- Design and synthesis of selenonium and sulfonium ions related to the naturally occurring glucosidase inhibitor salacinol
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Four series of analogues of the naturally occurring glucosidase inhibitor salacinol were synthesized for structure-activity studies with different glycosidase enzymes. The target zwitterionic compounds were synthesized by means of nucleophilic attack at t
- Liu, Hui,Pinto, B. Mario
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- DIACETAL DERIVATIVES AND THEIR USE AS CLARIFIER
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The invention relates to a nucleating agent of formula (I), wherein residues R1 and R2 are independently selected from substituted phenyl groups, wherein the substituents of said substituted phenyl groups are independently from each other selected from the group consisting of (C1-C4)-alkyl-; and wherein R3 is a -C(O)OR4, -C(O)NR4R5, or -C(O)-NR7-NR5R6 residue, wherein R4, R5, R6, and R7 are independently from each other hydrogen or (C1-C4)-alkyl-.
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Page/Page column 14
(2019/10/15)
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- The acidity and self-catalyzed lactonization of L-gulonic acid: Thermodynamic, kinetic and computational study
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Lactonization and proton dissociation of sugar acids take place simultaneously in acidic aqueous solutions. The protonation-deprotonation processes are always fast, whilst the formation and hydrolysis of γ- and δ-lactones are usually slower. Thus, both thermodynamic and kinetic information are required for the complete understanding of these reactions. The protonation constant (Kp) of L-gulonate (Gul–) was determined from potentiometric and polarimetric measurements, while the individual lactonization constants (KL,γ and KL,δ) for L-gulonic acid (HGul) were obtained via 13C NMR experiments. The applicability of this method was proven by measuring these well-known constants for D-gluconic acid (HGluc) and by comparing them to literature data. L-gulonic acid γ-lactone (γ-HGul) has remarkable stability in contrast with δ-HGul as well as γ- and δ-HGluc. The polarimetric measurement implies that the main factor responsible for the enhanced stability of γ-HGul is that its hydrolysis is much slower than that of δ-HGul. This higher stability of the γ-HGul ring over its δ-isomer was also confirmed by quantum chemical calculations. A new confirmed feature of the reaction is that in parallel to H3O+, HGul also catalyzes the formation and reverse hydrolytic processes of γ-HGul, similarly to other general acid catalysts.
- Kutus, Bence,Peintler, Gábor,Buckó, ákos,Balla, Zsolt,Lupan, Alexandru,Attia, Amr A.A.,Pálinkó, István,Sipos, Pál
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- Undemanding Synthesis of Novel C19 and C17 Analogues of C18-Guggultetrol
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A simple and undemanding synthesis of (2S,3R,4R,5R)-nonadecane-1,2,3,4,5-pentol and (2S,3R)-heptadecane-1,2,3-triol as novel C19 and C17 analogues of C18-guggultetrol was achieved by using l-ascorbic acid as a chiral pool.
- Dhage, Ganesh R.,Thopate, Shankar R.
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supporting information
p. 970 - 972
(2017/05/05)
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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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- Total synthesis of branimycin: An evolutionary approach
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The first total synthesis of the macrolactone antibiotic branimycin (4) has been described. The key disconnection leads to a cis-dehydrodecalone core and a polyketide side chain which are connected via organometallic addition. The dehydrodecalone core was targeted via altogether five different approaches featuring various kinds of chiral elements and ring-closing methodology. In the end the most successful method starting from diepoxynaphthalene 109 was chosen to carry on with the synthesis. Thus the oxygen functions and carbon appendages were introduced via organometallic desymmetrization reactions to generate epoxy ketone 107, to which vinyl iodide 11 was added after conversion into the organolithium species. The synthesis was completed by introducing the ester side chain via Michael addition and subsequent macrolactonization. Competitive approach: The first total synthesis of the macrolactone antibiotic branimycin is described (see figure). The dehydrodecalin core was targeted via five competing approaches featuring various kinds of chiral elements and ring-closing methodology. In this "Darwinian" struggle the most successful route emerged and led to the completion of the synthesis. Copyright
- Enev, Valentin S.,Felzmann, Wolfgang,Gromov, Alexey,Marchart, Stefan,Mulzer, Johann
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supporting information; experimental part
p. 9651 - 9668
(2012/09/21)
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- Synthesis of a functionalized 7,6-bicyclic spiroimine ring fragment of the spirolides
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The asymmetric synthesis of a functionalized 7,6-spiroimine related to the spirolides is described. Intermolecular Diels-Alder cycloaddition of a chiral trisubstituted dienophile and Danishefsky's diene enabled simultaneous installation of the C7 and C29 stereocenters. Further transformations and late-stage aza-Wittig cyclization afforded the spiroimine in good yield. During this study, an unprecedented 14-membered dialdimine was also obtained.
- Gueret, Stephanie M.,Furkert, Daniel P.,Brimble, Margaret A.
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supporting information; experimental part
p. 5226 - 5229
(2011/02/23)
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- A facile and general synthesis of rare L-sugar lactones
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A facile and general synthesis of rare L-sugar lactones from D-sugars by selectively inverting C-5 was developed. Selective 1-deacylation of sugar perpivaloates by hydroxylamine is described. More practically, β-D-glucose pentaacetate could be transformed to L-idono-1,4-lactones by this simple procedure. Georg Thieme Verlag Stuttgart.
- Hollingsworth, Rawle I.,Song, Xuezheng
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p. 1247 - 1250
(2007/12/31)
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- A practical synthesis of kifunensine analogues as inhibitors of endoplasmic reticulum α-mannosidase I
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A practical synthesis of the potent class I α-mannosidase inhibitor kifunensine (1) beginning from the inexpensive and readily available starting material L-ascorbic acid (15) is described. The protected amino-alcohol ((2R,3R,4R,5R)-5-amino-2,3:4,6-diisop
- Hering, Kirk W.,Karaveg, Khanita,Moremen, Kelley W.,Pearson, William H.
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p. 9892 - 9904
(2007/10/03)
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- N-(4-substituted phenyl)-anthranilic acid hydroxamate esters
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The present invention relates to oxygenated esters of 4-substituted-phenylamino benzhydroxamic acid derivatives, pharmaceutical compositions and methods of use thereof.
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- Oxygenated esters of 4-lodo phenylamino benzhydroxamic acids
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The present invention relates to oxygenated esters of 4-iodophenylamino benzhydroxamic acid derivatives, pharmaceutical compositions and methods of use thereof. The present invention also relates to crystaline forms of oxygenated esters of 4-iodophenylamino benzhydroxamic acid derivatives, pharmaceutical compositions and methods of use thereof.
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- N-(4-substituted phenyl)-anthranilic acid hydroxamate esters
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The present invention relates to oxygenated esters of 4-substituted-phenylamino benzhydroxamic acid derivatives, pharmaceutical compositions, and methods of use thereof.
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Page/Page column 12
(2010/02/06)
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- A new efficient access to glycono-1,4-lactones by oxidation of unprotected itols by catalytic hydrogen transfer with RhH(PPh3)4-benzalacetone system
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Treatment of unprotected pentitols and hexitols with RhH(PPh3)4-benzalacetone system leads exclusively to glycono-1,4-lactones in 60-96% yield.
- Isaac,Aizel,Stasik,Wadouachi,Beaupère
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p. 475 - 476
(2007/10/03)
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- Enantioselective synthesis of (R)-(-)-laudanosine and (R)-(-)-glaucine from L-ascorbic acid
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L-Ascorbic acid 1 was converted into L-gulonolactone 2 by catalytic hydrogenation. Treatment of 2 with 3,4-dimethoxyphenylethyl amine 3 afforded amide 4, which in several steps was transformed into the title alkaloids in good enantiomeric excesses. Also, chromium(III) oxide is proposed as an effective catalyst for the conversion of (R)-(-)-laudanosine into (R)-(-)-glaucine.
- Czarnocki, Zbigniew,Mieczkowski, Jozef B.,Ziolkowski, Marek
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p. 2711 - 2720
(2007/10/03)
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- 2-Acetamido-2-deoxyaldonolactones from sugar formazans
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A new approach towards simple aldonic acid derivatives starting from the corresponding aldoses via the 2-acetamido-2-deoxy formazans resulted in the synthesis of 2-acetamido-2-deoxy-D-galactono-1,4-lactone (8), and its 6-deoxy (11) and 6-azido-6-deoxy (14) analogues on treatment with trifluoroacetic acid.The five-membered ring structure of the lactones and that of the intermediate lactone phenylhydrazone (7) was proved by 1H and 13C NMR studies, including deuterium-induced differential isotope shift (DIS) measurements.With sodium borohydride, lactones 8 and 11 were converted into 2-acetamido-2-deoxy-D-galactitol (15) and its 6-deoxy analogue (17), respectively.
- Zsoldos-Mady, Virag,Pinter, Istvan,Neszmelyi, Andras,Messmer, Andras,Perczel, Andras
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- Enantiospecific Synthesis of D-Mannono-δ-lactam from Vitamin C
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An eight-step synthesis of the glycosidase inhibitor D-mannono-δ-lactam from vitamin C is described.
- Shing, Tony K. M.
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- Vitamin-C- and isovitamin-C-derived chemistry. Part I. Synthesis of 2,3-dideoxy derivatives of the Ascorbinic acids.
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5,6-O-Isopropylidene-L-gulono- and -D-mannono-1,4-lactones are converted into 2-(dimethylamino)-1,3-dioxolane derivatives on treatment with N,N-dimethylformamide dimethylacetal in chloroform with azeotropic removal of the methanol thus formed.Quaternisation of the products with iodomethane, followed by thermal decomposition yields the corresponding C(4)-substituted enantiomeric butenolides.Some aspects of the reactions, the characterisation of the products, and further transformation are described.
- Vekemans, Jozef A. J. M.,Boerekamp, Jack,Godefroi, Erik F.
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p. 266 - 272
(2007/10/02)
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- Process of making L-gulono gamma lactone
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L-gulono gamma lactone is made in a one-step process by the simultaneous hydrolysis and catalytic reduction with hydrogen in acid medium of polyglucuronic acid or a lower alkyl glucuronoside. A use statement--L gulono gamma lactone can be converted chemically or biologically to L-ascorbic acid (vitamin C).
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