bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaktionen von 1,3‐Dipolen mit Heterocyclen, 8. Synthese von 1,8a‐Dihydro[1,2,4]triazolo[4,3‐a]pyridinen und Benzologen
Authors: Grubert Lutz , Jugelt Werner , Breß Hans Joachim , Köppel Hubert , Strietzel Ute , Dombrowski Anke 
Published: July 2007

Reactions of 1,3‐Dipoles with Heterocycles, 8. — Synthesis of 1,8a‐Dihydro[1,2,4]triazolo[4,3‐a]pyridines and BenzologuesThe C,N double bond of pyridine, quinoline and isoquinoline as heterodipolarophile react with diarylnitrilimines 2, generated in situ by dehydrohalogenation of N‐phenylbenzhydrazonoyl chlorides 1, in a cycloaddition with complete regioselectivity. A facile route to hitherto unreported 1,3‐diaryl‐1,8a‐dihydro[1,2,4]triazolo[4,3‐a]pyridines 3, 1,3‐diaryl‐3,3a‐dihydro[1,2,4]triazolo[4,3‐a]quinolines 4, and 1,3‐diaryl‐1,10b‐dihydro[1,2,4]triazolo[3,4‐a]isoquinolines 5 has been developed. In a similar way, cycloadditions are carried out with C‐ethoxy‐carbonyl‐ and C‐acetyl‐N‐phenylnitrilimines. The ring cleavage of 3 in acidic medium yields the corresponding [(arylhydrazono)methyl]pyridinium chlorides 7. The conversion of the open‐chain products back to 3 has been carried out in pyridine containing triethylamine. Anodic oxidation of 3–5 in aprotic medium affords the [1,2,4]triazolohetarenium perchlorates 9–11. The yields in such reactions are either similar or better than with chemical oxidants. The thermally initiated cycloreversion of 3 and 5 is discussed, judging from the facts that the thermolysis afford 2:1 cycloadducts.
Regioselectivity of the Amination of Some Nitroquinoxalines by Liquid Ammonia/potassium Permanganate
Authors: Woźniak Marian , Barański Andrzej , Nowak Krystyna , Poradowska Henryka 
Published: July 2007

Abstract5‐ and 6‐Nitroquinoxalines and some of their derivatives are aminated in a liquid ammonia solution of potassium permanganate to yield the corresponding 2‐ and/or 3‐ and/or 5‐amino compounds. Quantum‐chemical calculations are made to explain the regioselectivity of the amination reactions.
Dithio‐ und Thionester, 56. Zur Reaktion von Thioestern und Thioamiden mit Azodicarbonsäurederivaten
Authors: Hartke Klaus , Brutsche Andreas , Gerber H.‐D. 
Published: July 2007

Dithio and Thiono Esters, 56. — Reaction of Thio Esters and Thio Amides with Azodicarboxylic Acid DerivativesDithio and thiono esters 1 react with azodicarboxylates 3 to form the addition products 4 or the oxidation products 5 in varying ratios. With malonates, malonamides and dithionomalonates only the addition products 7 were obtained. N,N,N′,N′‐Tetramethyldithiomalonamide yields with azodicarboxylic acid derivatives 3 either the normal addition product 8, the β‐elimination product 9 or N,N,N′,N′‐tetramethyltrithiomesoxalamide (10A), the first stable vicinal trithiocarbonyl compound.
Novel 1,6‐Stannylenes of Glucose, Galactose and Mannose
Authors: Köpper Sabine , Brandenburg Anna 
Published: July 2007

AbstractTreatment of 2,3,4‐tri‐O‐benzyl‐gluco‐, manno‐ and ‐galactopyranose with dibutyltin oxide leads to the 1,6‐di‐O‐stannylene products 2, 5 and 7, whereas no such products are formed by treatment of the 3‐O‐axially configured ido and allo sugars. Spectroscopic studies show that the tin atom is hexacoordinated in these compounds. The gluco derivative mainly exists as a dimer while the manno and galacto compounds are monomeric. All stannylenes easily eliminate the 3‐O‐benzyl group and are stereospecifically opened to give 6‐substituted α,β‐unsaturated aldehydes 3, 8 and 9. Both formation and further reactions can be correlated with the tendency of the tin atom to extend its coordination.
Lipidic Peptides, XIV. Conversion of Racemic Lipidic Amino Acids into Sphingosine and Ceramide Analogues and 1,2‐Diamines
Authors: Kokotos George , Constantinou‐Kokotou Violetta , Fernandez Esther Del Olmo , Toth Istvan , Gibbons William A. 
Published: July 2007

AbstractN‐Protected racemic lipidic amino acids 1a–h were converted directly into ceramide analogues 2a–h by chemoselective reduction of their corresponding mixed anhydrides with sodium tetrahydroborate. Conversion of the compounds 1a, b into the corresponding acyl azides, followed by catalytic hydrogenation gave the N‐monoprotected lipidic 1,2‐diamines 5a, b. The sphingosine analogues 7a–c and the free 1,2‐diamines 6a, b were synthesized by deprotection of the compounds 2a–c and 5a, b, respectively.
Pheromone Synthesis, CXL. Synthesis of Four Macrolide Pheromones to Define the Scope and Limitation of Enzymatic Macrolactonization
Authors: Mori Kenji , Tomioka Hiroki 
Published: July 2007

AbstractThe macrolides, (R)‐ferrulactone II (2), (Z)‐3‐dodecen‐12‐olide (3) and (5Z,13R)‐5‐tetradecen‐13‐olide (4), could be synthesized by enzymatic macrolactonization with lipases by starting from (±)‐12, 17 and (±)‐24, respectively. Ferrulactone I (1) was prepared by the Corey macrolactonization, and the S enantiomers of 2 and 4 by chemical macrolactonization of (S)‐11 and (S)‐23, respectively.
Structure‐Odor Correlation XVII. Synthesis and Olfactory Properties of further Theaspirane Analogs
Authors: Weyerstahl Peter , Schneider Kathleen 
Published: July 2007

AbstractAlkylation of ethyl geranate (5) with the bromo esters 7 and 8 gave the β,γ‐unsaturated esters 10 and 11, which could be isomerized to 13 and 14 by treatment with DBU. The α,β‐unsaturated esters 12–14 were cyclized to 15–17, and subsequent reduction of 15–17 led to the diols 18–20. Final cyclization afforded the spiro ethers 2–4. – The olfactive properties (intensity and quality) of the theaspirane analogs 1–4 are determined by the conformational flexibility of the respective molecule. Thus, the rigid 1 and 2 have strong camphoraceous odors. Augmenting flexibility (→3, →4) results in weaker, fruity‐woody notes.
Tetrahydrofurane und γ‐Lactone, V[1,2] Optisch aktive δ‐Hydroxy‐γ‐lactone aus Cyclooctin und Furan — Synthese von (—)‐(R,R)‐ und (+)‐(S,S)‐Muricatacin sowie verwandter Verbindungen
Authors: Tochtermann Werner , Scholz Gerhard , Bunte Gudrum , Wolff Christian , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: July 2007

Tetrahydrofurans and γ‐Lactones, V[1,2]. — Optically Active δ‐Hydroxy‐γ‐lactones from Cyclooctyne and Furan — Synthesis of (—)‐(R,R)‐ and (+)‐(S,S)‐Muricatacin and Related CompoundsThe γ‐lactone 1a, easily available from cyclooctyne and furan is converted to enantiomerically pure (—)‐(R,R)‐ and (+)‐(S,S)‐muricatacin (2e). Compound 2e was isolated recently as a biologically active (R,R/S,S) mixture from the seeds of Annona muricata. Optically active compounds were obtained by chromatographic separation of the diastereomeric camphanoates (4R)‐4a and (4S)‐4b and subsequent highly diastereoselective reduction with L‐Selectride≫ to give finally (4R,5R)‐ and (4S,5S)‐2c. The necessary side chain was introduced via Wittig reaction of the aldehyde 3c. Absolute configuration of all new products were established by X‐ray structural analysis of the δ‐lactone 7a and by comparison of (–)‐2f with its known dextrorotatory enantiomer as well. According to Mosher ester analysis of (—)‐2c and (—)‐2e the ee is ≥98%. The synthesis of rac‐muricatacin is also described. The scope of this new approach to functionalized dodecane (di)acid derivatives 3a–3c with (4R,5R) and (4S,5S) configuration is discussed.
Pheromone Synthesis, CXXXV. Synthesis of (4R,5R,6S,7E,9E)‐4,6,8‐Trimethyl‐7,9‐undecadien‐5‐ol and Its Antipode, the Female Specific Compound of the Woodroach Cryptocercus punctulatus
Authors: Mori Kenji , Itou Masamichi 
Published: July 2007

Abstract(4R,5R,6S,7E,9E)‐4,6,8‐Trimethyl‐7,9‐undecadien‐5‐ol (1) and its antipode 1′, the female specific compound of the woodroach Cryptocercus punctulatus, were synthesized by starting from methyl (R)‐3‐hydroxy‐2‐methylpropanoate (C).
Steroids, L. Ring D Cleavage of D‐Trisubstituted Steroids
Authors: Vincze Irén , Somlai Csaba , Schneider Gyula 
Published: July 2007

AbstractIn alkaline medium, 17β‐hydroxy‐15‐(hydroxymethylene)androst‐5‐en‐16‐one (2a) is cleaved in two ways to give D‐seco compounds. Dilute bases in protic solvents cause 1,3‐dicarbonyl splitting to the 15‐formyl‐15,16‐seco‐16‐oic acid 3, while the use of sodium methanolate in benzene solution gives rise to 16,17‐splitting to afford the 15‐formyl‐16,17‐seco‐16,17‐dioic acid 5. Both seco compounds readily undergo lactolone ring closure to give 4a and 6a, respectively. The malonaldehyde moiety of 5 is transformed in two directions: either loss of the formyl group to give 3β‐hydroxy‐16,17‐secoandrost‐5‐ene‐16,17‐dioic acid (7a) or decarboxylation to 3β‐hydroxy‐16‐oxo‐16,17‐secoandrost‐5‐en‐17‐oic acid (9) is observed.
Photochemistry of the Phthalimide System, 44. Photoinduced Reactions, 122. Regioselective Remote Photocyclization: Examples of a Photochemical Macrocyclic Synthesis with Sulfide‐Containing Phthalimides
Authors: Hatanaka Yasumaru , Sato Yasuhiko , Nakai Hideo , Wada Masao , Mizoguchi Tomishige , Kanaoka Yuichi 
Published: July 2007

AbstractS‐Substituted N‐(thioalkyl)phthalimides 2 underwent photocyclization to give azathiacyclols, up to 16‐membered ring compounds, in good yields. The cyclization occurred between an imide carbonyl group and a terminal sulfide group located in a remote position from the carbonyl group. The quantum yield of cyclization was determined as 0.042 (acetonitrile) for N‐(5‐methylthiopentyl)phthalimide (2a) and the efficiency of remote cyclization was not significantly affected by the chain length examined. Quenching studies of 2a using isoprene or 1,3‐cyclohexadiene showed linear Stern‐Volmer plots with the slopes of kqτ = 340 M−1 or 630 M−1, respectively. The effective concentration (Ceff) of photocyclization was estimated within the limits of 0.01 M < Ceff < 0.1 M for 2a from a competition experiment with the intermolecular photoaddition of dimethyl sulfide. The efficient cyclophilic nature of remote photocyclization can be rationalized by an enhanced proton transfer from the sulfide group which is possibly located close to the carbonyl group to form a radical ion pair complex by an electron transfer process.
Pheromone Synthesis, CXLV. Synthesis of the Enantiomers of Rhynchophorol [(E)‐6‐Methyl‐2‐hepten‐4‐ol], the Male‐Produced Aggregation Pheromone of the American Palm Weevil, Rhynchophorus palmarum
Authors: Mori Kenji , Ishigami Ken 
Published: July 2007

AbstractBoth the enantiomers of rhynchophorol [(E)‐6‐methyl‐2‐hepten‐4‐ol (1)], the male‐produced aggregation pheromone of the American palm weevil (Rhynchophorus palmarum), have been synthesized by reducing their precursors, (R)‐ and (S)‐6‐methyl‐2‐heptyn‐4‐ol (2), which have been prepared by lipasemediated asymmetric hydrolysis of the corresponding acetate and propionate.
Polycyclic Aromatic Alkaloids, 8. The Structure of Neocalliactine Acetate — Proof by Total Synthesis
Authors: Bracher Franz 
Published: July 2007

AbstractThe pentacyclic compound 1 is prepared in six steps by starting from 5,8‐quinolinedione (7). Its spectral data are in accordance with those of neocalliactine acetate, a derivative or the marine alkaloid calliactine. This represents the first definite confirmation of the structure of neocalliactine acetate.
[3 + 5]‐Anellierung mit Homophthalaldehyd: Schlüsselreaktion zur Gewinnung zentral wirksamer Tricyclen
Authors: Wünsch Bernhard , Zott Matthias , Höfner Georg 
Published: July 2007

[3 + 5] Annulation with Homophthalaldehyde: Key Step in the Synthesis of Central Active Tricycles[3 + 5] Annulation of the dinucleophile 11 with homophthalaldehyde (9) or homophthalaldehyde monoacetal 10 yielded regioselectively the β‐keto ester 12. The tricyclic ketone 4, obtained by saponification and decarboxylation of 12, was reductively aminated with dimethylamine/NaBH3CN to give the tricyclic amines 5a and 5b. The ketone 4 was transformed into the 1,2‐amino alcohol 17 by Neber rearrangement as the key step. Schmidt rearrangement of 4 followed by LiAlH4 reduction afforded the regioisomeric epoxybenzazonines 20a and 21a. In the mouse writhing test 21a and 5b exhibited strong analgesic effects with ED50 values in the range of those of pethidine and tramadol.
Ringöffnungen von 1,2‐Didehydroprolinen, I Darstellung von 4‐Hydroxyornithin und geschützten 4‐Amino‐3‐hydroxybutyronitrilen
Authors: Häusler Johannes 
Published: July 2007

Ring‐Opening Reactions of 1,2‐Didehydroprolines, I. — Synthesis of 4‐Hydroxyornithine and Protected 4‐Amino‐3‐hydroxybutyronitrilesThe cyclic azomethines 6a, b, d and f easily undergo ringopening reaction with hydroxylamine and its O‐alkyl derivatives leading to the oximino compounds 3a, b, d and f–i. Dissolved alkali metals in amines (Birch conditions) give satisfactory yields of reduction products with a stereochemistry depending on the substitution pattern in 3b, d, f–i. In case of 3d, the (2R,4R) stereoisomer 9b is the sole product, which can subsequently be cleaved to give 8b. Compounds 3g–i give predominantly the (2S,4R) product 8a. Acylation under alkaline conditions decarboxylates the oximino compounds 3b and d to the corresponding protected butyronitriles 14a–h. Trifluoroacetic anhydride transforms 3b into the nitrile 14i together with the cyclization product 15.
Thermochrome Furofurane, II. Synthese und Thermolyseverhalten substituierter Spirochinolether der Naphthalinreihe
Authors: Laatsch Hartmut , Ernst Bernd Peter 
Published: July 2007

Thermochromic Furofuranes, II. — Synthesis and Thermolytic Behavior of Spiroquinole Ethers with Naphthalene NucleusTo obtain further insight into the new photochromic system 2/3, various 3,4‐disubstituted spiroquinole ethers 7 have been synthesized by oxidation of 2‐alkyl‐4‐methoxy‐1‐naphtholes 5 via the corresponding quinone methides 6. Unlike 7a, the ethers 7b–d did not yield dimeric quinone methides or furofuranes (type 2/3) on heating, but decomposed by retro‐diene reaction yielding monomeric methides 6. The sterically hindered methides 6e, 6f are stable yellow compounds; 6c rearranged forming 12 which led to the naphthopyranes 11a/11b on further reaction with 6c.
Synthese von 1,2,4‐Triazinen, XV. Synthese von 1,2,4‐Triazin‐6(1H)‐onen
Authors: Neunhoeffer Hans , Klein‐Cullmann Birgit 
Published: July 2007

Synthesis of 1,2,4‐Triazines, XV. — Synthesis of 1,2,4‐Triazin‐6(1H)‐ones1,2,4‐Triazin‐6(1H)‐ones 3 have been prepared by cyclization of α‐ketoacyl chlorides 15 with amidrazones 14. 4,5‐Dihydro‐1,2,4‐triazin‐6(1H)‐ones 5 were obtained by cyclization of amino acid hydrazides 10 with orthocarboxylates 11.
Enzym‐katalysierte Reaktionen, 14. Stereoselektive Darstellung von Thiozuckern aus achiralen Vorstufen mittels Enzymen
Authors: Effenberger Franz , Straub Alexander , Null Volker 
Published: July 2007

Enzyme‐Catalyzed Reactions, 14. — Stereoselective Synthesis of Thiosugars from Achiral Starting Compounds by EnzymesA novel synthesis for thiosugars starting from achiral compounds by using enzymes as catalysts is described. 5‐Thio‐D‐threo‐2‐pentulofuranose (4), for example, is prepared either by the RAMA (rabbit muscle aldolase)‐catalyzed reaction of mercaptoacetaldehyde (1b) with dihydroxyacetonephosphate (2) or by the yeast transketolase‐catalyzed reaction of 2‐hydroxy‐3‐mercaptopanal (R/S)‐6 with lithium 3‐hydroxypyruvate (9). 6‐Thio‐D‐arabino‐2‐hexulopyranose (8a) and 6‐thio‐L‐xylo‐2‐hexulopyranose (8b) are obtained by the RAMA‐catalyzed reaction of racemic (R/S)‐6 with 2.
Bausteine von Oligosacchariden, CIV. Synthese von verzweigten Tetrasaccharid‐ und Pentasaccharid‐Strukturen von N‐Glycoproteinen, methyliert an 4′‐OH des Verzweigungsgliedes
Authors: Paulsen Hans , Wilkens Roland , Reck Folkert , Brockhausen Inka 
Published: July 2007

Building Units of Oligosaccharides, CIV. — Synthesis of Branched Tetrasaccharide and Pentasaccharide Structures of N‐Glycoproteins Methylated at 4′‐OH of the Branching UnitThe tetrasaccharide α‐D‐Manp‐(1→3)[α‐D‐Manp‐(1→6)]‐4‐O‐methyl‐β‐D‐Manp‐(1→4)‐D‐GlcNAc (15) and the pentasaccharide β‐D‐GlcpNAc‐(1→2)‐α‐D‐Manp‐ (→3)[α‐D‐Manp‐(→6)]‐4‐O‐methyl‐β‐D‐Manp‐ (→4)‐D‐GlcNAc (23) were synthesized by adding the respective functionalized building blocks. The compounds are useful for studies of the substrate specificities of GlcNAc transferases I and II in the biosynthesis of N‐linked oligosaccharides, respectively. In addition we developed an effective synthesis for the β‐glycosidically linked building block β‐D‐Manp‐(→4)‐α‐D‐GlcpNAc. The trichloroacetimidate method was particularly successful for synthesizing these glycosidic linkages.
β‐Carbolin‐Alkaloide, I. Synthese von 1‐Aryl‐ und 1‐Alkenyl‐β‐carbolinen durch Palladium‐katalysierte Kupplungsreaktionen
Authors: Bracher Franz , Hildebrand Dirk 
Published: July 2007

β‐Carboline Alkaloids, I. — Syntheses of 1‐Aryl‐ and 1‐Alkenyl‐β‐carbolines by Palladium‐Catalyzed Coupling Reactions1‐Chloro‐β‐carboline (6) is prepared in three steps starting from tryptamine (3). Palladium‐catalyzed coupling reactions of 6 with aryl boronic acids offer an easy access to the alkaloids komaroine (11) and perlolyrine (15). Pavettine (16) is prepared by coupling of 6 with tributylvinylstannane.
Synthesis of 2′,5′‐Dideoxyuridine‐5′‐phosphonates
Authors: Aly Youssef L. , Abdel‐Megied Ahmed E.‐s. , Pedersen Erik B. , Nielsen Claus 
Published: July 2007

AbstractMethyl 2,5‐dideoxy‐5‐iodo‐3‐O‐pivaloyl‐D‐erythro‐pentofur‐anoside (5) was synthesized from 2‐deoxy‐D‐ribose and treated with triethyl phosphite to give the phosphonate 6. Reaction of 6 with silylated 2,4‐dihydroxypyrimidine 7 in the presence of trimethylsilyl trifluoromethanesulfonate as catalyst afforded nucleoside phosphonates 8 and 9 which were deprotected with C2H5ONa in ethanol to give the diethyl 2′,5′‐dideoxyuridine‐5′‐phosphonate 10 and its α‐anomer 11. No activity was found for the nucleosides 8–11 against HIV or HSV‐1.
Total Synthesis of rac‐Sesquiterpenoid AE 1
Authors: Schinzer Dieter , Feßner Klaus , Ruppelt Martin 
Published: July 2007

Abstractrac‐Sesquiterpenoid AE 1 (rac‐1) can be obtained in an 11‐step sequence starting from 5‐methylresorcinol (2). The key compound 9 is synthesized by the use of a diastereoselective dienone cyclization with the allylic silane 8. Subsequent transformation of 9 leads to rac‐1.
Formylimin versus Isocyanat — eine ungewöhnliche Tautomerie eines Trifluoralanin‐Derivates
Authors: Matthies Dieter , Siewers Stefan 
Published: July 2007

Formylimine versus Isocyanate — an Unusual Tautomerism of a Trifluoroalanine DerivativeThe intermediate 7a formed by hydrogen chloride elimination of 6 can easily tautomerize to the isolable isocyanate 7b. Depending on the reaction conditions nucleophiles react with 7a and 7b to give the corresponding products 8 or 9, respectively.
Synthese aromatisch anellierter ϵ‐Lactone
Authors: Meise Werner , Arth Christoph 
Published: July 2007

Synthesis of Aromatic Annulated ϵ‐LactonesThe synthesis of three isomeric benzoxepinones 2, 7 and 8 by oxidation of the ω‐diols 1 and 6 with silver carbonate on Celite is reported.
Lipidic Peptides, IX. Synthesis and Structural Elucidation of Lipophilic Azidothymidine Conjugates
Authors: Hussain Rohanah , Toth Istvan , Gibbons William A. 
Published: July 2007

AbstractAzidothymidine (AZT) esters of lipidic amino acid and oligomers, together with AZT‐5′‐lipidic sulphide were synthesised. The AZT conjugates with ester linkages (3a–e) were prepared by coupling the lipidic amino acids and their oligomers to the 5′‐hydroxyl terminus of AZT. The sulphide conjugate 5 was synthesised by treating AZT‐5′‐tosylate (4) with octadecanethiol. In order to examine the effect of different lipophilicities on the activity of the AZT molecule conjugates, the lipidic amino acid units were varied from 1 to 3 and the length of the alkyl chain from 9 to 17 carbon atoms.
Zur Synthese von β‐Alkyl‐α‐methylen‐γ‐butyrolactonen
Authors: Röder Erhard , Krauß Hiltrud 
Published: July 2007

Synthesis of β‐Alkyl‐α‐methylene‐γ‐butyrolactonesThe ylene 1 reacts with aldehydes to give 3‐alkylidenesuccinic acid monoethyl esters 2, which form β‐alkylidene‐γ‐butyrolactones 3 when treated with sodium diethyldihydroaluminate. Hydrogenation of the double bond leads to the β‐alkyl‐γ‐butyrolactones 4. The β‐alkyl‐α‐methylene‐γ‐butyrolactones 5 are obtained by Mannich reaction.
Stereokontrollierte Synthesen von Mannich‐Basen und γ‐Aminoalkoholen
Authors: Risch Nikolaus , Esser Achim 
Published: July 2007

Stereocontrolled Syntheses of Mannich Bases and γ‐Amino AlcoholsThe reaction of enantiomerically pure SMP enamines 2 with iminium tetrachloroaluminates 3 yields optically active Mannich bases 4. Diastereoselective reduction of 4 gives γ‐amino alcohols 5 with the desired configuration.
Electrophile Aminierung von C‐H‐aciden Verbindungen mit 1‐Oxa‐2‐azaspiro[2.5]octan
Authors: Andreae Siegfried , Schmitz Ernst , Wulf Jens‐Peter , Schulz Burkhard 
Published: July 2007

Electrophilic Amination of C‐H‐Acidic Compounds with 1‐Oxa‐2‐azaspiro[2.5]octaneThe reactions of 1‐oxa‐2‐azaspiro[2.5]octane (1, 3,3‐pentamethyleneoxaziridine) with malonic (e.g. 4, 35) and cyanoacetic acid derivatives (e.g. 11, 13 20) and other C‐H acids [e.g. barbituric acid (6), Meldrum's acid, (diphenylmethyleneamino)‐acetonitrile (26) 1‐benzyl‐3‐hydroxy‐4‐methyl‐1 H‐pyrazol‐5(4H)‐one, and phenylbutazone (33)] have been studied. After the introduction of a 1‐hydroxycyclohexylamino group at the acidic position, five different stabilisation reactions of the intermediate 2 could be classified. The most important one is an intramolecular nucleophilic attack to a nitrile group giving disubstituted 1,4‐diazaspiro[4.5]decanones 2a. Their ring transformations (e.g. 2a → 3) or the introduction of a second amino group at the same carbon atom (2a → 3a) are further new reactions. Geminal diamino acid derivatives 3a thus obtained can be stable or rearrange to 3 (R1  NH2) or eliminate cyclohexanone (formation of 42) and/or ammonia (formation of 41 or 43). Amination of N‐cyanoacetyl‐protected amino acid esters (20, NHR = amino acid unit) with 1 yields cyclic dipeptide derivatives 41.
Isolation and Structure Determination of new Iridals from Iris sibirica and Iris versicolor
Authors: Marner Franz‐Josef , Longerich Irmgard 
Published: July 2007

AbstractFour novel iridals (compounds 8, 11, 12, and 13), representing new examples of these unusual monocyclic triterpenoids from sword lilies, have been isolated from rhizome extracts of I. sibirica and I. versicolor. Their structures have been elucidated by spectroscopic methods combined with oxidative degradation. Based on the stereochemistry of the 10‐deoxy‐17‐hydroxyiridal 13, the possible biosynthesis of these compounds is discussed.
Zur Umsetzung von N‐substituierten N′‐Chloramidinen mit Kalium‐S‐methyl‐N‐cyanimidodithiocarbonat — eine neue Thiadiazolsynthese
Authors: Sonnenschein Helmut , Walek Wolfgang , Schmitz Ernst , Reck Günter 
Published: July 2007

Reaction of N‐Substituted N′‐Chlorobenzamidines with Potassium S‐Methyl N‐Cyanimidodithiocarbonate — a New Thiadiazole SynthesisIn contrast to a known procedure for the synthesis of 1,2,4‐thiadiazoles 3 from N‐unsubstituted N′‐chlorobenzamidines 1a and potassium S‐methyl cyanimidodithiocarbonate (2) the substituted amidines 1b–1e form thiadiazoles 5a–d containing both nitrogen atoms of amidines in the ring system.
Notiz zur Synthese des 3,7‐Dicyan‐1,5‐dimethylsemibullvalens
Authors: Hüsing Nicola , Rothe Wolfgang , Kiefer Wolfgang , Quast Helmut 
Published: July 2007

Note of the Synthesis of 3,7‐Dicyano‐1,5‐dimethylsemibullvaleneThe crystalline mixture of the tetrabromodinitriles 6 and 7, which is readily available in three steps from 1,5‐dimethylbicyclo[3.3.0]octane‐3,7‐dione, is reduced by the zinc‐copper couple in dry tetrahydrofuran in the presence of copper(I) chloride under ultrasonic radiation affording brominated semibullvalenes. Addition of water to the reaction mixture and resumption of the procedure eventually results in complete reduction producing the title compound 3a in good yield.