bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of sphingosine relatives, IX. Synthesis of (2S,3R,4E)‐1‐O‐(β‐D‐glucopyranosyl)‐N‐ [24‐(linoleoyloxy)tetracosanoyl]‐4‐sphingenine. The structure proposed for the esterified cerebroside in the epidermis of guinea pigs
Authors: Mori Kenji , Nishio Hiroyuki 
Published: July 2007

Abstract(2S,3R,4E)‐1‐O‐(β‐D‐Glucopyranosyl)‐N‐[24‐(linoleoyloxy)tetracosanoyl)‐4‐sphingenine (1) was synthesized from D‐glucose (A), (2S,3R,4E)‐4‐sphingenine (sphingosine, B), 24‐hydroxytetracosanoic acid (C) and linoleic acid (D). The 1H‐NMR spectrum of synthetic 1 was different from that of the esterified cerebroside which was isolated as a tissue‐characteristic compound in the epidermis of footpad and dorsal skin of guinea pigs.
Synthetic and stereochemical studies on phthalideisoquinoline hemiacetals
Authors: Rozwadowska Maria D. , Matecka Dorota 
Published: July 2007

AbstractThe two new phthalideisoquinoline hemiacetals rac‐egenine (3) and rac‐corytensine (4) are prepared by stereoselective DIBAL reduction of rac‐bicuculline (1) and rac‐adlumidine (2), respectively. The identity of egenine (3) with decumbensine as well as of corytensine (4) with epi‐α‐decumbensine and humosine A is postulated. The configuration around the anomeric center in natural (+)‐egenine (3), (+)‐corytensine (4) and (−)‐narcotine hemiacetal (7) is deduced as (7′S), (7′R) and (7′R), respectively.
Über die Reaktion von 2‐Diazo‐1,3‐diketonen mit 1,3‐ambident‐nucleophilen Phosphor‐Yliden: Eine neue Synthese von Monoheteroatom‐Fünf‐ und ‐Sechsringen
Authors: Capuano Lilly , Drescher Stefan , Huch Volker 
Published: July 2007

Reaction of 2‐Diazo‐1,3‐diketones with 1,3‐Ambident‐Nucleophilic Phosphorus Ylides: A New Synthesis of Monoheteroatomic Five‐ and Six‐Membered RingsThe thermolysis of 2‐diazo‐1,3‐diketones 1 with 1,3‐ambidentnucleophilic 3‐imino‐ 3, 3‐thioxo‐ 10 or 3‐oxophosphoanes 11 proceeds either by Wittig reaction, leading to the formation of the pyrrole 7 or thiophene nucleus 12, or competitively via a mechanism which involves both Wolff rearrangement and Wittig reaction by the acylcarbonyl, whereby 2‐pyridones 8, 2‐pyrones 14 or the indenyl acetophenone 15, respectively, are formed. The rates of these processes are strongly determined by substituent effects. As an exception to the general pattern of behavior, the cyclic acyl ketene derived from diazodimedone undergoes Wittig reaction with 3 through the ketene carbonyl, giving the quinoline derivative 9. The structure of 9 was confirmed by X‐ray diffraction analysis.
Isolierung und Strukturaufklärung von Ergokonin A und B; zwei neue antifungische Sterol‐Antibiotika aus Trichoderma koningii
Authors: Augustiniak Hermann , Forche Edgar , Reichenbach Hans , Wray Viktor , Gräfe Udo , Höfle Gerhard 
Published: July 2007

Isolation and Structure Elucidation of Ergokonin A and B; Two New Antifungal Sterol Antibiotics from Trichoderma koningiiIsolation and structure elucidation by 2D‐NMR spectroscopy of the two new antifungal sterol antibiotics ergokonin A (1) and B (2a) from Trichoderma koningii are described. The structures of 1 and 2a are derived from ergosterol and characterized by an 18‐carboxy group. In addition ergokonin A (1) is esterified at the 3‐hydroxy group with (2S,3S)‐3‐hydroxyleucine 3‐O‐sulfate (3c). In the course of structure elucidation of the amino acid residue the stereoisomers of 3‐hydroxyleucine N‐sulfamate and 3‐O‐sulfate (3b, c) have been synthesized and characterized by NMR spectroscopy.
Azomethine ylides from the reaction of 4‐(dicyanomethylene)‐3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one with α‐amino acids and their esters
Authors: Metwally Saoud A. M. , Aly Moustafa F. , Abd‐Alla Mohamed A. , Atta Ferial M. , Abd‐El‐Monem Maisa E. 
Published: July 2007

Abstract4‐(Dicyanomethylene)‐3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one (1) readily reacts with α‐amino acids and their esters by Michael addition and subsequent elimination of HCN to the adducts 2a–k. One of these, 2i (obtained from methyl glycinate), adds stereoselectively to N‐phenylmaleimide with loss of the remaining cyano group. It is believed that the endo‐transition state of lower energy leads to the major cycloadduct 5, whereas the exo‐transition state gives 6 as the minor one.
Base‐catalyzed rearrangement of marginalin into a 2‐phenylbenzo[b]furan
Authors: Barbier Michel 
Published: July 2007

AbstractMarginalin [(E)‐1 or (Z)‐2] is rearranged by bases to the strongly fluorescent 5‐hydroxy‐2‐(4′‐hydroxyphenyl)‐3‐benzo[b]furancarboxylic acid (3) or to methyl 5‐hydroxy‐2‐(4′‐hydroxyphenyl)‐7‐methoxy‐3‐benzo[b]furancarboxylate (4).
Ein effektiver Weg zu GABA‐analogen Aminosäuren: Cyclopropanierung vonN‐silylierten Allylaminen und Enaminen
Authors: Paulini Klaus , Reißig Hans‐Ulrich 
Published: July 2007

An Efficient Route to GABA‐Analogous Amino Acids: Cyclopropanation ofN‐Silylated Allylamines and EnaminesN‐Silylated allylamines1are effectively transformed into methyl cyclopropanecarboxylates2by methyl diazoacetate under Rh2(OAc)4catalysis. Derivatives2aand2bare smoothly converted intotrans‐substituted amino acids6aand6b, respectively, and to bicyclic γ‐lactams5aand5b. The pharmacologically interesting γ‐aminobutyric acid (GABA) analoguetrans‐6ais now available in few steps. Photochemical and thermal Fe(CO)5‐induced hydrogen shift converts allylamine derivatives1intoN‐silylated enamines7. While enamine (E)‐7acan be cyclopropanated with methyl diazoacetate under Cu(acac)2catalysis to afford the desired cyclopropane derivatives8ain good yield, the other enamines are rather unreactive towards the carbenoid. Use of an optically active catalyst provides8awith an ee of 56% (cis) and 20% (trans). Acid‐induced ring cleavage of8agives the β‐formyl ester10a, and reduction of8afollowed by desilylation provides the aminocyclopropane14in good overall yield, thus demonstrating that cyclopropanes like8acan serve as useful synthetic intermediates.
Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols
Authors: Dahlhoff Wilhelm V. 
Published: July 2007

AbstractBoth the hemiacetal and acetal groups of 4,6‐O‐alkylidene‐α/β‐D‐glucopyranoses (hexylidene–decylidene, 1a–e) are quantitatively reduced by ethyldiboranes(6) in the presence of 9‐methylsulfonyloxy‐9‐borabicyclo[3.3.1]nonane (MSBBN) after conversion to their 1,2,3‐tri‐O‐diethylboryl derivatives 2a–e. Subsequent deboronations give ca. 1:1 mixtures of 4‐O‐alkyl‐D‐glucitols 3a–e and 6‐O‐alkyl‐D‐glucitols 4a–e, which are separated to give mesogenic 3 and 4. Both 3 and 4 exhibit smectic A liquid crystalline phases.
Addition von Dialkylphosphiten und Dialkyl(trimethylsilyl)phosphiten an 2‐(Benzyloxy)propanal Darstellung aller vier stereoisomeren (1,2‐Dihydroxy‐[1‐2H1]propyl)phosphonsäuren aus chiralen Lactaten
Authors: Hammerschmidt Friedrich 
Published: July 2007

Addition of Dialkyl Phosphites and Dialkyl Trimethylsilyl Phosphites to 2‐(Benzyloxy)propanal – Preparation of all Four Stereoisomeric (1,2‐Dihydroxy‐[1‐2H1]propyl)phosphonic Acids from Chiral LactatesDimethyl trimethylsilyl phosphite, diisopropyl trimethylsilyl phosphite, dimethyl phosphite, and diisopropyl phosphite were added to 2‐(benzyloxy)propanals 4 and 6 at different temperatures in THF and CH2Cl2. The ratio of diastereomers formed was highest for diisopropyl trimethylsilyl phosphite (erythro/threo 3:1) and dropped to about 1:1 for diisopropyl phosphite. Starting from chiral lactates all four stereoisomeric diisopropyl (2‐benzyloxy‐1‐hydroxy‐[1‐2H1]phosphonates were prepared and deprotected. The (1,2‐dihydroxy‐[1‐2H1]propyl)phosphonic acids formed were purified as cyclohexylammonium salts. The relative configuration of phosphonic acid of (−)‐11 was determined by comparison with the salt (1R,2R)‐12 derived from fosfomycin.
Syntheses with Nitriles, IXC. Preparation, Structure, and Color of 4‐[(Cyano)indolylmethylene]‐ and 4‐[(Cyano)pyrrolylmethylene]‐1H‐pyrazol‐5(4H)‐ones
Authors: Dworczak Renate , Fabian Walter M. F. , Sterk Heinz , Kratky Christoph , Junek Hans 
Published: July 2007

Abstract(Dicyanomethylene)pyrazolones 1a, b are treated with some indoles and pyrroles. The resulting disubstituted malono‐nitriles 2a–f, 4a–e, 6 yield cyanomethylene compounds 3a–f, 5a–e, 7 by irreversible thermal or photochemical decomposition. The compounds exist in different isomeric forms. Structures are proven by NMR spectroscopy and X‐ray analysis. UV‐Vis data are discussed by means of AM1 and INDO/S‐CI calculations.
Chirale 2‐Benzopyran‐3‐carbonsäure‐Derivate durch Oxa‐Pictet‐Spengler‐Reaktion von (S)‐3‐Phenylmilchsäure‐Derivaten
Authors: Wünsch Bernhard , Zott Matthias 
Published: July 2007

Chiral 2‐Benzopyran‐3‐carboxylates by Oxa‐Pictet‐Spengler Reaction of (S)‐3‐Phenyllactic Acid DerivativesStarting with (S)‐tyrosine, the methyl (S)‐3‐(3,4‐dihydroxy‐phenyl)lactate (15b) was prepared by acylation, desamination and Dakin oxidation. The phenyl moiety of 15b was sufficiently activated for the reaction with aromatic and aliphatic aldehydes and ketones to yield the alkyl (3S)‐2‐benzopyran‐3‐carboxylates 16 and 19. On the other hand, the oxa‐Pictet‐Spengler reaction of the aryl unsubstituted (S)‐3‐phenyllactic acid (6) succeeds only with aromatic aldehydes. It was shown that the enantiomeric purity of the compounds 13, 14, 15, 16 and 19 was greater than 96% ee.
Thermal Degradation of Glycosides, VI. Hydrothermolysis of Cardenolide and Flavonoid Glycosides
Authors: Kim Youn Chul , Higuchi Ryuichi , Komori Tetsuya 
Published: July 2007

AbstractThe hydrothermolysis of cardenolide and flavonoid glycosides is described. On heating with water or water/dioxane, cardenolide (1, 5, 11) and flavonoid glycosides (16, 20, 23, 27) are converted into their genuine aglycones and partially hydrolyzed products, together with saccharide components. Meanwhile, the glycosidic linkage of 2‐deoxy sugar moieties in cardenolide glycosides is more readily cleaved than that of the common sugar moieties by means of hydrothermolysis. Therefore, hydrothermolysis of the uzarigenin triglycoside (13), bearing a 2‐deoxy sugar moiety which is directly attached to the aglycone, leads to selective cleavage of the sugar—aglycone linkage. The hydrothermolyzed products have been isolated by chromatography and their structures elucidated by spectroscopic methods.
Chiral Organometallic Reagents, VI. Diastereomeric α‐Phenylseleno Alkyllithium Compounds, Generation and Reactions
Authors: Hoffmann Reinhard W. , Bewersdorf Martin 
Published: July 2007

AbstractThe selenoacetals 4 having a chiral center in the β‐position were subjected to selenium/lithium exchange by butyllithium in ether. The resulting α‐phenylseleno alkyllithium compounds 5 undergo rapid epimerization at −78°C. Trapping of these organolithium compounds by ketones or aldehydes appears to be faster than the epimerization. The ratio of the trapping products therefore reflects the equilibrium ratio of the diastereomeric α‐phenylseleno alkyllithium compounds. The dependence of this equilibrium on various structural parameters has been evaluated.
Mitrariosides, Five Bitter Labdane Glycosides from Mitraria coccinea (Gesneriaceae)
Authors: Cárdenas Luz Clarena , Rodríguez Jaime , Riguera Ricardo , Chamy Maria Cristina 
Published: July 2007

AbstractFrom Mitraria coccinea Cav. (Gesneriaceae), five strongly bitter labdane glycosides named mitrariosides A1, A2, B, C and D (1 — 5) were obtained. The structures were deduced by chemical and spectroscopic evidence (COSY, 13C‐1H CORR, NOESY and MS‐FAB) and found to be: mitrarioside A1 (1): (6S)‐19‐(β‐D‐galactopyranosyloxy)‐6‐hydroxy‐15‐(α‐Lrhamno‐pyranosyloxy)labda‐8(17),13‐diene, mitrarioside A2 (2): (6S)‐19‐(β‐D‐glucopyranosyloxy)‐6‐hydroxy‐15‐(α‐L‐rhamnopyranosyloxy)labda‐8(17),13‐diene, mitrarioside B (3):(6S)‐19‐(β‐D‐glucopyranosyloxy)‐6‐hydroxy‐15‐(β‐D‐glucopyranosyloxy)‐labda‐8(17),13‐diene, mitrarioside C (4): (6S)‐19‐(β‐D‐glucopyranosyloxy)‐6,15‐dihydroxylabda‐8(17), 13‐diene, and mitrarioside D (5): (6S)‐19‐(α‐L‐rhamnopyranosyloxy)‐6,15‐dihydroxy‐labda‐8(17),13‐diene. The known compounds acteoside and calceolarioside C were also isolated.
Properties and Reactions of Substituted 1,2‐Thiazetidine 1,1‐Dioxides: 4‐Alkylidene‐β‐sultams
Authors: Müller Martin , Otto Hans‐Hartwig 
Published: July 2007

Abstract4‐α‐Hydroxyalkylated β‐sultams 1/5 are transformed into 4‐alkylidene‐β‐sultams 4/7 by elimination and desilylation reactions. Another route to an exocyclic double bond in the β‐sultam system has been found to be the Peterson olefination starting from 4 silylated β‐sultams 8, 10, and 11. The elimination‐reaction sequence yields stereochemically defined products with either E or Z configuration but by use of the Peterson reaction we have always obtained mixtures of diastereomers, which have to be separated. The stereochemistry of all products is elucidated by spectroscopic methods.
Photochemische Studien, 63. Photostabilität einiger 1,4‐Benzodiazepine in kristallinem Zustand
Authors: Reisch Johannes , Ekiz‐Gücer Nurten , Tewes Gregor 
Published: July 2007

Photochemical Studies, 63. — Photostability of Some 1,4‐Benzodiazepines in the Crystalline State.UV irradiation of chlorodiazepoxide (1) and its hydrochloride led to three photoproducts: 2‐<[(3‐chlorophenyl)phenylmethylene]amino>‐N‐methylacetamide (2), 1‐benzoyl‐7‐chloro‐1,2‐dihydro‐3‐methylaminoquinoxaline (3) and 7‐chloro‐3,4‐dihydro‐2‐methylamino‐4‐phenyl‐5H‐1,4‐benzodiazepine‐5‐one (4). The photochemical degradation of 1, 1‐hydrochloride, diazepam and nitrazepam in the crystalline state have been investigated and determined densitometrically.
5‐(4‐Pyridyl)‐1,3‐dioxan‐4,6‐dione — Darstellung und Reaktionen mit O‐, N‐ und C‐Nucleophilen
Authors: Henning Hans‐Georg , Stemplinger Gunter , Rothe Kathrin 
Published: July 2007

5‐(4‐Pyridyl)‐1,3‐dioxan‐4,6‐diones — Preparation and Reactions with O‐, N‐ and C‐NucleophilesThe reaction between alkyl chloroformates, pyridine and 1,3‐dioxane‐4,6‐diones yields 5‐[1‐alkoxycarbonyl‐4(1H)‐pyridylidene]‐1,3‐dioxane‐4,6‐diones 3 via the dihydro intermediates 2. The compounds 3 transfer the alkoxycarbonyl group readily to O‐, N‐ and C‐nucleophiles. Hydrolysis of 3a–e affords 2,2‐dimethyl‐5‐(4‐pyridyl)‐1,3‐dioxane‐4,6‐dione (4a), which in solution exists in the NH tautomeric form. Nucleophilic reagents attack 4a at one of the carbonyl groups to yield derivatives of (4‐pyridyl)acetic acid. These reactions admit a convenient access to a number of 4‐pyridyl‐substituted heterocycles.
N‐Vinyl‐, N‐Allyl‐, N‐Propenyl‐ and N‐Propargyl‐benzotriazoles: Reactions of Their Lithium Derivatives
Authors: Katritzky Alan R. , Li Jianqing , Malhotra Nageshwar 
Published: July 2007

Abstract1‐Vinylbenzotriazole undergoes lithiation at the α‐carbon and subsequent reactions with electrophiles to afford 1‐(1‐substituted vinyl)benzotriazoles (3a–d). Similarly, 1‐(1‐substituted propenyl)‐ (9a–c, 9e, 10a–c, 10e) and 2‐(1‐methylpropenyl)‐benzotriazoles (14 and 15) were prepared by lithiation of the corresponding 1‐ and 2‐propenyl‐benzotriazoles followed by alkylation. 1‐ and 2‐Allylbenzotriazoles 4 and 5 are also lithiated at the α‐carbon and the intermediates react with electrophiles at this position. The structures of the propenyl derivatives were supported by an alternative synthetic route via rearrangements of the corresponding allyl isomers. 1‐Propargylbenzotriazole (16) undergoes lithiation first at the acetylenic CH and then at the CH2 group. The dilithiated species, produced by treatment of 16 with two equivalents of butyllithium, reacts with an electrophile first at the carbon atom adjacent to the nitrogen atom, and then at the terminal carbon atom. Hence lithiation of 16 and subsequent reactions with electrophiles afford alkylated products 17a–d, 18a–d, 19a–b and 20a–c depending upon the amount of butyllithium and of the electrophile(s) used. The structures of each class of product were supported by spectral and analytical data.
A Mild and Facile Preparation of Sulfoxides from Sulfides by Use of the H2O2‐Urea/Phthalic Anhydride System
Authors: Balicki Roman , Kaczmarek Lukasz , Nantka‐Namirski Pawel 
Published: July 2007

AbstractThe use of the system hydrogen peroxide‐urea/phthalic anhydride in the safe oxidation of dialkyl, diaryl and alkyl aryl sulfides under mild conditions is reported. The corresponding sulfoxides are formed in excellent yields.
Untersuchung der allergenen Prinzipien aus Kolophonium: Autoxidation, Synthese und Sensibilisierung
Authors: Krohn Karsten , Budianto Emil , Flörke Ulrich , Hausen Björn M. 
Published: July 2007

Investigation of the Allergenic Principles from Colophony: Autoxidation, Synthesis, and SensitizationThe autoxidation of abietic acid (1a), levopimaric acid (2a), and dehydroabietic acid (3a) was studied and the compounds 3a as well as (after esterification) 8b, 9b, 10b, 11b (from 1a); 6b (from 2a); and 4b, 5b (from 3a) were isolated for the first time. Some derivatives (6a, 6b, 13b/14b, and 7b) were semisynthezised. The isolated autoxidation products, the synthetic compounds and some polar fractions of natural colophony were tested for their sensitizing capacity. Compounds 4a, 10b, 16, and 18 as well as the combined polar fraction A–D of colophony show enhanced sensitizing capacity. Methylation of the acids to the ester significantly reduces their activity.
Thermal Degradation of Glycosides, VII. Application of Hydrothermolysis to the Studies on the Constituents of the Merck Saponin
Authors: Kim Youn Chul , Higuchi Ryuichi , Komori Tetsuya 
Published: July 2007

AbstractTwo new triterpenoid 3,28‐O‐bisglycosides, MS‐1 and MS‐2, were isolated from the Merck Saponin (origin: Gypsophila paniculata L.). Their structures were elucidated on the basis of chemical and spectral data as follows. MS‐1 (1): 3‐O‐β‐D‐galactopyranosyl‐(→2)‐[α‐L‐arabinopyranosyl‐(→3)]‐β‐D‐glucuronopyranosyl gypsogenin 28‐O‐β‐D‐xylopyranosyl‐(→3)‐ β‐D‐xylopyranosyl‐(→4)‐α‐L‐rhamnopyranosyl‐(→4)‐[β‐D‐quinovopyranosyl‐(→2)]‐β‐D‐ fucopyranoside. MS‐2(2): 3‐O‐β‐D‐galactopyranosyl‐(→2)‐[α‐L‐ arabinopyranosyl‐(→3)]‐β‐D‐glucuronopyranosyl quillaic acid 28‐O‐β‐D‐xylopyranosyl‐(→3)‐β‐D‐xylopyranosyl‐(→4)‐α‐L‐rhamnopyranosyl‐(→4)‐[β‐D‐quinovopyranosyl ‐(→2)]‐β‐D‐fucopyranoside. The hydrothermal degradation, which led to selective cleavage of the ester glycosidic linkage, was useful for the structure elucidation.
Synthesis of the Ring D‐Building Block of (24S)‐24‐Hydroxy Vitamin D3 from Menthol, I
Authors: Daniewski Andrzej Robert , Warchol Tadeusz 
Published: July 2007

AbstractNatural (—)‐menthol (4) was oxidized to the lactone 9 which was alkylated with allyl bromide to a single product 10. The latter compound was transformed into bromo epoxide 33 which was cyclized with the highly reactive copper to the desired ring D Building block 18 of (24S)‐24‐hydroxy vitamin D3. The title compound 18 was synthesized also by free‐radical cyclization of enaldehyde 40.
Biologically Active Glycosides from Asteroidea, XXIX. X‐Ray Crystallographic Analysis of Desulfated Asterosaponin P1 Isolated from the Starfish Asterina pectinifera
Authors: Cho Yuko , Higuchi Ryuichi , Marubayashi Nobuhiro , Ueda Ikuhiko , Komori Tetsuya 
Published: July 2007

AbstractBy X‐ray crystallographic analysis of desulfated asterosaponin P1 the absolute configuration at C‐24 in the aglycone moiety is confirmed. The unique conformation of the side chain part possessing the carbohydrate moiety is also revealed. This is the first report of an X‐ray crystallographic analysis of a steroid glycoside whose carbohydrate moiety is located in the C‐17 side chain.
Synthesis of the Enatiomers of Lasiol, the Major Volatile Component of the Mandibular Gland Secretion of Lasius meridionalis
Authors: Kuwahara Shigefumi , Shibata Yasuo , Hiramatsu Akira 
Published: July 2007

AbstractBoth enantiomers of lasiol, erythro‐2,3,6‐trimethyl‐5‐hepten‐1‐ol (1), were synthesized in 6 steps from the enantiomers of 3‐methyl‐4‐butanolide (2).
Sulfidierung ausgewählter Carbonsäure‐ und Kohlensäureamide mit dem (9‐BBN)2S‐Reagenz
Authors: Köster Roland , Kucznierz Ralf 
Published: July 2007

Sulfidation of Selected Carboxylic and Carbonic Acid Amides with the (9‐BBN)2S‐ReagentThe sulfidation of eight carboxylic and carbonic acid amides (A–H) with bis(1,5‐cyclooctanediylboryl) sulfide (1) is described. From the aliphatic acyclic amide A and the N‐substituted lactams C–E the corresponding thiocarbonyl compounds 2a and 2c–e, resp., are obtained in high yields. N,N‐Dimethylbenzamide (B) reacts with 1 to give monothiobenzoic acid 9‐BBN ester (3) and further dithiobenzoic acid 9‐BBN ester (4). From N‐methylphthalimide (F) and 1 the dithio derivative 5f is formed at room temperature. The carbonic acid amides (urea derivative G, caffeine H) are sulfidated slower than the carboxylic acid amides with formation of the monothio derivatives 2g and 2h, resp. H reacts regioselectively with 1 to yield 6‐thiocaffeine (2h) and further to give 2,6‐dithiocaffeine (5h).
Selective Acetate Hydrolysis of Diastereomers with Porcine Pancreatic lipase (PPL) as an Access to Useful Chiral Building Blocks
Authors: Mulzer Johann , Greifenberg Stefan , Beckstett Anne , Gottwald Matthias 
Published: July 2007

AbstractThe diastereomeric mixture of the propargylic acetates 2 was diastereomer selectively hydrolyzed with porcine pancreatic lipase (PPL) in water to give the acetate syn‐2 and the alcohol anti‐3, both more than 95% diastereomerically pure. From these products stereocontrolled routes to other useful chiral building blocks (4, 6, 11, 14, 15, 16) were developed.
Terpenes and Terpene Derivatives, XXX. Isolation and Synthesis of Isohumbertiol, the First Naturally Occurring Sesquiterpene Alcohol with a Humbertiane Skeleton
Authors: Weyerstahl Peter , Christiansen Christian , Marschall Helga 
Published: July 2007

AbstractFrom Vassoura oil (Baccharis dracunculifolia DC.) the four isomeric isohumbertiols A–D (7–10), the first naturally occurring sesquiterpene alcohols with a humbertiane skeleton could be isolated and assigned unambiguously by establishing a correlation with the known cabreuva oxides A–D (3–6). Reaction of the ketone (+)‐16 with vinylmagnesium bromide gave a mixture of the isohumbertiols B and D [(+)‐8 and ent‐10]. Treatment of 8/10 with SnCl4 furnished the tetraline derivative 18, whereas with hydrochloric acid the cabreuva oxides B and D (4 and 6) were obtained.
Pyrylium‐Mediated Synthesis of N‐(Benzyloxy)pyridinium Salts
Authors: Balaban Teodor Silviu , Tâmâşan Iuliana , Deleanu Câlin 
Published: July 2007

AbstractPyrylium salts 3 react with (benzyloxy)amines 2 generated by hydrazinolysis from their N‐(benzyloxy)phthalimides to afford in moderate (35–65%) yields the corresponding title salts 4. The 13C‐ and 1H‐NMR spectra of the latter compounds are reported.
Synthesis of Substituted Dibenzo[a,d]azepines via a Base‐Mediated Ring Expansion
Authors: Groth U. , Richter L. , Schöllkopf U. 
Published: July 2007

AbstractSubstituted dibenzoazepines5and10were synthesized in three steps by starting from acridine (6). The key step of the synthesis is a base‐mediated ring expansion reaction of the mesylates1.
A Facile Synthesis of [1]Benzopyrano[4,3‐b]pyridin‐5‐ones
Authors: Ivano Ivo C. , Karagiosov Stoyan K. , Simeonov Mario F. 
Published: July 2007

AbstractThe title compounds 5a‐c and 7a‐m have been prepared by Vilsmeier formylation of 4‐aminocoumarins 1 yielding aldehydes 2, and subsequent condensation of 2 with C‐H acids in the presence of piperidine. This condensation probably proceeds via the intermediate ylidenemalonic esters 4. By means of detailed 1H‐ and 13C‐NMR studies a Dimroth‐type rearrangement of intermediates 6f‐m has been found to take place in the course of the formation of products 7f‐m.
A New Stereoselective Synthesis of Grandisol
Authors: Langer Klaus , Mattay Jochen , Heidbreder Andreas , Möller Manfred 
Published: July 2007

AbstractGrandisol (10) is stereoselectively synthesized in 9 steps, starting from commercially available 3‐methyl‐3‐buten‐1‐ol (1). The key step of the synthesis is the Cu(I)‐catalyzed [2 + 2]‐photocycloaddition of 3 to 4a or 4b. Moreover, solvent effects on the endo/exo product ratio of the [2 + 2]‐photocycloaddition are investigated.