolated from Goniothalamus giganteus and its C-7 epimer (+)-7-epi-altholactone, (?)-etharvensin and (+)-alumheptolide-A were achieved. The lactone ring of these compounds was constructed using Pd-catalyzed carbonylation. 相似文献
5.
Dr. Qingpei Liu Dan Zhang Shuaibiao Gao Xianhua Cai Dr. Ming Yao Yao Xu Yifu Gong Ke Zheng Yigui Mao Liyan Yang Dr. Dengfeng Yang Dr. István Molnár Dr. Xiaolong Yang 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214379
Orsellinic acid (OA) derivatives are produced by filamentous fungi using nonreducing polyketide synthases (nrPKSs). The chain-releasing thioesterase (TE) domains of such nrPKSs were proposed to also catalyze dimerization to yield didepsides, such as lecanoric acid. Here, we use combinatorial domain exchanges, domain dissections and reconstitutions to reveal that the TE domain of the lecanoric acid synthase Preu6 of Preussia isomera must collaborate with the starter acyl transferase (SAT) domain from the same nrPKS. We show that artificial SAT-TE fusion proteins are highly effective catalysts and reprogram the ketide homologation chassis to form didepsides. We also demonstrate that dissected SAT and TE domains of Preu6 physically interact, and SAT and TE domains of OA-synthesizing nrPKSs may co-evolve. Our work highlights an unexpected domain–domain interaction in nrPKSs that must be considered for the combinatorial biosynthesis of unnatural didepsides, depsidones, and diphenyl ethers. 相似文献
6.
Eveline Vriens Dr. Dries De Ruysscher Dr. Angus N. M. Weir Dr. Sofie Dekimpe Dr. Gert Steurs Ahmed Shemy Leentje Persoons Dr. Ana Rita Santos Dr. Christopher Williams Prof. Dirk Daelemans Prof. Matthew P. Crump Prof. Arnout Voet Prof. Wim De Borggraeve Prof. Eveline Lescrinier Prof. Joleen Masschelein 《Angewandte Chemie (International ed. in English)》2023,62(34):e202304476
Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) are modular megaenzymes that employ unusual catalytic domains to assemble diverse bioactive natural products. One such PKS is responsible for the biosynthesis of the oximidine anticancer agents, oxime-substituted benzolactone enamides that inhibit vacuolar H+-ATPases. Here, we describe the identification of the oximidine gene cluster in Pseudomonas baetica and the characterization of four novel oximidine variants, including a structurally simpler intermediate that retains potent anticancer activity. Using a combination of in vivo, in vitro and computational approaches, we experimentally elucidate the oximidine biosynthetic pathway and reveal an unprecedented mechanism for O-methyloxime formation. We show that this process involves a specialized monooxygenase and methyltransferase domain and provide insight into their activity, mechanism and specificity. Our findings expand the catalytic capabilities of trans-AT PKSs and identify potential strategies for the production of novel oximidine analogues. 相似文献
7.
Three new spiculoic acids 1-3 and two members of a new closely related family of natural products named zyggomphic acids 4 and 5 were isolated from the very little studied marine sponge Plakortis zyggompha. Both families of compounds share a unique trans-hydrindan-2-one skeleton with six stereogenic centers. A total of 15 new metabolites were isolated from this sponge, all are of polyketide origin. The structures were elucidated using LC-MS, 1D, and 2D NMR methods. The absolute stereochemistry was determined by circular dichroism. The large number of close bioactive analogues allowed us to propose preliminary structure-activity relationships as antitumoral and antimycobaterial agents. 相似文献
8.
Ning Luo 《Journal of organometallic chemistry》2009,694(19):3058-3067
Reactions of anti-psoriasis drug dithranol with 1-alkynyl Fischer carbene complexes (CO)5MC(OEt)CCPh (M = Cr, W) were investigated under controlled conditions in which triethylamine-promoted C-addition, O-addition, electrophilic aromatic substitution, and cyclization consecutively occurred at up to five positions of dithranol. A remarkable solvent effect led to selective formation of polyphenolic organic and organometallic mono- and triscarbene complexes which were efficiently demetalated to the potentially bioactive aromatic polyketides with pyridine-N-oxide. All the organic and organometallic products were characterized by methods including X-ray single crystal structural determinations. These results have revealed the novel multiple reactivities of dithranol which might be associated to its clinical side effect, providing a new synthetic methodology to functionalize dithranol for medical purposes, and chemically synthesize aromatic polyketides. 相似文献
9.
Three new polyketide metabolites, the twelve‐membered macrolides (6R,12S)‐6‐hydroxy‐12‐methyloxacyclodoecane‐2,5‐dione ( 1 ), (10S,12S)‐10‐hydroxy‐12‐methyloxacyclododecane‐2,5‐dione ( 2 ), and 4,5‐dihydroxy‐12‐methyloxacyclododecan‐2‐one ( 3 ), were isolated from the endophytic fungal strain Cladosporium tenuissimum LR463 of Maytenus hookeri, together with three known compounds, cladospolide A, cladospolide B, and isocladospolide B. Their structures were elucidated by spectroscopic analysis including 1D‐ and 2D‐NMR experiments, and the absolute configurations of 1 and 2 were determined by the Mosher ester method. 相似文献
10.
3,5-Dioxoalkanoates, 3,5-dioxopimelates and 2,4-dioxoadipates were prepared by acylation of 1,3-bis-silyl enol ethers with carboxylic chlorides, methyl 3-chloro-3-oxopropanoate and ethyl 2-chloro-2-oxoacetate, respectively. 相似文献