- Total synthesis of isocladosporin and 3-epi-isocladosporin
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A convergent total synthesis of isocladosporin and 3-epi-isocladosporin is reported starting from commercially available homoallyl alcohol in 10 longest linear steps with 28% overall yield. The key steps involved in the synthesis are cross-metathesis, tan
- Mohapatra, Debendra K.,Maity, Saurabh,Banoth, Shivalal,Gonnade, Rajesh G.,Yadav
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Read Online
- Chemical Studies on the Lichen. I. The Structure of Isolecanoric Acid, a New ortho-Depside Isolated from Parmelia tinctorum Despr.
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A new ortho-depside, isolecanoric acid was isolated from Parmelia tinctorum Despr. and 2-(2,4-dihydroxy-6-methylbenzoyloxy)-4-hydroxy-6-methylbenzoic acid was assigned to this substance from studies on the hydrolysis products and from analyses of the 1H and 13C NMR spectra.This substance is the first ortho-depside isolated from the genus Lichen.
- Sakurai, Atsushi,Goto, Yohko
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Read Online
- Biomimetic Total Syntheses of Sanctis A-B with Structure Revision
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The first concise total syntheses of sanctis A and B were reported, and it enabled revision of the structure of sanctis B through single-crystal X-ray diffraction. The established synthetic approach mainly mimics a biosynthetic olefin isomerization/hemiac
- Dong, Chunmao,Huo, Luqiong,Liu, Hongxin,Lu, Xiuxiang,Qiu, Shengxiang,Tan, Haibo,Wang, Miaomiao,Yang, Bao,Yuan, Yunfei,Zhang, Wenge
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Read Online
- Photolytic Studies on the Generation and Trapping of 6-Oxomethylidenecyclohexa-2,4-diene-1-one Derivatives with Various Nucleophiles
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α-Oxoketenes and cyclohexadiene α-oxoketenes are reactive intermediates, particularly the latter due to their high re-aromatization potential. In this communication, we report photolytic studies on the generation of such species from 4-OMe and 4-OMOM protected resorcylate dioxinones and their trapping to give resorcylate esters and amides as well as the formation of adducts with enol-ethers as trapping reagents.
- Mies, Thomas,White, Andrew J. P.,Parsons, Philip J.,Barrett, Anthony G. M.
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- Biomimetic synthesis and anti-inflammatory evaluation of violacin A analogues
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Violacin A, a chromanone derivative, isolated from a fermentation broth of Streptomyces violaceoruber, has excellent anti-inflammatory potential. Herein, a biogenetically modeled approach to synthesize violacin A and twenty-five analogues was described, which involved the preparation of aromatic polyketide precursor through Claisen condensation and its spontaneous cyclization. The inhibitory effect on nitric oxide (NO) production of all synthetic molecules was evaluated by lipopolysaccharide (LPS)-induced Raw264.7 cells. The results revealed that introduction of aliphatic amine moieties on C-7 obviously improved the anti-inflammation effect of violacin A, and also the aromatic ether instead of ketone group at side chain was favorable to increase the activity. Among them, analogue 7a and 16d were screened as the most effective anti-inflammatory candidates. Molecular mechanism research revealed that 7a and 16d acquired anti-inflammatory ability due to the inhibition of NF-κB signaling pathway.
- Wu, Wenxi,Mu, Yu,Liu, Bo,Wang, Zixuan,Guan, Peipei,Han, Li,Jiang, Mingguo,Huang, Xueshi
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- CANNABIDIOL-TYPE CANNABINOID COMPOUND
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The present invention relates to a cannabidiol (CBD) type cannabinoid compound for use as a medicament. The CBD-type cannabinoid, cannabidiol-C1 (CBD-C1), is a naturally occurring cannabinoid that can be found in minor quantities in the cannabis plant. Furthermore, the 5 cannabinoid can be produced by synthetic means and a method for the production of CBD-C1 is described herein. In addition, disclosed herein are data which demonstrate the efficacy of CBD-C1 in models of disease.
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Paragraph 0037; 0039
(2021/05/29)
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- Novel benzyl phenyl sulfide derivatives as antibacterial agents against methicillin-resistant Staphylococcus aureus
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Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major threat to human health due to its resistance to almost all classes of antibiotics. Discovery of novel antibacterial agents with new structures which combat the pathogens responsible f
- Lu, Kuo,Chen, Qi,Xu, Xiao-Fang,Meng, Ying,Lin, Jing,Chen, Wei-Min
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- Benzyl aryl thioether derivative as well as preparation method and application thereof
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The invention belongs to the field of medicines and discloses a benzyl aryl thioether derivative as well as a preparation method and an application thereof. The benzyl aryl thioether derivative has astructure shown in the following description, wherein R1
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Paragraph 0272; 0273; 0274; 0275
(2019/11/18)
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- Asymmetric synthesis of natural cis-dihydroarenediols using tetrahydroxynaphthalene reductase and its biosynthetic implications
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Asymmetric reduction of hydroxynaphthoquinones to secondary metabolites, (3S,4R)-3,4,8- A nd (2S,4R)-2,4,8-trihydroxy-1-tetralone, a putative biosynthetic diketo intermediate and a probable natural analogue, (3S,4R)-7-acetyl-3,4,8-trihydroxy-6-methyl-3,4-
- Saha, Nirmal,Müller, Michael,Husain, Syed Masood
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supporting information
p. 2204 - 2208
(2019/03/29)
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- Inhibition of mushroom tyrosinase activity by orsellinates
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Several applications have been proposed for tyrosinase inhibitors in the pharmaceutical, food bioprocessing, and environmental industries. However, only a few compounds are known to serve as effective tyrosinase inhibitors. This study evaluated the tyrosinase-related activity of resorcinol (1), orcinol (2) lecanoric acid (3), and derivatives of this acid (4-15). Subjected to alcoholysis, lecanoric acid (3), a depside isolated from the lichen Parmotrema tinctorum, produces orsellinic acid (2,4-dihydroxy-6-methylbenzoic acid) (4) and orsellinates (2,4-dihydroxy-6-methyl benzoates) (5-15). At 0.50 mM, methyl (5), ethyl (6), n-propyl (7), tert-butyl (11), and n-cetyl orsellinates (15) acted as tyrosinase activators, whereas n-butyl (8), iso-propyl (9), sec-butyl (10), n-pentyl (12), n-hexyl (13), and n-octyl orsellinates (14) behaved as inhibitors. Tyrosinase inhibition rose with chain elongation-n-butyl (8) n-pentyl (12) n-hexyl (13) n-octyl orsellinates (14)-suggesting that the enzyme site can accept an eight-carbon alkyl chain. A kinetic study of n-octyl orsellinate (14) revealed uncompetitive inhibition of tyrosinase, with an inhibition constant of 0.99 mM.
- Lopes, Thiago Inácio Barros,Coelho, Roberta Gomes,Honda, Neli Kika
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- Diarylvinylene similar structure compound and its preparation method and application
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The invention discloses a group of diarylethene structure similar compounds as well as a preparation method and application thereof. The provided compounds have a structure of a general formula I. Moreover, the invention further provides medicinal compositions containing the compounds serving as active ingredients. Researches discover that the compounds have pharmacological activities of resisting influenza viruses, Coxsackie B3 viruses, AIDS viruses, hepatitis B viruses, hepatitis C viruses and the like. Therefore, the invention further provides the application of the compounds and the medicinal compositions containing the compounds serving as active ingredients in preparation of anti-virus medicaments. The invention lays a foundation for deeply researching and developing the application of the compounds as clinical medicaments. The general formula I is as shown in the specification.
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Paragraph 0102; 0103
(2016/10/09)
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- Synthesis of (3R,5S)-5-hydroxy-de-O-methyllasiodiplodin: A facile and stereoselective approach
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A concise and facile synthesis of (3R,5S)-5-hydroxy-de-O-methyllasiodiplodin has been demonstrated in 12 steps starting from methylacetoacetate and (±)propylene oxide. The key reactions involved are Jacobsen's hydrolytic kinetic resolution, Sharpless asymmetric epoxidation, Mitsunobu, and ring closing metathesis reaction for the construction of macrolactone with two chiral substitutions on it.
- Bujaranipalli, Sheshurao,Das, Saibal
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supporting information
p. 3747 - 3749
(2015/06/08)
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- DIHYDROOROTIC ACID DEHYDROGENASE INHIBITOR
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The present invention provides a novel dihydroorotic acid dehydrogenase inhibitor which is applicable to various diseases. When used as an active ingredient, a compound represented by formula (I): (wherein X represents a halogen atom, R1 represents a hydrogen atom, R2 represents an alkyl group containing 1 to 7 carbon atoms, R3 represents -CHO, and R4 represents -CH2-CH=C(CH3)-R0 (wherein R0 represents an alkyl group containing 1 to 12 carbon atoms which may have a substituent on the terminal carbon and/or on a non-terminal carbon, etc.)), an optical isomer thereof or a pharmaceutically acceptable salt thereof has a high inhibitory effect on dihydroorotic acid dehydrogenase and can be used as an immunosuppressive agent, a therapeutic agent for rheumatism, an anticancer agent, a therapeutic agent for graft rejection, an antiviral agent, an anti-H. pylori agent, a therapeutic agent for diabetes or the like.
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Paragraph 0111; 0115; 0116; 0119
(2015/04/15)
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- First stereoselective total synthesis of Neocosmosin A: A facile approach
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First stereoselective concise synthesis of Neocosmosin A, with in vitro binding affinity for human opioid and cannabinoid receptors, has been reported using readily available starting materials such as methylacetoacetate, cyclohexanone, and homoallyl alco
- Dachavaram, Soma Shekar,Kalyankar, Kondbarao Balasaheb,Das, Saibal
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supporting information
p. 5629 - 5631
(2014/12/11)
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- Synthesis of macrolactam analogues of radicicol and their binding to heat shock protein Hsp90
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A series of macrolactam analogues of the naturally occurring resorcylic acid lactone radicicol have been synthesised from methyl orsellinate in 7 steps, involving chlorination, protection of the two phenolic groups, and hydrolysis to the benzoic acid. Formation of the dianion and quenching with a Weinreb amide results in acylation of the toluene methyl group that is followed by amide formation and ring closing metathesis to form the macrocyclic lactam. Final deprotection of the phenolic groups gives the desired macrolactams whose binding to the N-terminal domain of yeast Hsp90 was studied by isothermal titration calorimetry and protein X-ray crystallography.
- Dutton, Bridie L.,Kitson, Russell R. A.,Parry-Morris, Sarah,Roe, S. Mark,Prodromou, Chrisostomos,Moody, Christopher J.
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p. 1328 - 1340
(2014/03/21)
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- CAJANINE STRUCTURE ANALOGOUS COMPOUND, PREPARATION METHOD AND USE
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Provided are cajanine structure analogous compounds, synthesis method and pharmacological effects thereof, the compounds of the present invention having the structure as represented by general formulas I, II, III, IV and V. Also provided are pharmaceutical compositions containing the compounds as active ingredient, and uses thereof; the compounds of the present invention having the pharmacological activities such as anti-virus, anti-virus-infection, nerve protection, anti-metabolic-diseases and the like. Also provided is a chemical total synthesis preparation method of the natural products cajanine, cajanine A and cajanine C. The present invention lays a foundation for the in-depth study and development of the compounds as clinical drugs in the future.
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Paragraph 0070
(2014/11/13)
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- CAJANINE STRUCTURE ANALOGOUS COMPOUND, PREPARATION METHOD AND USE
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Provided are cajanine structure analogous compounds, synthesis method and pharmacological effects thereof, the compounds of the present invention having the structure as represented by general formulas I, II, III, IV and V. Also provided are pharmaceutical compositions containing the compounds as active ingredient, and uses thereof; the compounds of the present invention having the pharmacological activities such as anti-virus, anti-virus-infection, nerve protection, anti-metabolic-diseases and the like. Also provided is a chemical total synthesis preparation method of the natural products cajanine, cajanine A and cajanine C. The present invention lays a foundation for the in-depth study and development of the compounds as clinical drugs in the future.
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Paragraph 0081
(2015/01/06)
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- Synthesis of diastereomeric, deoxy and ring-expanded sulfone analogues of aigialomycin D
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Several analogues of the fungal natural product aigialomycin D (AmD) have been synthesised. These include the stereoisomer 5′R,6′S-AmD, 2,4-di-deoxyAmD, 1′,2′,7′,8′-tetrahydroAmD and a 15-membered macrocyclic sulfone. Growth inhibitory activities of these compounds against the HL-60 leukaemic cell line were measured. The ring-expanded sulfone and tetrahydro-analogue were found to have similar IC50 values to the natural product, whereas the 5′R,6′S-stereoisomer was inactive. Energy minimisation of AmD and the synthesised analogues resulted in a range of lowest energy conformers, from planar, open arrangements of the macrocycle in AmD and tetrahydroAmD to bent, L-shaped structures for the sulfone. The synthesis of methyl orsellinate was investigated and optimised as part of this work. A stereodivergent route to both enantiomers of the diol fragment from d-ribose was also achieved.
- Ting, Samuel Z.Y.,Baird, Lynton J.,Dunn, Elyse,Hanna, Reem,Leahy, Dora,Chan, Ariane,Miller, John H.,Teesdale-Spittle, Paul H.,Harvey, Joanne E.
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supporting information
p. 10581 - 10592
(2013/11/19)
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- First Total Synthesis of (3 R,4 S)-4-Hydroxylasiodiplodin: A Facile and Stereoselective Approach
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A first total synthesis of (3R,4S)-4-hydroxylasiodiplodin is described starting from methyl acetoacetate and a commonly available carbohydrate, d-mannitol, which is regularly used in organic synthesis. The facile and stereoselective approach involves the
- Bujaranipalli, Sheshurao,Eppa, Gyan Chander,Das, Saibal
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p. 1117 - 1120
(2013/06/27)
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- Assembly of melleolide antibiotics involves a polyketide synthase with cross-coupling activity
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Summary Little is known about polyketide biosynthesis in mushrooms (basidiomycota). In this study, we investigated the iterative type I polyketide synthase (PKS) ArmB of the tree pathogen Armillaria mellea, a producer of cytotoxic melleolides (i.e., polyketides esterified with various sesquiterpene alcohols). Heterologously produced ArmB showed orsellinic acid (OA) synthase activity in vitro. Further, we demonstrate cross-coupling activity of ArmB, which forms OA esters with various alcohols. Using a tricyclic Armillaria sesquiterpene alcohol, we reconstituted the biosynthesis of melledonol. Intermolecular transesterification reactions may represent a general mechanism of fungal PKSs to create structural diversity of small molecules. Phylogenetic network construction of thioesterase domains of both basidiomycetes and ascomycetes suggests that the fungal nonreducing PKS family has likely evolved from an ancient OA synthase and has gained versatility by adopting Claisen-like cyclase or transferase activity.
- Lackner, Gerald,Bohnert, Markus,Wick, Jonas,Hoffmeister, Dirk
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p. 1101 - 1106
(2013/10/01)
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- NOVEL DIHYDROXYBENZENE DERIVATIVES AND ANTIPROTOZOAL AGENT COMPRISING SAME AS ACTIVE INGREDIENT
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Novel compounds below are useful for preventing or treating diseases caused by protozoans. At least one of a compound represented by Formula (I) (wherein, X represents a hydrogen atom or a halogen atom; R1 represents a hydrogen atom; R2 represents a hydrogen atom or a C1-7 alkyl group; R3 represents -CHO, -C(=O)R5, -COOR5 (wherein R5 represents a C1-7 alkyl group), -CH2OH or -COOH; and R4 represents a C1-16 alkyl group having one or more substituents on a terminal carbon atom and/or non-terminal carbon atom(s), a C2-16 alkenyl group having one or more substituents on a terminal carbon atom and/or non-terminal carbon atom(s), or a C2-16 alkynyl group having one or more substituents on a terminal carbon atom and/or non-terminal carbon atom(s)), an optical isomer thereof, and a pharmaceutically acceptable salt is used.
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Paragraph 0122; 0126; 0127
(2013/09/26)
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- Total synthesis of chlorocyclinone A, a PPAR-γ antagonist
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The first total synthesis of chlorocyclinone A (1) is regioselectively completed in 28 steps. The key steps are Pd-catalyzed methoxycarbonylation, unprecedented Hauser annulation, Krohn photo-oxidation, and regioselective gem-dichlorination.
- Karmakar, Raju,Mal, Dipakranjan
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p. 10235 - 10248
(2013/01/15)
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- Studies on the resorcylates: biomimetic total syntheses of (+)-montagnetol and (+)-erythrin
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6-(2,4-Dioxopentyl)-2,2-trimethyl-4H-1,3-dioxin-4-one on reflux in toluene gave MeCOCH2COCH2COCH{double bond, long}C{double bond, long}O, which cyclized to 6-(2-oxopropyl)-4-hydroxy-2H-pyran-2-one or was trapped with alcohols to produce resorcylate esters. The method was used for the synthesis of both enantiomers of montagnetol and erythrin.
- Basset, Jean-Fran?ois,Leslie, Colin,Hamprecht, Dieter,White, Andrew J.P.,Barrett, Anthony G.M.
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supporting information; experimental part
p. 783 - 785
(2010/03/24)
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- Antimycobacterial activity of lichen substances
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We describe here the extraction and identification of several classes of phenolic compounds from the lichens Parmotrema dilatatum (Vain.) Hale, Parmotrema tinctorum (Nyl.) Hale, Pseudoparmelia sphaerospora (Nyl.) Hale and Usnea subcavata (Motyka) and determined their anti-tubercular activity. The depsides (atranorin, diffractaic and lecanoric acids), depsidones (protocetraric, salazinic, hypostictic and norstictic acids), xanthones (lichexanthone and secalonic acid), and usnic acid, as well seven orsellinic acid esters, five salazinic acid 8',9'-O-alkyl derivatives and four lichexanthone derivatives, were evaluated for their activity against Mycobacterium tuberculosis. Diffractaic acid was the most active compound (MIC value 15.6 μg/ml, 41.6 μM), followed by norstictic acid (MIC value 62.5 μg/ml, 168 μM) and usnic acid (MIC value 62.5 μg/ml, 182 μM). Hypostictic acid (MIC value 94.0 μg/ml, 251 μM) and protocetraric acid (MIC value 125 μg/ml, 334 μM) showed moderate inhibitory activity. The other compounds showed lower inhibitory activity on the growth of M. tuberculosis, varying from MIC values of 250 to 1370 μM.
- Honda,Pavan,Coelho,de Andrade Leite,Micheletti,Lopes,Misutsu,Beatriz,Brum,Leite
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experimental part
p. 328 - 332
(2011/06/10)
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- A flexible asymmetric synthesis of the tetracyclic core of berkelic acid using a Horner-Wadsworth-Emmons/oxa-Michael cascade
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The one-pot Horner-Wadsworth-Emmons/oxa-Michael cascade followed by spiroketalisation affords the tetracyclic benzannulated spiroketal core of berkelic acid, an extremophile natural product with selective activity against ovarian cancer.
- Wilson, Zoe E.,Brimble, Margaret A.
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supporting information; experimental part
p. 1284 - 1286
(2010/06/13)
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- Total synthesis of graphislactone G
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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
- Cudaj, Judith,Podlech, Joachim
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supporting information; experimental part
p. 3092 - 3094
(2010/07/18)
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- Enantioselective synthesis of the 3C-protease inhibitor (-)-thysanone by a Staunton-Weinreb annulation strategy
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The total synthesis of (-)-thysanone is described. The key step involves the addition of an o-toluate anion to a lactone to create the naphthopyran framework (Staunton-Weinreb annulation). This synthesis further confirms the absolute stereochemistry of th
- Sperry, Jonathan,Tsz, Ying Yuen,Brimble, Margaret A.
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experimental part
p. 2561 - 2569
(2009/12/25)
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- Total synthesis of aigialomycin D using a Ramberg - Baecklund/ RCM strategy
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The bioactive resorcylic acid lactone aigialomycin D (1) has been synthesized by a novel combination of ring-closing metathesis (RCM) and Ramberg - Baecklund reactions. This synthetic strategy enables the Cl - C2 alkene to be masked as a sulfone during formation of the macrocycle by ring closing metathesis at the C7 - C8 olefin, thus avoiding competing formation of a cyclohexene. A subsequent Ramberg-Baecklund reaction efficiently produces the C1- C2 E-alkene. This combined RCM/ Ramberg-Baecklund reaction strategy should be widely applicable to the synthesis of maerocyclic dienes.
- Baird, Lynton J.,Timmer, Mattie S. M.,Teesdale-Spittle, Paul H.,Harvey, Joanne E.
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supporting information; experimental part
p. 2271 - 2277
(2009/08/07)
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- Radical-scavenging activity of orsellinates
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Lichens are an important source of phenolic compounds and have been intensively investigated for their biological and pharmacological activities. Lecanoric acid (1), a lichen depside, was isolated from a Parmotrema tinctorum specimen and treated with alcohols to produce orsellinic acid (2) and orsellinates (3) to (9) (2,4-dihydroxy-6-n-methyl benzoates). Free radical scavenging activity of methyl (3), ethyl (4), n-propyl (5), n-butyl (6), iso-propyl (7), sec-butyl (8), tert-butyl (9) orsellinates was evaluated using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) method. Results showed that chain elongation of methyl (3) to n-butyl (6) causes a rise in the antioxidant activity. However, iso-propyl (7) and tert-butyl (9) were more active than the correspondent linear compounds, although sec-butyl (8) was less active among the chain ramified compounds. All the orsellinates were less active than lecanoric acid (1) and orsellinic acid (2). Orcinol (10) and resorcinol (11) were also determined for comparison with activities of orsellinates. Gallic acid (12) was used as control.
- Lopes, Thiago Inacio Barros,Coelho, Roberta Gomes,Yoshida, Nidia Cristiane,Honda, Neli Kika
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experimental part
p. 1551 - 1554
(2009/09/06)
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- COMPOUNDS FOR THE PREVENTION AND TREATMENT OF CARDIOVASCULAR DISEASES
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The present disclosure relates to compounds, which are useful for regulating the expression of apolipoprotein A-I (ApoA-I), and their use for treatment and prevention of cardiovascular disease and related disease states, including cholesterol- or lipid-related disorders, such as, for example, atherosclerosis.
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Page/Page column 30-31; 41-42
(2008/12/07)
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- COMPOUNDS FOR THE PREVENTION AND TREATMENT OF CARDIOVASCULAR DISEASES
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The present disclosure relates to compounds, which are useful for regulating the expression of apolipoprotei? A-I (ApoA-l), and their use for the treatment and prevention of cardiovascular disease and related disease states, including cholesterol- or lipid-related disorders, such as, for example, atherosclerosis.
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Page/Page column 94-97
(2008/12/07)
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- A facile phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2 + 2] annulation reactions: An easy access to complex bioactive natural and unnatural benzopyran congeners
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The complex bioactive natural and unnatural benzopyran congeners have been synthesized using one-/two-step approaches in very good yields from the reactions of two different dihydroxyphthalides, natural resorcyclic acid derivative, and trihydroxybenzophenone with citral and/or farnesal, via the phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions and three different thermal intramolecular cyclization reactions. The effects of the nature and the position of phenolic groups in the starting materials on the course of these cycloaddition reactions have also been described. Depending upon the absence or presence of intramolecular hydrogen bonding of the phenolic group with the carbonyl moiety in the starting materials, these phenol-driven intramolecular thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions either furnished the kinetically controlled products or directly formed the thermodynamically controlled rearranged products, respectively.
- Mondal, Mukulesh,Puranik, Vedavati G.,Argade, Narshinha P.
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p. 2068 - 2076
(2007/10/03)
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- An anionic polycondensation strategy for the synthesis of dibenzoxanthenones: Progress toward the synthesis of hypoxyxylerone
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An anionic polycondensation has been used as the key step in a highly convergent strategy for the preparation of hypoxyxylerone derivatives.
- Chevenier, Emmanuel,Lucatelli, Christophe,Pandya, Urvish,Wang, Wei,Gimbert, Yves,Greene, Andrew E.
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p. 2693 - 2696
(2007/10/03)
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- Total synthesis of (S)-(+)-citreofuran by ring closing alkyne metathesis
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A concise total synthesis of citreofuran 4 is described, a structurally unique octaketide derivative belonging to the curvularin family. Key steps involve the elaboration of orsellinic acid methyl ester 5 to acid 14, which converts, on attempted formation of the corresponding acid chloride, to the 3-alkoxyisocoumarin derivative 20. This heterocycle can be used as an activated ester to give ketone 21 on treatment with 3-pentynylmagnesium bromide in the presence of TMSCl as the activating agent. Ring-closing alkyne metathesis (RCAM) of diyne 21 catalyzed by (tBuO)3W≡CCMe3 affords the strained cycloalkyne 22. Treatment with acid renders its triple bond susceptible to nucleophilic attack by the adjacent carbonyl group, thus leading to a transannular cycloaromatization with formation of the intact skeleton of citreofuran. An X-ray crystallographic study reveals conformational details about this natural product. Finally, it is shown that 4 as well as its protected precursor 23 are able to cleave double-stranded DNA under oxidative conditions.
- Fuerstner, Alois,Castanet, Anne-Sophie,Radkowski, Karin,Lehmann, Christian W.
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p. 1521 - 1528
(2007/10/03)
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- Total synthesis of cristatic acid.
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The first total synthesis of cristatic acid 1, an antibiotic endowed with considerable activity against Gram-positive bacteria, hemolytic properties, and significant cytotoxicity, is described. Key to success are the formation of its 2,4-disubstituted fur
- Fuerstner,Gastner
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p. 2467 - 2470
(2007/10/03)
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- Total synthesis of everninomicin 13,384-1 - Part 1: Retrosynthetic analysis and synthesis of the A1B(A)C fragment
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In this first of a series of four articles we introduce everninomicin 13,384-1 (1), a powerful antibiotic effective against drug resistant bacteria, as a target for total synthesis and discuss its retrosynthetic analysis. From the three defined fragments required for the synthesis (2: A1B(A)C fragment; 4: DE fragment; 5: FGHA2 fragment), we describe herein two approaches to the A1B(A)C block. The first strategy relied on an olefin metathesis reaction to construct a common intermediate for rings B and C, but was faced with final protecting group problems. The second, and successful approach, involved a 1,2-phenylsulfeno migration and a sulfur directed glycosidation procedure to link rings B and C, as well as an acyl fluoride intermediate to install the sterically hindered aryl ester moiety (ring A1). The final stages of the synthesis of the required 2-phenylseleno glycosyl fluoride 2 required introduction of a phenylseleno group at C-1 of ring C followed by a novel, DAST-promoted 1,2-migration to produce the desired 2-β-phenylseleno glycosyl fluoride moiety.
- Nicolaou,Rodriguez, Rosa Maria,Mitchell, Helen J.,Suzuki, Hideo,Fylaktakidou, Konstantina C.,Baudoin, Olivier,Van Delft, Floris L.
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p. 3095 - 3115
(2007/10/03)
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- Stereoselective total syntheses of atrochrysone, torosachrysone and related 3,4-dihydroanthracen-1(2H)-ones
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The total synthesis of the pre-anthraquinones atrochrysone 1 and torosachrysone 2 in both enantiomeric forms is described. The synthesis relies on the regioselective Tebbe methylenation of a chiral diester followed by an intramolecular enol ether acylation with N-triflyl-4-(dimethylamino)pyridinium triflate. The resulting 3-methoxycyclohex-2-enone 9 is condensed with suitable orsellinic acid derivatives to yield after deprotection the optically active 3,4-dihydroanthracen-1(2H)-ones 1 and 2. This flexible approach can be used for the synthesis of 13C-labelled compounds and should provide access to a series of analogues. The Royal Society of Chemistry 2000.
- Mueller, Michael,Lamottke, Kai,Loew, Erich,Magor-Veenstra, Eva,Sieglich, Wolfgang
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p. 2483 - 2489
(2007/10/03)
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- Total synthesis of everninomicin 13,384-1 - Part 1: Synthesis of the A1B(A)C fragment
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The powerful antibiotic everninomicin 13,384-1 (1, Ziracin) has been prepared for the first time through a total synthesis. The (1 → 1-disaccharide and the two orthoesters of this target molecule were introduced by new methodologies using a tin acetal and 1,2-phenylseleno migrations. The reaction sequence also relies on stereoselective glycosidations and subtle manipulations of protecting groups. In addition to the introduction of new synthetic methodologies, this total synthesis should allow the preparation of combinatorial libraries of semisynthetic analogues of this highly promising antibiotic for biological screening purposes.
- Nicolaou,Mitchell, Helen J.,Suzuki, Hideo,Rodriguez, Rosa Maria,Baudoin, Olivier,Fylaktakidou, Konstantina C.
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p. 3334 - 3339
(2007/10/03)
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- Catalytic enantioselective synthesis of macrolides via asymmetric alkylation
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Catalytic enantioselective syntheses of the macrolides (R)-(-) phoracantholide and (R)-(+) lasiodiplodin have been achieved. Stereochemistry was introduced in using an arene chromium tricarbonyl derived catalyst, which mediated the enantioselective additi
- Jones, Graham B.,Huber, Robert S.,Chapman, Brant J.
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p. 1797 - 1809
(2007/10/03)
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- Oxidation of Alkyl 1,6-Dihydroorsellinates. A New Method for the Synthesis of Methyl Orsellinate and Homologues
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An efficient new procedure has been developed for the oxidation of the title compounds, utilizing one mole of bromine in the presence of acetic anhydride.
- Dyke, Hazel J.,Elix, John A.,Marcuccio, Sebastian M.,Whitton, Andrew A.
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p. 431 - 434
(2007/10/02)
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- Chemistry of 1,3,5-Tris(trimethylsiloxy)-1-methoxyhexa-1,3,5-triene, a β-Tricarbonyl Trianion Equivalent
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The title compound has been synthesized and its chemistry studied.Condensation with orthoesters, acid chlorides, or imidazolides gave aromatic compounds in a 5C + 1C condensation.A formal synthesis of lasiodiplodin has been completed.
- Chan, T. H.,Stoessel, D.
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p. 2423 - 2428
(2007/10/02)
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- TERT-BUTANOLYSIS OF LICHEN DEPSIDES
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The scope and limit of the tert-butanolysis of 12 lichen depsides is described.Neither 2-O-methylated nor 2-O-acylated compounds are cleaved by heating with tert-butanol.Key Word Index - Depsides: tert-butanolysis.
- Huneck, Siegfried
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p. 2697 - 2698
(2007/10/02)
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- Isolation and Structure (X-Ray Analysis) of the Orsellinate of Armillol, a New Antibacterial Metabolite from Armillaria mellea
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The structure of the orsellinate of armillol (2a), a new member of the protoilludane group and one of several sesquiterpenoid esters isolated from Armillaria mellea, was established by spectral and chemical means and confirmed by single-crystal X-ray analysis of its oxidation product, the hydroxy-aldehyde (5a).
- Donnelly, Dervilla,Sanada, Shuichi,O'Reilly, Joseph,Polonsky, Judith,Prange, Thierry,Pascard, Claudine
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p. 135 - 137
(2007/10/02)
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- Convenient Syntheses of Alkyl β-Resorcylate Derivatives
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Syntheses of methyl 2,4-dihydroxy-6-methyl- (1a) and -3,6-dimethylbenzoates (1b) and methyl 2,4-dihydroxy-6-pentylbenzoate (1c) are described.Condensation reactions of dimethyl sodiomalonate with the dianion derived from pentane-2,4-dione or the dimerisation of the methyl acetoacetate dianion or the acetylation of the trianion derived from methyl 3,5,7-trioxo-octanoate gave (1a) (78percent) after work-up at pH 9.Analogous convenient, short, optimised syntheses of (1b and c) are given in detail.
- Barrett, Anthony G. M.,Morris, Timothy M.,Barton, Derek H. R.
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p. 2272 - 2277
(2007/10/02)
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- A New Route to 5-Substituted Resorcinols and Related Systems
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Michael-type additions of phenylsulphinylacetate esters to αβ-unsaturated ketones produce cyclohexane-1,3-dione derivatives, which, after thermal elimination of benzenesulphenic acid, give the corresponding 5-substituted resorcinols, such as olivetol.The scope of this entry into other aromatic systems, such as 3,5-disubstituted and 2,3,5-trisubstituted phenols and orsellinic acid has been explored.
- Jaxa-Chamiec, Albert A.,Sammes, Peter G.,Kennewell, Peter D.
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p. 170 - 175
(2007/10/02)
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