bluuebunny/crossref_metadata_2025_split huggingface dataset:
Switching Selectivity in o‐Benzoquinone Cycloadditions
Authors: Al‐Talib Mahmoud , Gerstenberger Ina , Jones Peter G. , Winterfeldt Ekkehard 
Published: July 2007

AbstractWhereas m‐methoxy‐o‐benzoquinone 6, like other unsaturated ketones, operates as a dienophile in Diels–Alder cycloadditions, the corresponding methyl derivative 7a behaves as an electron‐poor 4π‐system under exactly the same conditions. With the nonsymmetric cyclopentadiene 2 (X = MeO), adduct 9a is formed with excellent chemoselectivity, face‐selectivity, and regioselectivity.
The Reaction of Hexachloroacetone with Diamines
Authors: Rezende Marcos Caroli , Marques Carlos Alberto , Dall'Oglio Evandro Luiz , Zucco Cesar 
Published: July 2007

AbstractThe reaction of hexachloroacetone (HCA) with various diamines led either to the corresponding diamides or to cyclic ureas, depending on the molar ratio of the reactants. In the cases of ethylenediamine, 1,2‐diaminocyclohexane and o‐phenylenediamine, the reaction with HCA also formed bisimidazole derivatives. These latter unexpected products were also formed when the diamine reacted with trichloroacetate esters or with carbon dioxide.
A Crown Ether Bearing Fulgide: The Regulation of Photochromism by Supramolecular Effects
Authors: Guo Zhixin , Wang Guijun , Tang Yingwu , Song Xinqi 
Published: July 2007

AbstractA novel benzo‐15‐crown‐5 modified fulgide (CF) has been prepared. The absorption spectra of CF and its colored form (CFDHN) are hypsochromically shifted and the decolouring rate of CFDHN is apparently decreased through selective cation binding.
Strategy for the Synthesis of Epoxide‐ and Carbonate‐Containing Dienediyne Models of the Neocarzinostatin Chromophore – Application to the 6‐Ring/11‐Ring Case[1]
Authors: Eckhardt Matthias , Brückner Reinhard 
Published: July 2007

AbstractA novel synthetic strategy leading to bicyclic dienediyne models of the chromophore 1 of the anti‐tumor antibiotic neocarzinostatin is described. Its key step is a ring‐closing McMurry reaction of the dienediyne keto aldehydes 17 or 23. It leads to dienediynediols (compounds 19 and 24, respectively) or to trienediynes (compounds 18 and 25, respectively). Low temperatures favor the formation of dienediynediols while high temperatures favor the formation of trienediynes, so that the McMurry reactions of keto aldehyde 23 show an almost perfect temperature‐dependent chemoselectivity (Scheme 6). The trienediyne 25 contains a ketal group which was removed by acid‐catalyzed methanolysis (Scheme 8). The resulting diol 31 was mono‐tert‐butylsilylated to provide the allyl alcohol 36 (Scheme 10). It was epoxidized regio‐ and stereoselectively with Sharpless' asymmetric epoxidation reagent. The resulting epoxide 37 was converted into the dienediyne epoxycarbonate syn‐33 in the final step of a sequence totaling seven steps and 5% yield starting from the bistriflate 3b; 3b itself is accessible from 2‐formylcyclohexa none in two steps and 47% overall yield. The dienediyne epoxycarbonate syn‐33 is the first synthetic congener of the neocarzinostatin chromophore furnished both with the – correctly configured – epoxide and carbonate rings.
Chemistry of Ginkgolides, VII. Preparation and Crystal Structure Analysis of a Secondary Ozonide from Ginkgolide A
Authors: Weinges Klaus , Schick Hartmut , Pritzkow Hans 
Published: July 2007

AbstractBy hydrogenation of 3,14‐didehydro‐10‐hydroxyginkgolide (3,14‐anhydroginkgolide A, 1) the 3,14‐didehydro‐10‐hydroxyginkgolide‐15‐acid (2) was obtained. Reaction with diazomethane led to the methyl ester 2a, which was transformed into its MOM derivative 2b. Ozonolysis of 2b gave a stable secondary ozonide 3 and 10‐methoxymethoxy‐3‐oxo‐14,15,16‐trinorginkgolide (4).
Anellation Reactions of Pyranose Derivatives
Authors: Peseke Klaus , Thiele Gabriela , Michalik Manfred , Powell Douglas R. 
Published: July 2007

AbstractThe “push‐pull”‐activated pyranosidulose 1 reacts with acetylacetone and ethyl acetoacetate to give the methyl pyrano‐[2′,3′:7,8]pyrano[3,2‐D][1,3]dioxin‐9‐yl ketone 2a and the pyrano[2′,3′:7,8]pyrano[3,2‐D][1,3]dioxine‐9‐carboxylate 2b. Treatment of 1 with 1,3‐cyclohexanediones leads to the 1,3‐dioxino[5′,4′:3,4]pyrano[3,4‐B]chromen‐11‐ones 4a and 4b. Dialkyl benzo[7,8]pyrano[3,2‐D][1,3]dioxine‐7,9‐dicarboxylates 5a and 5b were obtained by reaction of ulose 1 with dialkyl 3‐oxoglutarates.
Photoaddition of 2‐Morpholinoacrylonitrile to Substituted 1‐Acetonaphthones
Authors: Memarian Hamid Reza , Nasr‐Esfahani Masoud , Boese Roland , Döpp Dietrich 
Published: July 2007

AbstractSubstituted 1‐acetonaphthones 6b–d and 2‐morpholinoacrylonitrile (2a) undergo a photocycloaddition. The type of addition ([2 + 2] vs. [4 + 2]) is dependent on the location of additional substituents. Whereas compound 6c with a methoxy group at C‐2 gave only the [4 + 2]‐cycloadduct 11, the formation of [2 + 2]‐cycloadducts was observed with 6b, d with cyano and methoxy groups, respectively, at C‐4. In the case of the 4‐bromo derivative 6a, photosubstitution was observed. The endo or exo orientation of the morpholino group in the cycloadducts was determined by an X‐ray crystal structure analysis for 9b, as well as by NOE signal intensity difference determination experiments for 9a and 11.
Pheromone Synthesis, CLXXXV Synthesis of the Analogues of Lurlenic Acid with a Modified Sugar Part: Chlamydomonas responds only to the D‐xyloside
Authors: Takanashi Shin‐Ichi , Mori Kenji 
Published: July 2007

AbstractSix analogues of lurlenic acid [(4E,8E,12E)‐14‐[2′‐hydroxy‐3′,4′‐dimethyl‐5′‐(1″‐β‐D‐xylopyranosyloxy)phenyl]‐4,8,12‐trimethyltetradeca‐4,8,12‐trienoic acid(1)], the mating pheromone of Chlamydomonas allensworthii, were synthesized as E/Z mixtures (E/Z = 3:2) at C‐12. They possess a tetrahydropyranyl (1a), β‐L‐xylopyranosyl (1b), β‐D‐glucopyranosyl (1e) or β‐D‐arabinopyranosyl (1f) group, respectively, as the sugar part. Only lurlenic acid (1) was bioactive as the pheromone.
Synthesis of Medium and Large Rings, XLIV. Synthesis of Optically Active Bridged Bicyclobutane Derivatives
Authors: Tochtermann Werner , Panitzsch Torsten , Peschanel Matthias , Wolff Christian , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: July 2007

AbstractIrradiation of the dihydrooxepine monoester (+)‐4 gives the bridged bicyclobutane (+)‐5 in 77% yield. On the other hand, the corresponding diester 1 yields the cyclobutene 2. Possible explanations for this differing behaviour are discussed.
A Facile Route to Some [n.1.1]Propellanes
Authors: Kreuzholz Rüdiger , Szeimies Günter 
Published: July 2007

AbstractThe 1,7‐disubstituted tricyclo[4.1.02,7]heptanes 1a and b could be synthesized using FeIII‐catalyzed cross coupling methods. The reaction of LDA with 1a and 1b afforded an equilibrium mixture of the organolithium compounds 6 and 7, respectively. Whereas 6a/7a cyclized to the stable [4.1.1]propellane 8 in a 40% yield, 6b/7b gave rise to a 59% yield of [6.1.1]propelladiene 9 which polymerized on attempted distillation.
Chiral Bifluorophoric Perylene Dyes with Unusually High CD Effects – a Simple Model for the Photosynthesis Reaction Center
Authors: Langhals Heinz , Gold Josef 
Published: July 2007

AbstractThe synthesis of a bifluorophoric perylene dye (4a) is described, in which the two chromophores are linked by a chiral binaphthyl unit. A strong exciton coupling of the two chromophores, a bathochromically shifted fluorescence and strong CD effects are observed. The structure of 4 is compared to the photosynthesis reaction center.
Stereoselective Synthesis of Some γ‐ and δ‐Fluoro‐α‐amino Acids
Authors: Kröger Stefan , Haufe Günter 
Published: July 2007

Abstract(R)‐(−)‐2‐Amino‐4‐fluorobutyric acid (4c) (32% ee) and six of its homologues 9 have been synthesized by diastereoselective alkylation (54–72% yield) of (R)‐(+)‐camphor‐based glycine ester imines 1 with 1‐bromo‐2‐fluoro‐alkanes 6, at low temperature, followed by deprotection. Similarly 1‐bromo‐3‐fluoropropane was used for the preparation of (R)‐(−)‐5‐fluornorvaline (4d) (42% ee). With 1‐bromo‐2‐fluoropropane (6a) and its homologues (prepared by bromofluorination of 1‐alkenes) partial resolution occurs in the alkylation step, yielding mixtures of four diastereomers. Using (R)‐1‐bromo‐2‐fluoro‐4‐methylpentane two diastereomeric alkylation products are formed (58% de). The overall yield of the three‐step procedure varied from 10% to 32%.
Thermal Interconversions of the C16H10 Cyclopenta‐Fused Polycyclic Aromatic Hydrocarbons Fluoranthene, Acephenanthrylene and Aceanthrylene Revisited
Authors: Sarobe Martin , Jenneskens Leonardus W. , Wesseling Jolanda , Snoeijer Judith D. , Zwikker Jan W. 
Published: July 2007

AbstractThe thermal interconversion of the C16H10 cyclopenta‐fused polycyclic aromatic hydrocarbons (CP‐PAH) fluoranthene (1), acephenanthrylene (2) and aceanthrylene (3) has been studied using Flash Vacuum Thermolysis (FVT). In contrast to previously reported flow‐pyrolysis results, which gave the unexpected thermodynamic stability order 1 > 3 > 2, FVT temperature‐conversion data unequivocally show the expected order 1 > 2 > 3. These results are supported by independent FVT experiments with 9‐ethynylphenanthrene (4), 9‐ethynylanthracene (5) and 5‐(anthryl‐9′‐methylene)‐2,2‐dimethyl‐1,3‐dioxan‐4,6‐dione (6), which are precursors for acephenanthrylene (2) and aceanthrylene (3), respectively. The interpretation of the FVT results is corroborated by semiempirical AM1 calculations of the C16H10 potential energy surface.
Enzymatic Cleavage of N‐Phenylacetyl‐Protected Ethanolamine Phosphates
Authors: van Straten Nicole C. R. , Duynstee Howard I. , de Vroom Erik , van der Marel Gijsbert A. , van Boom Jacques H. 
Published: July 2007

AbstractImmobilized penicillin‐G acylase mediated removal of the N‐phenylacetyl protective group in ethanolamine phosphates 7 and 9 furnished compounds 8 and 10, respectively. Deblocking of N‐phenylacetyl‐protected ethanolamine phosphate heptosyl disaccharide 22, a protected spacer‐containing fragment of the inner‐core lipopolysaccharide region of Neisseria meningitidis, immunotype L3 was readily accomplished with penicillin‐G acylase, yielding target dimer 2. Disaccharide 22 was accessible by elongation of ethyl 1‐thio‐L‐glycero‐α‐D‐manno‐heptopyranosyl donor 13 with acceptor 14 under the influence of N‐iodosuccinimide/triflic acid. Protective group manipulations, phosphorylation with the reagent 2‐cyanoethyl 2‐(phenylacetylamino)ethyl N,N‐diisopropylphosphoramidite (5) and deprotection furnished LD‐Hepp dimer 22.
Synthesis of Protected Hexp‐(1 → 4)‐β‐D‐GlcpNAc‐(1 → 2)‐α‐D‐Manp‐(1 → O)(CH2)7CH3 sequences (hex = β‐D‐Glc, 4‐deoxy‐4‐fluoro‐β‐D‐Gal, or 4‐deoxy‐β‐D‐Gal) Using a Glc–GlcNPhth Donor, Eventually Fluorinated or Deoxygenated at the Oligosaccharide Level
Authors: van Dorst Johannes A. L. M. , Voskamp Anton F. , Kamerling Johannis P. , Vliegenthart Johannes F. G. 
Published: July 2007

AbstractThree trisaccharide derivatives of the type β‐D‐Hexp‐(1 → 4)‐β‐D‐GlcpNAc(1 → 2)‐α‐D‐Manp‐(1 → O)(CH2)7CH3 have been synthesized, with Hex being either glucose (15), 4‐deoxy‐4‐fluorogalactose (20), or 4‐deoxygalactose (27). These trisaccharides have been designed for the study of the acceptor specificity of glycosyltransferases involved in termination of N‐acetyllactosamine‐type N‐glycans. Allyl (2‐O‐acetyl‐3,6‐di‐O‐benzyl‐β‐D‐glucopyranosyl)‐(1 → 4)‐3,6‐di‐O‐benzyl‐2‐deoxy‐2‐phthalimido‐β‐D‐glucopyranoside (10) was synthesized by condensation of 2,4,6‐tri‐O‐acetyl‐3‐O‐benzyl‐α‐D‐glucosypanosyl trichloroacetimidate with allyl 3,6‐di‐O‐benzyl‐2‐deoxy‐2‐phthalimido‐β‐D‐glucopyranoside, followed by 4′,6′‐de‐O‐acetylation, 4′,6′‐O‐benzylidenation (8), and specific acetal ring opening. Acetylation or inverted fluorination of 10, followed by deallylation and imidation, gave suitable disaccharide donors which were each condensed with octyl 3,4,6‐tri‐O‐benzyl‐α‐D‐mannopyranoside (14) to afford the fully protected trisaccharides 15 and 20. Deallylation and imidation of 8, followed by coupling to 14 and subsequent specific acetal ring opening, triflation, halogenation, and reductive dehalogenation gave the protected 4″‐deoxytrisaccharide.
Reversible Redox Systems, LXII. 2,3‐Disubstituted 1,4‐Benzoquinones and Their N,N′‐dicyanimines: Syntheses, Physical Properties, and CT Complexes with TTF
Authors: Erk Peter , Hünig Siegfried , Klebe Gerhard , Metzenthin Tobias , Werner Hermann P. , von Schütz Jost‐ U. 
Published: July 2007

AbstractSynthesis, redox potentials, and AM1 calculations for 2,3‐disubstituted 1,4‐benzoquinones 3a–3j are described together with those of N,N′‐dicyanimines (DCNQIs) 4. All data compare well with the corresponding 2,5‐disubstituted derivatives, except R1,R2 = OMe, SMe. The special effect of these groups is discussed on the basis of low energy out of plane conformers. All DCNQIs 4 occur as syn isomers with respect to the =NCN groups except 4d, where the five membered ring formed with R1,R2 = −[CH2]3– forms 20% anti‐4d in solution. All DNCQIs form CT complexes with TTF (derivatives) with powder conductivities of 10−1 to 10−3 Scm−1.
Synthesis of Thio‐Linked Analogues of Lewis X and Sialyl Lewis X
Authors: Eisele Thomas , Schmidt Richard R. 
Published: July 2007

AbstractThe synthesis of thio‐linked Lewis X and sialyl Lewis X‐derived epitopes 3–5 has been achieved using a small number of building blocks. The key building‐block was 1‐O‐silyl‐protected 4‐S‐acetyl‐2,6‐di‐O‐benzoyl‐3‐S‐(2,3,4‐tri‐O‐acetyl‐α‐L‐fucopyranosyl)‐3,4‐dithio‐β‐D‐glucopyranose (15), which was obtained from the fucosyl donor 6 together with 3‐thiogalactose 7 as the acceptor. Their acid‐catalyzed S‐glycosylation afforded the thio‐linked disaccharide 8 which was subsequently converted to the 4a‐O‐unprotected derivative 12. Conversion to the 4a‐triflate followed by treatment with KSAc in tetrahydrofuran led, under inversion of configuration, to 15 in good overall yield. Selective removal of the S‐acetyl group followed by base‐promoted S‐glycosylation with acetobromogalactose gave the acyl‐protected Lewis X analogue 25. Acetobromogalactose gave the acyl‐protected Lewis X analogue 25. Transformation into trichloroacetimidate 27, followed by acid‐catalyzed S‐glycosylation of heptylthiol and complete deacylation afforded target molecule 3. Similarly, acid‐catalyzed reaction of donor 27 and the 3b,4b‐O‐unprotected lactose derivative 31 as acceptor led to pentasaccharide 32, complete deacylation of which afforded target molecule 4. Transformation of 15 into the donor trichloroacetimidate 34, followed by acid‐catalyzed S‐glycosylation of heptylthiol afforded thioglycoside 35. Selective removal of the S‐acetyl group and subsequent base‐promoted S‐glycosylation with the known donor 37 furnished the thio‐linked tetrasaccharide 38. Cleavage of all the O‐acyl groups and hydrolysis of the methyl ester moiety afforded the sialyl Lewis X analogue 5.
Thermal and Electron‐Transfer Induced Reactions of Enediynes and Enyne‐Allenes, 9. Electron‐Transfer versus Acid Catalysis in Enediyne Cyclizations
Authors: Schmittel Michael , Kiau Susanne 
Published: July 2007

AbstractFour novel aryl‐substituted enediynes 3 have been synthesized. While their cyclization to the Bergman products 4 could be accomplished at temperatures of 240–320°C, α‐functionalization rather than cyclization was observed during anodic oxidation and in the presence of one‐electron oxidants. In contrast, enediyne 1a was cyclized in the presence of two one‐electron oxidants to the indenone 2a as indicated in the literature; mechanistic investigations clearly indicate the occurrence of an acid‐catalyzed mechanism.
Improved Synthesis of Anhydrohexitol Building Blocks for Oligonucleotide Synthesis
Authors: De Bouvere Bart , Kerremans Luc , Rozenski Jef , Janssen Gerard , van Aerschot Arthur , Claes Paul , Busson Roger , Herdewijn Piet 
Published: July 2007

AbstractThe synthesis of the four building blocks used for the preparation of hexitol nucleic acids were optimized. The nucleoside analogues with a purine base moiety are best prepared by a nucleophilic substitution reaction, whereas the pyrimidine nucleosides can best be obtained using Mitsunobu‐type conditions.
Sulfurization of Thiones: 2,2,4,4‐Tetramethyl‐3‐thioxocyclobutanone
Authors: Huisgen Rolf , Rapp Jochen , Huber Helmut 
Published: July 2007

AbstractBy treatment with elemental sulfur and a catalytic amount of sodium thiophenolate in acetone at room temp., the title compound 9 is converted to the bis‐spiro derivatives of 1,2,4,5‐tetrathiane, 13, and 1,2,3,5,6‐pentathiepane, 14. The initial attack by the phenyl oligosulfide anion takes place at the C‐atom of the thiocarbonyl group. There is 13C NMR evidence for the twist conformation 15 of the tetrathiane ring; dynamic 1H NMR led to ΔG≠ = 15.9 ± 1.0 kcal mol−1 for the enantiomerization. For the pentathiepane 14, twelve coalescence phenomena in the 1H and 13C NMR spectra point to ΔG≠ = 13.4 ± 0.2 kcal mol−1; the process is interpreted as a stereomutation on the pseudorotation circuit for twist‐chair and chair. The MS of 13 reveals a diversity of fragmentation patterns with several “thiologous” sequences. By prolonged treatment with the thiophenolate catalyst, 13 and 14 are converted to a γ‐butyrodithiolactone 36 in a Baeyer‐Villiger type reaction.
Reactions of Uracils, 22. Synthesis of Pyrimido[5,4‐c]quinolizines
Authors: Wamhoff Heinrich , Kramer‐Hoß Vera 
Published: July 2007

AbstractSeveral heterocyclization reactions of uracil derivatives are described. 1,3‐Dimethyl‐6‐(triphenylphosphoranylideneamino)uracil‐5‐acrylic ester (1) undergoes aza‐Wittig cyclization to give pyrido[2,3‐d]pyrimidine 2. In a special application of the tert‐amino effect, 6‐tert‐amino‐substituted uracil‐5‐ylmethylenemalodinitriles 8a–f are cyclized with ZnCl2/toluene to afford pyrimido[5,4‐c]quinolizines 10b, d–f, and 1,4‐oxazino[3,4‐a]pyrido[2,3‐d]pyrimidine 10c, while the corresponding diesters 12a, b and 13 could not be cyclized. Alternative reaction mechanisms involving 1,6‐ and 1,5‐H shifts are discussed.
A Butyrolactone → 1,3‐Diol Strategy for the Obtention of Tolypothrix Polyethers – Stereoselective Synthesis of a Key Lactone Precursor
Authors: Priepke Henning , Weigand Stefan , Brückner Reinhard 
Published: July 2007

AbstractA novel access to 1,3,5,7,…︁‐polyols is developed. It follows – in the context of the planned synthesis of the natural permethylated 1,3,5,7,9‐pentaol 1a from the blue‐green alga Tolypothrix conglutinata – the strategy depicted in Scheme 4. The present paper concerns the enantioselective synthesis of the key building block syn‐9a. This γ‐lactone was derived from O‐tert‐butyldiphenylsilylglycidol (R−15) via a synthetic equivalent of the 6‐hydroxy‐4‐ketoester 12 (cf. Scheme 5). As such, we used the hydroxydiene 28 rather than the 2‐(5‐hydroxy‐3‐methylenepentyl)‐1,3‐oxazoline 26 or the (5‐hydroxy‐3‐methylenepentyl)‐substituted orthoester 27 because of its greater ease of preparation (cf. Scheme 7). A double ozonolysis of the hydroxydiene 28 provided the desired 6‐hydroxy‐4‐ketoester 12 itself (Scheme 8). The CO bond of this compound was reduced syn‐selectively (ds = 100:0) through successive additions of Et2B(OMe) and NaBH4 and anti‐selectively (ds = 80:20) through the addition of NaBH(OAc)3 (Scheme 9). The dihydroxy ester syn‐34 formed in the mentioned syn‐selective reduction was isolable or could be lactonized in the presence of acid so that the syn‐configured hydroxy lactone syn‐9a was obtained directly (Scheme 10).
Total Synthesis of the Tolypothrix Pentaether via A Bis(γ‐butyrolactone) → 1,3,7,9‐Tetraol Route
Authors: Allerheiligen Swen , Brückner Reinhard 
Published: July 2007

AbstractA total synthesis of the permethylether 1 from Tolypothrix conglutinata via a bis(γ‐lactone) intermediate was achieved. It constitutes a methodological complement of our previous syntheses (summarized in Scheme 7) of the same ether via mono(γ‐lactones) as key intermediates. The readily available γ‐lactone 4 and the allyl‐bromide containing lactone cis‐13 derived from 4 as shown in Scheme 3 were combined by a cis‐selective alkylation to the bislactone cis,trans‐14 (Scheme 4). From this bislactone, we removed both carboxylic centers and replaced each of them by a hydroxy group to obtain a single 1,3,7,9‐tetraol. Without purification, this tetraol was protected as bis‐acetonide 15 (Scheme 4; 43% yield over the two steps). In the next three steps the bis‐acetonide olefin 15 was transformed into the bis‐acetonide alcohol 19 (Scheme 5). Compound 19 gave epoxide 21 (Scheme 6) with concomitant inversion of the configuration at the hitherto incorrectly configured stereocenter. Opening the epoxide 21 at the less hindered side with a higher‐order lithium vinyl cyanocuprate, acetonide cleavage, and permethylation of the obtained pentaol finished the synthesis of the target ether 1 (Scheme 6).
Synthesis of rac‐Bisabola‐3(15),10‐dien‐7‐ol
Authors: Weyerstahl Peter , Schlicht Volker 
Published: July 2007

Abstract1‐Acetyl‐4‐methylenecyclohexane (6) was obtained from ethyl 4‐methylenecyclohexane carboxylate (2), by DIBAH reduction (→ 4), Grignard reaction (→ 5) and oxidation. A further Grignard reaction furnished the rac‐bisabola‐3(15),10‐dien‐7‐ol (1), which we isolated recently from Vetiver oil. Its odor is mainly aldehydic (fatty, floral).
Biologically Active Glycosides from Asteroidea, 37. Glycosphingolipids from the Starfish Luidia maculata, 1 Structure of A New Sulfatide Molecular Species
Authors: Kawatake Satoshi , Inagaki Masanori , Isobe Ryuichi , Miyamoto Tomofumi , Higuchi Ryuichi 
Published: July 2007

AbstractA sulfatide molecular species [LMG‐1 (1)] have been obtained from the water soluble lipid fraction of the chloroform/methanol extract of the starfish Luidia maculata. On the basis of chemical and spectroscopic findings, the structure of 1 has been elucidated. Negative FAB mass spectrometry provided important information both on the structure of the sugar moiety and on the molecular mass of the sulfatide. 1 is, to the authors' knowledge, new sulfatide molecular species and first sulfatide obtained from starfish. In addition, 1 shows neuritogenic activity toward the rat pheochromocytoma cell line, PC‐12 cell.
Stereoselective Synthesis of the Core Structure of the Nephritogenoside Glycopeptide
Authors: Zhang Hong , Wang Yali , Thürmer René , Meisenbach Mark , Voelter Wolfgang 
Published: July 2007

AbstractA new strategy for the construction of the O‐glycoside bond in the nephritogenoside unit using the phenylsulfenyl method is reported. The readily accessible phenylsulfinyl glycoside proved to be an excellent glycosyl donor, leading to high yields and good selectivity. The extremely mild conditions utilized in glycosylation reactions allow trityl and other sensitive protecting groups to be used for temporary protection. The fact that phenyl thioglycosides function as glycosyl acceptors during the coupling reaction and can easily be transformed into glycosyl donors by conversion to phenylsulfinyl glycosides, enables complex oligosaccharides to be prepared in a highly convenient manner.
Practical Syntheses of (S)‐4‐Hydroxytetrahydrofuran‐2‐one, (S)‐3‐Hydroxytetrahydrofuran and Their (R)‐Enantiomers
Authors: Yuasa Yoshifumi , Tsuruta Haruki 
Published: July 2007

AbstractOptically active 4‐hydroxytetrahydrofuran‐2‐one (3) has been synthesized in good yield from optically active ethyl 4‐chloro‐3‐hydroxybutanoate (2) by refluxing with dilute hydrochloric acid. In a similar manner, optically active 3‐hydroxytetrahydrofuran (5) was prepared from optically active 4‐chloro‐1,3‐butanediol (4), which was derived from 2 by NaBH4 reduction. These new cyclizations proceed without racemization.