bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaktionen von Benzothiet mit Iminen
Authors: Meier Herbert , Saul Klaus , Jacob Dominic 
Published: July 2007

Reactions of Benzothiete with IminesA great variety of compounds 3a–w containing CN double bonds was studied in the reaction with benzothiete (1). H, alkyl, aryl, OR, SR and NR groups can be attached to the imino function. The azomethines 3a–f, the thiazolines 3g–i, the lactim 3n, the oximes 3r–t, the isoxazolinone 3u and the azine 3v show [8π + 2π] cycloaddition reactions yielding derivatives of 1,3‐benzothiazine (4a–i, n, r–v). In the case of 4n, s, t secondary reactions occur, initiated by elimination processes. [8π + 2π] Cycloadditions account also for the reactions 3e → 10, 11, 3o → 18(I), and 3q → 19; however, CC double bonds are representing the 2π component in these examples. The thiazoline 3j and the oxazolines 3k–m afford dibenzo‐1,8,4‐thiazaundecine derivatives 14j–m, in which two benzothiete units are incorporated. The hydrazone 3w gives the linear adduct 22. Compounds with a heteroaromatic tautomeric form like 3p don't react at all. The reactions of 1 and 3 are very sensitive towards electronic and steric effects and have always to compete with the dimerisation 1 → 5. Thus, the product yields vary between 90 and 2%.
Asymmetric Synthesis via Heterocyclic intermediates, L. – Trichloroacetimidates, II. Asymmetric Synthesis of α‐Amino Acid Benzyl Esters via the Bisbenzyl Bislactim Ether of cyclo(‐L‐Val‐Gly‐)
Authors: Groth Ulrich , Schmeck Carsten , Schöllkopf Ulrich 
Published: July 2007

AbstractThe diketopiperazine cyclo(‐L‐Val‐Gly‐) (1) can be O‐alkylated under mild acidic reaction conditions with the alkyl trichloroacetimidates 2 to the corresponding bisalkyl bislactim ethers. Alkylation of the bisbenzyl bislactim ether anion of cyclo(‐L‐Val‐Gly‐) 4c with benzyl bromide and subsequent hydrolysis with aqueous trifluoroacetic acid afforded D‐phenylalanine benzyl ester (8) with an enantiomeric excess of > 95%.
Studies on the Constituents of the Leaves of Tinospora tuberculata, I. – Isolation and Structure Elucidation of two New Furanoid Diterpenes, Tinotufolin A and B
Authors: Fukuda Naomichi , Nakamura Motoyuki , Yonemitsu Michiko , Kimura Takeatsu , Isobe Ryuichi , Komori Tetsuya 
Published: July 2007

AbstractTwo new furanoid diterpenes, tinotufolin A (1) and B (2) were isolated from the fresh leaves of Tinospora tuberculata Beumée (Menispermaceae). The structures of 1 and 2 were elucidated on the basis of chemical and spectroscopic findings.
Photochemische Reaktion von Aminophenazon mit Ephedrin
Authors: Wolff Joachim H. , Wolff J. Jens , Nuber Bernhard 
Published: July 2007

Photochemical Reaction of Aminophenazone with EphedrineHerrn Dr. Wolfgang Seiffert aus Anlaß seiner Pensionierung gewidmet.
The structure of 3, a reaction product of aminophenazone 1 and ephedrine 2 under UV irradiation in the presence of water, is elucidated by X‐ray structure analysis. The proposed mechanism of its formation features the aziridinone 4 as a key intermediate.
The Structure of Verbascosaponin
Authors: Schöderh Harald , Haslinger Ernst 
Published: July 2007

AbstractThe structure of verbascosaponin was revised. Using 2D‐NMR techniques (COSY, TOCSY, NOESY, ROESY, HMQC, DEPT‐COSY, HMQC‐TOCSY and HMBC) and selective excitation, we established the structure of 1 as 3β‐O‐{α‐L‐rhamnopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→3)‐[β‐D‐glucopyranosyl‐(1→2)‐]‐β‐D‐fucopyranosyl}‐13β,28‐epoxyolea‐11‐en‐23α‐ol. A second saponin 2 was isolated from the officinal drug Flores Verbasci and its structure determined as 11‐methoxy‐3β‐O‐{α‐L‐rhamnopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→3)‐[β‐D‐glucopyranosyl‐(1→2)‐β‐D‐fucopyranosyl]olea‐12‐en‐23α,28β‐diol.
A Practical Syntheis of the Khapra Beetle Pheromones
Authors: Pawar Archana S. , Chattopadhyay Subrata , Mamdapur Vasant R. 
Published: July 2007

AbstractA practical synthesis of the title pheromones is described. The features of the synthesis include high optical purities of the target compounds, utilization of easily accessible materials and employment of operationally simple and facile reactions.
A Simple Procedure for the Synthesis of Carbohydrate Ortholactones
Authors: Žagar Cyrill , Scharf Hans‐Dieter 
Published: July 2007

Abstract3,4‐Di‐O‐benzyl‐2,6‐dideoxy‐L‐arabino‐hexono‐1,5‐lactone (1b) was synthesized in three steps by starting from di‐O‐acetyl‐L‐rhamnal (6). Sequential treatment of 1b or 3,4,6‐tri‐O‐benzyl‐2‐deoxy‐D‐arabino‐hexono‐1,5‐lactone (1a) with triethyloxonium tetrafluoroborate and sodium ethanolate produced the diethyl ortholactones 2a and b. Acid‐catalyzed reaction of 2a or b with 1,2‐ethanediol (5a) or (1S,2S)‐1,2‐cyclohexanediol (5b) gave the spiro ortholactones 3a, b, and 4a, b.
Synthesis of Substituted Indoles and Pyrimido[4,5‐b]indoles by Dehydrogenation of Tetrahydroindoles and Tetrahydropyrimidoindoles
Authors: Eger Kurt , Lanzner Wolfgang , Rothenhäusler Klaus 
Published: July 2007

AbstractThe synthesis of N1‐substituted 2‐amino‐4,5,6,7‐tetrahydroindole‐3‐carbonitriles 2 and 5,6,7,8‐tetrahydropyrimido[4,5‐b]‐indoles 3–5 and their subsequent dehydrogenation to the corresponding 2‐aminoindole‐3‐carbonitriles 8 and pyrimido[4,5‐b]indoles 9, 11, 12, using DDQ in toluene or palladium on charcoal in 1‐methylnaphthalene, is described. Palladium on charcoal proves to be a versatile reagent in dehydrogenation. The application of DDQ fails in the case of the 5,6,7,8‐tetrahydropyrimido[4,5‐b]indole‐4‐amines 4, 5, which are of special interest in regard of their affinity to the adenosine receptor. With sodium periodate, instead of the expected aromatization a new class of spiro‐heterocycles is formed.
Asymmetrische Synthesen mit chiralen 1,4‐Oxazin‐2,5‐dionen: Darstellung enantiomerenreiner 2‐substituierter Pipecolinsäurederivate
Authors: Wanner Klaus Th. , Stamenitis Stamatios 
Published: July 2007

Asymmetric Synthesis with Chiral 1,4‐Oxazine‐2,5‐diones: Preparation of Enantiomerically Pure 2‐Substituted Pipecolic Acid Derivatives Herrn Prof. Dr. H.‐D. Stachel mit den besten Wünschen zum 65. Geburtstag gewidmet.
A new asymmetric synthesis of α‐amino acids is presented. This synthesis is based on the chiral 1,4‐oxazine‐2,5‐diones 5 and 14 relying on the α‐hydroxy acid 12 as a chiral auxiliary. A base‐mediated alkylation of these chiral amino acid building blocks (5, 12) with different alkyl halides proceeds, after deprotonation with sec‐butyllithium, with high yields and excellent d.s. (up to 99.5/0.5). As exemplified by the synthesis of 15 (in comparison to that of 7a) the absolute configuration of the stereocenter in the amino acid unit is determined by the sequence the substituents are introduced. In the enolate 6 and in that of 14 the electrophile adds consistently to the re face of the prochiral carbon. From the alkylation products the corresponding 2‐substituted pipecolic acid derivatives are obtained in good yields upon hydrolysis under basic or acidic conditions.
“Head‐to‐Tail” Cyclization of Hexapeptides Using Different Coupling Reagents
Authors: Zimmer Susanne , Hoffmann Eike , Jung Günther , Kessler Horst 
Published: July 2007

AbstractIn the synthesis of cyclic hexapeptides the cyclization step was examined by using different procedures for activation. Three coupling methods were tested for “head‐to‐tail” cyclization of the resin‐cleaved peptides in solution: (1) DPPA/NaHCO3; (2) TBTU/HOBt/DIEA and (3) HBTU/HOBt/DIEA. The best results were obtained by using TBTU. Reaction rates were 5 to 70 times faster with the TBTU procedure compared to the DPPA activation and generally complete conversions to cyclopeptides were observed. The kinetics of the cyclizations under high dilution conditions were monitored by HPLC. During the synthesis of the linear peptides the formation of an aminosuccinimide was observed. This by‐product was characterized by electrospray MS and NMR.
Tetrahydrofurane und γ‐Lactone, VI. Optisch aktive N‐Boc‐δ‐Amino‐γ‐lactone aus Cyclooctin und Furan
Authors: Meints Martin , Wolff Christian , Tochtermann Werner 
Published: July 2007

Tetrahydrofurans and γ‐Lactones, VI. – Optically Active N‐Boc‐δ‐Amino‐γ‐lactones from Cyclooctyne and FuranThe stereoselective synthesis of the title compounds (−)‐(2′R,8S)‐2b and (+)‐(2′S,8R)‐2b from (2′R,8R)1a and (2′S,8S)‐1a is described. The unprotected amino lactone 2c undergoes rearrangement to the γ‐hydroxy‐δ‐lactam 3a by treatment with hydrogen chloride.
The Biosynthesis of the Cularine Alkaloids
Authors: Mueller Martin J. , Zenk Meinhart H. 
Published: July 2007

AbstractIn order to study the cularine biosynthesis, L‐[β‐13C]tyrosine (L‐18), [α‐13C]tyramine (20), L‐[3′‐18O]DOPA (L‐19) and [α‐13C, 3′‐18O]dopamine (21) were synthesized and fed to Corydalis claviculata and Sarcocapnos crassifolia plants, which are rich sources of cularine‐type alkaloids. (S)‐Crassifoline [(S)‐15, an established cularine (1) precursor] and cularine‐type alkaloids subsequently isolated, showed upon L‐[β‐13C]tyrosine feeding approximately equal labeling (1:0.8) of the isoquinoline and benzyl moiety, whereas the other precursors were solely incorporated into the isoquinoline half, indicating that three of the four oxygen functions present in cularine‐type alkaloids are derived from simple, early precursors. The fourth oxygen atom appears to be introduced later into a trioxygenated alkaloidal intermediate. [α‐13C, 3‐18O]Dopamine was incorporated into the upper half of the 7,8‐oxygenated (S)‐crassifoline [(S)‐15] molecule, without loss of 18O‐label. This fact excludes an isomerization mechanism of 6,7‐oxygenated isoquinolines through a dehydroxylation/hydroxylation step. Furthermore, these findings proved to be correct by separate feeding experiments with a novel 3′,7,8‐trihydroxylated (S)‐tetrahydrobenzylisoquinoline [(S)‐10] and its 3′,6,7‐trihydroxylated isomer, (S)‐norcoclaurine [(S)‐9], the common precursor of benzylisoquinoline alkaloids in nature. The first alkaloid was exclusively biotransformed into (S)‐crassifoline [(S)‐15] and cularine‐type alkaloids, whereas (S)‐norcoclaurine [(S)‐9] was only metabolized to its well established metabolite, (S)‐reticuline [(S)‐16], but not to cularine‐type alkaloids. Feeding experiments with (S)‐ and (R)‐[1‐13C]norjuziphine [(S)‐11, (R)‐11], (RS)‐[N‐13C]juziphine [(RS)‐13], (RS)‐[N‐13C]3′‐hydroxyjuziphine [(RS)‐14] and (RS)‐[N‐13C]crassifoline [(RS)‐15] confirmed a new pathway to (S)‐crassifoline and the (S)‐configurated cularine‐type alkaloids 1–5, and showed in addition that there must be at least one enzyme in the pathway which is (S)‐stereospecific.
Zur Konformation und Konfiguration der Cholecalciferol‐Isoxazolin‐Addukte
Authors: Reischl Wolfgang , Hofer Otmar , Weissensteiner Walter 
Published: July 2007

On the Conformation and Configuration of the Cholecalciferol‐Isoxazoline AdductsThe conformation and configuration of compounds 1–4, generated by 1,3‐dipolar addition of nitrile oxides to the exomethylene group of (5Z)‐ and (5E)‐vitamin D3 has been assigned. A combination of force‐field calculations, LIS measurements, LIS simulations and CD spectroscopy has been used. In addition, the assignment has been verified by chemical correlation of 1 and 3 to 5 as well as of 2 and 4 to 6.
Electroorganic Synthesis, 54. Enantioselective Cathodic Reduction of 4‐Substituted Coumarins with Alkaloids as Catalysts, 1
Authors: Schoo Norbert , Schäfer Hans‐J. 
Published: July 2007

AbstractThe optical yield in the alkaloid‐catalyzed enantioselective electroreduction of 4‐methylcoumarin (1a) was increased from 17% to 47.4% by systematic variation of the electrolysis conditions. The results are explained by an induction mechanism in which the adsorbed protonated alkaloid acts as a chiral proton donor towards a prochiral carbanion derived from 1a. The preferred configuration of the product and the results obtained by variation of the alkaloid structure allow us to propose a model of the transition state. Furthermore, 4‐phenylcoumarin (1b) and 4‐(trifluoromethyl)coumarin (1c) were reduced with 13.2% and 8.4% ee, respectively.
Enantioselective cathodic reduction of 4‐substituted coumarins with alkaloids as catalysts, 2. AM1 and force‐field study of the transition‐state model
Authors: Höweler Udo , Schoo Norbert , Schäfer Hans‐J. 
Published: July 2007

AbstractThe experimental data presented in Part 1 of this series lead to a refined model for the transition state of the alkaloid‐induced enantioselective electroreduction of 4‐methylcoumarin. This model is based on a zwitterionic complex formed by the protonated alkaloid and the reduced species of the coumarin. The complex is studied by a combination of quantum chemical and molecular mechanics methods. The reactant geometries and their charge distributions are determined by the semiempirical AM1 method. The MOBY force field is used for a complete conformational analysis and optimization of the complexes. In agreement with experiment, an optical induction is found for yohimbine while its isomer rauwolscine shows no stereoselectivity. An upper limit for the distance between the reactants in the zwitterionic complex is determined and criteria for improved inductors are developed.
A novel selective route to 1‐substituted benzotriazoles via lithiation of simple 1‐alkylbenzotriazoles
Authors: Katritzky Alan R. , Wu Jing , Kuzmierkiewicz Wojciech , Rachwal Stanislaw 
Published: July 2007

Abstract1‐Methylbenzotriazole (2a) is lithiated readily with butyllithium or LDA at the methyl group to 4 and the subsequent reaction with various electrophiles provides 1‐substituted benzotriazoles 5. Other 1‐(n‐alkyl)benzotriazoles 2 also undergo lithiation with LDA, the carbanions can be trapped with alkyl halides giving benzotriazoles 6 bearing secondary alkyl groups on the N‐1 atom. On standing in the absence of electrophiles, all the lithium derivatives decompose to afford complex mixtures. magnified image
Unusual reactivity of lithiated 2‐alkylbenzotriazoles
Authors: Katritzky Alan R. , Wu Jing , Kuzmierkiewicz Wojciech , Rachwal Stanislaw , Balasubramanian Marudai , Steel Peter J. 
Published: July 2007

AbstractTreatment of a 2‐alkylbenzotriazole (BtCH2R) (2) with LDA at −78°C produces rapidly a mixture of a coupling product (BtCHR–CHRBt) (5) and a compound formed from four molecules of the starting material (BtCHR–CHR–CHR–CHRBt) (6). A mixture of 2‐methylbenzotriazole and benzophenone, treated with LDA, gives adduct Ph2C(OH)CH2Bt (14) quantitatively whereas benzaldehyde does not react under these conditions. 2‐Alkylbenzotriazoles (2) are alkylated at the α‐carbon atom when their mixtures with alkyl halides are treated with LDA. magnified image
Neue Synthesen von Heterocyclen mit Vinyl‐ und Divinylcarbodiimiden: Pyrrole, Triazole, Pyrimidine, Pyrindine, Isochinoline und Thiazolyl‐isothiazole
Authors: Capuano Lilly , Hammerer Volker , Huch Volker 
Published: July 2007

New Syntheses of Heterocycles with Vinyl‐ and Divinylcarbodiimides: Pyrroles, Triazoles, Pyrimidines, Pyrindines, Isoquinolines and Thiazolyl‐isothiazolesThe title compounds 3 and 4 react with diazomethane either by loss or by retention of the diazo nitrogen, to afford 3,4‐dihydro‐2‐imino‐2H‐pyrroles 6 and 10 or the vic‐triazole 5, respectively. The structure of 5 has been established by X‐ray diffraction analysis. – The [4 + 2] addition of benzylidene methylamine or alicyclic enamines 9 to 4 results in the formation of partially hydrogenated pyrimidine 7, pyrindine 11a or isoquinoline 11b. – Thermolysis of 4 proceeds with spontaneous dehydrogenation, giving high yields of 1‐(1‐in‐dolyl)isoquinolines 8. – The derivative 10a, when melted with sulfur, undergoes both dehydrogenation and sulfur insertion, whereby the hitherto unknown thiazolyl‐isothiazole 13 is formed. Its structure has been elucidated by an X‐ray diffraction analysis. – A synthesis of the imidazo[2,1‐a]isoquinoline derivative 16 is reported. magnified image
Synthese von (+)‐Coriolin B aus (+)‐Präcoriolin
Authors: Weinges Klaus , Braun Ralf 
Published: July 2007

Synthesis of (+)‐Coriolin B from (+)‐PrecoriolinEnantiomerically pure (3aS,3bR,4R,6aS,7S)‐(+)‐3,3a,4,5,6,6a,7‐Octahydro‐4,7‐dihydroxy‐3a,5,5‐trimethyl‐3‐methylene 2H‐cyclopenta[a]pentalen‐2‐one [(+)‐precoriolin] (4), produced from (S)‐(+)‐carvone (3), is converted via the epoxides 5 and 7 into (+)‐coriolin B (2). magnified image
Pseudosugars, 33. Synthesis of some 5a‐carbaglycosylamides, glycolipid analogs of biological interests
Authors: Tsunoda Hidetoshi , Ogawa Seiichiro 
Published: July 2007

AbstractFive carbocyclic analogs of glycosylamides, N‐(5a‐carba‐D‐glycopyranosyl)‐N‐octadecyldodecanamides 2–6, having β‐galacto, α‐ and β‐gluco‐, and α‐ and β‐manno configurations, were synthesized by coupling of the protected anhydro derivatives 12, 15, and 21 of 5a‐carba‐sugars with octadecylamine, followed by N‐acylation. Walden inversion of the 2‐OH functions of 17 and 24 was carried out through O‐sulfonylation. A bioassay (in vivo) of 5a‐carbaglycosylamides showed that they are potent immunomodulators, obviously comparable to the true sugar analogs, suggesting that the 5acarbasugar analogs may provide appropriate model compounds for biochemical studies in glycolipid chemistry. magnified image
Pheromone, 95. Darstellung und Einsatz deuteriummarkierter Lepidopterenpheromone und Analoger zum Studium der Pheromonbiosynthese
Authors: Bestmann Hans Jürgen , Fett Dieter , Garbe Wolfgang , Gunawardena Neelakanta , Martichonok Valerij , Vostrowsky Otto 
Published: July 2007

Pheromones, 95. – Synthesis and Application of Deuterium‐Labelled Lepidoptera Pheromones and Analogues for the Study of Pheromone BiosynthesisBy deuteration of suitable alkynes with D2 and Wilkinson catalyst deuterium‐labelled building blocks are obtained which can be transformed into the corresponding [D4]‐, [D8]‐ and [D9]‐labelled pheromones and pheromone analogues. These unsaturated deuterium‐marked compounds can be converted into saturated [D6]‐ and [D8]‐analogues of Lepidoptera pheromones by a second deuteration or subsequent hydrogenation. The analogues, comprising potential biosynthesis precursors of pheromones, were applied in vivo to female insects and deuterium incorporation into the final products of biosynthesis was recorded by GCMS. magnified image
Synthese von fungicid wirksamen (1H‐1,2,4‐Triazol‐1‐yl‐methyl)silanen und ‐siloxanen
Authors: Liebner Falk , Bankwitz Uwe , Rühlmann Klaus 
Published: July 2007

Synthesis of Fungicidal (1H‐1,2,4‐Triazol‐1‐yl‐methyl)silanes and ‐siloxanesThe synthesis of FlusilazoleTM (1a) was substantially improved by thorough exclusion of oxygen nucleophiles in the reaction of (chloromethyl)bis(4‐fluorophenyl)methylsilane with sodium 1H‐1,2,4‐triazolide. New α,α‐diaryl‐α‐(1H‐1,2,4‐triazol‐1‐yl‐methyl)siloxanes 3 were obtained firstly from diaryl(1H‐1,2,4‐triazol‐1‐yl‐methyl)silanols or ‐silanolates, which were prepared by different methods from the corresponding silanol hydrochlorides and further treated with functional, linear oligodimethylsiloxanes or secondly from α,α‐diaryl‐α‐(chloromethyl)siloxanes and 1‐(trimethylsilyl)‐1H‐1,2,4‐triazole. The siloxane 4 containing a triazolylmethyl group and additionally silicofunctional coupling groups could be synthesized by hydrosilylation of an α‐triazolylmethyl‐ω‐vinylsiloxane with triethoxysilane. magnified image
Ringtransformationen von 1‐Oxa‐5,6‐diazaspiro[2.4]hept‐6‐en‐4‐onen zu 4,5‐Dihydro‐4‐hydroxy‐1H‐pyrazol‐4‐carbonsäure‐Derivaten
Authors: Kirschke Klaus , Hübner Petra , Lutze Gerhard , Gründemann Egon , Ramm Matthias 
Published: July 2007

Ring Transformations of 1‐Oxa‐5,6‐diazaspiro[2.4]hept‐6‐en‐4‐ones into 4,5‐Dihydro‐4‐hydroxy‐1H‐pyrazole‐4‐carboxylic Acid DerivativesSpiro epoxides 3 were synthesized from 1H‐pyrazol‐5(4H)‐ones 1 by Knoevenagel condensation with acetone or benzaldehyde and subsequent epoxidation of 2 with hydrogen peroxide. 3 reacts with nucleophiles under ring transformation to 4,5‐dihydro‐4‐hydroxy‐1H‐pyrazole‐4‐carboxylic acid derivatives 5. In three cases the intermediate 6 was isolated. 5b, c undergo by dehydrogenation with chloranil rearrangement to 4,5‐dihydro‐4‐oxo‐1H‐pyrazole‐5‐carboxylic acid derivatives 7b, c. magnified image
Eine umlagerung S‐substituierter cyclohexanonthioxime
Authors: Andreae Siegfried , Schmitz Ernst , Schulz Burkhard 
Published: July 2007

A Rearrangement of S‐Substituted Cyclohexanone ThioximesMercaptoheterocycles like 2‐mercaptobenzazoles 5, 2‐mercaptouracils 10, and ketene S,S‐acetals 18 are aminated by 1‐oxa‐2‐azaspiro[2.5]octane (1). The intermediate cyclohexanone thioximes, which can be isolated in some cases (6a–c, 11), undergo a 1,3‐shift of the mercapto fragment from the nitrogen to the carbon atom followed by cyclization and/or hydrolysis. Thus, new heterocyclic systems as 14–17 or 19 can be created. magnified image
Das trans‐decalingerüst als Abstandshalter für axial konfigurierte Diamine: Herstellung eines phosphatbindenden Bis(guanidins)
Authors: Gross Ralf , Bats Jan W. , Göbel Michael W. 
Published: July 2007

trans‐Decalin as a Spacer for Axially Configurated Diamines: Preparation of a Phosphate Binding Bis(guanidinium) CompoundA new type of bis(guanidinium) compound 2 is described which was prepared from trans‐decalin spacers bearing nitrogen substituents in axial positions. Starting from 2, 7‐dimethoxynaphthalene, a sequence of three Birch reductions produced gram amounts of the saturated intermediate and established the stereochemistry of the decalin framework. Guanidinium salt 2a turned out to be a good receptor molecule for phosphoric acid diester anions. However, the catalytical influence on phosphoryl transfer reactions is only weak. magnified image
A short synthesis of (6R)‐6‐methyl‐3‐octanone
Authors: Pawar Archana S. , Chattopadhyay Subrata , Mamdapur Vasant R. 
Published: July 2007

AbstractA short and efficient synthesis of the title pheromone in optically pure form was developed by starting from R‐citronellol as the chiral template. The salient features of the synthesis were the use of easily accessible inexpensive materials/reagents and operationally simple reactions. magnified image
Verwertung industrieller Abfallstoffe, 1. Synthese neuer, chiraler primärer und sekundärer, 1,2‐Diamine
Authors: Stingl Klaus , Martens Jürgen 
Published: July 2007

Utilization of Industrial Waste Materials, 1. – Synthesis of New Primary and Secondary Chiral 1,2‐DiaminesPrimary and secundary 1,2‐diamines with three or four stereogenic centers were synthesized starting from the benzyl ester of the bicyclic proline analogue (all‐R)‐2‐azabicyclo[3.3.0]octane‐3‐carboxylic acid [(all‐R)‐2b] by a four‐ or five‐step procedure. This is an example for the utilization of the industrial waste material (all‐R)‐2b. magnified image
Glycal‐1‐ylmethylphosphonates – precursors of glycosyltransferase inhibitors
Authors: Frische Klaus , Schmidt Richard R. 
Published: July 2007

AbstractDirect lithiation of 2‐phenylsulfinyl‐ and 2‐phenylsulfonylsubstituted galactal derivatives 3a–c and subsequent reaction with DMF gave 1‐C‐formyl derivatives 4a–c. Reduction afforded hydroxymethyl derivatives 5a–c which were transformed into mesylates 7 and 9, respectively. Treatment with trimethyl phosphite furnished phosphonates 8 and 10; by treatment with sodium in liquid ammonia and subsequent reaction with acetic anhydride in pyridine both compounds were converted into monomethyl galactal‐1‐ylmethylphosphonate (11) which could not be completely demethylated without structural change. O‐Acetyl‐protected mesylate 18, obtained from galactosyl cyanide in a few steps, was transformed into bromide 19 which on treatment with P(OSiMe3)3 gave bis(trimethylsilyl) phosphonate 20. Reaction with NaOMe/MeOH afforded the unprotected disodium salt of D‐galactal‐1‐ylmethylphosphonate 1. Similarly, from L‐fucopyranosyl cyanide 22 the corresponding target molecule 2 was obtained. magnified image