- A convenient synthesis of 1-[6-Fluoro-(2S)-3H,4H-dihydro-2H-2-chromenyl]- (1R)-1,2-ethanediol and 1-[6-fluoro-(2R)-3H,4H-dihydro- 2H-2-chromenyl]-(1R)-1, 2-ethanediol
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1-[6-Fluoro-(2S)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol and 1-[6-fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol, important pharmaceutical intermediates, were synthesized from natural chiral pool D-mannitol. Georg Thieme Verlag Stuttgart.
- Yu, An-Guang,Wang, Nai-Xing,Xing, Ya-Lan,Zhang, Jun-Ping,Yang, Yun-Xu,Wang, Wu-Wei,Sheng, Rui-Long
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- Synthesis of Substituted Cyclopentenol Derivatives via Intramolecular Addition Reaction of Vinylcopper Species
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A new method for the synthesis of substituted cyclopentenes is developed, based on an intramolecular 1,2-addition reaction of vinylcopper species generated from 1,1-dibromoalkene derivatives. The substrates are prepared from ketones through the aldol reaction with 3,3-dibromoacrolein followed by silylation of the hydroxyl group. Treatment of the substrate with excess Me 2 CuLi results in the formation of 3-methyl-2-cyclopenten-1-ol derivatives with good yields.
- Yamaga, Hideomi,Tanino, Keiji
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- An Esterase-like Lyase Catalyzes Acetate Elimination in Spirotetronate/Spirotetramate Biosynthesis
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Spirotetronate and spirotetramate natural products include a multitude of compounds with potent antimicrobial and antitumor activities. Their biosynthesis incorporates many unusual biocatalytic steps, including regio- and stereo-specific modifications, cyclizations promoted by Diels–Alderases, and acetylation-elimination reactions. Here we focus on the acetate elimination catalyzed by AbyA5, implicated in the formation of the key Diels–Alder substrate to give the spirocyclic system of the antibiotic abyssomicin C. Using synthetic substrate analogues, it is shown that AbyA5 catalyzes stereospecific acetate elimination, establishing the (R)-tetronate acetate as a biosynthetic intermediate. The X-ray crystal structure of AbyA5, the first of an acetate-eliminating enzyme, reveals a deviant acetyl esterase fold. Molecular dynamics simulations and enzyme assays show the use of a His-Ser dyad to catalyze either elimination or hydrolysis, via disparate mechanisms, under substrate control.
- Lees, Nicholas R.,Han, Li-Chen,Byrne, Matthew J.,Davies, Jonathan A.,Parnell, Alice E.,Moreland, Pollyanna E. J.,Stach, James E. M.,van der Kamp, Marc W.,Willis, Christine L.,Race, Paul R.
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- Formal synthesis of nanaomycin D via a Hauser-Kraus annulation using a chiral enone-lactone
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Abstract A formal total synthesis of nanaomycin D has been achieved. The strategy employed made use of a one-pot cyclisation-stereoselective reduction of a hydroxyketone to install the pyranonaphthalene moiety after execution of a Hauser-Kraus annulation using a chiral enone-lactone as the Michael acceptor to append the γ-lactone ring. The chirality in the chiral enone-lactone was established using a Sharpless asymmetric dihydroxylation. The enone-lactone used herein represents an attractive chiral synthon for the construction of other γ-lactone containing pyranonaphthoquinones such as griseusin A and crisamicin A.
- Hassan, Najmah P.S.,Naysmith, Briar J.,Sperry, Jonathan,Brimble, Margaret A.
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- Synthesis of (-)-tetrodotoxin: Preparation of an advanced cyclohexenone intermediate
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The preparation of an advanced intermediate toward the enantioselective synthesis of tetrodotoxin is outlined. The enantiomerically pure cyclopentene 15 was generated from ketone 14 by alkylidene carbene insertion with retention of absolute configuration. An ozonolysis/aldol sequence first produced the trans cyclohexenone, which upon epimerization gave the more stable cis enone 18.
- Taber, Douglass F.,Storck, Pierre H.
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- Preparation of chiral sugar-derived fluorides using new nucleophilic fluorinating reagents
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New fluorinating reagents, composed of (S)-2-(diphenylmethyl)pyrrolidine and 1,1,3,3,3-pentafluoropropene/hexafluoropropene, have been found to be an effective system for nucleophilic deoxyfluorination. Regio- and stereoselectivity of deoxyfluorination of sugar-derived allylic, benzylic and propargylic alcohols with new reagents have been studied.
- Bilska-Markowska, Monika,Koroniak, Henryk
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- An efficient synthesis of epoxydiynes and a key fragment of Neocarzinostatin chromophore
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(Chemical Equation Presented) A key structural feature of the Neocarzinostatin chromophore is a reactive epoxydiyne. We present here a new method for the preparation of epoxydiynes by the addition of an allenyl zinc bromide to a propargylic ketone.
- Baker,Thominet,Britton,Caddick
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- Synthesis of (3S)-cyclopentanone, Potential Versatile Chiral Synthon for Natural Products from (R)-1,2-Isopropylideneglyceraldehyde
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(3S)-cyclopentanone (1) has been synthesised from an easily available chiral starting material, (R)-1,2-isopropylideneglyceraldehyde (4), through orthoester Claisen rearrangement of (5) and (7).
- Kametani, Tetsuji,Suzuki, Toshio,Sato, Etsuko,Nishimura, Masahiro,Unno, Katsuo
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- CHRALITY OF PLECTANIAXANTHIN
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The chirality of plectaniaxanthin, a carotenoid vic. glycol from Plectania coccinea, colud not be determined by the modified Horeau method.Chiroptical correlation of plectaniaxanthin acetonide and (2'S)-16',17'-dinorplectaniaxanthin acetonide was taken as proof of 2'R chirality for natural plectaniaxanthin and its mono- and diesters.The synthesis of the chiral model carotenoid was effected from D-mannitol via 2,3-isopropylidene-D-glyceraldehyde as key synthon.Key Word Index - Plectania coccinea; Ascomycetes; chirality; characteristic carotenoid; plectaniaxanthin; (2'R)-3',4'-didehydro-1',2'-dihydro-β,ψ-carotene-1',2'-diol.
- Roenneberg, Harald,Borch, Gunner,Buchecker, Richard,Arpin, Noel,Liaaen-Jensen, Synnoeve
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- Preparation and storage of (R)-2,3-O-isopropylideneglyceraldehyde (D-glyceraldehyde acetonide)
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This is a report on the synthesis and on the storage of D-glyceraldehyde acetonide for as long as three years after initial preparation while retaining its enantiomeric purity.
- Hertel,Grossman,Kroin
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- Synthesis, spectroscopic characterization and biological properties of new natural aldehydes thiosemicarbazones
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As part of a research programme aimed at the synthesis of compounds with antiviral, antibacterial and antitumor properties and their spectroscopic characterization, new thiosemicarbazones deriving from natural aldehydes have been investigated. These substances contain in the same molecule both a chain with nucleophilic centres N, S with tubercolostatic activity, and a glycosidic or alkyl moiety (modified glycosides and nucleosides have recently received a great deal of attention in the fields of neoplastic diseases and viral infections). In this paper the synthesis and the characterization of these compounds by means of 1H NMR, IR, and MS techniques is reported. Biological studies have involved both inhibition of cell proliferation and apoptosis tests on human leukemia cell line U937. (C) 2000 Elsevier Science Ltd.
- Tarasconi, Pieralberto,Capacchi, Silvia,Pelosi, Giorgio,Cornia, Mara,Albertini, Roberto,Bonati, Antonio,Dall'Aglio, Pier Paolo,Lunghi, Paolo,Pinelli, Silvana
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- Formal Synthesis of 3-Deoxy-D-manno-2-Octulosonic Acid (KDO) via a Highly Double-Stereoselective Hetero Diels-Alder Reaction Directed by a (Salen)CoII Catalyst and Chiral Diene
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This paper presents a formal total synthesis of 3-deoxy-D-manno-2-octulosonic acid (KDO) based on a highly double-stereoselective hetero Diels-Alder reaction between an electron-rich diene and ethyl glyoxylate catalyzed by (Salen)CoII complex, a new catalyst for Diels-Alder reactions. A facial specific hydrofaoration followed by oxidative workup leads to a diol system with the trans-diequatorial arrangement of hydroxyl groups at the C-4 and C-5. Inversion of the configuration of the C-5 hydroxyl group in 12 and then ketal formation afford the desired target diisopropylidene-2-deoxy-KDO methyl ester (18), which can be converted to KDO according to the literature procedure.
- Hu, Yun-Jin,Huang, Xiao-Dong,Yao, Zhu-Jun,Wu, Yu-Lin
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- Measuring stereoselectivity in lipase-catalyzed acidolysis reactions by ultra-high resolution 13C nuclear magnetic resonance
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Elucidating the stereoselectivity of lipases in synthetic reactions of triacylglycerols has hitherto been carried out using traditional analytical techniques to determine the composition of the reaction products. These methods are laborious and are not always appropriate for analysis of certain triacylglycerol types. A direct method, utilizing a stereospecific deuterium-labeled triacylglycerol substrate, has been developed where the stereoisomeric composition of the reaction product is determined by ultra-high resolution 13C nuclear magnetic resonance (NMR) spectroscopy. Through lipase-catalyzed transesterification of deuterium-labeled trilauroylglycerol with oleic acid, chemical shifts were induced in the 13C NMR spectrum by the deuterium atom and olefinic double bonds, enabling unambiguous stereospecific assignment of triacylglycerol species. By this method of analysis, we found an effect of the degree of reaction conversion on the extent of stereoisomerism in the triacylglycerol product. Stereoselectivity was greatest (for sn-1) with lipase from Rhizomucor miehei. Lipases from Rhizopus niveus, Candida rugosa, Carica papaya, and the cutinase from Fusarium sp. were also found to exhibit stereoselectivity, with preference for either sn-1 or sn-3 acyl exchange.
- Chandler,Howarth,Crout
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- A nitrilase-mediated entry to 4-carboxymethyl-β-lactams from chemically prepared 4-(cyanomethyl)azetidin-2-ones
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(3R,4S)-3-Alkoxy/aryloxy-4-(cyanomethyl)azetidin-2-ones were efficiently prepared from readily available 1,2:5,6-di-O-isopropylidene-d-mannitol by means of a classical organic synthesis approach via 4-hydroxymethyl-β-lactams as key intermediates. The corresponding 4-carboxymethyl-β-lactams were subsequently obtained after selective hydrolysis of the nitrile functionality by means of a nitrilase enzyme without affecting the sensitive four-membered ring system, hence overcoming the difficulties associated with the chemical hydrolysis approach. Thus, the implementation of a biocatalytic step allows a convenient synthetic route to new 4-carboxymethyl-β-lactams as versatile building blocks for further elaboration.
- Decuyper, Lena,Piens, Nicola,Mincke, Jens,Bomon, Jeroen,De Schrijver, Bert,Mollet, Karen,De Winter, Karel,Desmet, Tom,D'Hooghe, Matthias
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- Studies towards the synthesis of secoiridoids
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A new approach to secoiridoids, based on the synthesis of the key functionalized intermediates 4 and 5, is presented. These compounds were tested in formal [3+3] cycloadditions. Acyl-chloride 15 was transformed into enol α,β-unsaturated ester 16, which was involved in a N-heterocyclic carbene rearrangement to give an advanced precursor 17 in the total synthesis of secoiridoids.
- Wu, Shaoping,Zhang, Yongmin,Agarwal, Jyoti,Mathieu, Emilie,Thorimbert, Serge,Dechoux, Luc
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- SYNTHESIS OF A NOVEL PROSTAGLANDIN H2 (PGH2) ANALOGUE
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We describe a five-step synthesis of a PGH2 analogue from (R)-glyceraldehyde acetonide via formation of 1,2(S)-O-isopropylidene-hex-3(E)-en-5-one, conjugate addition of prostanoid C13-C20 side-chain as the cuprate with C1-C7 side-chain used to quench the resultant enolate, and finally acid-catalysed ketal exchange to provide the desired analogue.
- Elder, John S.,Mann, John,Walsh, E. Brian
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- An improved synthesis of (4S)-4,5-O-isopropylidenepent- (2Z)-enoate
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(4S)-4,5-O-Isopropylidenepent-(2Z)-enoate (1) has been prepared on a multigram scale from 1,2: 5,6-di-O-isopropylidene-D-mannitol (4) in a one pot, two step sequence with improved selectivity (16:1 Z:E) and yield (71% Z) over previous literature procedures.
- Koenig, Stefan G.,Loewe, Ralf S.,Austin, David J.
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- Synthesis of the AB ring system of clifednamide utilizing Claisen rearrangement and Diels-Alder reaction as key steps
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In order to construct the functionalized AB ring system of clifednamide, member of the class of macrocyclic tetramic acid lactams, a synthesis was developed which utilized an Ireland-Claisen rearrangement and an intramolecular Diels-Alder reaction. Starting from di-O-isopropylidene-d-mannitol the allyl carboxylate precursor for the sigmatropic rearrangement was prepared. This rearrangement proceeded diastereoselectively only in the presence of an allyl silyl ether instead of the parent enone in the side chain, as suggested by deuteration experiments. A subsequent Diels-Alder reaction yielded the target ethyl hexahydro-1H-indene-carboxylate with high diastereoselectivity. Quantum-chemical investigations of this intramolecular Diels-Alder reaction support the proposed configuration of the final product.
- Loke, Inga,Bentzinger, Guillaume,Holz, Julia,Raja, Aruna,Bhasin, Aman,Sasse, Florenz,K?hn, Andreas,Schobert, Rainer,Laschat, Sabine
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- Solubility-switchable ionic liquids: A control of hydrophilicity and hydrophobicity using a protective group
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Hydrophilicity and hydrophobicity of ionic liquids are readily controlled by attaching or removing a protective group of a diol unit in their cationic part.
- Kamimura, Akio,Shiramatsu, Yuto,Murata, Kengo,Kawamoto, Takuji
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- Diastereomeric enols and enol derivatives of 8-fluoro-5,11-dihydro-10H- dibenzo[a,d]cyclohepten-10-one with a chiral 11-substituent
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Aldol condensation of 8-fluoro-5,11-dihydro-10H-dibenzo[a,d]cyclohepten-10- one and (4S)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde provides access to the corresponding (E,Z)-α,β-unsaturated ketones with a (4R)-chiral 11-substituent. Subsequent hydrogenation affords a mixture of (11R)/ (11S)-epimeric ketones, which undergoes base-catalysed equilibration resulting in selective crystallisation of the (11R) epimer. The enol intermediate and acyclic enol derivatives are shown to exist as two slowly interconverting conformers with a high inversion barrier of the 10,11-disubstituted ring. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Compernolle, Frans,Toppet, Suzanne,Brossette, Thierry,Mao, Hua,Koukni, Mohamed,Kozlecki, Tomasz,Medaer, Bart,Guillaume, Michel,Lang, Yolande,Leurs, Stef,Hoornaert, Georges J.
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- An expedient one-step preparation of (S)-2,3-O-isopropylidene-glyceraldehyde
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One-step PCC oxidation of (R)-2,3-O-isopropylideneglycerol in dichloromethane provides (S)-2,3-O-isopropylideneglyceraldehyde 2 in 30% yield after its separation from ester 3 by careful distillation. The same procedure with (S)-2,3-O-isopropylideneglycerol affords (R)-2,3-O-isopropylideneglyceraldehyde.
- Ermolenko,Sasaki,Potier
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- Clavulanic Acid Biosynthesis: the Stereochemical Course of β-Lactam Formation from Chiral Glycerol
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The overall stereochemical course of β-lactam formation in clavulanic acid was determined to be retention from (1R,2R)- and (1S,2R)-,glycerol.
- Townsend, Craig A.,Mao, Shi-shan
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- An intramolecular oxa-Michael addition on prebuilt β-lactam tethered α, β-unsaturated ester: A remarkable synthesis of a unique scaffold of 2,3-fused β-lactam-1,4-dioxepane
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An expeditious base assisted highly diastereoselective intramolecular oxy-Michael addition reaction in the synthesis of enantiomerically pure 1,4-dioxepane fused β-lactam has been described. This present study has been portrayed a rapid intramolecular 7-e
- Yadav, Ram N.,Paniagua, Armando,Banik, Bimal K.
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- Preparation method R - (+) -2, 2 - dimethyl -1 and 3 - dioxolane -4 - formaldehyde
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The invention relates to R - (+) -2. 2 - Dimethyl -1, 3 - dioxolane -4 - formaldehyde preparation method belongs to the technical field of drug intermediate synthesis. In order to solve the problems that the existing wastewater is large in pollution and not high in selectivity, the method comprises R - or -2 of catalytic amount of a phase transfer catalyst quaternary ammonium salt and an oxidizing agent, wherein the substrate type 2 - compound diacetone -1 BPCC mannitol catalytic oxidation reaction is converted into a product type - D - II 3 - compound -4 - (-2 I +) PCC in an alkyl halide hydrocarbon solvent R . 2 - Dimethyl -1, 3 - dioxolane -4 - formaldehyde. The method has the effects of high product yield and purity quality, the product yield reaches above 95%, the purity reaches 99.5% or more, a large amount of wastewater is greatly reduced, and the method has the advantage of environmental friendliness.
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Paragraph 0021-0037
(2021/11/19)
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- Nitrosocarbonyl Carbohydrate Derivatives: Hetero Diels-Alder and Ene Reaction Products for Useful Organic Synthesis
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The generation and trapping of two new nitrosocarbonyl intermediates bearing carbohydrate-based chiral substituents is achieved by the mild oxidation of the corresponding nitrile oxides with tertiary amine N -oxides. Their capture with suitable dienes and alkenes afforded the corresponding hetero Diels-Alder cycloadducts and ene adducts from fair to excellent yields. The entire methodology looks highly promising by the easy conversion of aldoximes into hydroxymoyl halides, widening the access to nitrosocarbonyls, versatile tools in organic synthesis.
- Corti, Marco,Leusciatti, Marco,Moiola, Mattia,Mella, Mariella,Quadrelli, Paolo
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p. 574 - 586
(2020/10/06)
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- High-selectivity synthesis method for gemcitabine intermediate
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The invention discloses a high-selectivity synthesis method for a gemcitabine intermediate. The high-selectivity synthesis method specifically comprises the following process: Step 1, synthesis of T1;Step2, synthesis of T2, to be specific, 550kg of hydrogen peroxide is dropwise added into the T1, and a reaction is controlled to produce the T2; Step3, synthesis of T3, to be specific, sodium acetate trihydrate or sodium carbonate is added into a reaction kettle, the PH value is adjusted with glacial acetic acid, a 10%-15% sodium hypochlorite aqueous solution is dropwise added, and a reaction iscontrolled to produce the T3; Step 4, synthesis of T4; Step 5, synthesis of T5; Step 6, synthesis of T6; Step 7, synthesis of T7; Step 8, synthesis of T8; and Step9, T8 configuration transformation.The high-selectivity synthetic method for the gemcitabine intermediate can reduce the production cost, and meanwhile, can also increase the yield of the gemcitabine intermediate.
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Paragraph 0051-0052
(2021/01/29)
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- Total Synthesis of the Putative Structure of Asperipin-2a and Stereochemical Reassignment
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The total synthesis of the putative structure of asperipin-2a is described. The synthesis features ether cross-links between the phenolic oxygen of Tyr6 and the β position of Tyr3 and the phenolic oxygen of Tyr3 and the β position of Hpp1 in the unique 17- and 14-membered bicyclic structure of asperipin-2a, respectively. The synthesized putative structure does not match the natural product, and a stereochemical reassignment is postulated.
- Hutton, Craig A.,Shabani, Sadegh,White, Jonathan M.
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supporting information
p. 7730 - 7734
(2020/10/09)
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- Diverted total synthesis of melodorinol analogues and evaluation of their cytotoxicity
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A series of melodorinol analogues were synthesized via a diverted total synthesis approach, leading to structural modifications on several regions of the molecule. Their cytotoxicity was evaluated against five human cancer cell lines (KB, HeLa-S3, MCF-7, HT-29 and A549). Structure-activity relationship studies revealed key parameters that affect the cytotoxicity. In particular, the novel 4-bromo-furanone analogues exhibited greater cytotoxicity compared to the corresponding non-brominated analogues. The stereochemistry at C-6 and the nature of acyl substituents on the C-6 and C-7 hydroxyl groups also play an important role. The most potent analogues exhibit approximately 15-fold higher cytotoxicity towards KB and HeLa-S3 than melodorinol and also show exceptionally high potency against MCF-7, HT-29 and A549 cell lines.
- Khotavivattana, Tanatorn,Khamkhenshorngphanuch, Thitiphong,Rassamee, Kitiya,Siripong, Pongpun,Vilaivan, Tirayut
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p. 2711 - 2715
(2018/06/12)
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- Method for preparing R-glyceraldehyde acetonide
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The invention relates to a method for preparing R-glyceraldehyde acetonide and belongs to the technical field of medicine intermediate synthesis. To solve the problems that a conventional method is long in route, high in cost and low in yield, the invention provides the method for preparing R-glyceraldehyde acetonide. The method comprises the following step: in the presence of a TEMPO (TetramethylPiperidine Nitric Oxide) and a crown ether type catalyst, converting diacetone-D-mannitol into R-glyceraldehyde acetonide through an oxidation reaction under the action of pypocholoride in a solventsystem of a non-water-soluble organic solvent and water. The method has the advantages of being short in reaction route and high in conversion rate, is capable of achieving effects of high yields andhigh purity, in addition is simple to operate, and is applicable to large-scale industrial production.
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Paragraph 0019; 0021; 0022; 0023; 0025; 0027; 0029; 0033
(2018/10/19)
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- Synthesis and Structure-Activity Relationship Studies of Anti-Inflammatory Epoxyisoprostane Analogues
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The lactone derivative of the epoxyisoprostane EC is a highly effective inhibitor of the secretion of the proinflammatory cytokine IL-6. Herein, a modular synthesis of analogues is described, allowing flexible variations of the cyclic side chain of the parent lactone. A structure-activity relationship study identified a lactam analogue that retains the high activity. Furthermore, the exocyclic allylic alcohol was shown to be crucial for the observed effect.
- Wolleb, Helene,Ogawa, Seiji,Schneider, Michael,Shemet, Andrej,Muri, Jonathan,Kopf, Manfred,Carreira, Erick M.
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supporting information
p. 3014 - 3016
(2018/05/28)
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- Chemical synthesis method of L-xylose
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The invention discloses a novel chemical synthesis method of L-xylose. According to the novel chemical synthesis method, 2, 2-dimethoxypropane protects hydroxyl of L-(-)2,3-dihydroxypropionaldehyde, and then a product is coupled with (1-bromovinyl)trimethylsilane so as to establish a basic framework of a target product; after production of 99% of ee is guaranteed by a sharpless epoxidation or Jacobsen-Katsuki expoxidation method, a three-membered ring is opened by protecting groups to guarantee that the configuration thereof is unchanged; then, the hydroxyl group produced by selectively removing one protecting group is oxidized into an aldehyde group; finally, the remaining protecting groups are removed to obtain the target product L-xylose, and the total yield is 46-48%. By the novel chemical synthesis method, the condition is mild, raw materials are cheap and easy to obtain, and a synthesis thought and the synthesis method are provided for chemical synthesis of a series of aldoses.
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Paragraph 0048-0050
(2018/11/22)
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- Novel preparation method for gemcitabine hydrochloride
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The invention discloses a preparation method for gemcitabine hydrochloride. The preparation method comprises the steps: carrying out condensation, cracking and addition on D-mannitol serving as an initial raw material, and protecting hydroxyl by TESC1 to prepare an intermediate; and after carrying out condensation on the intermediate and cytosine under the catalysis of chiral phosphoric acid, carrying out salification to prepare gemcitabine hydrochloride. The preparation method has the advantages that the reaction steps are reduced, and the cost is reduced. Due to the use of the chiral phosphoric acid, the proportion of a required beta structure is greatly increased, the ratio of beta to alpha can reach 9:1, and the yield is increased. The chiral phosphoric acid belongs to an organic acidand is recyclable, little to environment pollution and particularly suitable for industrial production of gemcitabine hydrochloride.
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Paragraph 0008; 0014
(2018/04/21)
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- BENZOXAZEPIN OXAZOLIDINONE COMPOUNDS AND METHODS OF USE
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Described herein are benzoxazepin oxazolidinone compounds with phosphoinositide- 3 kinase (PI3K) modulation activity or function having the Formula (I) structure: or stereoisomers, tautomers, or pharmaceutically acceptable salts thereof, and with the substituents and structural features described herein. Also described are pharmaceutical compositions and medicaments that include the Formula I compounds, as well as methods of using such PI3K modulators, alone and in combination with other therapeutic agents, for treating diseases or conditions that are mediated or dependent upon PI3K dysregulation.
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Page/Page column 74
(2017/01/26)
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- BENZOXAZEPIN OXAZOLIDINONE COMPOUNDS AND METHODS OF USE
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Described herein are benzoxazepin oxazolidinone compounds with phosphoinositide-3 kinase (PI3K) modulation activity or function having the Formula I structure: or stereoisomers, tautomers, or pharmaceutically acceptable salts thereof, and with the substituents and structural features described herein. Also described are pharmaceutical compositions and medicaments that include the Formula I compounds, as well as methods of using such PI3K modulators, alone and in combination with other therapeutic agents, for treating diseases or conditions that are mediated or dependent upon PI3K dysregulation.
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Paragraph 0233-0234
(2017/01/23)
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- 1,3-dimethyl-7-substituted quinazoline-2,4-dione fluorine-containing amide compound and synthesizing method and application thereof
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The invention discloses a 1,3-dimethyl-7-substituted quinazoline-2,4-dione fluorine-containing amide compound. The 1,3-dimethyl-7-substituted quinazoline-2,4-dione fluorine-containing amide compound is shown as a general formula in the specification, wherein R1 refers to hydrogen or ethyl, and R2 refers to a benzene ring, a benzene ring derivative, a heterocyclic ring or fatty hydrocarbon. Biological activity test experiments prove that the 1,3-dimethyl-7-substituted quinazoline-2,4-dione fluorine-containing amide compound shows good inhibiting activity for Monilia albicans, Cryptococcus neoformans and Aspergillus fumigates, is remarkable in chitin synthetase inhibiting activity and good in antibacterial effect and can be used for preparing drugs for resisting pathogenic microorganisms.
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Paragraph 0044; 0045; 0046
(2017/07/31)
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- Enzyme-Mediated Directional Transport of a Small-Molecule Walker with Chemically Identical Feet
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We describe a small-molecule "walker" that uses enzyme catalysis to discriminate between the relative positions of its "feet" on a track and thereby move with net directionality. The bipedal walker has identical carboxylic acid feet, and "steps" along an isotactic hydroxyl-group-derivatized polyether track by the formation/breakage of ester linkages. Lipase AS catalyzes the selective hydrolysis of the rear foot of macrocyclized walkers (an information ratchet mechanism), the rear foot producing an (R)-stereocenter at its point of attachment to the track. If the hydrolyzed foot reattaches to the track in front of the bound foot it forms an (S)-stereocenter, which is resistant to enzymatic hydrolysis. Only macrocyclic walker-track conjugates are efficiently hydrolyzed by the enzyme, leading to high processivity of the walker movement along the track. Conventional chemical reagents promote formation of the ester bonds between the walker and the track. Iterative macrocyclization and hydrolysis reactions lead to 68% of walkers taking two steps directionally along a three-foothold track.
- Martin, Christopher J.,Lee, Alan T. L.,Adams, Ralph W.,Leigh, David A.
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supporting information
p. 11998 - 112002
(2017/09/07)
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- Diastereoselective synthesis of β-lactams via Kinugasa reaction of acyclic chiral nitrones
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An approach to β-lactams via a Kinugasa reaction between chiral copper acetylides and chiral acyclic nitrones bearing either 1,3-dioxane or 1,3-dioxolane moieties is reported. The stereochemical preferences observed in these reactions are discussed. The reaction provides access to a variety of interesting β-lactam structures. Electronic circular dichroism in combination with NMR spectroscopy was shown to be a useful and effective method for the reliable determination of the absolute configuration of all components of a complex mixtures of azetidinones. The effectiveness of the chiral analysis of complex mixtures was demonstrated for HPLC coupled on-line with electronic circular dichroism detection as well.
- Mucha, ?ukasz,Parda, Kamil,Staszewska-Krajewska, Olga,Stecko, Sebastian,Ulikowski, Artur,Frelek, Jadwiga,Suszczyńska, Agata,Chmielewski, Marek,Furman, Bart?omiej
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- Synthesis of Cryptochiral (R,R)-2,3-Dideuterooxirane as Stereochemical Reference Compound and Chemical Correlation with D-(+)-Glyceraldehyde
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Chirality plays a pivotal role in chemistry and biology, e.g., structure-specific targeting in drug development or the lock-and-key theory of enzyme interactions. Determining absolute configurations of chiral molecules is essential to understanding such mechanisms and to developing chemical processes involving chiral compounds. In particular, this becomes obvious in the understanding of chemical reaction networks in the context of the origins of life. A stereochemical reference compound that can be correlated with sugars, amino acids, etc. is of great interest. Here, we present the synthesis of enantiopure (R,R)-2,3-dideuterooxirane, of which the absolute configuration has been unambiguously determined by foil-induced Coulomb explosion imaging, and the correlation with the configuration of D-(+)-glyceraldehyde.
- Trapp, Oliver,Zawatzky, Kerstin
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p. 1082 - 1090
(2016/11/23)
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- A Native Ternary Complex Trapped in a Crystal Reveals the Catalytic Mechanism of a Retaining Glycosyltransferase
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Glycosyltransferases (GTs) comprise a prominent family of enzymes that play critical roles in a variety of cellular processes, including cell signaling, cell development, and host-pathogen interactions. Glycosyl transfer can proceed with either inversion
- Albesa-Jov, David,Mendoza, Fernanda,Rodrigo-Unzueta, Ane,Gomolln-Bel, Fernando,Cifuente, Javier O.,Urresti, Saioa,Comino, Natalia,Gmez, Hansel,Romero-Garca, Javier,Lluch, Jos M.,Sancho-Vaello, Enea,Biarns, Xevi,Planas, Antoni,Merino, Pedro,Masgrau, Laura,Guerin, Marcelo E.
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supporting information
p. 9898 - 9902
(2015/08/19)
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- Self-Assembly of Disorazole C1 through a One-Pot Alkyne Metathesis Homodimerization Strategy
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Abstract Alkyne metathesis is increasingly explored as a reliable method to close macrocyclic rings, but there are no prior examples of an alkyne-metathesis-based homodimerization approach to natural products. In this approach to the cytotoxic C2-symmetric marine-derived bis(lactone) disorazole C1, a highly convergent, modular strategy is employed featuring cyclization through an ambitious one-pot alkyne cross-metathesis/ring-closing metathesis self-assembly process.
- Ralston, Kevin J.,Ramstadius, H. Clinton,Brewster, Richard C.,Niblock, Helen S.,Hulme, Alison N.
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supporting information
p. 7086 - 7090
(2015/06/08)
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- PROCESS FOR THE PREPARATION OF A FLUOROLACTON DERIVATIVE
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A novel process for the preparation of a fluorolactone derivative of the formula (I) and of its acylated derivative of formula (V) wherein R1 stands for a hydroxy protecting group is described. The acylated fluorolactones of formula (V), particularly the benzoyl derivative with R1 =benzyl are important precursors for the synthesis of prodrug compounds which have the potential to be potent inhibitors of the Hepatitis C Virus (HCV) NS5B polymerase.
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Page/Page column 8
(2014/07/23)
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- Ruthenium-catalyzed asymmetric N -demethylative rearrangement of isoxazolidines and its application in the asymmetric total syntheses of (-)-(1 r,3 s)-hpa-12 and (+)-(1 s,3 r)-hpa-12
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An asymmetric N-demethylative rearrangement of 1,2-isoxazolidines catalyzed by ruthenium is described. Enantioenriched syn-1,3-aminoalcohols as well as cis-1,3-oxazinanes, which are useful building blocks, can be efficiently prepared stereospecifically by this reaction in good yields, via the isoxazolidine intermediates in situ generated from a nitrone bearing a chiral auxiliary and styrenes. This asymmetric reaction was also applied in the asymmetric total syntheses of both (-)-(1R,3S)-HPA-12 and (+)-(1S,3R)-HPA-12.
- Xiao, Zu-Feng,Yao, Chuan-Zhi,Kang, Yan-Biao
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supporting information
p. 6512 - 6514
(2015/02/19)
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- Coulomb explosion imaged cryptochiral (R,R)-2,3-dideuterooxirane: Unambiguous access to the absolute configuration of (+)-glyceraldehyde
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The absolute configuration of (R,R)-2,3-dideuterooxirane, which has been independently determined using Coulomb explosion imaging, has been unambiguously chemically correlated with the stereochemical key reference (+)-glyceraldehyde. This puts the absolute configuration of D(+)-glyceraldehyde on firm experimental grounds. 100% Absolute: The absolute configuration of (R,R)-2,3-dideuterooxirane, which has been independently determined by Coulomb explosion imaging (CEI), has been unambiguously chemically correlated with the stereochemical key reference (+)-glyceraldehyde. This puts the absolute configuration of D(+)-glyceraldehyde on firm experimental grounds (see scheme).
- Zawatzky, Kerstin,Herwig, Philipp,Grieser, Manfred,Heber, Oded,Jordon-Thaden, Brandon,Krantz, Claude,Novotny, Oldrich,Repnow, Roland,Schurig, Volker,Schwalm, Dirk,Vager, Zeev,Wolf, Andreas,Kreckel, Holger,Trapp, Oliver
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supporting information
p. 5555 - 5558
(2014/05/20)
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- Formal synthesis of dysiherbaine
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A formal synthesis of dysiherbaine was achieved from D-mannitol using Grignard addition on chiral imine, RCM and Michael addition as key steps.
- Rao, Maddimsetti Venkateswara,Naresh, Annavareddi,Saketh, Gudipati,Rao, Batchu Venkateswara
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p. 6931 - 6933
(2019/04/10)
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- Syntheses of 2-keto-3-deoxy-D-xylonate and 2-keto-3-deoxy-L-arabinonate as stereochemical probes for demonstrating the metabolic promiscuity of sulfolobus solfataricus towards D-xylose and L-arabinose
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Practical syntheses of 2-keto-3-deoxy-D-xylonate (D-KDX) and 2-keto-3-deoxy-L-arabinonate (L-KDA) that rely on reaction of the anion of ethyl 2-[(tert-butyldimethylsilyl)oxy]-2-(dimethoxy phosphoryl) acetate with enantiopure glyceraldehyde acetonide, followed by global deprotection of the resultant O-silyl-enol esters, have been developed. This has enabled us to confirm that a 2-keto-3-deoxy-D-gluconate aldolase from the archaeon Sulfolobus solfataricus demonstrates good activity for catalysis of the retro-aldol cleavage of both these enantiomers to afford pyruvate and glycolaldehyde. The stereochemical promiscuity of this aldolase towards these enantiomeric aldol substrates confirms that this organism employs a metabolically promiscuous pathway to catabolise the C5-sugars D-xylose and L-arabinose.
- Archer, Robert M.,Royer, Sylvain F.,Mahy, William,Winn, Caroline L.,Danson, Michael J.,Bull, Steven D.
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supporting information
p. 2895 - 2902
(2013/03/28)
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- Scope and mechanism of the Pt-catalyzed enantioselective diboration of monosubstituted alkenes
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The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion into a Pt-B bond. Density functional theory analysis, combined with other experimental data, suggests that the insertion reaction positions platinum at the internal carbon of the substrate. A stereochemical model for this reaction is advanced that is in line both with these features and with the crystal structure of a Pt-ligand complex.
- Coombs, John R.,Haeffner, Fredrik,Kliman, Laura T.,Morken, James P.
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supporting information
p. 11222 - 11231
(2013/08/23)
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- Trifluoroacetic anhydride promoted tandem conjugate addition of boronic acids/acetal ring opening
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A new stereoselective tandem reaction consisting of the metal-free conjugate addition of boronic acids followed by an intramolecular ring opening of a cyclic acetal has been disclosed. Optically pure polysubstituted tetrahydropyrans have been synthesized
- Roscales, Silvia,Csaky, Aurelio G.
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supporting information; experimental part
p. 1187 - 1189
(2012/04/17)
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- Synthesis of modified peptidoglycan precursor analogues for the inhibition of glycosyltransferase
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The peptidoglycan glycosyltransferases (GTs) are essential enzymes that catalyze the polymerization of glycan chains of the bacterial cell wall from lipid II and thus constitute a validated antibacterial target. Their enzymatic cavity is composed of a donor site for the growing glycan chain (where the inhibitor moenomycin binds) and an acceptor site for lipid II substrate. In order to find lead inhibitors able to fill this large active site, we have synthesized a series of substrate analogues of lipid I and lipid II with variations in the lipid, the pyrophosphate, and the peptide moieties and evaluated their biological effect on the GT activity of E. coli PBP1b and their antibacterial potential. We found several compounds able to inhibit the GT activity in vitro and cause growth defect in Bacillus subtilis. The more active was C16-phosphoglycerate-MurNAc-(l-Ala-d-Glu)-GlcNAc, which also showed antibacterial activity. These molecules are promising leads for the design of new antibacterial GT inhibitors.
- Dumbre, Shrinivas,Derouaux, Adeline,Lescrinier, Eveline,Piette, Andre,Joris, Bernard,Terrak, Mohammed,Herdewijn, Piet
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scheme or table
p. 9343 - 9351
(2012/07/14)
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- Asymmetric synthesis of a 12-membered macrolactone core and a 6-epi analogue of amphidinolide W from 4-pentenoic acid
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A flexible and efficient asymmetric route to the synthesis of a 12-membered macrolactone core and a 6-epi analogue of amphidinolide W has been accomplished from commercially available 4-pentenoic acid. The successful generation of stereocenters was achieved by utilizing an Evans' chiral auxiliary-based alkylation and aldol reaction. Other key reactions such as a Julia-Kocienski olefination, Kita's macrolactonization, ring closing metathesis (RCM) reaction, and Yamaguchi's esterification were significant for the construction of the macrolactone cores.
- Chatterjee, Bhaskar,Mondal, Dhananjoy,Bera, Smritilekha
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p. 1170 - 1185,16
(2020/09/09)
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- Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
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More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright
- Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
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supporting information; scheme or table
p. 521 - 524
(2012/03/11)
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- Synthesis of the C5-C30 fragment of cyclodidemniserinol trisulfate via I2-mediated deprotection and ring closure tandem reaction
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The marine natural product cyclodidemniserinol trisulfate displayed moderate HIV-1 integrase inhibitory activity. Its novel structure triggered our interest to synthesize it. In our total synthesis effort, the natural product was dissected into four fragments based on the rational retrosynthetic analysis. All four fragments were successfully prepared with orthogonal protection. And the assembly of fragment A and B furnished the C5-C30 key subunit by employing the I2-mediated deprotection and intramolecular ketal formation tandem reaction in the presence of NaHCO3 in MeCN. Our work provided flexible and practical approaches to synthesize and derive the 3,5,7-trisubstituted 6,8-dioxabicyclo [3.2.1] octane based analogs to search for new structure HIV-1 integrase inhibitors.
- Liu, Jian-Hua,Jin, Yi,Long, Ya-Qiu
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experimental part
p. 1267 - 1273
(2010/04/02)
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- A new route for the synthesis of (R)-glyceraldehyde acetonide: A key chiral building block
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A new route for the synthesis of (R)-glyceraldehyde acetonide via asymmetric dihydroxylation of allyl 4-methoxybenzoate using the (DHQ) 2PHAL, K2OsO4·2H2O catalyst system is described. This route involves the asymmetric dihydroxylation of allyl-methoxybenzoate, acetonide protection of vicinyl dihydroxyl groups followed by cleavage of p-methoxybenzoate ester and subsequent oxidation to give the (R)-glyceraldehyde acetonide.
- Babu, K. Chandra,Ramadasu,Gangaiah,Madhusudhan,Mukkanti
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experimental part
p. 260 - 263
(2010/10/20)
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- Asymmetric synthesis of (4S,5S)-2-oxo-4-phenyloxazolidine-5-carboxylic acid using a 1,2-addition of PhMgBr to an N-sulfinimine derived from (R)-glyceraldehyde acetonide and (S)-t-BSA
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We report an asymmetric synthesis of (4S,5S)-2-oxo-4-phenyloxazolidine-5- carboxylic acid via stereoselective addition of phenylmagnesium bromide (PhMgBr) to an N-sulfinimine derived from (R)-glyceraldehyde acetonide. (S)- and (R)-Glyceraldehyde acetonides, important chiral synthons in synthetic organic chemistry, are prepared from the corresponding epichlorohydrin using an identical synthetic methodology.
- Babu, K. Chandra,Vysabhattar, Raman,Srinivas,Nigam, Satish,Madhusudhan,Mukkanti
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experimental part
p. 2619 - 2624
(2011/01/05)
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- A general approach to chiral building blocks via direct amino acid-catalyzed cascade three-component reductive alkylations: Formal total synthesis of HIV-1 protease inhibitors, antibiotic agglomerins, brefeldin A, and (R)-γ-hexanolide
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(Chemical Equation Presented) Multicatalysis cascade (MCC) process for the synthesis of highly substituted chiral building blocks (2-alkyl-CH-acids, 2-alkylcyclohexane-1,3-diones, 2-alkylcyclopentane-1,3-diones, andH-P ketone analogues) is presented based on the cascade three-component reductive alkylation's (TCRA) platform. Herein, we developed the high-yielding alkylation of a variety of CH-acids with (R)-glyceraldehyde acetonide/(S)-Garner aldehyde and Hantzsch ester through amino acid-catalyzed TCRA reaction without racemization at the α-position to carbonyl. Direct sequential combination of the L-proline-catalyzed TCRA reaction with other reactions like cascade alkylation/ketenization/ esterification (A/K/E), alkylation/ketenization/ esterification/alkylation (A/K/E/A), Bronsted acid-catalyzed cascade hydrolysis/lactonization/esterification (H/L/E), hydrolysis/esterification (H/E), hydrolysis/oxy-Michael/dehydration (H/OM/DH), and Robinson annulation (RA) of CH-acids, chiral aldehydes, Hantzsch ester, diazomethane, methyl vinyl ketone, various active olefins, and acetylenes furnished the highly functionalized chiral building blocks in good to high yields with excellent diastereoselectivities. In this context, many of the pharmaceutically applicable chiral building blocks were prepared via MCC reactions.
- Ramachary, Dhevalapally B.,Reddy, Y. Vijayendar
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scheme or table
p. 74 - 85
(2010/04/24)
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- An efficient and enantioselective total synthesis of naturally occurring L-783277
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Naturally occurring L-783277 which belongs to 14-membered resorcylic acid lactones (RALs) turned out to be a potent kinase inhibitor against MEK (MAP kinase kinase). We successfully accomplished efficient and enantioselective total synthesis of L-783277 based on convergent assembly of one aromatic unit and two chiral building blocks with efficient orthogonal protection-deprotection strategy. Three key steps composed of olefin cross metathesis, addition of acetylene derivative to aldehyde, and Yamaguchi macrolactonization were subsequently employed to construct the framework of L-783277. The optical rotation value of L-783277 is for the first time presented in this Letter.
- Choi, Hwan Geun,Son, Jung Beom,Park, Dong-Sik,Ham, Young Jin,Hah, Jung-Mi,Sim, Taebo
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scheme or table
p. 4942 - 4946
(2011/01/04)
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- Enantioselective total synthesis of (-)-Clavosolide A and B
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Enantioselective total synthesis of (-)-clavosolide A and B was reported in full including the synthesis of proposed structure of (-)-clavosoldie A (1), revised structure of (-)-clavosoldie A (5), and revised structure of (-)-clavosoldie B (6). The relative and absolute stereochemistries of the natural products were confirmed unambiguously by comparing the optical rotation values and 1H and 13C NMR spectra of them.
- Son, Jung Beom,Kim, Si Nae,Kim, Na Yeong,Hwang, Min-Ho,Lee, Wonsun,Lee, Duck Hyung
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scheme or table
p. 653 - 663
(2010/08/19)
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- Synthesis and bioluminescence-inducing properties of autoinducer (S)-4,5-dihydroxypentane-2,3-dione and its enantiomer
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The autoinducer (4S)-4,5-dihydroxypentane-2,3-dione ((S)-DPD, AI-2) facilitates chemical communication, termed 'quorum sensing', amongst a wide range of bacteria, The synthesis of (S)-DPD is challenging in part due to its instability. Herein we report a novel synthesis of (S)-DPD via (2S)-2,3-O-isopropylidene glyceraldehyde, through Wittig, dihydroxylation and oxidation reactions, with a complimentary asymmetric synthesis to a key precursor. Its enantiomer (R)-DPD, was prepared from d-mannitol via (2R)-2,3-O-isopropylideneglyceraldehyde. The synthesized enantiomers of DPD have AI-2 bioluminescence-inducing properties in the Vibrio harveyi BB170 strain.
- Kadirvel, Manikandan,Stimpson, William T.,Moumene-Afifi, Souad,Arsic, Biljana,Glynn, Nicola,Halliday, Nigel,Williams, Paul,Gilbert, Peter,McBain, Andrew J.,Freeman, Sally,Gardiner, John M.
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supporting information; experimental part
p. 2625 - 2628
(2010/07/13)
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- Synthesis of β-hydroxyphosphonate and 1,2-dihydroxy acyclic nucleoside analogs via 1,3-dipolar cycloaddition strategy
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A convenient synthetic approach toward nucleoside analogs where β-hydroxyphosphonate- or 1,2-dihydroxy units are connected to the nucleic acid base through a triazole spacer is discussed.
- Ganesan,Muraleedharan
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scheme or table
p. 91 - 96
(2011/08/02)
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- Chiral amino diol derivatives as new modular organocatalysts for the enantioselective α-chlorination of cyclic β-keto esters
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Highly modular chiral amino diol derivatives have been used as organocatalysts in the enantioselective α-chlorination of cyclic β-keto esters. Optimization of the catalyst structure and the reaction conditions has allowed the synthesis of optically active α-chlorinated products with high enantioselectivities (up to 96% ee) using inexpensive commercially available N-chlorosuccinimide (NCS) as the chlorine source under mild conditions. Copyright
- Etayo, Pablo,Badorrey, Ramon,Diaz-De-Villegas, Maria D.,Galvez, Jose A.
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experimental part
p. 3329 - 3338
(2011/02/26)
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- An improved two-step synthetic route to primary allylic alcohols from aldehydes
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An improved two-step synthetic route to allylic alcohols from aldehydes has been developed. A modification of the HWE reaction in H2O-2-PrOH (1 : 1) and a convenient protocol to prepare AlH3 in THF from LiAlH 4 and n-BuBr are the key factors in the improvement.
- Liu, Zheng,Gong, Yaqiong,Byun, Hoe-Sup,Bittman, Robert
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experimental part
p. 470 - 475
(2010/06/14)
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- Process for the enantioselective preparation of pregabalin
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The invention provides a new enantioselective process for the preparation of (S)-pregabalin, or a pharmaceutical acceptable addition acid salt comprising: acid hydrolysis of the dioxolan ring of a chiral compound of general formula (I) to obtain compound
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Page/Page column 8-10
(2009/02/10)
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- Synthesis and anti-HIV activity of conformationally restricted bicyclic hexahydroisobenzofuran nucleoside analogs
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A chiral synthesis of a series of hexahydroisobenzofuran (HIBF) nucleosides has been accomplished via glycosylation of a stereo-defined (syn-isomer) sugar motif 16 with the appropriate silylated bases. All nucleoside analogs were obtained in 52-71% yield as a mixture of α- and β-anomeric products increasing the breadth of the novel nucleosides available for screening. The structure of the novel bicyclic HIBF nucleosides was established by a single crystal X-ray structure of the β-HIBF thymine analog 22b. Furthermore, the sugar conformation for these nucleosides was established as N-type. Among the novel HIBF nucleosides synthesized, twenty-five compounds were tested as inhibitor of HIV-1 in human peripheral blood mononuclear (PBM) cells and seven were found to be active (EC50 = 12.3-36.2 μM). Six of these compounds were purine analogs with β-HIBF inosine analog 22o being the most potent (EC50 = 12.3 μM) among all compounds tested. The striking resemblance between didanosine (ddI) and 22o may explain the potent anti-HIV activity.
- Diaz-Rodriguez, Alba,Sanghvi, Yogesh S.,Fernandez, Susana,Schinazi, Raymond F.,Theodorakis, Emmanuel A.,Ferrero, Miguel,Gotor, Vicente
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scheme or table
p. 1415 - 1423
(2009/10/24)
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- A regio- and stereoisomeric study of allylic alcohol fluorination with a range of reagents
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A range of dehydroxyfluorination reagents was reacted with separate diastereoisomers of a chiral allylic alcohol to explore both the regio- and stereoselectivity ratios of direct versus allylic fluorination. The allylic alcohol stereoisomers gave the same
- Bresciani, Stefano,Slawin, Alexandra M.Z.,O'Hagan, David
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experimental part
p. 537 - 543
(2009/12/25)
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- A concise synthesis of lentiginosine derivatives using a pyridinium formation via the Mitsunobu reaction
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(Chemical Equation Presented) A four-step synthesis of (-)-lentiginosine and its epimers is described starting from 2-bromopyridine. The key step consisted of a quaternarization of a fully unprotected pyridinium-polyol unit using Mitsunobu methodology. Su
- Azzouz, Rabah,Fruit, Corinne,Bischoff, Laurent,Marsais, Francis
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p. 1154 - 1157
(2008/09/18)
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