Studies on annelation of (+)-2-caranone

Summary The Michael reaction of (+)-2-caranone (1) with methyl vinyl ketone, ethyl vinyl ketone or methyl acrylate was utilized for synthesis of corresponding diketones4 and5 and keto ester8. These compounds were subjected to cyclization to obtain the sesquiterpenoid systems.

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Untersuchungen über die Annelierung von (+)-2-Karanon

Zusammenfassung Die Michaelreaktion von (+)-2-Karanon mit Methylvinylketon, Ethylvinylketon oder Methylakrylat wurde zur Synthese der entsprechenden Diketone4 und5 und des Ketoesters8 genutzt. Diese Verbindungen wurden weiterhin einer Zyklisierung unterworfen, um zu Sesquiterpenoidstrukturen zu gelangen.

     

Synthese und Reaktionsverhalten von 3-(Bis(alkylthio)methylen)-3H-isobenzofuran-1-on-und 2-(Bis(alkylthio)methylen)-3(2H)-benzofuranon-Derivaten

Summary 3(Bis(alkylthio)methylene)-3H-isobenzofuran-1-ones2a–e and 2-(bis(alkylthio)methylene)-3(2H)-benzofuranone derivatives4a–c are obtained by reaction of phthalides1a–d or 3(2H)-benzofuranone (coumaranone3), respectively, with carbon disulfide under basic conditions followed by alkylation. The reaction behaviour of the new compounds2 and4 is investigated. 2-((2-Dimethylthio-1-oxo)ethyl)benzoic acid N,N-dimethylamide (7a) and 2-((2-dimethylthio-1-oxo)ethyl)-benzoic acid 2-methylpiperidide (7b) are surprisingly formed instead of the methylthio substitution products by treatment of2a with the corresponding amine in the presence of aluminum chloride.

Herrn Professor Dr. Dr. h. c.Waldemar Adam zum 60. Geburtstag gewidmet     

Reaktionen von 4,4-Bis(trifluormethyl)-1,3-diazabuta-1,3-dienen. Synthese trifluormethyl-substituierter Heterocyclenvia Baylis-Hillman-Reaktion

Summary 4,4-Bis(trifluoromethyl)-1,3-diazabuta-1,3-dienes and ,-unsaturated heteromultiple bond systems react to givebis(trifluoromethyl) substituted heterocycles. The first step of the formal [4+2] cycloaddition represents aBaylis-Hillman reaction.

Prof. Dr. Rolf Huisgen zum 75. Geburtstag gewidmet     

Dinitramide and its salts

Dinitramide readily adds to acrolein, methyl vinyl ketone, and phenyl vinyl ketone, but not to acrylonitrile or methyl acrylate. Treatment of dinitro compounds (O₂N)₂NCH₂CH₂COR (R = H, Me, Ph, OMe) with bases results in dinitramide salts in 66–83 % yields.For part 1, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1264–1266, July, 1994.     

Stereoregularity of poly(alkyl α-chloroacrylates) and mechanism of isotactic polymerization

The catalytic activity of the complexes prepared by the reaction of Grignard reagents with ketones, esters, and an epoxide as polymerization catalysts of methyl and ethyl α-chloroacrylates was investigated. The modifiers which gave isotactic polymers were α,β-unsaturated ketones such as benzalacetophenone, benzalacetone, dibenzalacetone, mesityl oxide, and methyl vinyl ketone, and α,β-unsaturated esters such as ethyl cinnamate, ethyl crotonate, and methyl acrylate. Catalysts with butyl ethyl ketone, propiophenone, and propylene oxide as modifiers produced atactic polymers but no isotactic polymers. It was revealed that the complex catalysts having a structure ? C?C? O? MgX (X is halogen) gave isotactic polymers. The mechanism of isotactic polymerization was discussed. In addition, for radical polymerization of ethyl α-chloroacrylate, enthalpy and entropy differences between isotactic and syndiotactic additions were calculated to give ΔH_i^* ? ΔH_s^* = 910 cal/mole and ΔS_i^* ? ΔS_s^* = 0.82 eu.     

Cyano-Carbonates (II) -Eficient Iatent Acyl Carbanious in 1,4-Additions

Alkylations of cyano-carbonate anions with ethyl acrylate or methyl vinyl ketone followed by hydrolysis yield 1,4-addition products in excelleat yields.     

Catalytic, asymmetric aza-Baylis-Hillman reaction of N-sulfonated imines with activated olefins by quinidine-derived chiral amines

The chiral nitrogen Lewis base, tricyclic cinchona alkaloid derivative TQO, is an effective promoter in the catalytic, asymmetric aza‐Baylis–Hillman reaction of N‐sulfonated imines Ar? CH?NR′ 1 (R′ = Ts, Ms, Ns, SES) with various activated olefins such as methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), acrolein, methyl acrylate, phenyl acrylate, or α‐naphthyl acrylate to give the corresponding adducts in moderate to good yields with good to high ee (up to 99 %) at ?30 °C or 45 °C in various solvents, including DMF/MeCN (1:1, v/v). The first such reaction of 1 with the simplest Michael acceptor MVK and methyl acrylate has been achieved with excellent enantioselectivity. The adducts derived from MVK and EVK had the opposite absolute configuration to those from acrolein, methyl acrylate, phenyl acrylate, and α‐naphthyl acrylate. A plausible mechanism has been proposed on the basis of previous reports and the authors’ investigations. An effective bifunctional chiral nitrogen Lewis base–Brønsted acid system has been revealed in this type of aza‐Baylis–Hillman reaction.     

Spectrophotometric studies on the solvatochromism of the Fe(CN)2(phen)2 complex

Summary The solvatochromic behaviour ofbis-(cyano)-bis-(9,10-phenanthroline)-iron(II) has been reexamined spectrophotometrically in a series of 19 solvents including water, alcohols and dipolar. aprotic media. Satisfactory correlations between the wave numbers of the long-wavelength band and solvent acceptor numbers are obtained in all media; only values, for carboxylic acids deviate from the regression line.

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Spektrophotometrische Untersuchungen über die Solvatochromie der Komplexverbindung Fe(CN)₂(phen)₂

Zusammenfassung Das solvatochrome Verhalten vonbis-(Cyano)-bis-(9,10-phenanthrolin)-eisen(II) wurde in 19 Lösungsmitteln, darunter Wasser, Alkohole und dipolare aprotische Medien, spektrophotometrisch überprüft. In allen Medien wurden zufriedenstellende Korrelationen zwischen den Wellenzahlen der langwelligen Bande und den Akzeptorzahlen der Lösungsmittel erhalten; lediglich die Werte für Carbonsäuren weichen von der Ausgleichgeraden ab.

     

The (E)/(Z)-ratio in the reaction of 5-(2-aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidines with bromine

Summary 3-Aryl-, 3-benzyl-, and 3H-5-(2-aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidines3a–h react with bromine in acetic acid solution to give mixtures of the respective 5-aroylmethylene (E) and (Z) diastereomeric derivatives5 and6. They contain more than 85% of the (E)-diastereomers along with some pure isomers. The intermediacy of the 5-bromo derivatives4 is proven and a plausible route of the reaction is presented. Structures of compounds3–6 are evidenced by analytical and spectral data.

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Das Verhältnis von (E)- und (Z)-Isomeren bei der Reaktion von 5-(2-Aryl-2-oxomethyl)-2-thioxo-4-oxo-1,3-thiazolidinen mit Brom

Zusammenfassung 3-Aryl-, 3-Benzyl- und 3H-5-(2-Aryl-2-oxoethyl)-2-thioxo-4-oxo-1,3-thiazolidine3a–h reagieren mit Brom in essigsaurer Lösung zu Gemischen der entsprechenden diastereomeren 5-Arylmethylen-Derivate ((E) und (Z))5 und6. Sie enthalten mehr als 85% des (E)-Diastereomeren. Die intermediäre Natur der 5-Brom-Derivate4 wird bewiesen; ein Reaktionsweg wird vorgeschlagen. Die Strukturen der Verbindungen3–6 werden durch analytische und spektroskopische Daten abgesichert.

     

A New BINOL-Derived Chiral Bifunctional Phosphine Organocatalyst: Preparation and Application in Asymmetric (Aza)-Morita-Baylis-Hillman Reactions

Abstract

A new BINOL-derived chiral bifunctional phosphine has been designed and successfully prepared, which features a cyclic substructure of 1,3,5-diazaphosphinane. This chiral phosphine possesses good air stability in solid state, and it can be conveniently used as a relatively more nucleophilic phosphine organocatalyst. Preliminary investigations showed that it could generally afford fair to excellent yields but only modest enantioselectivity in the (aza)-Morita–Baylis–Hillman reactions of activated olefins such as ethyl acrylate and methyl vinyl ketone with aldehydes or imines.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus Sulfer and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Über N1- und N2-substituierte 2-Amino-5,6-dihydro-4(1H)-pyrimidinone

The reactions of the monosubstituted guanidines2 b-h with methyl acrylate in dimethylformamide or ethanol as solvent preferentially afford 1-substituted 2-amino-5,6-dihydro-4(1H)-pyrimidinones6 b-h. The structures of 1-hexyl- and 1-benzyl-4-pyrimidinones6 c, e and of the picrate of 1-phenylpyrimidinone6 g were proved by comparison with authentic samples, which were prepared from N-substituted ethyl 3-amino-propionates14 c, e andg and cyanamide. Accordingly,6 g is not identical with authentic 2-phenylaminopyrimidinone7 g (prepared from 2-methylthio-4-pyrimidinone10 and 2-thioxo-4-pyrimidinone12 respectively, compare¹⁰).N,N-Disubstituted guanidines2 i-m react with methyl acrylate in dimethylformamide as solvent to afford N²,N²-disubstituted 2-amino-5,6-dihydro-4-(1H)-pyrimidinones7 i-m. Action of morpholine-4-carboxamidine (21) on methyl acrylate in ethanol yields 2-morpholinopyrimidinone71 as byproduct and 3-ethoxy-N-[morpholino(amino)methylene]propionamide (91) as mainproduct.

Herrn Prof. Dr.Robert Ott mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Convenient synthesis of microspheres by self-assembly of random copolymers in supercritical carbon dioxide

A novel and convenient synthesis of microspheres was attained by molecular self-assembly of random copolymers in supercritical carbon dioxide. Poly{2-(perfluorooctyl)ethyl acrylate-ran-2-(dimethylamino)ethyl acrylate} random copolymers (P[POA-r-DAA]), with 7:3, 8:2, and 9:1 as the molar ratios of 2-(perfluorooctyl)ethyl acrylate (POA)/2-(dimethylamino)ethyl acrylate (DAA), were soluble in supercritical CO₂ and had their cloud points at about 75 bar higher than the critical pressure of CO₂. The CO₂ density at the cloud points decreased with an increase in temperature. Although the copolymers made a slight difference in the cloud point in the absence of perfluoroazelaic acid (PA), they made a marked difference in the presence of PA. The copolymer with a lower DAA content had a cloud point at lower CO₂ density. The scanning electron microscopy observation demonstrated that the copolymers produced microspheres in the presence of PA at 0.5 as PA/DAA in the heterogeneous state below the cloud points. The microspheres were unstable to pressure and changed to unspecific forms as a result of increasing the CO₂ pressure, although the microspheres were stable to temperature. The POA/DAA ratio in the copolymer had effect not only on the cloud point but also on the size of the microspheres. The copolymer with a lower DAA content formed smaller microspheres.     

Solution polymerization of vinyl monomers in the presence of poly(N-acetyliminoethylene) macroazoinitiators

New block copolymers with poly(N-acetyliminoethylene) and vinyl sequences were obtained by a two-step synthetic approach. In the first stage macroinitiators of poly(N-acetyliminoethylene) type, with azo groups inserted in the main chain, were prepared. They were latter used in the radical polymerization of some vinyl monomers [styrene, methacrylic acid, methyl methacrylate, butyl methacrylate, β-(N-carbazolyl)ethyl acrylate, β-(methacryloyfoxy)ethyl 3,5-dinitrobenzoate]. The resulting block copolymers were characterized by spectral methods, elemental analysis, gel permeation chromatography, and electron microscopy. The kinetic study of the thermal and photochemical decomposition of the synthesized macroazoinitiators, as well as the polymerization data, suggest a dependence of their initiating efficiency on the length of the poly(N-acetyliminoethylene) segments. © 1994 John Wiley & Sons, Inc.     

Aza-Morita-Baylis-Hillman reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone

Aza-Morita-Baylis-Hillman (aza-MBH) reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone has been investigated. We found that aza-MBH adducts 1 could be formed in the presence of DABCO (30 mol %) and the corresponding adducts 2 could be obtained in the presence of PPh₃ (30 mol %) in moderate to good yields in acetonitrile under mild conditions, respectively.     

Zur Synthese von Imidazo(2,1-b)-1,3,4-thiadiazolo(3,2-a)-pyrimidonen-(6)

2-Amino-6-aryl-imidazo(2,1-b)-1,3,4-thiadiazoles (1 a-f) were condensed with 1,3-ketocarboxylates e. g. ethyl-butyroacetate, ethyl-benzoylacetate, 4-nitrobenzoylacetate or ethyl-cyclopentanone(2)-carboxylate and ethyl-cyclohexanone(2)-carboxylate directly to imidazo(2,1-b)-1,3,4-thiadiazolo(3,2-a) pyrimidones-(6) (4 a-f, 5 a-f, 6 d, e, 7 a-f, 8 a, d).

11. Mitt. über Heterocyclen; 10. Mitt.Paul, H., Sitte, A., Wessel, R., Arch. Pharm. (Weinheim), im Druck.     

SYNTHESIS OF THE BIOLOGICALLY ACTIVE 5-(INDOLYL-3-METHYLENE)THIAZOLIDINE-2,4-DIONE DERIVATIVES

Abstract

The cycloaddition reaction of the biologically active 5-(indolyl-3-methylene) derivatives of thiazolidi-none-4-thiones 2a-c to acrylonitrile, ethyl acrylate, N-phenylmaleimides and dimethyl fumarate has been evaluated.     

Morita-Baylis-Hillman route to 4H-pyrrolo[1,2-a][1]benzazepine derivatives

A simple method for synthesizing substituted 4H-pyrrolo[1,2-a][1]benzazepines using acid-assisted cyclization of the Morita-Baylis-Hillman adducts of 2-(1H-pyrrol-1-yl)benzaldehydes with methyl acrylate or methyl vinyl ketone as a key step has been developed.     

Straightforward Synthesis of (R,S)-β-Methyleneaspartic Acid, an Inhibitor of Glutamate-Aspartate Transaminase

Summary. A Baylis-Hillman adduct of methyl acrylate and ethyl glyoxalate was converted into the trichloroacetimidate that in the presence of DABCO rearranged to the corresponding trichloroacetamide. Eventually, hydrolysis under acidic conditions, led to the hydrochloride of racemic β-methyleneaspartic acid.     

Superhydrophobic surfaces of microspheres obtained by self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-<Emphasis Type="Italic">ran</Emphasis>-2-(dimethylamino)ethyl acrylate] in supercritical carbon dioxide

Superhydrophobic surfaces were obtained by coating with microspheres formed by the self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-ran-2-(dimethylamino)ethyl acrylate] (P[POA-r-DAA]) in the presence of dicarboxylic acids in supercritical carbon dioxide. The P[POA-r-DAA] random copolymer aggregated into micellar microspheres through the hydrogen bond cross-linking of the amino groups via the carboxylic acids. The size of the microspheres and the amount of the acids needed to produce them were dependent on the kinds of acids. Glutaric acid (Glu) and perfluorosuccinic acid (Psuc) provided microspheres at a 0.5 molar ratio of the acid/DAA. Psuc produced smaller microspheres than Glu. Maleic acid (Ma), succinic acid (Suc), and azelaic acid (Az) required a higher molar ratio to produce the microspheres. These acids provided spherical particles at the ratio of 1.0. The microspheres produced by Suc and Az contained particles with a several hundred nanometer size. The surface coated with the microspheres showed high water contact angles of 164°–172°.

Diborane as a reducing agent IX: Reduction of aTris(trifluoroacetyl)enaminospiroindoline

Summary Reduction of the title compound (2) with diborane furnishes 1-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindoline (4), 1-hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indole (5), and 1-methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carboline (6). However, treatment of2 with lithium aluminum hydride, H₂/Pd on charcoal, and sodium borohydride affords hydroxyspiroindolenine8, hydroxy-bis(trifluoroacetyl)enaminospiroindoline9, andN-ethyltryptamine7, respectively. The results are discussed and the mechanisms of the reactions leading to4–8 are presented.

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Diboran als Reduktionsmittel, 9. Mitt.: Reduktion einesTris(trifluoroacetyl)enaminospiroindolins

Zusammenfassung Reduktion der Titelverbindung (2) mit Diboran ergibt 1-Trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindolin (4), 1-Hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indol (5) und 1-Methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carbolin (6). Behandlung von2 mit Lithiumaluminiumhydrid, H₂/Pd auf Aktivkohle und Natriumborhydrid führt jedoch zu Hydroxyspiroindolenin8, Hydroxy-bis(trifluoroacetyl)enaminospiroindolin9 und N-Ethyltryptamin (7). Die Ergebnisse werden diskutiert und die Mechanismen der zu den Produkten4–8 führenden Reaktionen werden vorgestellt.