bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbohydrates as chiral templates: Stereoselective Strecker synthesis of D‐α‐amino nitriles and acids using O‐pivaloylated D‐galactosylamine as the auxiliary
Authors: Kunz Horst , Sager Wilfried , Schanzenbach Dirk , Decker Mathias 
Published: July 2007

AbstractThe asymmetric synthesis of N‐galactosyl D‐α‐amino nitriles is accomplished by application of 2,3,4,6‐tetra‐O‐pivaloyl‐β‐D‐galactopyranosylamine (4) as the stereodifferentiating template in Strecker reactions. Aldimines 6 derived from 4 and aromatic or aliphatic aldehydes react with trimethylsilyl cyanide in 2‐propanol or tetrahydrofuran in the presence of Lewis acids, e.g. ZnCl2 or SnCl4′ to give the N‐galactosyl α‐amino nitriles 5 in high yield and with diastereomeric ratios between 6:1 and 13:1 favoring the D diastereomers. Pure D‐amino nitrile diastereomers D‐5 are obtained in high yields by recrystallization from n‐heptane. Acid‐catalyzed hydrolysis of compounds D‐5 delivers the free D‐amino acids. A mechanistic interpretation of the stereoselection observed is given in terms of stereoelectronic, steric and complexing effects exhibited by the carbohydrate.
Herstellung chiraler elektrophiler Glycin‐ und (E)‐2,3‐Dehydroaminosäure‐Derivate aus 2‐t‐Butyl‐3‐methyl‐4‐oxo‐1‐imidazolidincarbonsäure‐t‐butylester (Boc‐BMI)
Authors: Schickli Christof P. , Seebach Dieter 
Published: July 2007

Preparation of Chiral Electrophilic Glycine and (E)‐2,3‐Dehydroamino Acid Derivatives from t‐Butyl 2‐t‐Butyl‐3‐methyl‐4‐oxo‐1‐imidazolidinecarboxylate (Boc‐BMI)Boc‐BMI, the compound specified in the title, is brominated under radical‐chain conditions (NBS/AIBN) to give trans‐bromo‐BMI 2, which is highly reactive in nucleophilic substitutions [see the 5‐carbo‐ and ‐hetero‐substituted (N, O, S, P) 2‐t‐butyl‐3‐methylimidazolidinones 4 – 23 and Tab. 1]. The substitutions occur preferentially with inversion of the configuration, the mechanism being not clear at all. – The Boc‐BMI dimethyl phosphonate 23 (Michaelis‐Arbusov product from 2) reacts with aldehydes (15 examples) to give preferentially (E)‐5‐alkylidene‐imidazolidinones, chiral α‐aminoacrylic acid derivatives which are available in either the R or the S form, see 24 – 38 (Tab. 2). Best yields and highest (E) selectivities (> 25:1), with short reaction times, are obtained by using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene. (DBU)/LiBr in dry THF in a very special variant of the Horner olefination. α‐Branched, racemic aldehydes may give alkylidene derivatives with efficient kinetic resolution (38). Some speculations are made about the mechanism and the observed stereochemical outcome of the reaction (I, J, K). A comparison is made with other chiral electrophilic glycine (A – C) and α,β‐dehydroamino acid derivatives (D, E), as well as with other methods for the preparation of enantiomerically pure methylenedioxolan‐, ‐oxazolidin‐, and ‐imidazolidinones (H), containing an α,β‐unsaturated carbonyl system.
A novel synthesis of indanopyrazolopyrimidines by CT‐complexation
Authors: Hassan Alaa A. , Ibrahim Yusria R. , Mohamed Nasr K. , Mourad Aboul‐Fetouh E. 
Published: July 2007

AbstractIntermolecular charge‐transfer (CT) complexes of arylazoaminopyrazoles as donors with 2‐(dicyanomethylen)indane‐1,3‐dione (CNIND) and 9‐(dicyanomethylene)‐2,4,7‐trinitrofluorene (DTF) as π‐acceptors have been investigated spectroscopically. Arylazoaminopyrazoles react with CNIND via charge‐transfer complexes to yield indanopyrazolo[1,5‐α]‐pyrimidines 5.
Synthesis of 5‐amino‐4‐cyano‐1‐imidazolyl 2‐Deoxy‐β‐D‐ribofuranoside by photolysis of 2‐aza‐2′‐deoxyadenosine or glycosylation
Authors: Kazimierczuk Zygmunt , Seela Frank 
Published: July 2007

AbstractThe photolysis of 2‐aza‐2′‐deoxyadenosine (1) results in the formation of a single reaction product. Its structure was assigned as 5‐amino‐4‐cyano‐1‐imidazolyl 2‐deoxyribofuranoside (2). The latter is also obtained independently from the glycosylation of the 5‐amino‐4‐imidazolecarbonitrile (4) anion with the halogenose 5. The reaction is stereoselective but regioisomers are formed: the N‐1 compound 6 in 21% and the N‐3 regiosomer 7 in 45% yield. The structures of the regioisomeric imidazole nucleosides 2 and 3 have been assigned by 13C‐NMR and 1H‐NMR NOE difference spectroscopy.
Synthesis of isoquinoline alkaloids. Total synthesis of (±)‐tetrahydroescholamine and its (±)‐threo‐ and (±)‐erythro‐α‐hydroxy analogs
Authors: Rozwadowska Maria D. , Matecka Dorota , Brózda Danuta 
Published: July 2007

AbstractThe studied tetrahydroisoquinolines 1, 2 and 3 were synthesized from a common intermediate 6, which was prepared by addition of the lithium salt of dithiane 5 to hydrastinine chloride (4).
2‐Deoxyglycosyl fluorides in oligosaccharide synthesis
Authors: Jünnemann Josef , Lundt Inge , Thiem Joachim 
Published: July 2007

Abstract3,4‐Di‐O‐acetyl‐2,6‐dibromo‐2,6‐dideoxy‐α‐D‐mannopyranosyl fluoride (1) was treated with Lewis acid catalysts to give α‐glycosides exclusively. Reactions with α‐ and β‐glucosyl analogs yield α/β mixtures under the same conditions. With no assistance of anchimeric substituents at C‐2 the stereoselectivity is directed by a glycosyl fluoride/catalyst/solvent complex. As shown in the 2‐deoxy‐arabino‐hexopyranosyl series this leads to improved α/β ratios and yields.
Chiral organometallic reagents, IV. Stereoselective formation of β‐silyloxy‐α‐bromoalkyllithium compounds
Authors: Hoffmann Reinhard W. , Julius Manfred 
Published: July 2007

AbstractThe diastereomeric carbenoids 4 have been generated by diastereoselective (84:16) exchange of the diastereotopic bromine atoms in the dibromo compound 3 for lithium at −120°C. The implication of the observed diastereoselectivity for the Nozaki ring‐expansion method is discussed.
Asymmetric Syntheses via Heterocyclic Intermediates, XLIV. Asymmetric Synthesis of Methyl (2R,3S)‐2‐Amino‐3‐cyclopropyl‐3‐hydroxyalkanoates via Diastereoselective Simmons‐Smith Reactions
Authors: Groth Ulrich , Schöllkopf Ulrich , Tiller Thomas 
Published: July 2007

AbstractThe cyclopropanation of the bislactim ethers 3 with diiodomethanes and diethylzinc proceeds in good yields and with high diastereoselectivities, affording the cyclopropyl bislactim ethers 6. Protection of the hydroxy group and subsequenthydrolysis furnish virtually enantiomerically and diastereomerically pure methyl (2R,3S)‐2‐amino‐3‐cyclopropyl‐3‐hydroxyalkanoates 8. The bislactim ethers of type 3 are obtained by a known method diastereomerically pure, starting from the bislactim ether of cyclo(‐L‐Val‐Gly‐).
Synthesis of isopentabromopseudilin
Authors: Hanefeld Ulf , Laatsch Hartmut 
Published: July 2007

AbstractIsopentabromopseudilin (4) and the analogous compounds 12g, 12h have been synthesized by base‐catalyzed cyclization of substituted benzaldehydes with isocyanoacetic acid methyl ester (6). In contrast to the highly antibiotic and cytotoxic active natural product 1, compounds 4, 12g and 12h have been shown to be inactive.
Chemie der Ginkgolide, IV. Herstellung von Ginkgolid B aus Ginkgolid C
Authors: Weinges Klaus , Schick Hartmut 
Published: July 2007

Chemistry of Ginkgolides, IV1). – Synthesis of Ginkgolide B from Ginkgolide CThe reaction of ginkgolide C (3) with tert‐butylchlorodiphenylsilane results exclusively in the formation of the 1‐O‐tert‐butyldiphenylsilyl ether 5, which when treated with O‐phenylchlorothioformate leads to the 7‐phenyloxythiocarbonyl derivative 6. The reduction of 6 with tributyltin hydride/AIBN yields the 1‐O‐tert‐butyldiphenylsilyl ether 7 of ginkgolide B (2). Removal of the silyl protective group with tetrabutylammonium fluoride gives pure ginkgolide B (2). The structures of the reaction products were confirmed by analytical and spectroscopic methods.
Total synthesis of all four diastereomers of 2‐acetamido‐2,4‐dideoxy‐D‐hexapyranose as potential competitive inhibitors of N‐acetylneuraminic acid synthase
Authors: Mulzer Johann , Seilz Carsten , Luger Peter , Weber Manuela , Reutter Werner 
Published: July 2007

AbstractA nine‐step gram‐scale total synthesis of all four diastereomers 3–6 of 2‐acetamido‐2,4‐dideoxy‐D‐hexapyranose from aldehyde 9, a known derivative of (S)‐malic acid, is described.
Lipidic peptides, VII. Synthesis and structure elucidation of γ‐aminobutyric acid conjugates with lipidic acids, lipidic amino acids and lipidic peptides
Authors: Hussain Rohanah , Toth Istvan , Gibbons William A. 
Published: July 2007

AbstractA series of γ‐aminobutyric acid esters of lipidic acids, lipidic peptides and γ‐aminobutyric acid amides of lipidic α‐amino acids and oligomers were synthesised. The GABA conjugates with ester linkages (6j–r) were prepared by coupling the lipidic acids and peptide conjugates to the carboxyl terminus of GABA. Two types of GABA conjugates linked by amide bonds were synthesised. This class included compounds 5d–f in which the amino group of the lipidic amino acid is condensed with the carboxyl function of GABA and compounds 7a–b with the carboxyl terminus of the α‐amino acid coupled to the amino group of GABA. The lipidic amino acid peptide oligomers were varied from 1–3 units, and the alkyl side chains ranged from 5–17 carbon atoms in length in order to impart different lipophilicities to the GABA molecule conjugates.
Photooxygenation of some potentially skin‐photosensitizing furocoumarins: Imperatorin, alloimperatorin and its methyl ether and acetate derivatives
Authors: Abou‐Elzahab Mohamed M. , Adam Waldemar , Saha‐Möller Chantu R. 
Published: July 2007

AbstractThe photooxygenation of imperatorin (1a) afforded the corresponding allylic hydroperoxides 2a and 3a in very good yields. Similarly, the photooxygenation of alloimperatorin derivatives 1c, d gave the allylic hydroperoxides 2c, d and 3c, d in quantitative yields. On the other hand, on photooxygenation of alloimperatorin (1b) exclusively the dienone hydroperoxide 4b was obtained. When the reaction time was prolonged, the bis(hydroperoxide) 5b was also formed by successive photooxygenation of 4b.
Concave reagents, 8. Concave pyridines and 1,10‐phenanthrolines with sulfonamide bridgeheads. Increased basicity by 4‐diethylamino substitution of the pyridine unit
Authors: Lüning Ulrich , Baumstark Roland , Müller Michael 
Published: July 2007

AbstractBimacrocyclic concave pyridinebissulfonamides 2 and concave 1,10‐phenanthrolinebissulfonamides 4 have been synthesized by bridging macrocyclic pyridinediamines 12 or 1,10‐phenanthrolinediamines 16 with alkylenebis(sulfonyl chloride)s 14. In contrast to concave pyridine‐ and 1,10‐phenanthrolinebislactams 1 and 3, the new compounds 2 and 4 exhibit simpler 1H‐NMR spectra and sharper melting points due to the absence of amide conformers; in comparison to 1, the basicities of 2 are decreased by a factor of ca. 100. By introduction of donor substituents into the 4‐position of the pyridine ring the basicity loss can be easily compensated. The 4‐diethylamino substituent increases the basicity of the concave pyridines 1 and 2 as expected (ca. + 4 pK units). Since no deviations from the expected basicity and reactivity for the amino‐substituted concave pyridines 1 and 2 have been found, also in these sterically hindered pyridines, the pyridine nitrogen atom is the centre of basicity and reactivity. – The synthesis of new building blocks is described, i.e. 4‐diethylamino‐2,6‐pyridinedicarbaldehyde (9c), the polyether‐based bis(sulfonyl chloride) 14b, the monomacrocyclic diamines 12e–h with a pentaethyleneglycol chain or a 4‐diethylamino substituent.
Steroids, XLIV. Neighbouring group participation, XI. Decomposition of 2‐amidomethylene‐3‐hydroxysteroids
Authors: Vincze Irén , Somlai Csaba , Schneider Gyula 
Published: July 2007

AbstractDuring reduction with sodium tetrahydroborate the 2‐[acetyl‐(alkyl)aminomethylene]‐3‐keto steroids 1aa, ba and 2aa – ca undergo transformation into the 2,4‐diene‐2‐aldehydes 5a and 6, respectively. These compounds are the decomposition products of the cyclic orthoester amides of the type 4a, b, formed by NAc‐6 neighbouring group participation from the 3‐hydroxy derivative A, which cannot be isolated.
Preparative bioorganic chemistry, XV. Preparation of optically pure 2,4,4‐trimethyl‐2‐cyclohexen‐1‐ol, a new and versatile chiral building block in terpene synthesis
Authors: Mori Kenji , Puapoomchareon Prapai 
Published: July 2007

AbstractEnzymatic hydrolysis of (±)‐2,4,4‐trimethyl‐2‐cyclohexenyl acetate [(±)‐3] with pig liver esterase yielded (R)‐(+)‐2,4,4‐trimethyl‐2‐cyclohexen‐1‐ol [(R)‐2] and unchanged (S)‐(−)‐acetate (S)‐3. Enantiomerically pure (S)‐2 was converted into (R)‐dihydro‐α‐ionone (10).
Glycosyl imidates, 47. Stereospecific synthesis of α‐ and β‐L‐fucopyranosyl phosphates and of gdp‐fucose via trichloroacetimidate
Authors: Schmidt Richard R. , Wegmann Barbara , Jung Karl‐Heinz 
Published: July 2007

AbstractReaction of the benzyl‐ and acetyl‐protected α‐trichloroacetimidates 1 and 6α with dialkyl and diaryl phosphates in the presence of traces of acid affords stereoelectively the thermodynamically more stable α‐L‐fucopyranosyl phosphates 2, 7 and 8, respectively, in high yields. The use of very pure, recrystallized dibenzyl phosphate results in the stereoeletive formation of the β‐L‐fucopyranosyl phosphates 3 and 9. In each case separation of the anomers is not required because of the very high stereoselectivity of the reactions. After deprotection the fucose 1‐phosphate 12 is coupled with GMP morpholidate 10 to yield GDP‐fucose 13. After the development of a new purification procedure for GDP‐fucose 13 we have obtained a very pure compound suitable for biochemical investigations. Analytical and preparative HPLC has been performed on reversed‐phase columns using a volatile buffer system (triethylammonium hydrogen carbonate) as the eluant.
Structural Variations on N‐acetylneuraminic acid, 20. Synthesis of some 2,3‐didehydro‐2‐deoxysialic Acids structurally varied at C‐4 and their behavior towards Sialidase from Vibrio cholerae
Authors: Schreiner Erwin , Zbiral Erich , Kleineidam Reinhard G. , Schauer Roland 
Published: July 2007

AbstractThe peracetylated methyl ester 1 of N‐acetylneuraminic acid was transformed into the oxazoline derivative 2, which was hydrogenated with Pd/C/H2 to give the 4‐deoxy‐Neu5Ac2en derivative 3. Acid cleavage of the oxazoline 2 by trifluoroacetic acid (THF) gave the 4‐epi‐Neu5Ac2en derivative 4a, which was saponified to the known 4‐epi‐Neu5Ac2en 4b. Treatment of 4a with triphenylphosphane/diethylazodicarboxylate (DEAD)/HN3 in toluene gave the 4‐azido‐4‐deoxy‐Neu5Ac2en derivative 5a as well as the 4‐epi‐azido‐4‐deoxy‐Neu5Ac2en derivative 6a. Both epimers could be saponified yielding the free dehydrosialic acid derivatives 5b and 6b. Furthermore, 4‐formamido‐4‐deoxy‐Neu5Ac2en 7b was prepared via the derivative 7a, which was formed from 5a by reaction with triphenylphosphane/formyl acetate. In addition, the free dehydrosialic acid derivatives 5b and 6b were transformed into the stable PN ylides 8 and 10, but only 8 could be hydrolyzed to the triethylammonium salt of 4‐amino‐4‐deoxy‐Neu5Ac2en 9a, which was converted into the zwitter ionic compound 9b. Finally 4‐acetamido‐4‐deoxy‐Neu5Ac2en 11e was prepared from 4‐acetamido‐4‐deoxy‐N‐acetylneuraminic acid 10 via the derivatives 11a and 11b by well‐known methods. The compounds 4b, 5b, 6b, 7b, 9b, and 11c were investigated as inhibitors of Vibrio cholerae sialidase, and their Ki values were determined.
Synthesis and conformational analysis of methyl 2‐O‐(α‐D‐Mannopyranosyl)‐α‐D‐mannopyranoside
Authors: Peters Thomas 
Published: July 2007

AbstractNMR experiments such as steady state NOE experiments and spin lattice 1H relaxation time measurements were performed on the synthetic disaccharide 10 that constitutes part of the polysaccharide backbone in fungal mannans. The spectro‐scopic data were compared with a theoretical model that is based upon the HSEA force field and statistical mechanics, taking into account the flexibility around the glycosidic linkage. Potential energy calculations were performed with a modified version of the GESA program in order to derive the global minimum conformation of disaccharide 10 and to calculate ensemble average NOE and T1 values by averaging all energetically accessible conformational microstates, using a normalized Boltzmann distribution function. The fit between experimental and theoretical results improved significantly when we applied a dynamic model instead of a single state model based solely on the global minimum conformation of 10. Efficient synthesis of 10 was achieved by a recently published protocol for the in situ activation of thioglycosides.
Enzymes in organic synthesis, 4. Investigation of the pancreatin‐catalyzed acylation of cis‐cyclopent‐2‐ene‐1,4‐diol with various trichloroethyl and vinyl Alkanoates
Authors: Theil Fritz , Schick Hans , Lapitskaya Margarita A. , Pivnitsky Kasimir K. 
Published: July 2007

AbstractDuring the pancreatin‐catalyzed acetylation of the meso‐diol 1 with 2,2,2‐trichloroethyl acetate (2a) in tetrahydrofuran/tri‐ethylamine, the enantiomeric monoacetates 3a and ent‐3a are formed at nearly equal rates. ent‐3a is rapidly acetylated in a second enzyme‐catalyzed step, forming 4a, whereas 3a resists further enzymatic acetylation. Thus, the monoacetate 3a can be obtained in 48% yield with an enantiomeric excess (e.e.) of more than 99%. 2,2,2‐Trichloroethyl propanoate and butanoate give the corresponding monoacylation products even in slightly better yield, whereas the octanoate affords the mono‐acylation product with a lower enantiomeric excess. 2,2,2‐Trichloroethyl monochloroacetate provides the monoacylation product in a 40% yield with an e.e. of 90%. The dichloroacetate, however, affords the diacylation product exclusively in an enzyme‐independent chemical reaction. With the 2,2,2‐trichloroethyl esters of isobutyric, phenylacetic, and benzoic acid no transesterification could be achieved within 24 hours. The application of vinyl acetate, however, represents a significant improvement in the synthesis of enantiomerically pure monoacetate 3a from meso‐diol 1.
Pheromone synthesis, CXXVI. Synthesis and biological activity of four stereoisomers of 6,10,14‐trimethyl‐2‐pentadecanol, the female‐produced sex pheromone of rice moth (Corcyra cephalonica)
Authors: Mori Kenji , Harada Hironori , Zagatti Pierre , Cork Alan , Hall David R. 
Published: July 2007

AbstractThe synthesis of four stereoisomers of the female‐produced sex pheromone [(2R,6R,10R)‐, (2S,6R,10R)‐, (2S,6S,10S)‐, and (2R,6S,10S)‐1a] of the rice moth (Corcyra cephalonica) was achieved by starting from (R)‐2a, (R)‐ or (S)‐3a, and (R)‐ or (S)‐4 and using alkylation of alkyl phenyl sulfones as the coupling reaction. Behavioral bioassay of each isomer revealed (2R,6R,10R)‐1a to be eight times more active than a diastereomeric mixture of equal amounts of the eight possible stereoisomers, indicating that (2R,6R,10R)‐1a is probably the natural pheromone or at least the major component of the female blend. Electrophysiological bioassay also confirmed the high activity of (2R,6R,10R)‐1a.
Enzym‐katalysierte Reaktionen, 8. Stereoselektive Darstellung von 2‐Aminoalkoholen aus (R)‐ und (S)‐Cyanhydrinen
Authors: Effenberger Franz , Gutterer Beate , Ziegler Thomas 
Published: July 2007

Enzyme‐Catalyzed Reactions, 8. – Stereoselective Synthesis of 2‐Amino Alcohols from (R)‐ and (S)‐Cyanohydrinserythro‐2‐Amino alcohols (1R,2S)‐ and (1S,2R)‐4 may be synthesized stereoselectively by addition of Grignard compounds to cyanohydrins (R)‐, (S)‐1 and their O‐trimethylsilyl derivatives 3, respectively, followed by hydrogenation. The threo‐2‐amino alcohols (1S,2S)‐ and (1R,2R)‐4 are easily accessible by inversion at C‐1 of the (1R,2S) and (1S,2R) compounds.
Boussingoside D1, a new triterpenoid saponin from Boussingaultia baselloides
Authors: Espada Alfonso , Rodríguez Jaime , Villaverde M. Carmen , Riguera Ricardo 
Published: July 2007

AbstractFour triterpenoid saponins have been isolated from the leaves of Boussingaultia baselloides by a combination of DCCC with HPLC. One is the new triterpenoid saponin boussingoside D1,3‐O‐[β‐D‐xylopyranosyl‐(1→3)‐O‐β‐D‐glucoronopyranosyl]‐30‐noroleana‐12,20(29)‐dien‐28‐oic acid, the structure of which has been elucidated by 1H‐ and 13C‐NMR spectroscopy, FAB‐MS and chemical methods.
Short enantioselective approach to a building block for macrolide syntheses
Authors: Stürmer Rainer 
Published: July 2007

AbstractThe protected α,β‐dihydroxy aldehyde 2 a key building block for several macrolide antibiotics, has been synthesized from the epoxy alcohol 6. Oxidation furnishes the corresponding aldehyde 7, which is acetalized with ketones in the prescence of SnCl4 with complete inversion of configuration at C‐3.
(10E,12Z)‐9‐Hydroxy‐10,12‐octadecadiensäure, ein Aromatase‐Hemmstoff aus dem Wurzelextrakt von Urtica dioica
Authors: Kraus Rupert , Spiteller Gerhard , Bartsch Wilfried 
Published: July 2007

(10E,12Z)‐9‐Hydroxy‐10,12‐octadecadienoic Acid, an Aromatase Inhibitor from Roots of Urtica dioicaAqueous‐methanolic extracts from roots of Urtica dioica were fractionated and tested for aromatase‐inhibition activity. After derivatization the most active fraction was separated by GC/ MS. Besides common fatty acids (10E,12Z)‐9‐hydroxy‐10,12‐octadecadienoic acid (1) was identified as a main component and confirmed to be the active principle. Lipoxygenase from tomatoes was used for synthesis of (9S)‐1, which caused also inhibition of aromatase. Stereo models of the compound showed some structural similarity to steroidal natural substrates of aromatase. For that reason (10E,12Z)‐9‐oxo‐10,12‐octadecadienoic acid (2) was also synthesized. It showed an about tenfold higher activity compared to 1.
Pheromone synthesis, CXXVII. A new synthesis of the enantiomers of grandisol and lineatin
Authors: Mori Kenji , Nagano Eiki 
Published: July 2007

AbstractThe enantiomers of grandisol (1) and lineatin (2) have been synthesized by resolving the key (±)‐hydroxy ether (±)‐7 as its diastereomeric esters 8 and 8′ with (−)‐camphanic acid.
Zur Selbstzersetzung von 2‐Chlor‐4‐methoxy‐1‐naphthol
Authors: Laatsch Hartmut 
Published: July 2007

On the Self‐Decomposition of 2‐Chloro‐4‐methoxy‐1‐naphtholOn standing, 2‐chloro‐4‐methoxy‐1‐naphthol (1a) rapidly decomposes under formation of the dinaphthofuranol 10a. The reaction is interpreted as a dehalogenation of 1a yielding 6, oxidation of the latter and acid‐catalyzed cyclisation of the intermediate 9.
Synthese und Geruch von Homoisocamphanylcyclohexanolen
Authors: Spreitzer Helmut , Laszloffy Beata , Lebada Phillipine , Buchbauer Gerhard 
Published: July 2007

Synthesis and Odour of HomoisocamphanylcyclohexanolsDiels‐Alder reaction of dienone 2 with 3‐methoxystyrene (3) leads to 4, which has been converted into a mixture of homoisocamphanylcyclohexanols (±)‐9a/b. The epimeric axial and equatorial alcohols have been separated by TLC, and their olfactory properties are described.
Organic azides in heterocyclic synthesis, 12. Thermal cyclization of 4‐azido‐3‐formyl‐2‐quinolones to isoxazolo[4,3‐c]quinolones
Authors: Roschger Peter , Stadlbauer Wolfgang 
Published: July 2007

AbstractThermolysis of the 4‐azido‐3‐formyl‐2‐quinolone 6, which was prepared from the 4‐hydroxy‐2‐quinolone 1, afforded the ringclosed isoxazoloquinolone 7. 3‐(Arylaminomethylene)‐2,4‐quinolinediones 2 could not be transformed into an azide precursor in order to obtain the corresponding pyrazoloquinolone but yielded by attempted chlorination either 5‐methyldibenzo[b,h][1,6]naphthyridine‐6(5H)‐one (9) or 4‐chloro‐3‐formyl‐1‐methyl‐2(1H)‐quinolone (5).