Reaction of R-pulegone with P–H phosphonium salts

1. Download : Download high-res image (48KB)
2. Download : Download full-size image

     

Reaction of β-acyl-β-nitrostyrenes with benzenethiols

β-Acetyl- and β-benzoyl-β-nitrostyrenes reacted with benzenethiols under mild conditions to give previously unknown 4-aryl-4-(arylsulfanyl)-3-nitrobutan-2-ones and 3-aryl-3-(arylsulfanyl)-2-nitro-1-phenylpropan-1-ones, respectively, which were isolated as pure diastereoisomers or mixtures of two diastereoisomers.     

Reaction of diazonium salts with transition metals: XII. Palladium-catalyzed aryldestannylation of α-styrylstannanes by arenediazonium salts

Under palladium(0) catalysis, Ph(R₃Sn)CCH₂ (R = Me, Et and Bu) easily reacted with ArN₂BF₄ (Ar = XPh, X = H, 4-Me, 4-I, 4-MeCO, 4-EtOCO, 3-NO₂ and 4-NO₂) and selectively produced (Z)-PhCHCHAr but not Ph(Ar)CCH₂. An addition-elimination mechanism instead of the transmetallation from tin to palladium is postulated for this unusual regiochemistry.     

Cyclopropanation of active methylene compounds with β-alkoxycarbonyl vinylsulfonium salts

An efficient synthesis of β-alkoxycarbonyl vinylsulfonium salts had been developed. Their reaction with indene-1,3-diones and other active methylene compounds provided cyclopropane carboxylates in good yields. A tentative reaction mechanism was proposed.     

Syntheses with pyridinium and sulfonium salts of acylated β-enaminonitriles

Summary Pyridinium and sulfonium salts2a–e which can be prepared from 3-amino-2-(-haloacetyl)-crotonitriles and 3-amino-2-(-halo-acetyl)-3-phenyl-acrylonitriles react with malononitrile in the presence of a base to 3-amino-2-pyridinio-phenolates3a,b and 3-amino-2-sulfonio-phenolates3c–e. In an analogous way, 3-amino-2-(diethyloxyphosphoryl)-phenol5a and 3-amino-2-(p-tolyl-sulfonyl)-phenol5b have been prepared. 2,3-Diamino-phenoles6a,b are formed from the pyridinium salts3a,b. The behaviour of the pyridinium salts2a,b towards heterocumulenes has been investigated. Cyanamide leads to the (2-amino-4-hydroxy-pyrid-3-yl)-pyridinium salt8c. Phenylisothiocyanate gives the 3-pyridinio-2-thioxo-pyridin-4-olates9a,b. Carbon disulfide gives rise to 3-pyridinio-2-thioxo-pyridin-4-olate10 or 3-pyridinio-2-thioxo-thiopyran-4-olate11, depending on the substituent at the 6-position. Phenylisocyanate reacts to the pyrimidin-2,4-dione12 with loss of N-methyl-pyridinium chloride. S-methylation of9a and cleavage of the pyridine moiety yields the 3-amino-2-methylthio-pyrid-4-one14. The structures were investigated by¹H and¹³C NMR spectroscopy.

---

Synthesen mit Pyridinium- und Sulfoniumsalzen von acetylierten -Enaminonitrilen

Zusammenfassung Pyridinium- und Sulfoniumsalze2a–e, die aus 3-Amino-2-(-halo-acetyl)-crotonsäurenitril und 3-Amino-2-(-halo-acetyl)-zimtsäurenitril hergestellt werden können, reagieren mit Malonsäuredinitril in Gegenwart einer Base zu 3-Amino-2-pyridinio-phenolaten3a,b und 3-Amino-2-sulfonio-phenolaten3c–e. In Analogie wurden 3-Amino-2-(diethyloxyphosphoryl)-phenol5a und 3-Amino-2-(p-tolyl-sulfonyl)-phenol5b erhalten. 2,3-Diamino-phenole6a,b werden aus den Pyridiniumsalzen3a,b gebildet. Das Verhalten der Pyridiniumsalze2a,b gegenüber Heterokumulenen ist untersucht worden. Cyanamid führt zum (2-Amino-4-hydroxy-pyrid-3-yl)-pyridiniumsalz8c. Phenylisothiocyanat liefert die 3-Pyridinio-2-thioxo-pyridin-4-olate9a,b. In Abhängigkeit vom Substituenten in der Position 6 entsteht bei der Reaktion mit Schwefelkohlenstoff ein 3-Pyridinio-2-thioxo-pyridin-4-olat10 oder ein 3-Pyridinio-2-thioxo-thiopyran-4-olat11. Phenylisocyanat reagiert zum Pyrimidin-2,4-dion12 unter Verlust von N-Methyl-pyridiniumchlorid. S-Methylierung von9a und Spaltung des Pyridiniumringes ergibt das 3-Amino-2-methylthio-pyrid-4-on14. Die Verbindungen wurden¹H- und¹³C-NMR-spektroskopisch untersucht.

     

Gas-Chromatographic Study of Hydrazine Reaction with Metal β-Diketonates

When treated with hydrazine, metal -diketonates undergo decomposition to form the corresponding pyrazoles, irrespective of the kinetic stability of the chelates. With substituted metal chelates, the main reaction products are pyrazoles bearing in position 4 the -substituent of the compex. Other products are formed when the substituent has centers sensitive to nucleophilic substitution and/or elimination. The reaction can be used for structural assessment of the starting -diketonate.     

Recent advances in oxidative C–C coupling reaction of amides with carbon nucleophiles

The C–C coupling reaction of N-electron withdrawing group (EWG) protected amides with coupling partners is one of the most important methods for C–C bond formation at the α-position of amides to directly give α-substituted amides. Of the four reactions, namely, the reaction via the generation of carbanion with an electrophile, that via the generation of carbon radical with a radical donor, that via the generation of iminium ion species with a nucleophile (oxidative coupling reaction), and that using a transition metal carbenoid, the oxidative coupling reaction presents a challenge although the reaction products are very useful for the transformation of a wide range of nitrogen-containing derivatives. In this review, recent developments in the oxidative coupling reaction of N-EWG protected amides with nucleophiles are summarized with focus on the reaction using a transition metal, the transition-metal-free reaction, the enantioselective reaction using a chiral catalysts, and the organocatalyzed oxidative coupling reaction.     

Reaction of 8-chloro-5,7-dinitroquinoline with β-dicarbonyl compounds

3-(5,7-Dinitroquinolin-8-yl)pentane-2,4-dione, 5-(5,7-dinitroquinolin-8-yl)pyrimidine-2,4,6-trione, and 5-(5,7-dinitroquinolin-8-yl)-2,2-dimethyl-1,3-dioxane-4,6-dione cesium salts have been synthesized by a simple and efficient procedure via C-arylation of the corresponding β-dicarbonyl compounds with 8-chloro-5,7-dinitroquinoline.     

Photoinitiated Reaction of β-Bromonaphthalene with Pinacolone Ion in DMSO

The radical nucleophilic substitution reaction (SRN1) has been studied widely. The reaction has constituted an important synthetic possibility to achieve substitution of different substrates with different nucleophiles1-3. The main steps of the reaction process are presented in Scheme 1.Scheme 1. Pinacolone enolate ions are widely used as nucleophiles within SRN1reaction 4-6 because it can introduce six carbon atoms into substitution products. In the paper, the photoinitiated reaction of …     

Reaction of 2-aminopyridines with α, β-unsaturated acids

The reaction of 2-amino- and 2-amino-5-halopyridines with acrylic, methacrylic, and crotonic acids forms N-(2-pyridyl)- and N-(5-halo-2-pyridyl)--alanines and the betaines 2-amino-1-(2-carboxylatoethyl)pyridinium or 3,4-dihydropyrido[1,2-a]pyrimidin-2-ones, or their homologs.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–85, January, 1992.     

Photoinduced Reaction of α-Bromoacetophenone with Thiosulfonate: Synthesis of β-Keto Thiosulfone

A photoinduced synthesis of β-keto thiosulfone/β-keto selenosulfone by the reaction of α-bromoacetophenone with thiosulfonate/selenosulfonate under metal-free and visible light irradiation conditions is developed. Two C−S bonds or one C−S bond and one C−Se bond were constructed simultaneously.     

Combination self-assembly of β-sheet peptides and carbon nanotubes: functionalizing carbon nanotubes with bioactive β-sheet block copolypeptides

Understanding the self-assembly behavior of β-sheet peptides is important, not only in constructing bioactive peptide nanostructures, but also in inhibiting uncontrollable protein aggregation in protein-misfolding diseases. Here, the first systematic investigation of combination self-assembly between β-sheet block copolypeptides and CNTs is presented, demonstrating the presence of several different association modes during the combination self-assembly process. Bioactive β-sheet block copolypeptides can self-assemble by themselves, or can be used to functionalize CNT hybrids depending on the situation. This behavior may be important both for fabricating bioactive peptide/CNT hybrids and for controlling/inhibiting protein-misfolding diseases.     

Selective binding of bile salts by β-cyclodextrin derivatives with appended quinolyl arms

Two β-cyclodextrin derivatives bearing appended quinolyl and isoquinolyl arms,i.e.mono-(6-quinolyl- 6-deoxy)-β-cyclodextrin(1) and mono-(6-isoquinolyl-6-deoxy)-β-cyclodextrin(2) were synthesized in satisfactory yields and fully characterized.Their original conformations and binding behaviors toward four bile salt guests,that is,sodium cholate(CA),sodium deoxycholate(DCA),sodium glycocholate (GCA),and sodium taurocholate(TCA),were investigated by means of fluorescence,circular dichroism and 2D NMR spectroscopy.The study of solution structures revealed that both quinolyl and isoquinolyl arms were located outside the cyclodextrin cavity.The results obtained from the fluorescence titrations showed that the binding abilities of hosts 1 and 2 with selected bile salts varied in an order of DCA > CA > GCA.The selective binding of hosts toward bile salt guests was discussed from the viewpoints of induced-fit and multiple binding.     

A New Condensation Reaction of β-Keto-δ-valerolactone with Substituted Aniline

Pyronesareimportantintermediatesofpesticidesandpharmaceuticals'.Recentlythebiologicalactivitiesofpyronederivativeshavedrawngreatinterest,butfewliteraturesonthebiologicalactivitiesof0-keto-8-valerolactonederivativeswerereported.The3positionof0-keto-5-valerolactonesisparticularlyreactive,acylationcantakeplaceinthisposition'-'.Herewereportanewcondensationreactionof6-keto-5-valerolactone,bymeansofwhichnewcarbon-carbondoublebondwasformedandaserisofnewanilinomethylenecompoundswereobtained.Synthesiso…