bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antarctic Marine Metabolites: New Polyhydroxylated Steroidal Glycosides from the Starfish Odontaster validus
Authors: Vázquez M. Jesús , Quiñoá Emilio , Riguera Ricardo , Martin Aurelio San , Darias José 
Published: July 2007

AbstractTwo new asterosaponins, validosides A and B, were isolated from the butanolic extract of the starfish Odontaster validus and their structures established as (24S)‐24‐O‐[2,4‐di‐O‐methyl‐β‐xylopyranosyl‐(1→2)‐α‐arabinofuranosyl]‐5α‐cholestane‐3β,4β,6α,8,15β,24‐hexaol 6‐O‐sodium sulfate (1) and (24S)‐24‐O‐(3‐O‐methyl‐β‐xylopyranosyl)‐5α‐cholestane‐3β,6α,8,15β,24‐pentaol 2′‐O‐sodium sulfate (2) on the basis of extensive spectroscopic investigations and chemical correlations. Validoside A and B are extremely rarely occurring saponins due to the presence of a sulfated group at C‐6 of the aglycone in 1 and at C‐2′ of a pyranose in 2. The absolute configuration at C‐24 was found to be S by the application of the Trost‐Mosher methodology.
Pheromone Synthesis, CLVIII. New Synthesis and Revision of the Absolute Configuration of the Hemiacetal Pheromone of the Spined Citrus Bug Biprorulus bibax
Authors: Mori Kenji , Amaike Masayasu , Watanabe Hidenori 
Published: July 2007

AbstractThe enantiomers and the racemate of (3R,4S,1′E)‐3,4‐bis(1′‐butenyl)tetrahydro‐2‐furanol (1) were synthesized by employing Ireland's ester enolate Claisen rearrangement of 5 as the key reaction to provide the corresponding lactone 3 via 4. Optically active 3 was prepared by employing either chemical asymmetric reduction [12 → (S)‐8b] or lipase‐mediated asymmetric hydrolysis (9→10) and acetylation (meso‐2 → ent‐10) as the key transformations. The absolute configuration of the naturally occurring 1 was revised as (3R,4S) on the basis of the chemical asymmetric synthesis of (3S,4R)‐3 by starting from (S)‐8b of known stereochemistry.
Ring Transformations of Oxazoles and Their Derivatives. – Synthesis of 2,3‐Dihydro‐2‐(2‐hydroxyphenylimino)‐4‐methylthiazoles by Reaction of 2‐(2‐Oxopropylthio)benzoxazoles with Amines
Authors: Kalcheva Veneta , Tosheva Madlena , Hadjieva Petia 
Published: July 2007

AbstractTreatment of 2‐(2‐oxopropylthio)benzoxazoles 1a–d with an excess of primary amines in acetic acid or in perchloric acid affords 3‐substituted 2‐(2‐hydroxyphenylimino)‐4‐methylthiazoles 4a–q. Interaction of thiazoles 4a,i with diazomethane leads to the corresponding O‐methyl derivatives. The structure of compounds 4a–q is confirmed by an X‐ray analysis of compound 4d.
Untersuchungen mit selektiven Abspaltungsreagenzien für ADPOC‐geschützte Aminosäuren und Peptide
Authors: Voelter Wolfgang , Kalbacher Hubert 
Published: July 2007

Investigations with Selective Deblocking Reagents for Adpoc‐Protected Amino Acids and PeptidesSelective reagents for the removal of the Adpoc group have been developed. For this purpose several peptides containing tryptophan and Nϵ‐Boc‐lysine have been synthesized. Among several acidolytic reagents, 0.1 N HCl/TFEt/CHCl3 (1:9:1) and 50% HCOOH/TFEt/CHCl3 (1:9:1) show high selectivity especially for the Nϵ‐tert‐butyloxycarbonyl group of lysine. Cleavage rates are determined by HPLC and TLC.
Synthese und polarographisches Verhalten neuer Isoindole. – 1‐Aryl‐ und 1‐Styryl‐2H‐isoindol‐4,7‐dione
Authors: Schubert‐Zsilavecz Manfred , Michelitsch Astrid , Likussar Werner , Gusterhuber Dagmar 
Published: July 2007

Synthesis and Polarographic Behaviour of Novel Isoindoles. – 1‐Aryl‐ and 1‐Styryl‐2H‐isoindole‐4,7‐dionesReactions of quinones 4a–c and sarcosine (2) with seven differently substituted aldehydes 1 yield – via the azomethine ylides 3 – the isoindolediones 5 and 6. The structures of all compounds were elucidated from spectral data, mainly by mass and NMR spectra.
Synthese der Theonelladine A, B, C, D und von Niphatesin A
Authors: Teubner Achim , Gerlach Hans 
Published: July 2007

Syntheses of the Theonelladines A, B, C, D and of Niphatesine AThe pyridine alkaloids theonelladine A–D (1–4) and niphatesine (5) of marine origin have been synthesized starting either from 3‐(4,4‐dibromo‐3‐butenyl)pyridine (6) or from 3‐pyridinecarbaldehyde. Reaction of 6 with two equivalents of BuLi gave the lithiated derivative of the alkyne 7, which could be alkylated with 1‐bromo‐10‐(tetrahydro‐2‐pyranyloxy)decane (8) to yield the alkynol 9 after methanolysis. Selective hydrogenation of 9 with Lindlar palladium catalyst gave (Z)‐14‐(3‐pyridyl)‐11‐tetradecan‐1‐ol (11). – Addition of the Grignard reagent of 12‐(benzyloxy)‐1‐bromododecane (13) to 3‐pyridinecarbaldehyde gave 17, which was first oxidized (Swern) to give 18 and then reduced (Wolff‐Kishner) to give 14. Hydrogenolysis of the benzyl ether 14 yielded 15. The alcohol group in 9, 11, and 15 was converted into the tosyloxy group by reaction with tosyl chloride/pyridine. Subsequent reactions of the tosylates 10, 12, and 16 either with an excess of methylamine/ethanol or of ammonia/ethanol gave the pyridine alkaloids 1–5 in high yields as p‐toluenesulfonates.
Solanum Alkaloids, 126. Degradation of Solasodine to 16β,22‐Epoxy‐23,24‐dinorchol‐5‐ene‐3β,22β‐diol and Partial Synthesis of (23s)‐23‐Hydroxysolasodine
Authors: thi Quyen Le , Ripperger Helmut , Adam Günter , Schreiber Klaus 
Published: July 2007

Abstract(22R,23S,25R)‐N‐Chloro‐22,26‐epiminocholest‐5‐ene‐3β,16β,23‐triol (11) and its 3,16,23‐O‐triacetyl derivative 15 were prepared from solasodine (1). Treatment of 11 or 15 with sodium methanolate yielded the 22,23‐secoaldehyde 16 as major product (Grob fragmentation) and (23S)‐23‐hydroxysolasodine (2) as minor product (Ruschig reaction). Hydrolysis of 16 with methanolic hydrochloric acid afforded 16β,22‐epoxy‐23,24‐dinorchol‐5‐ene‐3β,22β‐diol (17) and its 22‐O‐methyl derivative 18, the 3‐O‐acetate 19 of which was oxidized to the known acetyldiosgenin lactone (20), thus confirming the structures of 16–19. Compound 2 was shown to be identical in every respect with a rare spirosolane alkaloid, recently isolated from some Solanum species. Photolysis of (22R,23S,25R)‐3β,16β‐diacetoxy‐N‐chloro‐22,26‐epiminocholest‐5‐en‐23‐ol (10) yielded also via 22,23‐carbon‐carbon cleavage (20S)‐3β,16β‐diacetoxypregn‐5‐ene‐20‐carbaldehyde (21) as major product, which was converted by treatment with methanolic hydrochloric acid into the compound 18.
Synthesis and Stereochemistry of 7,9‐Disubstituted 3‐Azabicyclo[3.3.1]nonanes
Authors: Nemes Peter , Janke Frank , Scheiber Pál 
Published: July 2007

AbstractThe azabicyclic endo compound 3 was synthesized by reaction of enamine 1 with 2‐benzoyl‐1,3‐dichloropropane (2). The thermodynamically more stable exo isomer 4 was obtained by epimerization of 3 with sodium methoxide. The reduction of 3 and 4 was carried out with different reducing agents. The syn/anti isomeric amino alcohols 7a/7b and 8a/8b were separated either by fractional crystallization of their fumarate salts or by column chromatography. The relative configurations at C‐7 and C‐9 and the conformations of the molecules were determined by chemical and/or NMR spectroscopic methods.
Synthesis of β‐Glycosidically Linked Deoxydisaccharides in the L‐Ribo Series
Authors: Sajus Henry , Thiem Joachim 
Published: July 2007

AbstractBy Fischer glycosylation, alkylidenation, methylation, and subsequent reaction with dibromomethyl methyl ether L‐rhamnose 2 was converted into the L‐gluco‐configurated glycosyl bromide 5. According to classical routes 2 was transformed into the 2,6‐dideoxy compound 7 and further into the acceptor derivative 9 with arabino‐configuration. Glycosylation with 5 gave predominantly the β‐1 → 4‐linked disaccharides 11. After deacylation and simultaneous Mitsunobu inversion at C‐3 and C‐3′ the D–B disaccharide unit of kijanimicin was obtained.
Pheromone, 89 – Wittig‐Synthese alkylverzweigter und cyclischer Analoger von (Z)‐5‐Decenylacetat, dem Sexualpheromon von Agrotis segetum (Lepidoptera: Noctuidae)
Authors: Albores Martha , Bestmann Hans Jürgen , Döhla Bodo , Hirsch Hans‐Ludwig , Rösel Peter , Vostrowsky Otto 
Published: July 2007

Pheromones, 89, – Wittig Syntheses of Alkyl‐Branched and Cyclic Analogs of (Z)‐5‐Decenyl Acetate, the Sex Pheromone of Agrotis segetum (Lepidoptera: Noctuidae)By means of (Z)‐selective Wittig olefination alkyl‐branched and cyclic analogs of (Z)‐5‐decenyl acetate, the sex pheromone of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae), have been synthesized.
Antibiotika aus Gleitenden Bakterien, L – Chemische Modifikation von Sorangicin A und Struktur‐Wirkungs‐Beziehung II: Derivate aus Reduktions‐, Oxidations‐ und Umlagerungsreaktionen
Authors: Schummer Dietmar , Irschik Herbert , Höfle Gerhard 
Published: July 2007

Antibiotics from Gliding Bacteria, L. – Chemical Modification of Sorangicin A and Structure‐Activity Relationship II: Derivatives Obtained by Reduction, Oxidation and Rearrangement ReactionsThe synthesis of 38 derivatives of sorangicin A (1) with modifications of the three hydroxyl groups and the conjugated triene is described. By oxidation and reduction reactions 21‐desoxy‐21‐oxo sorangicin (8), 21‐epi‐sorangicin (9) and 21‐desoxysorangicins 14, 15 were obtained. With protection of the 21,22‐diol the 24,25‐didehydro‐25‐desoxysorangicin (18), 25‐desoxy‐25‐oxosorangicins 21, 22 and 25‐epi‐sorangicins 23, 24 were prepared. Further, the 25‐oxo derivatives 21, 22 were transformed into the oximes 25–28 and the 25‐desoxy‐25,25‐difluoro sorangicin (31). Catalytic reduction of sorangicin A (1) gave the 37,43‐dihydro derivative 35, thermolysis the cyclohexadienes 36, 37 and fluoride‐induced isomerisation the 36,38,40‐trienol ethers 38, 39. – Activities against Staphylococcus aureus, Escherichia coli, and in vitro inhibition of RNA polymerase of selected derivatives were examined. With most compounds a reduced biological activity was observed, some derivatives retained their activity (23–28, 31) and three were improved for certain strains (18, 21, 22) although they showed reduced enzyme inhibition activity.
Kondensierte Dithiole, III. Synthese von 1,2‐Dithiolo‐furanen
Authors: Stachel Hans‐Dietrich , Zoukas Thomas , Hußlein Manfred , Nienaber Julyane , Schorp Matthias 
Published: July 2007

Ring‐Fused 1,2‐Dithioles, III. – Synthesis of 1,2‐Dithiolo‐furansA series of 1,3‐dithiino‐furans 4/9 has been synthesized by starting with the β‐ketoester 5a or the cyclic ketone 5b. The dithiines undergo oxidative ring contraction to give the corresponding 1,2‐dithiolo‐furans 3/14. The ester function of 3h is easily removed to give 2, the oxaanalog of the antibiotic thiolutine. In general, the lactone group is the most sensitive part in compounds 3, 4 and 14. In marked contrast the dithiine 9a is cleaved by amines at the thioketale site forming the tetronic acid derivatives 10a/b.
Totalsynthese von Isokalafunginen und Isonanaomycinen
Authors: Hoffmann Bernd , Schönebaum Andreas , Lackner Helmut 
Published: July 2007

Total Synthesis of Isokalafungins and IsonanaomycinsThe total synthesis of isokalafungins (2) and isonanaomycins (12), the first members of a nonnatural group of benzoisochromanquinone antibiotics hydroxylated only at C‐6, is described. Pathway A (Scheme 1) yields the separated (±)‐cis and ‐trans diastereomers of 2 and 12 and is especially suited for modifications of the dihydropyrane ring. On pathway B the chirality of C‐1 is preformed by using 3,4,6‐trideoxy‐α‐L‐glycero‐hex‐3‐enopyranosid‐2‐ulose (22) as a main building block, for the first time synthesized from L‐fucose (Scheme 2). According to Scheme 3, condensation of 22 with the intermediate 23 gives the new 6‐hydroxylated variants (1S,3S,4S)‐isonanaomycin D (30) and (1R,3R,4R)‐isokalafungin (2). Pathway B favours modifications of the phenolic ring, which can strongly influence the spectrum of activity. Unexpectedly, the shifting of the hydroxy group from C‐9 to C‐6 changes the antibacterial properties unessentially.
1,2,3‐Triazine, IV Synthese von 1,2,3‐Triazincarbonsäureestern
Authors: Neunhoeffer Hans , Bopp Ralf , Diehl Werner 
Published: July 2007

1,2,3‐Triazines, IV. – Synthesis of 1,2,3‐Triazinecarboxylates1,2,3‐Triazinecarboxylates 5 have been prepared by rearrangement of the cyclopropenyl azides 6 as well as by oxidation of the 1‐aminopyrazoles 9, 10. Reaction of 1‐aminopyrazole‐5‐carboxylates 10 with triethyl orthoformate (19) and ammonia affords pyrazolo[3,2‐f][1,2,4]triazin‐4‐ones 18.
Pheromone Synthesis, CXLIX. Synthesis of (2E,4E,6R,10S)‐4,6,10‐Trimethyl‐2,4‐dodecadien‐7‐one – the Major Component of the Sex Pheromone of the Maritime Pine Scale (Matsucoccus feytaudi) – and its Three Stereoisomers
Authors: Mori Kenji , Harashima Susumu 
Published: July 2007

Abstract(2E,4E,6R,10S)‐4,6,10‐Trimethyl‐2,4‐dodecadien‐7‐one (1) – the major component of the sex pheromone of the maritime pine scale – and its three stereoisomers were synthesized by starting from (R)‐ or (S)‐citronellol (4) and employing the asymmetric epoxidation (9 → 10) and the palladium‐catalyzed reductive cleavage of the epoxy ring (13 → 14) as the key steps.
Radikalische Cyclisierung von Dienen, V. Substratkontrollierte asymmetrische Synthese von (−)‐Hirsuten und (−)‐3‐Hydroxyhirsuten aus (R)‐(−)‐Carvon
Authors: Weinges Klaus , Reichert Hans , Huber‐Patz Ursula , Irngartinger Hermann 
Published: July 2007

Radical‐Type Cyclization of Dienes, V. – Substrate‐Controlled Asymmetric Synthesis of (−)‐Hirsutene and (−)‐3‐Hydroxyhirsutene from (R)‐(−)‐Carvone(3aR,6aR)‐(−)‐6a‐Methyl‐3,3a,4,6a‐tetrahydro‐2H‐cyclopenta‐ [b]furan‐2‐one (6) and (1R,4S)‐(−)‐3‐[4‐(but‐3‐inyl)‐3‐methyl‐cyclopent‐2‐enyl]‐2,2‐dimethylpropan‐1‐ol (11) are key compounds in the synthesis reported in this paper. Enantiomerically pure 6 was obtained in five straightforward steps from the inexpensive precursor (R)‐(−)‐carvone (1). Compound 11 was prepared from 6 via an SN2′ reaction, by analogy with the synthesis reported by Curran et al. The linear triquinanes 13 and 15 were obtained in gram quantities in two additional steps. The utilisation of (S)‐(+)‐carvone (ent‐1) allows access to the other enantiomeric forms. X‐ray analysis of 15a confirmed the structure of 15 and, by correlation, that of 13.
Metabolic Products of Microorganisms, 266. Serpentene, a Novel Polyene Carboxylic Acid from Streptomyces
Authors: Ritzau Michael , Drautz Hannelore , Zähner Hans , Zeeck Axel 
Published: July 2007

AbstractFrom the culture filtrate of Streptomyces sp. a novel, bright yellow polyene carboxylic acid, named serpentene (1), was isolated by chemical screening methods. The structure elucidation of 1 is described. Remarkably, the C20 skeleton contains an ortho‐substituted benzene ring bearing a dienoic acid and a nonatetraenyl residue. Concerning its structure and biosynthetic origin 1 is a unique secondary metabolite.
A Convenient Synthesis of Centperazine, an Antifilarial Candidate Drug
Authors: Sengupta Sreela , Sahu Devi Prasad , Chatterjee Sunil Krishna 
Published: July 2007

Abstract7‐Ethyl‐octahydro‐2‐methyl‐6H‐pyrazino[1,2‐c]pyrimidin‐6‐one (centperazine) (1), an antifilarial candidate drug, currently undergoing phase II clinical trials, has been synthesized by a more economically viable alternative route. Condensation of N,N′‐dibenzylethylenediamine (2) with 3,4‐dibromobutyronitrile (3) gives 2‐(1,4‐dibenzyl‐2‐piperazinyl)acetonitrile (4), which, on catalytic reduction, debenzylation, cyclocarbamation and N‐alkylation yields the target molecule 1 in 10.1% overall yield.
Amination and Synthesis of Some Nitronaphthyridines
Authors: Woźniak Marian , Tomula Maria 
Published: July 2007

Abstract3‐Nitro and 3,6‐dinitro‐1,8‐naphthyridines 1, 4 and 5 are dehydroaminated with a liquid ammonia solution of potassium permanganate to the corresponding 4‐amino‐substituted compounds 3, 8 and 9. The intermediate 4‐amino σ‐adducts 2, 6 and 7 of the nitro‐1,8‐naphthyridines are detected by 1H‐NMR spectroscopy. The syntheses of some nitro‐substituted naphthyridines are described.
Synthesis of Fluorescent 7,8,9‐Tri‐O‐acetyl‐N‐acetyl‐ and 4‐O‐Acetyl‐N‐acetylneuraminic Acid α‐Thioketosides
Authors: Roth Andreas , Faillard Hans 
Published: July 2007

AbstractTwo new fluorescent regioselective O‐acetylated N‐acetylneuraminic acid (Neu5Ac) thioketosides, 2α‐[4‐(dansylamino)phenylthio]‐7,8,9‐tri‐O‐acetyl‐N‐acetylneuraminic acid {2α‐[4‐(dansylamino)phenylthio]‐Neu5,7,8,9Ac4} (3) and 2α‐[4‐(dansylamino)phenylthio]‐4‐O‐acetyl‐N‐acetylneuraminic acid {2α‐[4‐(dansylamino)phenylthio]‐Neu4,5Ac2} (9) were synthesized. The synthesis of both derivatives started with the peracetylated benzyl ester 1 as precursor. The 7,8,9‐tri‐O‐acetylated compound was prepared by partial deacetylation of 1 with sodium methoxide or with hydrazine hydrate, followed by catalytic benzyl ester hydrogenolysis. – Complete Zemplén deacetylation of 1 gave the Neu5Ac benzyl ester thioketoside 4, which was converted into the 8,9‐isopropylidene‐protected compound 5. By carefully performed regioselective 4‐O‐acetylation with acetic anhydride/pyridine in dichloromethane we obtained the desired fluorescent 4‐O‐acetyl derivative 6 and the nonfluorescent sulfonacetamide 7 as byproduct. Acidic 8,9‐deprotection of 6 and finally catalytic hydrogenolysis of the benzyl ester 7 terminated this synthetic route, yielding 2α‐[4‐(dansylamino)phenylthio]‐Neu4,5Ac2 (9). – The 4‐O‐acetylated derivative 9 could not be de‐O‐acetylated by influenza‐C virus esterase. However, the virus esterase transformed the tri‐O‐acetylated derivative 3 in small amounts into the Neu5Ac thioketoside 10.
Studies on the Constituents of the Stems of Tinospora tuberculata, IV. Isolation and Structure Elucidation of the Five New Furanoid Diterpene Glycosides Borapetoside C–G
Authors: Fukuda Naomichi , Yonemitsu Michiko , Kimura Takeatsu 
Published: July 2007

AbstractFive new furanoid diterpene glycosides, named borapetoside C (1), D (2), E (3), F (4), and G (5), were isolated from the stems of Tinospora tuberculata Beumée (Menispermaceae). The structures of 1–5 were elucidated by chemical and spectroscopic methods.
First Synthesis of the Cytotoxic and Antifungal C14‐Amine (2S,3E,5Z)‐2‐Amino‐3,5,13‐tetradecatriene Isolated from the New Zealand Ascidian Pseudodistoma novaezelandiae
Authors: Enders Dieter , Finkam Michael 
Published: July 2007

AbstractThe synthesis of (2S,3E,5Z)‐2‐amino‐3,5,13‐tetradecatriene [(S‐1)] with high enantiomeric purity in excellent overall yield is described. In the crucial step the stereogenic center was generated by nucleophilic addition of tert‐butyl carbamate to a planar‐chiral tetracarbonyliron(1 +) complex.
Ein selektiver Abbau der Exomethylengruppe von Vitamin D. – Ein einfacher Zugang zu 10‐Oxo‐19‐norcholecalciferol und 10‐Oxo‐19‐norergocalciferol
Authors: Reischl Wolfgang 
Published: July 2007

A Selective Degradation of the Exomethylene Group of Vitamin D. – A Simple Entry to 10‐Oxo‐19‐norcholecalciferol and 10‐Oxo‐19‐norergocalciferolNitrile oxides, generated in situ from nitroalkanes, add exclusively to the exomethylene group of (Z)‐ and (E)‐vitamin D3 acetates (1a, 12a) and D2 acetates (1b, 12b). The so generated spirocyclic isoxazoline derivatives are transformed through a Mo(CO)6‐induced fragmentation into (5Z,7E)‐ and (5E,7E)‐(3S)‐3‐acetoxy‐19‐nor‐9,10‐secocholesta‐5,7‐dien‐10‐one (20a, 22a) as well as (5Z,7E,22E)‐ and (5E,7E,22E)‐(3S)‐3‐acetoxy‐19‐nor‐9,10‐secoergosta‐5,7,22‐ trien‐10‐one (19a, 21a). The discribed method allows the synthesis of 19‐nor‐10‐oxo vitamin D derivatives without partial isomerisation of the Δ5‐double bond.
4‐disubstituted furans, 5. Regiospecific mono‐ipso‐iodination of 3,4‐bis(trimethylsilyl)furan and regiospecific ipso‐iodination of tris[(4‐alkyl‐ or ‐aryl)furan‐3‐yl]boroxines to 4‐substituted 3‐(trimethylsilyl)furans and unsymmetrical, 3,4‐disubstituted furans
Authors: Song Zhi Zhong , Wong Henry N. C. 
Published: July 2007

Abstract4‐Iodo‐3‐trimethylsilylfuran (2), obtained through the regio‐Specific iodination of 3,4‐bis(trimethylsilyl)furan (1), underwent either palladium‐ or nickel‐catalyzed cross‐coupling reactions with terminal alkenes, terminal alkynes, areneboronic acids, bis(p‐methoxycarbonylbenzyl)zinc and Grignard reagents to give 4‐substituted 3‐(trimethylsilyl)furans 3–7, which were converted into boroxines 8. Regiospecific iodination of 8 gave iodofurans 9, which afforded in the usual way unsymmetrical 3,4‐disubstituted furans 10. Boroxines 8 gave also 3,4‐disubstituted furans 11 via palladium‐catalyzed cross‐coupling reactions with piperonyl chloride and vinyl bromide. magnified image
Synthesis of (3R,25R)‐3,25‐dihydroxyhexacosyl α‐D‐glucopyranoside, the heterocyst glycolipid of the marine cyanobacterium Nodularia harveyana
Authors: Mori Kenji , Qian Zhao‐Hui 
Published: July 2007

Abstract(3R,25R)‐3,25‐Dihydroxyhexacosyl α‐D‐glucopyranoside (1a), the heterocyst glycolipid of Nodularia harveyana, was synthesized by starting from D‐glucose, (S)‐malic acid (4), 1‐octadecyne (5) and ethyl (R)‐3‐hydroxybutanoate (6). magnified image
Synthesis of sphingosine relatives, XIV. A new synthesis of symbioramide, a Ca++‐ATPase activator from Symbiodinium sp.
Authors: Mori Kenji , Uenishi Keiji 
Published: July 2007

AbstractSymbioramide [(2S,2′R,3R, 3′E)‐N‐(2′‐hydroxy‐3′‐octadecenoyl)dihydrosphingosine, 1] was synthesized from D‐erythro‐dihydrosphingosine (19) and (R, E)‐2′‐tert‐butyldimethylsilyloxy‐3′‐octadecenoic acid (14), which was prepared from (E)‐2‐octadecen‐1‐ol (4) by employing the Sharpless asymmetric epoxidation. The (2S,2′S,3R,3′E)‐isomer 28 of 1 was also synthesized to further confirm the structure of 1. magnified image
Indium‐assisted allylation in carbohydrate chemistry: A convenient route to D‐glycero‐D‐galacto‐ and D‐glycero‐L‐galacto‐heptose
Authors: Prenner Reinhard H. , Binder Wolfgang H. , Schmid Walther 
Published: July 2007

AbstractStarting with unprotected D‐pentoses 1–4 we achieved a chain elongation reaction by utilizing indium‐assisted allylation. After acetylation, the polyol derivatives 1a–4a were transformed into the corresponding α,β‐unsaturated aldehydes 1b–4b. Protection of the carbonyl group yielded the diethyl acetals 1c–4c. Subsequent dihydroxylation of the double bond by catalytic osmylation followed by acetylation of the newly introduced hydroxyl functions gave a mixture of diastereomeric products. However, only those diastereomers could be easily separated by column chromatography which were derived from 1c and 2c, giving access to D‐glycero‐D‐galacto and D‐glycero‐L‐galacto precursor 5 and 7, respectively. Final deprotection yielded the title aldoheptoses 6 and 8. magnified image
Synthesis of sphingosines, 9. Synthesis of phytosphingosine derivatives
Authors: Birk Rolf , Jung Karl‐Heinz , Schmidt Richard R. 
Published: July 2007

AbstractReaction of the lithium acetylide prepared from bromooctene 2 with 2,4‐O‐benzylidene‐D‐threose (1) yielded the epimeric dodec‐5‐ynetetrol derivatives 3a, b. Reaction of the Grignard reagent of bromooctene 2 with 1 gave (E,Z)‐dodec‐5‐ene‐tetrol derivatives (E,Z)‐12a,b. From these precursors D‐ribo‐phytosphingosine derivatives 7b, (E)‐18, and (Z)‐18, respectively, were obtained. Also interesting anhydro derivatives, for instance 3,4‐epoxides 11a and (E)‐21, and 1,4‐anhydro phytosphingosine derivatives 9a, 10a, and (E)‐23, respectively, were synthesized. A very useful method is described for the assignment of the configuration at C‐4 of the 1,3‐O‐benzylidene‐1,2,3,4‐tetrol derivatives 3a, 3b, (E,Z)‐12a, and (E,Z)‐12b by means of NMR spectroscopy. magnified image