bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pheromone, 76. Synthese der Enantiomeren von 10‐Methyldodecylacetat und 12‐Methyltetradecylacetat, chiralen Pheromonkomponenten von Adoxophyes‐Arten (Lepidoptera: Tortricidae)
Authors: Bestmann Hans Jürgen , Frighetto Rosa T. S. , Frighetto Nelson , Vostrowsky Otto 
Published: July 2007

Pheromones, 76. Synthesis of the Enantiomers of 10‐Methyldodecyl Acetate and 12‐Methyltetradecyl Acetate, Chiral Pheromone Components of Adoxophyes Species (Lepidoptera: Tortricidae)From enantiomeric (R)‐(−)‐ and (S)‐(+)‐2‐methylbutyl bromide (3), available by resolution of (R)‐(−)‐phenylglycinol amides of rac‐2‐methylbutanoic acid, and from enantiomeric 6‐methyloctyl bromide (7) the corresponding phosphonium salts were obtained. Wittig olefination yielded the optically active methyl‐branched olefinic THP ethers 12 and 13, hydrolysis, catalytic hydrogenation, and acetylation gave rise to the formation of the chiral title compounds (R)‐(−)‐ and (S)‐(+)‐10‐methyldodecyl acetate (1) and (R)‐(−)‐ and (S)‐(+)‐12‐methyltetradecyl acetate (2).
The synthetic utility and mechanisms of the hydrogen iodide isomerization and the oxo reaction in the modification of chlorophyll derivatives
Authors: Hynninen Paavo H. 
Published: July 2007

AbstractHydrogen iodide in glacial acetic acid has served as a versatile reagent in modifications of chlorophyll and its closely related derivatives, e.g. pheophorbides and 3‐vinylchlorins, to 3‐ethyl‐porphyrins (HI isomerization) or to 31‐oxoporphyrins (oxo reaction). Nevertheless, the mechamisms of these important reactions have remained obscure. In this paper, the reaction conditions used by H. Fischer for the HI isomerization and the oxo reaction are first thoroughly examined. Secondly, a carbocation rearrangement mechanism is suggested for the HI isomerization. Thirdly, the oxo reaction is rationalized by means of a reaction between a chlorin 31‐carbocation and water nucleophile and subsequent dehydrogenation by triplet oxygen. Finally, some related unsolved problems of chlorophyll chemistry are briefly discussed.
4,5‐dihydroisoxazoles, IX. Reactions of 3‐aryl‐4,5‐dihydro‐4‐methylene‐5‐morpholinoisoxazoles with 2,4‐diaryl‐5(4H)‐oxazolones: A new synthesis of tetrahydro‐6‐oxo‐3‐pyridinecarbaldehydes
Authors: Erba Emanuela , Pocar Donato 
Published: July 2007

AbstractThe 5(4H)‐oxazolones 1a–e react with 5‐morpholinoisoxazoles 2a–b to afford the 4‐[(4‐isoxazolyl)methyl]‐5(4H)‐oxazolones 3a–g. Compounds 3 are hydrogenated with Pd/C in dioxane to yield the corresponding 1,4,5,6‐tetrahydro‐6‐oxo‐3‐pyridinecarbaldehydes 6a–d.
Stereoselektive Totalsynthese von rac‐Yohimb‐15‐enon
Authors: Rosenmund Peter , Brandt Bernhard , Flecker Peter , Hoffmann Eberhard 
Published: July 2007

Stereoselective Synthesis of rac‐Yohimb‐15‐enoneThe Robinson annulation of an octahydroindolo[2,3‐α]quinolizin‐2‐one is a general concept for the synthesis of yohimbine alkaloids. Using the phenylsulfonyl group for activation, a diastereoselective synthesis of rac‐yohimben‐17‐one 21 has been developed. A new synthesis of aromatic amines 23 and 24 has been discovered.
Synthesen von Galactose‐Cluster‐haltigen Steroid‐Derivaten
Authors: Peter Martin G. , Boldt Peter C. , Niederstein Yvonne , Peter‐Katalinić Jasna 
Published: July 2007

Synthesis of Galactose‐Cluster‐Containing Steroid DerivativesThe synthesis of galactose clusters that are linked to a steroid moiety by a peptide‐like spacer unit is described. The galactose cluster is obtained by Koenigs‐Knorr glycosylation of TRIS‐Gly‐Fmoc (2b) under Helferich conditions. Peptide and ester bonds are formed after activation of carboxylic acids as diphenylthiophene dioxide (TDO) esters. 6a is synthesized in a convergent way by coupling of (Ac4Gal)3‐TRIS‐Gly (3e) with cholesteryl TDO succinate (5b). Coupling of (Ac4Gal)3‐TRIS‐Gly hydrogen succinate (3f) with Gly‐O‐Chol (5d) by means of EEDQ yields 6d. Reaction of (Ac4Gal)3‐TRIS‐Gly‐SUCC‐O‐TDO (3g) with 25‐hydroxycholesterol leads in a linear sequence to the oxysterol derivative 6f. Selective cleavage of the acetyl groups from galactose units yields the known compound 6b and the new derivatives 6e and 6g.
The synthesis and analysis of the conformation in solution of the dolastatin 3 diastereomer cyclo[‐L‐Pro‐L‐Leu‐D‐(Gln)Thz‐(Gly)Thz‐L‐Val‐]
Authors: Bredenkamp Martin W. , Holzapfel Cedric W. , van Zyl Wynand J. 
Published: July 2007

AbstractThe cyclic peptide cyclo[‐L‐Pro‐L‐Leu‐D‐(Gln)Thz‐(Gly)Thz‐L‐Val‐] (1a), which is a diastereomer of the antineoplastic agent dolastatin 3 (1b), and contains the unusual thiazole amino acids, was synthesized. All the peptide bonds of the cyclic peptide 1a are trans in solution, and the compound is conformationally homogeneous, as deduced by CD spectroscopy and comprehensive NMR spectroscopy. The conformation was refined by SYBYL molecular force‐field calculations. The saddle‐like conformation contains three intramolecular, but no transannular hydrogen bonds.
Heterocyclische Siebenring‐Verbindungen, XXXVI. Synthese und Eigenschaften des 1,4‐Benzoxazepins und einiger monosubstituierter Derivate
Authors: Hofmann Hans , Fischer Herbert 
Published: July 2007

Heterocyclic Seven‐Membered Ring Compounds, XXXVI. — Synthesis and Properties of 1,4‐Benzoxazepine and of Some Monosubstituted DerivativesO‐Alkylation of salicylamide with bromoacetaldehyde diethyl acetal and subsequent thermal ring closure yields the lactam 2, which is converted into the imide chloride 3. Pd(0)‐catalyzed dehalogenation of compound 3 with tributyltin hydride leads to the desired 1,4‐benzoxazepine (4), a thermally very unstable compound which prefers polymerization to valence isomerization. O‐Alkylation of the lactam 2 and S‐alkylation of the thiolactam 8 yield the 5‐substituted 1,4‐benzoxazepines 6 and 9, resp., which are thermally considerably more stable than the parent compound 4. Thus, they are capable of the expected thermal isomerization to the corresponding hydroxyisoquinolines 10 and 11, resp. The photoisomerization of the 1,4‐benzoxazepines 4, 6, and 9 leads to the thermally very unstable dihydroazetes 12, 13, and 14, of which only the methylthio compound 14 could be isolated as crystalline compound.
Orthoamide, XLVI. Beiträge zur Chemie von Bis(dialkylamino)malononitrilen
Authors: Kantlehner Willi , Greiner Ulrich 
Published: July 2007

Ortho Amides, XLVI. — Contributions to the Chemistry of Bis(dialkylamino)malononitrilesThe reaction of chloroformamidinium chlorides 2 with sodium cyanide in the two‐phase system ether/water affords bis(di‐alkylamino)malononitriles 3 with good yields. From 3a and morpholine or aniline the guanidines 5 and 6 can be obtained, respectively. Alcohol‐free sodium ethoxide transforms 3a into the urea acetal 10b, whereas in the reaction of 3a with alkoxides in alcohol ortho carbamic esters 11a, b are produced. The malonic esters and acetoacetic esters 12 react with 3a in the presence of two equivalents of sodium hydride to give the ketene aminals 13. The reactions of 3a with malononitrile furnishes the guanidinium salt 14, which is cyclized by hydrogen chloride to the pyridinetricarbonitrile 15. In the presence of sodium hydride, 3a and malononitrile or cyanoacetic esters 17 form the ketene aminal 16 and the 1,2,3‐tricyanopropenides 18a–c, respectively. The analogous salts 20 and 21 result from the reaction of 3a with the barbituric acid derivatives 19a, and b, respectively. Hydrogen chloride reacts in ether with 3a to afford the piperazinetetracarbonitrile 22. Reaction of carboxylic acid chloride yields the cyanoformamidinium salt 28a; byproducts are acyl cyanides 29 and dimeric acyl cyanides 30. Triethyloxonium tetrafluoroborate transforms 3a into the salt 28b. Bromine and iodine react with 3a to produce the salts 28c, d and 28e, f, respectively, depending on the stoichiometric ratios of the starting materials. The thiocyanate 28g is prepared from sulfur and 3a.
Heterocyclische β‐Enaminoester, 53. Neue 5,8‐Dihydropyrido‐ und 4H‐Pyrano[2,3‐d]pyrimidine
Authors: Wamhoff Heinrich , Paasch Joachim 
Published: July 2007

Heterocyclic β‐Enamino Esters, 53. — Novel 5,8‐Dihydropyrido‐ and 5H‐Pyrano[2,3‐d]pyrimidinesThe 1,4‐dihydropyridine enamino esters 1a and 4 react with phenyl isocyanate to afford the ureas 2 and 5, resp., which are cyclized to yield the 5,8‐dihydropyrido[2,3‐d]pyrimidines 3 and 6, resp., while the 1,4‐dihydropyridine bisenamino ester 7a gives accordingly, via bisurea 8, the pyrido[2,3‐d:6,5‐d′]dipyrimidine 10. The 2‐amino‐4H‐pyran‐3‐carboxylate 11 is smoothly phosphorylated to form 12. Treatment of 12 with phenyl isocyanate results in a ring closure to the 4H‐pyrano[2,3‐d]pyrimidine 14. Similarly and according to this principle, the 5,8‐dihydropyrido[2,3‐d]pyrimidine 16 is smoothly formed upon treatment of the iminophosphorane 15 with phenyl isocyanate, while the 2,6‐diamino‐1,4‐dihydropyridine 7b after phosphorylation affords the mono‐iminophosphorane 17, which undergoes cyclization with isocyanate to the 5,8‐dihydropyrido[2,3‐d]pyrimidine 18. With isopropylsulfamoyl chloride 1b and 7a form the mono‐ and bissulfamides 20 and 21, resp., which could not be cyclized further.
Amphiphilic carbohydrate‐based mesogens, VI. Synthesis of a series of alkyl 1‐thio‐D‐glucopyranosides and their regioselective reductions to 1‐alkylthio‐1‐deoxy‐D‐glucitols
Authors: Dahlhoff Wilhelm V. 
Published: July 2007

AbstractAlkyl 1‐thio‐α,β‐D‐glucopyranosides (hexyl to decyl, 1a–e) are prepared by reaction of penta‐O‐acetyl‐β‐D‐glucopyranose with the respective thiols in the presence of diethyl ether — trifluoroborane, followed by deacetylation. 1a–e are converted into their tetra‐O‐diethylboryl derivatives 2a–e and reduced with ethyldiboranes(6) in the presence of the catalyst 9‐methylsulfonyloxy‐9‐borabicyclo[3.3.1]nonane (9‐BBN‐mesylate, MSBBN) to give the mesogenic 1‐alkylthio‐1‐deoxy‐D‐glucitols 3a–e after deboronation.
Enzymatische Acetylierung von (±)‐1‐Phthalimido‐2‐propanol
Authors: Jeromin Günter E. , Weise Sven 
Published: July 2007

Enzymatic Acetylation of (±)‐1‐Phthalimido‐2‐propanol1‐Phthalimido‐2‐propanol [(±)‐1] is an N‐protected derivative of 1‐amino‐2‐propanol. By irreversible enzymatic acetylation of the racemate (±)‐1, (+)‐2‐acetoxy‐1‐(phthalimido)propane [(+)‐2] and (+)‐1‐phthalimido‐2‐propanol [(+)‐1] have been isolated on a preparative scale in good optical and chemical yields. Both optically active compounds are useful chiral intermediates.
Regio‐ and diastereoselective ene reactions of singlet oxygen with dialkyl‐substituted acrylic esters
Authors: Adam Waldemar , Nestler Bernd 
Published: July 2007

AbstractPhotooxygenation of methyl (E)‐ and (Z)‐2‐methyl‐4‐phenyl‐2‐pentenecarboxylates (E‐1, Z‐1) afforded the hydroperoxy esters (R*,S*)‐2a and (S*,S*)‐2b through regiospecific and diastereo‐selective ene reaction of singlet oxygen at the α‐methyl group with a diastereomeric ratio (d.r.) of 2a:2b ca. 80:20 for E‐1 and ca. 65:35 for Z‐1. The relative configurations of 2a, b were established by chemical correlation through triphenylphosphine reduction of the allylic hydroperoxy esters 2a, b to the allylic hydroxy esters 4a, b and subsequent catalytic hydrogenation to the literature‐known saturated hydroxy esters 5a, b (from pure 4a) and 5c, d (from pure 4b). The appreciable diastereoselectivity (d.r. ca. 80:20) observed for the E‐1 isomer is explained in terms of the cis effect, by coordinating the allylic hydrogen of the stereogenic C‐4 position to the terminal oxygen of the postulated perepoxide‐like structure.
Mikrobiologische und Enzymatische Reaktionsstufen in der Synthese von Prostacyclin‐Analoga
Authors: Petzoldt Karl , Dahl Helmut , Skuballa Werner , Gottwald Matthias 
Published: July 2007

Microbiological and Enzymatic Transformations in the Synthesis of Prostacyclin AnaloguesFor the synthesis of prostacyclin analogues, enzymatic and microbiological transformations are described leading to homochiral bicyclooctane building units.
Organoboron monosaccharides, XVIII. Stereoselective syntheses of β‐D‐lyxofuranosyl glycosides
Authors: Dahlhoff Wilhelm V. 
Published: July 2007

AbstractMethyl and phenyl β‐D‐lyxofuranoside (3a and 3b) are prepared by reaction of 5‐O‐acetyl‐2,3‐O‐ethylboranediyl‐α‐D‐lyxofuranosyl bromide (1) with sodium methoxide and sodium phenoxide to give the protected glycosides 2a, b followed by deboronation and deacetylation. The protected α‐D‐lyxofuranosyl disaccharides 2c, d are synthesized by treatment of 1 with 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose and 1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose after the former has been converted to its sodium organooxytriethylborate and the latter has been O‐tributylstannylated. 2c and 2d are deboronated and deacetylated to give 3c and 3d, respectively. 2,3,5‐Tri‐O‐acetyl‐β‐D‐lyxofuranosyl glycosides (4a–d) are obtained from 3a–d by acetylation.
Variceramides, three new sphingolipids from the marine sponge Ircinia variabilis
Authors: Cafieri Francesco , Fattorusso Ernesto 
Published: July 2007

AbstractFrom the marine sponge Ircinia variabilis, three new ceramides, variceramides 1a–3a, have been isolated. Their structures were deduced from spectroscopic studies and by acid hydrolysis.
Synthese von 4,8‐Dimethoxy‐1,5‐naphthalindiol und dessen Oxidation zu 4,8‐Dimethoxy‐1,5‐naphthochinon
Authors: Laatsch Hartmut 
Published: July 2007

Synthesis of 4,8‐Dimethoxy‐1,5‐naphthalenediol and Its Oxidation to 4,8‐Dimethoxy‐1,5‐naphthoquinoneFormation of the new 1,5‐naphthoquinone 3 was achieved by methylation of 1,4,5,8‐naphthalenetetrol (1a) and oxidation of the dimethyl ether 1c obtained thereof. In the presence of water, 3 yields the monoether 5a. Methylation of binaphthazarin (6a) seems to proceed in a similar manner.
Synthesis of 1‐aminoalkylphosphonic acids via amidoalkylation of phosphorous acid by N,N′‐alkylidenebisamides
Authors: Soroka Miroslaw , Jaworska Dorota , Szczȩsny Zbigniew 
Published: July 2007

AbstractN,N′‐Alkylidenebisamides 1, totally unsuitable as amidoalkylating agents toward phosphorous acid, react with its “activated” form prepared “in situ” from phosphorus(III) chloride and acetic acid to give the desired 1‐aminoalkylphosphonic acids 2 in high yields.
Furocoumarin‐, naphthofuran‐, and furoquinoline‐annulated 1,2‐dioxetanes: Synthesis, thermolysis, and mutagenicity
Authors: Adam Waldemar , Hauer Hermann , Mosandl Thomas , Saha‐Möller Chantu R. , Wagner Willi , Wild Dieter 
Published: July 2007

AbstractThe low temperature photooxygenation of the furocoumarins1a–e, the naphthofurans1f–h, and the furoquinoline1iafforded the corresponding dioxetanes2in good yields, except the linearly annulated naphthofuran1f, which led exclusively to the allylic hydroperoxide5fby ene reaction with singlet oxygen. The dioxetanes2were rigorously purified by means of low temperature silica gel chromatography and fully characterized. Thermolysis of the furocoumarin dioxetanes2a–eled to the expected cleavage products3a–e(acetyloxy‐ and acetyl‐substituted coumarins), while the naphtho‐ and quino‐linofuran dioxetanes2g–igave in addition to the cleavage products3g–ialso the spiroepoxides4g–i. Intramolecular electron transfer from the aromatic moiety to the dioxetane ring, with subsequent cyclization of the radical‐ion species and fragmentation is postulated as mechanism for the formation of this novel rearrangement product of dioxetanes. On heating in chloroform the spiroepoxides4g,hrearranged into the 1,3‐dioxole6g, but heating of4gin methanol gave the dioxine7gby trapping of the dipolar intermediate. — The furocoumarin dioxetanes2a,c,dshowed high mutagenic activity in theSalmonella typhimuriumstrain TA 100 but not in the strain TA 2638. The naphtho‐ and quinolinofuran dioxetanes2h,iand the spiroepoxides4g,hwere nonmutagenic in the TA 100 strain. Epoxide‐like DNA damage appears to be responsible for the mutagenicity of the furocoumarin dioxetanes2a,c,d.
Concave reagents, 3. Synthesis, basicity, and conformation of new concave pyridines
Authors: Lüning Ulrich , Baumstark Roland , Peters Karl , von Schnering Hans Georg 
Published: July 2007

AbstractEight new bimacrocyclic concave pyridines 9 and six monomacrocyclic and open‐chain analogues 10–12 were synthesized in overall yields up to 40% (up to 75% for nonmacrocyclic pyridines) starting from 2,6‐pyridinedicarbaldehydes 1, diamines 2 and diacyl dichlorides 7. Their basicities cover a range of more than three orders of magnitude. They are determined not only by the substitution pattern of the pyridine ring, but also by the overall structure of the whole molecule and by its ability to stabilize the positive charge of a proton intramolecularly. The conformations of the bimacrocyclic bislactams 9 in solution and in the solid state were investigated spectroscopically, the structure of 9b could be determined by X‐ray analysis.
Synthesis of acyclic analogs of N‐acetylmuramyl‐L‐alanyl‐D‐isoglutamine (MDP)
Authors: Danklmaier Johann , Hünig Helmut 
Published: July 2007

AbstractThe syntheses of the acyclic MDP analogs 27–37 is described, the carbohydrate moiety of muramic acid being replaced by acyclic amino alcohol structures. Their preparation was accomplished by hydrolytic cleavage of the cyclic, disubstituted 3‐morpholinones 2–5 and protection of the free amino group to give the compounds 6–9. Coupling with the dipeptide L‐alanyl‐D‐isoglutamine benzyl ester, cleavage of the N‐protecting group, acylation with acyl chains of various lengths and hydrogenation produced the title compounds 27–37. The latter exhibit variable lipophilic character.
Pheromone synthesis, CXVIII. Synthesis of the enantiomers of (E)‐1‐ethyl‐5‐methyl‐4‐heptenyl acetate (quadrilure), the aggregation pheromone of Cathartus quadricollis
Authors: Mori Kenji , Puapoomchareon Prapai 
Published: July 2007

AbstractThe synthesis of (R)‐ and (S)‐quadrilure (1) was achieved starting from (R)‐ and (S)‐methyl 3‐hydroxypentanoate (2) in 8 steps (34–35% yield).
Cyclit‐Reaktionen, XVII. Synthese von Pseudodisacchariden und Varianten von Valiolamin und Valiol
Authors: Paulsen Hans , Mielke Burkhard 
Published: July 2007

Cyclitol Reactions, XVII. — Synthesis of Pseudodisaccharides and of Derivatives of Valiolamine and ValiolEpoxid 8 has been synthesized from 2. Oxirane ring cleavage of 8 yields 1L‐6‐Amino‐6‐desoxy‐2‐C‐hydroxymethyl‐myo‐inositol 11. Analogous epimino compound 19 is obtained by neighbour group participation from inosamine 18. Debenzylation of 19 results in 1L‐2,3‐Didesoxy‐2,3‐epimino‐4‐C‐hydroxymethyl‐epi‐inositol 28 having structural analogy to the α‐glucosidase inhibitor conduritol B epoxide. Imino‐linked pseudodisaccharide 43 is prepared by condensation of 18 with 36. Ether‐linked pseudodisaccharide 49 can be obtained by coupling of 44 and 45.
Synthese neuer heteroanellierter 8‐Azapurine
Authors: Ried Walter , Laoutidis Joannis 
Published: July 2007

Synthesis of New Heteroannulated 8‐AzapurinesThe 1,2,3‐Triazoles 1 react with biselectrophiles 2, 3, 4, 7, and 9 to the pyrimido‐annulated 8‐Azapurines 5a–d, 6a, b, 8a–c, and 10a–d.
Natural product chemistry, 134. Syntheses of the natural coumarins gleinene and gleinadiene
Authors: Reisch Johannes , Wickramasinghe Anura , Wickremaratne D. B. Mahinda 
Published: July 2007

AbstractThe 5,7‐dimethoxycoumarins, gleinene (3b) and gleinadiene (2), which naturally occur in Murraya gleinei root bark, have been synthesized in four steps from 7‐hydroxy‐5‐methoxycoumarin (1a) in overall yields of 45% and 19%, respectively.
Synthesis and oxidation of pregna‐3,5‐dien‐20‐ols and ‐20‐one and selective reduction of pregna‐3,5‐dien‐20‐one
Authors: Göndös György , Orr James C. 
Published: July 2007

AbstractPregna‐3,5‐dien‐20‐one (4) and (20S)‐ and (20R)‐pregna‐3,5‐dien‐20‐ol (2 and 3) were synthesized from progesterone. Oxidation of a mixture of 2 and 3 with Jones reagent gave 4, while a large excess of Jones reagent afforded besides 4, 6‐oxoprogesterone (5), 6β‐hydroxyprogesterone (6) and 5α‐pregnane‐3,6,20‐trione (7). With L‐selectride as reducing agent, reduction of 4 led to 2 and 3 in a ratio of about 1:1. However, some reducing agents gave a higher ratio of isomer 3.
Synthesis of trialkylsiloxy‐substituted and other 5,6‐dihydro‐4H‐1,2‐oxazines by hetero diels‐alder reactions of nitroso alkenes — Preparative scope and diastereoselectivity
Authors: Hippeli Claudia , Reißig Hans‐Ulrich 
Published: July 2007

AbstractA variety of 5,6‐dihydro‐4H‐1,2‐oxazines 3 and 4 is prepared in good yields from silyl enol ethers 1 and nitroso alkenes 2a or 2b, respectively. A systematic variation of substituents reveals preparative scope and limitations of this hetero Diels‐Alder reaction with inverse electron demand. The cycloaddition is rather sensitive with regard to steric effects – in particular, large groups at C‐1 of the silyl enol ethers 1 completely prevent the reaction. On the other hand, excellent diastereo‐selectivities are observed employing appropriately substituted olefins. The presented method for the synthesis of 1,2‐oxazines also displays high regio‐ and periselectivity as is demonstrated by transformations 1r→3r and 13→14.
Allo‐, Epiallo‐ und Pseudoyohimbane sowie Heteroyohimbane durch Reaktion eines tetracyclischen Aldehyds mit Acetessigester in verschiedenen Lösungsmitteln
Authors: Rosenmund Peter , Casutt Michael , Wittich Michael 
Published: July 2007

Allo‐, Epiallo‐, and Pseudoyohimbanes as well as Heteroyohimbanes by Reaction of a Tetracyclic Aldehyde with Acetoacetate in Different SolventsThe reaction of methyl acetoacetate with 4 in CH3OH/ CH3ONa leads to 11 and 12 with yohimbane skeleton but bicyclo ring E. In DMF/tBuOK, the epialloheteroyohimbane 13 is produced in fairly good yield, whereas in THF/NaH the allo‐19‐hydroxyyohimbinone 17 is formed, which undergoes thermal decomposition to the alloyohimb‐18‐enone 19. Finally, a full description of an early mentioned synthesis of rac‐de‐plancheine (7) is given.
Darstellung und Charakterisierung von diastereomeren (4S)‐3‐Acetyl‐2‐aryl‐5,5‐dimethyl‐4‐thiazolidincarbonsäuren
Authors: Györgydeák Zoltán , Kajtár Judit , Kajtár Márton , Kajtár‐Peredy Mária 
Published: July 2007

Synthesis and Characterisation of Diastereomeric (4S)‐3‐Acetyl‐2‐aryl‐5,5‐dimethyl‐4‐thiazolidinecarboxylic AcidsThe condensation of aromatic aldehydes 1 and D‐penicillamine (2) in aqueous methanol gives (4S)‐2‐aryl‐5,5‐dimethyl‐4‐thiazolidinecarboxylic acids 3 with alternating diastereoselectivity in position 2. Acetylation of the products with acetic anhydride in pyridine or in water gives rise to (2S,4S)‐3‐acetyl‐2‐aryl‐5,5‐dimethyl‐4‐thiazolidinecarboxylic acids 5. Use of a HCl/dioxane system in the reaction of N‐acetyl‐D‐penicillamine (6) with aldehydes made possible the effective preparation of (2R,4S) compounds 8. The diastereomeric compounds 5 and 8 were characterized by 1H‐ and 13C‐NMR data and optical rotation and CD. The results were compared with those compiled from the already synthesized diastereomeric (4R)‐3‐acetyl‐2‐aryl‐4‐thiazolidinecarboxylic acids.
Synthesis of mono‐ and sesquiterpenoids, XIX. Synthesis of the enantiomers of ancistrofuran, a defensive compound from Ancistrotermes cavithorax
Authors: Mori Kenji , Suzuki Norio 
Published: July 2007

AbstractThe synthesis of the enantiomers (1 and 1′) of ancistrofuran was achieved starting from (S)‐3‐hydroxy‐2,2‐dimethylcyclohexanone.
Synthesis of polyfunctionally substituted pyridazines
Authors: Ghozlan Said Ahmed Soliman , Mohamed Mona Hassan , Fakhr Yehia , Elnagdi Mohamed Hilmy 
Published: July 2007

AbstractThe pyridazines 3, 4, 5, and 7 were obtained by reaction of the hydrazone derivatives 2 with several reagents. By treatment of 5 with acetic acid/hydrochloric acid, the pyrazolo[4,3‐c]‐pyridazine 6 was formed. The pyrido‐pyridazine derivatives 8 and 9 were obtained by reaction of 2 and 3 with malononitrile and ethyl cyanoacetate, respectively, and the isoxazolo‐pyridazines 11 by reaction of 3a, b with hydroxylamine hydrochloride in ethanolic sodium ethoxide solution. The intermediate 9 was separated by reaction of 3a, b with hydroxylamine hydrochloride in ethanolic sodium acetate solution.