bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Darstellung der Anomeren des Hepta‐O‐acetylcellobiosyl‐, ‐lactosyl‐, ‐maltosyl‐ und ‐melibiosylazids
Authors: Pető Csaba , Batta Gyula , Györgydeák Zoltán , Sztaricskai Ferene 
Published: July 2007

Synthesis of the Anomers of Hepta‐O‐acetylcellobiosyl, ‐lactosyl, ‐maltosyl, and ‐melibiosyl AzideSynthesis and characterization by 13C‐NMR spectroscopy of the O‐acetylated 1,2‐cis and 1,2‐trans azides of cellobiose, lactose, maltose, and melibiose have been accomplished. 1,2‐trans Azides 1c, 2b–4b result from the stannic chloride catalyzed reaction of the β‐octa‐O‐acetates 1a–4a with trimethylsilyl azide, whereas the β‐chlorohepta‐O‐acetyldisaccharides 1d, 2c–4c afford, in an SN2 reaction in HMPT with lithium azide, the hitherto inaccessible 1,2‐cis azides 1e, 2d–4d.
Artificial deoxy glycosides of anthracyclines
Authors: Klaffke Werner , Pudlo Peter , Springer Dirk , Thiem Joachim 
Published: July 2007

AbstractIn Lewis acid mediated allylic rearrangement reactions of L‐rhamnal (1) and L‐fucal (2) with daunomycinon (6) 2′‐deoxyhex‐2′‐enopyranosides have been obtained exclusively. Furthermore, glycals 1 and 4 have been treated with the glycosyl acceptors 6, 7, and 9 and N‐iodosuccinimide (NIS) to produce the corresponding α‐configurated 2′‐deoxy‐2′‐iodo glycosides. Among these, 16 represents a bis (glycoside) with both benzylic aglycon positions substituted. In none of the above cases has a substantial amount of β‐glycoside been detected. Attempts to convert ε‐isorhodomycinon (8) into a glycoside on a preparative scale, under Lewis acid conditions have been unsuccessful. However, the α‐glycoside 13 has been obtained by the Helferich method.
Novel photocycloadditions of electron‐deficient nitrones to 2‐methyl‐2‐butene
Authors: Sehgal R. K. , Griffin G. W. 
Published: July 2007

AbstractIn Order to decrease the ground state reactivity and increase their potential for [3+2] cycloadditions, cyano‐ and methoxy‐carbonyl‐substituted nitrones 1a and 1b, respectively, were prepared and irradiated in the presence of electron‐rich alkenes such as 2 to afford the corresponding oxazolidines in which th oxygen atom becomes attached to the least substituted terminus of the olefin and nitrogen attaches to the more highly substituted counterpart. While the oxazolidines 12a and 12b obtained from 1b, via the intermediacy of oxaziridine(s) 15 and subsequent NO bond scission, are isolated and characterized, the oxazolidin(s) 18 formed bny cyclization of 1a are more labile and may undergo ionization to the stabilized oxazolinium ion 19 followed by nucleophilic attack by cyanide ion with accompanying ring opening to afford 6. A sequential diradical mechanism is proposed to rationalize the formation of the observed photoproducts 5 and 6.
Enantiomers of the muscarinic antagonist 1‐cyclohexyl‐1‐(4‐fluorophenyl)‐4‐piperidino‐1‐butanol (p‐fluoro‐hexahydro‐difenidol): Synthesis, absolute configuration, and enantiomeric purity
Authors: Strohmann Carsten , Bauerecker Sigurd , Cammenga Heiko K. , Jones Peter G. , Mutschler Ernst , Lambrecht Günter , Tacke Reinhold 
Published: July 2007

AbstractThe enantiomers of the antimuscarinic agent 1‐cyclohexyl‐1‐(4‐fluorophenyl)‐4‐piperidino‐1‐butanol [(R)‐ and (S)‐p‐fluorohexahydro‐difenidol] [(R)‐ and (S)‐2a] and their methiodides (R)‐3 and (S)‐3 were prepared with high enantiomeric purity. (R)‐2a and (S)‐2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1‐cyclohexyl‐1‐(4‐fluorophenyl)‐4‐piperidino‐2‐butyn‐1‐ol [(R)‐ and (S)‐4]. Reaction of (R)‐2a and (S)‐2a with methyl iodide led to (R)‐3 and (S)‐3, respectively. The unsaturated precursors (R)‐ and (S)‐4 (enantiomeric purity ⩾99.80 and ⩾99.94% e.e.; calorimetric analysis) were prepared by resolution of rac‐4 [available from 4‐FC6H4C(O)C6H11 by reaction with LiCCCH2NC5H10] using (R)‐ and (S)‐mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X‐ray crystal‐structure analysis of (S)‐5, the methiodide of (S)‐4. (R)‐2a and (R)‐3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)‐2a and (S)‐3, the degree of stereoselectivity depending on the receptor subtype involved. (R)‐2a represents a useful tool for muscarinic receptor research (affinity profile: M1 ≈ M3 ≈ M4 > M2).
Synthesis of sphingosine relatives, X. Synthesis of (2S,3R4E)‐1‐O‐(β‐D‐glucopyranosyl)‐N‐[30′‐(linoleoyloxy)triacontanoyl]‐4‐icosasphingenine, a new esterified cerebroside isolated from human and pig epidermis
Authors: Mori Kenji , Matsuda Hiroyuki 
Published: July 2007

Abstract(2S,3R,4E)‐1‐O‐(β‐D‐Glucopyranosyl)‐N‐[30′‐(linoleoyloxy)triacontanoyl]‐4‐icosasphingenine (1) was synthesized from D‐glucose, L‐serine, 15‐pentadecanolide, and linoleic acid. The high‐field 1H‐NMR spectrum of 1 was identical with that of the esterified cerebroside isolated from human and pig epidermis.
N‐Vinylketenimine
Authors: Capuano Lilly , Braun Claudia , Kühn Frank 
Published: July 2007

N‐Vinylketenimines.The title compounds 5 are generated in situ from N‐vinyl‐iminotriphenylphosphoranes 1 and ketenes 2 in a Wittig‐type reaction. The phosphoranes are useful intermediates for the preparation of numerous heterocycles as illustrated by the formation of 1,3‐oxazines 8, pyridinones 9, pyrimidinones 10 and 1,3‐thiazines 11. Water adds readily to 5 to yield vinylacetamides 7, whereas thermal rearrangement gives rise to the isoquinoline 4 or the spiro system 6, respectively. Under very mild conditions, crystalline precursors (type 3) of the N‐vinylketenimines, which still contain the triphenylphosphonio group, have been isolated. These react like the N‐vinylketenimines generated in situ, giving however less byproducts.
Heterocyclisch [c]‐anellierte Cumarine aus 4‐Azido‐3‐cumarincarbaldehyden
Authors: Steinführer Thorsten , Hantschmann Achim , Pietsch Michael , Weißenfels Manfred 
Published: July 2007

Heterocyclic [c]‐Condensed Coumarins from 4‐Azido‐3‐coumarincarbaldehydes4‐Azido‐3‐coumarincarbaldehydes 2a–d are useful starting materials for syntheses of a variety of 3,4‐disubstituted coumarins as well as heterocyclic [c]‐fused coumarins, e. g. isoxazoles, pyrazoles and 1,5‐diazepines, under mild conditions. In these reactions, 2a–d are – despite of their thermolability — superior to the corresponding 4‐chloro‐3‐coumarincarbaldehydes 1a–d, from which they were prepared. An improved method for the preparation of 1a–d from 4‐hydroxy‐coumarins is described.
Reactions of 4‐Oxoalkanoic Acids, 4. Synthesis of (±)‐6‐Alkyl‐5‐oxa‐1‐azabicyclo[4.3.0]nonan‐9‐ones, (±)‐5‐Alkyl‐4‐oxa‐1‐azabicyclo[3.3.0]octan‐8‐ones, and Substituted 1,6‐Dioxa‐3,8‐diazacyclodecanes by Reaction of Ethyl 4‐Oxoalkanoates with 3‐Aminopropanol and 2‐Aminoethanol
Authors: Wedler Christine , Schick Hans , Scharfenberg‐Pfeiffer Doris , Reck Günter 
Published: July 2007

AbstractEthyl 4‐oxoalkanoates 1 react at ambient temperature in dry methanol in the presence of molecular sieve 3 Å in almost quantitative yield with 3‐aminopropanol and 2‐aminoethanol to form the bicyclic lactams rac‐2 and rac‐3, respectively. Surprisingly, the (±)‐5‐alkyl‐4‐oxa‐1‐azabicyclo[3.3.0]octan‐8‐ones rac‐3a–d dimerize in trichloromethane saturated with 2 N HCl to the ten‐membered heterocycles 4a–d. The structures of the substituted 1,6‐dioxa‐3,8‐diazacyclodecanes 4a and 4c have been determined by an X‐ray crystal analysis.
Cycloadditions of Nitrile Oxides to Itaconimides
Authors: Svêtlík Jan , Liptaj Tibor , Hanuš Vladimír 
Published: July 2007

AbstractNew spiro heterocycles, 1‐oxa‐2,7‐diazaspiro[4.4]non‐2‐ene‐6,8‐diones 3a–c and 8a, c were obtained in the reaction of itaconimides 1a–c with nitrile oxides 2 and 7.
Dithio‐ und Thionester, 53. Darstellung N‐geschützter α‐Aminodithiosäureester aus α‐Aminonitrilen und α‐Aminocarbonsäuren
Authors: Kohrt Arne , Hartke Klaus 
Published: July 2007

Dithio and Thiono Esters, 53. — Synthesis of N‐Protected α‐Amino Dithioesters from α‐Amino Nitriles and α‐Amino AcidsThe α‐amino nitriles 1 and 5 have been transformed into the thiolimido ester hydrochlorides 2 and 6 and sulfhydrolyzed to give the N‐protected α‐amino dithioesters 3 and 7. The α‐amino dithioesters 10 were obtained from 1 via the thioamides 8 and their S‐alkylation products 9. The optically active thioamides 12, prepared from naturally occurring L‐α‐amino acids, were converted into the optically active α‐amino dithioesters 7. The optical purity of the N‐protected dithioalanine esters 14 was determined by an HPLC analysis of the diastereomeric menthyloxycarbonyl derivatives 17.
Reaktionen der Trialkylsilyl‐trifluormethansulfonate, XI. Synthese von Derivaten der α‐Ketocarbonsäuren aus 2‐O‐funktionell substituierten Trimethylsilylketenacetalen
Authors: Simchen Gerhard , Siegl Gerald 
Published: July 2007

Reactions of Trialkylsilyl Trifluoromethanesulfonates XI. — Synthesis of α‐Oxocarboxylic Acid Derivatives from 2‐O‐Functionalized Trimethylsilyl Ketene AcetalsThe cyclic ketene acetals 3, 5 are prepared from the dioxolanone 2 resp. the oxazolidinediones 4 by silylation with trimethylsilyl triflate (1)/triethylamine. In an aldol addition/Peterson olefination reaction catalysed by 1 the ketene acetals 3, 5 yield the (E/Z)‐benzylidene derivatives 7, 12, 13 in reaction with aromatic aldehydes 6. In a side reaction the α‐(trimethylsilyl)benzylidene derivatives 8 are formed from 3 and 6. Compounds 7 can be hydrolysed to yield α‐ketocarboxylic acids 14. The latter are also obtained via β‐elimination of trimethylsilanol from 2,3‐bis(trimethylsiloxy)carboxylic acid esters 15 with trifluoroacetic acid anhydride/DMAP/pyridine.
Unerwartete Bildung von γ‐Lactamen aus 6H‐1,2,‐Oxazinen unter Lewis‐Säure‐Einwirkung
Authors: Zimmer Reinhold , Reißig Hans‐Ulrich , Lindner Hans Jörg 
Published: July 2007

Unexpected Formation of γ‐Lactams from 6H‐1,2‐Oxazines Promoted by Lewis AcidsThe reaction of 6H‐1,2‐oxazine 1 with trimethylsilyl cyanide in the presence of titanium tetrachloride provides α,β‐unsaturated γ‐lactam 3. Similarly, Lewis acid‐promoted addition of trimethyl phosphite towards 1 affords a mixture of γ‐lactams 8 and 9. The structure of 9 was established by X‐ray analysis. A plausible mechanism for the formation of these γ‐lactams by Lewis acid‐induced ring contraction is proposed.
threo‐3‐Alkyl‐ and ‐Arylglutamic Acid Derivatives by Michael Additions of Boc‐BMI Li‐Enolates to 2,6‐Di‐t‐butyl‐4‐methoxyphenyl Alkenoates on the Diastereoselectivity of the Coupling of Trigonal Centers Involving Heterocyclic Li‐Enolates
Authors: Suzuki Keisuke , Seebach Dieter 
Published: July 2007

AbstractThe conjugated esters5,6,8,9mentioned in the title are prepared from the corresponding aryl acetate4and aldehydes by aldol condensation (direct enoylation of the hindered phenol with the corresponding unsaturated acid chlorides gave only poor yields). To avoid double‐bond shifts, the 4‐phenyl 2‐butenoate7awas prepared from the saturated one by selenation/elimination (see7b,cin Scheme 1). In contrast to methyl and ethyl crotonates, reacting in poor yields and with low selectivities (→11,12), the hindered aryl enoates combine with the Li‐enolate of1[(S)‐Boc‐BMI, a chiral glycine derivative] to give single products13a–17a(⩾95% ds) in high yields (78–96% of purified samples, Scheme 2). The configuration of the two newly formed stereogenic centers and thus the mode of coupling of the trigonal centers in the Michael addition (DandEin Scheme 4) is derived for the methyl (13a) and benzyl substituted (15a) derivatives by multiple chemical correlation (see19–24in Scheme 3). It is shown that pure (2S,3R)‐glutamic acids22,23can be isolated by hydrolysis of the adducts13a, 15aof conjugate addition. — The results of the aldol, Michael and nitro olefin additions of heterocyclic Li‐enolates are collected and compared (Scheme 5, Table 1). Possible reasons for the high diastereoselectivity and a typical coupling mode of most reactions involvingN‐acylimidazolidinone andN‐acyloxazolidinone Li‐enolatesM,Oare discussed (seeWin Scheme 6).
Antibiotika aus Gleitenden Bakterien, 45. Phenalamide, neue HIV‐1‐Inhibitoren aus Myxococcus stipitatus Mx s40
Authors: Trowitzsch‐Kienast Wolfram , Forche Edgar , Wray Victor , Reichenbach Hans , Jurkiewicz Elke , Hunsmann Gerhard , Höfle Gerhard 
Published: July 2007

Antibiotics from Gliding Bacteria, 45. — Phenalamides, New HIV‐1 Inhibitors from Myxococcus stipitatus Mx s40We report on the isolation and structure elucidation of the phenalamides A1 (1), A2 (2), A3 (3), B (4), and C (5), amides from alaninol and ω‐phenyl‐substituted unsaturated carboxylic acids (a pentaene carboxylic acid in 1 — 4, and a tetraene carboxylic acid chromophore in 5). Compounds 1 — 3 are E/Z isomers with the configuration: 6Z for 1, 4 represents 8‐methyl‐1, and for 5 we determined the 10,11‐double bond in 2 to be epoxidated. C‐16 in 1 has the S configuration, as revealed by ozonisation and isolation of the (2S)‐(+)‐2‐methyl‐4‐phenylbutyric acid. By comparison of their respective CD spectra all the other centers of chirality in 1 should have the same stereochemistry as in the related compound myxalamid B. 1 seems to be identical to stipiamide. First results of enrichment experiments show that the biogenesis of 1 starts with phenylalanine, which after transamination and decarboxylation is connected with propionate and acetate units to generate the highly unsaturated fatty acid. The second amino acid unit alanine terminates the biosynthesis.
Terpenes and Terpene Derivatives, XXIX. Synthesis and Olfactive Properties of (—)‐ and rac‐Silphiperfol‐5‐en‐3‐ol and of Some Tris‐nor Derivatives
Authors: Weyerstahl Peter , Brendel Joachim 
Published: July 2007

AbstractThe new sesquiterpene alcohols silphiperfol‐5‐en‐3‐ol [(—)‐1a] and the corresponding 7‐epi compound (+)‐1b, important constituents of the essential oil of Artemisia laciniata have been synthesized in 13 steps by starting from (R)‐(+)‐pulegone (6) in an overall yield of 8%. The key reaction is the coppercatalyzed 1,4‐Grignard addition of the iodo acetal 34 to the enone (+)‐4 in the presence of TMSCI and TMEDA to give the silyl ether 38. Hydrolysis with spontaneous aldol cyclization and dehydration leads to the silphiperfolenones (+)‐2a, b which are separable by flash chromatography. The reduction with L‐selectride® gives the alcohols (—)‐1a and (+)‐1b which are identical in all physical properties with the isolated natural compound. With LiAlH4 the diastereoisomers 42a, b are formed. Olfactive evaluation of the isomers (—)‐1a and (+)‐1b has shown that the odor of the naturally occurring mixture of 1a, b with the descriptors woody, ambergris, slightly camphoraceous is correctly assigned. (—)‐1a represents the more woody and camphoraceous, (+)‐1b the more animal facette of ambergris. The odor of rac‐1a, b of the diastereoisomers 42a, b and of the ketones (+)‐2a, b is also described as well as that of the tris‐nor‐silphiperfolene derivatives 29–31.
Synthesis of Methyl 2‐O‐Benzyl‐6‐deoxy‐3‐c‐methyl‐α‐D‐mannopyranoside and Methyl α‐D‐Evalopyranoside
Authors: Žagar Cyrill , Scharf Hans‐Dieter 
Published: July 2007

AbstractMethyl 2‐O‐benzyl‐6‐deoxy‐3‐C‐methyl‐α‐D‐mannopyranoside (2) was synthesized in ten steps by starting from the readily available methyl 2,3‐anhydro‐4,6‐O‐benzylidene‐α‐D‐allo‐pyranoside (3). The key step was the stereoselective cis‐hydroxylation (cat. osmium(VIII) oxide) of methyl 2‐O‐benzyl‐4,6‐O‐benzylidene‐3‐deoxy‐3‐C‐methylene‐α‐D‐arabino‐hexo‐pyranoside (9), producing methyl 2‐O‐benzyl‐4,6‐O‐benzylidene‐3‐C‐hydroxymethyl‐α‐D‐mannopyranoside (11) and its C‐3 epimer in a ratio of 20: 1. Catalytic hydrogenation of 2 gave methyl 6‐deoxy‐3‐C‐methyl‐α‐D‐mannopyranoside (methyl‐α‐D‐evalopyranoside, 1).
Chiral Organometallic Reagents, VII. On the Configurational Stability of α‐Methylbenzyllithium
Authors: Hoffmann Reinhard W. , Rühl Thomas , Chemla Fabrice , Zahneisen Thomas 
Published: July 2007

Abstractα‐Methylbenzyllithium (6) should possess either central or planar chirality. The rate of enantiomerization of 6 at — 78°C was found to be faster than its addition to the amide 7, the ketone 8, or to the aldehyde 10, according to a test based on kinetic resolution. The benzyllithium compound 6 thus behaves in THF essentially as a prochiral entity.
Bausteine von Oligosacchariden, CIII. Synthese von modifizierten Derivaten des Disaccharides β‐D‐Gal‐(1 → 3)‐α‐D‐GalNAc zur Untersuchung der Substratspezifität der Core‐2‐β6‐GlcNAc‐Transferase und α‐3‐Sialyltransferase der Biosynthese von O‐Glycoproteinen
Authors: Paulsen Hans , Rutz Volker , Brockhausen Inka 
Published: July 2007

Building Units of Oligosaccharides, CIII. — Synthesis of Modified Derivatives of the Disaccharide β‐D‐Gal‐(→3)‐α‐D‐GalNAc for the Examination of Substrate Specificities of Core 2‐β6‐GlcNAc‐Transferase and α‐3‐Sialyltransferase Involved in the Biosynthesis of O‐GlycoproteinsDerivatives of benzyl β‐D‐galactopyranosyl‐(1→3)‐2‐acet‐amido‐2‐deoxy‐α‐D‐galactopyranoside have been synthesized. The 6′‐, 4′‐ and 3′‐OH group of the galactose moiety as well as the 6‐ and 4‐OH and the 2‐acetamido group of the 2‐acet‐amido‐2‐deoxy‐D‐galactose moiety have been selectively substituted by the corresponding deoxy function. The compounds are useful in studies of the substrate specificities of the core 2‐β6‐GlcNAc‐transferase and the α3‐sialyltransferase involved in the biosynthesis of O‐glycoproteins.
Westphal Condensation of N‐Aminocycloiminium Salts Synthesis of Fused Pyridazinium Derivatives
Authors: Matia María P. , García‐Navío José L. , Vaquero Juan J. , Alvarez‐Builla Julio 
Published: July 2007

AbstractA series of α‐alkyl‐N‐aminoazinium and ‐azolium salts 1–15 have been condensed with 1,2‐dicarbonyl compounds to produce new heterocyclic cationic species 17–25 with a quaternary nitrogen atom in the bridgehead position.
Zur Chemie der Mucohalogensäuren, VII. Asymmetrische Synthese von β‐Lactam‐Derivaten durch Keten — Imin‐Cycloaddition unter Verwendung chiraler Mucochlorsäure‐Derivate
Authors: Duczek Wolfram , Jähnisch Klaus , Kunath Annamarie , Reck Günter , Winter Gabriele , Schulz Burkhard 
Published: July 2007

Chemistry of Mucohalic Acids, VII. — Asymmetric Synthesis of β‐Lactam Derivatives by the Ketene—Imine Cycloaddition Utilizing Chiral Mucochloric Acid DerivativesThe ketene derivative 5 of the chiral pyrrolinon 4 underwent nonconcerted [2 + 2] cycloadditions with imines leading to cis‐β‐lactams 6a–d with ≫99% diastereomeric excess. rac‐4 was resolved efficiently by crystallisation of diastereoisomeric ammonium salts with brucine. (5S)‐4 provided the β‐lactam (3′S,4′R,5S)‐6a. The absolute configuration of 6a was determined by X‐ray analysis. The synthesis of the minor β‐lactam 7 was achieved independently.
Synthesis of α‐N‐Ketosides of N‐Acetylneuraminic Acid by Using Phase‐Transfer Catalysis
Authors: Rothermel Jörg , Weber Bernd , Faillard Hans 
Published: July 2007

Abstractα‐N‐Ketosides of N‐acetylneuraminic acid (Neu5Ac) can be synthesized by using azide and thiocyanate salt as aglycone under conditions of phase‐transfer catalysis (PTC). The catalytic hydrogenation of the 2‐α‐azido ketoside 3 leads to the 2‐α‐amino ketoside 4 in good yield. This 2‐α‐amino ketoside 4 can be transformed into the 2‐α‐acetamido ketoside 5 and the 2‐α‐benzoylamido ketoside 6. Zemplén deacetylation and saponification give the corresponding 2‐N‐acyl ketosides 7 and 8, which cannot be hydrolyzed by neuraminidase (Clostridium perfringens). Treatment of the 2‐α‐amino ketoside 4 with p‐nitrobenzaldehyde results in the formation of p‐nitrobenzylideneamine 9. Based on the strict stereoselectivity of the PTC glycosidation reaction with sialic acid derivatives and the exclusive formation of the N‐ketoside 10 in the reaction with potassium thiocyanate, a model of the mechanism of the PTC glycosidation procedure with sialic acid derivatives has been evaluated.
Fused Heterocycles, VII. Synthesis and Stereochemistry of Tetracyclic Benzodiazepines
Authors: Tóth Gábor , Lévai Albert , Szőllősy ÁRon 
Published: July 2007

AbstractBenzodiazepines 3a–d have been synthesized by the reaction of exocyclic α,β‐unsaturated ketones 1a–d with 1,2‐phenylenediamine in hot ethanol. Acetylation of compounds 3a–d with a mixture of acetic anhydride and anhydrous pyridine affords the N‐acetyl derivatives 4a–d. Structure and stereochemistry of the synthesized compounds have been elucidated by various NMR techniques.
Synthesis of Heterocyclic Propellanes by 1,3‐Dipolar Cycloaddition of 2,6‐Dichlorobenzonitrile Oxide to 2,3‐Fused Indoles. Catalytic Hydrogenation of the Cycloadducts
Authors: Malamidou‐Xenikaki Elizabeth , Coutouli‐Argyropoulou Evdoxia 
Published: July 2007

AbstractN‐Methylcycloalkano[b]indoles 1a, 1c–d and N‐methylindeno[1,2‐b]indole (1e) react with 2,6‐dichlorobenzonitrile oxide (2) to afford regioselectively propellanes 3. Catalytic hydrogenation of compounds 3 proceeds via the labile β‐hydroxyimines 4, which are further decomposed to the starting indole and 2,6‐dichlorobenzonitrile. In one case the intermediate imine 4e is stable and isolated in pure form.
Asymmetric Syntheses of α‐Aminophosphonic Acids, V. Synthesis of Enantiomerically Pure Diethyl 2‐Pyrrolidinyl‐ and 5‐Oxo‐2‐pyrrolidinylphosphonates
Authors: Groth Ulrich , Richter Lutz , Schöllkopf Ulrich 
Published: July 2007

AbstractEnantiomerically pure 3‐ and 4‐substituted phosphonic acid derivatives 5 of pyroglutamic acid were prepared by a Michael addition of the lithiated (+)‐camphor derivative 2 to α,β‐unsaturated esters and subsequent hydrolysis. The reduction of the lactams 5 with LiBH4/BF3 · OEt2 afforded substituted phosphonic acid analogues 7 of proline.
Dithio‐ und Thionester, 55. Synthese von N‐geschützten, optisch aktiven α‐Aminothionsäureestern
Authors: Brutsche Andreas , Hartke Klaus 
Published: July 2007

Dithio and Thiono Esters, 55. — Synthesis of N‐Protected, Optically Active α‐Amino Thiono EstersThe N‐protected α‐amino amides 1 are O‐alkylated with trialkyloxonium tetrafluoroborates to form the iminium salts 2. Sulfhydrolysis of 2 yields the α‐amino thiono esters 3. This reaction sequence allows the preparation of enantiomerically pure 3.
Pheromone Synthesis, CXLII. A New Synthesis of (3S,4R)‐8‐Nonene‐3,4‐diol, the Key Intermediate for the Synthesis of (+)‐endo‐Brevicomin
Authors: Mori Kenji , Kiyota Hiromasa 
Published: July 2007

Abstract(3S,4R)‐8‐Nonene‐3,4‐diol (2), the key intermediate for the synthesis of the bark beetle pheromone (+)‐endo‐brevicomin (1), has been synthesized in 46% overall yield (10 steps) based on erythritol (6) by employing lipase‐mediated asymmetric acetylation as one of the steps.
Pheromone Synthesis, CXXXIV. Synthesis of the Four Possible Stereoisomers of 13,17‐Dimethylnonatriacontane, a Kairomone for the Wasp Trichogramma nubilale
Authors: Mori Kenji , Wu Jiang 
Published: July 2007

AbstractThe synthesis of the four possible stereoisomers of 13,17‐dimethylnonatriacontane (1) has been achieved by starting from (R)‐citronellol (4) and the enantiomers of methyl 3‐hydroxy‐2‐methylpropanoate (5).
Kondensierte 1,2‐Dithiole, II. Synthese von Thieno‐1,2‐dithiolen
Authors: Stachel Hans‐Dietrich , Schorp Matthias , Zoukas Thomas 
Published: July 2007

Ring‐Fused 1,2‐Dithioles, II. — Synthesis of Thieno‐1,2‐dithiolesA series of thieno‐1,3‐dithiines 5 has been synthesized starting with the β‐thioxoester 4. The dithiines undergo oxidative ring contraction to the corresponding thieno‐1,2‐dithioles 6. Analogously, the dithiolo‐dithiines 8 form the 1,2‐dithiolo‐1,2‐dithioles (1,2,4,5‐tetrathiapentalenes) 14 by ring contraction. — The ester function of 6f is easily removed to give 2, the thioanalog of the antibiotic thiolutine.