61229-03-6Relevant academic research and scientific papers
Concise, scalable and enantioselective total synthesis of prostaglandins
Zhang, Fuhao,Zeng, Jingwen,Gao, Mohan,Wang, Linzhou,Chen, Gen-Qiang,Lu, Yixin,Zhang, Xumu
, p. 692 - 697 (2021/06/01)
Prostaglandins are among the most important natural isolates owing to their broad range of bioactivities and unique structures. However, current methods for the synthesis of prostaglandins suffer from low yields and lengthy steps. Here, we report a practicability-oriented synthetic strategy for the enantioselective and divergent synthesis of prostaglandins. In this approach, the multiply substituted five-membered rings in prostaglandins were constructed via the key enyne cycloisomerization with excellent selectivity (>20:1 d.r., 98% e.e.). The crucial chiral centre on the scaffold of the prostaglandins was installed using the asymmetric hydrogenation method (up to 98% yield and 98% e.e.). From our versatile common intermediates, a series of prostaglandins and related drugs could be produced in two steps, and fluprostenol could be prepared on a 20-gram scale. [Figure not available: see fulltext.]
The curved front row neil intermediate preparation method
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Paragraph 0129; 0130; 0133, (2019/04/02)
The invention relates to a preparation method for a treprostinil intermediate (I). The preparation method comprises the steps that: a compound of a formula (II) and a compound of a formula (III) or acidic salt thereof react in the presence of a condensing agent to obtain a compound of a formula (IV); the compound of the formula (IV) and a compound of a formula (V) react to obtain a compound of a formula (I). According to the preparation method for the treprostinil intermediate, weinreb amide and alkyne negative ions react to directly obtain a ketone compound (I), so that environment pollution caused by heavy metal (a PCC oxidant) is avoided, and the adoption of a butyl lithium low-temperature reaction method is also avoided. The preparation method for the treprostinil intermediate has the advantages that reaction conditions are mild, the yield is high, the purity of products is high, and the industrial application prospect is wide. (Formulae (I), (II), (III), (IV) and (V) are shown in the specification)
Total synthesis of natural (?)- and unnatural (+)-Melearoride A
Reed, Carson W.,Fulton, Mark G.,Nance, Kellie D.,Lindsley, Craig W.
supporting information, p. 743 - 745 (2019/02/09)
This communication details the first total synthesis of the 13-membered macrolide, (?)-Melearoride A, as well as unnatural (+)-Melearoride A. The synthesis features a concise 13 step synthesis (11 steps longest linear sequence) that offers flexible stereo-control and multiple opportunities for unnatural analog synthesis to delve into antifungal SAR. The route features a cuprate addition, an Evans asymmetric alkylation, and a ring-closing metathesis (RCM) to close the 13-membered macrocyclic core.
Synthesis of treprostinil: Key claisen rearrangement and catalytic pauson-khand reactions in continuous flow
García-Lacuna, Jorge,Domínguez, Gema,Blanco-Urgoiti, Jaime,Pérez-Castells, Javier
, p. 9489 - 9501 (2019/11/14)
A new synthesis of treprostinil is described using a plug flow reactor in two of the key steps. First, a Claisen rearrangement reaction is described in scaled flow at multigram amounts. Yields and selectivity of this step are sharply improved compared to those from previous syntheses. Second, the key Pauson-Khand reaction in flow is described under catalytic conditions with 5 mol% of cobalt carbonyl and only 3 equiv. of CO. Scaling up of this reaction safely ensures a good yield of an advanced intermediate which is transformed into treprostinil in three steps. Other improvements are the introduction of the carboxymethyl chain into the phenol from the beginning to reduce the protection-deprotection steps. The synthesis is completed in 14% global yield after 12 linear steps from (S)-epichlorhydrin.
Total Synthesis of Emmyguyacins A and B, Potential Fusion Inhibitors of Influenza Virus
Jana, Santanu,Sarpe, Vikram A.,Kulkarni, Suvarn S.
supporting information, p. 6938 - 6942 (2018/10/25)
Fungal glycolipids emmyguyacins A and B inhibit the pH-dependent conformational change of hemaglutinin A during replication of the Influenza virus. Herein, we report the first total synthesis and structure confirmation of emmyguyacins A and B. Our efficient route, which involves regioselective functionalization of trehalose, allows rapid access to adequate amounts of chemically pure emmyguyacin analogues including the desoxylate derivatives for SAR studies.
Photocatalytic Asymmetric Epoxidation of Terminal Olefins Using Water as an Oxygen Source in the Presence of a Mononuclear Non-Heme Chiral Manganese Complex
Shen, Duyi,Saracini, Claudio,Lee, Yong-Min,Sun, Wei,Fukuzumi, Shunichi,Nam, Wonwoo
supporting information, p. 15857 - 15860 (2016/12/23)
Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epoxidation of terminal olefins under stoichiometric reaction conditions. Mechanistic details of each individual step of the photoinduced catalysis, including formation of the Mn(IV)-oxo intermediate, are discussed on the basis of combined results of laser flash photolysis and other spectroscopic methods.
Bioproduction of chiral epoxyalkanes using styrene monooxygenase from rhodococcus sp. ST-10 (RhSMO)
Toda, Hiroshi,Imae, Ryouta,Itoh, Nobuya
, p. 3443 - 3450 (2015/02/05)
We describe the enantioselective epoxidation of straight-chain aliphatic alkenes using a biocatalytic system containing styrene monooxygenase from Rhodococcus sp. ST-10 and alcohol dehydrogenase from Leifsonia sp. S749. The biocatalyzed enantiomeric epoxidation of 1-hexene to (S)-1,2-epoxyhexane (44.6 mM) using 2-propanol as the hydrogen donor was achieved under optimized conditions. The biocatalyst had broad substrate specificity for various aliphatic alkenes, including terminal, internal, unfunctionalized, and di- and tri-substituted alkenes. Here, we demonstrate that this biocatalytic system is suitable for the efficient production of enantioenriched (S)-epoxyalkanes.
A mononuclear manganese complex of a tetradentate nitrogen ligand - Synthesis, characterizations, and application in the asymmetric epoxidation of olefins
Shen, Duyi,Miao, Chengxia,Wang, Shoufeng,Xia, Chungu,Sun, Wei
supporting information, p. 5777 - 5782 (2015/02/19)
A new chiral manganese complex (C1) bearing a tetradentate nitrogen ligand containing chiral bipyrrolidine and benzimidazole moieties was prepared. The structure of C1 was confirmed by ESI-MS and crystallography. This manganese complex is an active catalyst for the asymmetric epoxidation of various olefins with excellent conversion (up to 99%) and high enantiomeric excess (up to 96%ee) with hydrogen peroxide as the oxidant in the presence of 2-ethylhexanoic acid or acetic acid. Compared with previous structurally similar manganese complexes with different diamine backbones (C2, cyclohexanediamine; C3, diamine from L-proline), C1 showed improved asymmetric induction, especially for simple olefins such as styrene derivatives and substituted chromene. The possible reasons for the improvement of the ee values are discussed in the text on the basis of the crystal structures of the manganese complexes.
Total synthesis of the macrocyclic n -methyl enamides palmyrolide a and 2 s -sanctolide a
Wadsworth, Andrew D.,Furkert, Daniel P.,Brimble, Margaret A.
, p. 11179 - 11193 (2015/01/08)
Full details of the total syntheses of the initially reported and revised structures of the neuroprotective agent palmyrolide A are reported. The key macrocyclization step was achieved using a sequential ring-closing metathesis/olefin isomerization reaction. Furthermore, the total synthesis of the related macrolide (2S)-sanctolide A is reported. The synthesis used key elements from the synthesis of palmyrolide A, including the RCM/olefin isomerization sequence. The synthetic work described herein serves to facilitate the assignment of stereochemistry of the natural product sanctolide A and demonstrates the utility of this approach for the synthesis of macrocyclic tertiary enamide natural products.
Synthesis of prostaglandin and phytoprostane B1 via regioselective intermodular pauson-khand reactions
Vazquez-Romero, Ana,Cardenas, Lydia,Blasi, Emma,Verdaguer, Xavier,Riera, Antoni
supporting information; experimental part, p. 3104 - 3107 (2009/12/05)
A new approach to the synthesis of prostaglandin and phytoprostanes B 1 is described. The key step is an intermolecular Pauson-Khand reaction between a silyl-protected propargyl acetylene and ethylene. This reaction, promoted by NMO in the presence of 4 A molecular sieves, afforded the 3-fert-butyldimethylsilyloxymethyl-2-substituted-cyclopent-2-en-1- ones (III) in good yield and with complete regioselectivity. Deprotection of the silyl ether, followed by Swern oxidation, gave 3-formyl-2-substituted- cyclopent-2-en-1-ones (II). Julia olefination of the aldehydes II with the suitable chiral sulfone enabled preparation of PPB1 type I and PGB1.
