Direct diastereoselective introduction of l-menthol residue into 1,2,4-triazin-5(4H)-one

The reaction of 3-phenyl-1,2,4-triazin-5(4H)-one (1) with l-menthol in the presence of aliphatic acid anhydrides results in (6S)- and (6R)-1-acyl-6-(l-menth-3-yl)-1,6-dyhydro-3-phenyl-1,2,4-triazin-5(4H)-ones. The reaction is diastereoselective with predominant formation of (6S)-isomers. The reaction diastereoselectivity increases with enhancement of the steric hindrance in the vicinity of the reaction center of the azine.     

Structure of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone as chiral component of liquid-crystalline systems

The spatial structure of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone prepared by photochemical isomerization of the E-isomer was studied by analyzing the magnitudes and temperature dependence of the proton spin-spin coupling constants obtained by ¹H NMR spectroscopy and the results of molecular modeling using semiempirical quantum chemical AM1 and PM3 methods and the density functional theory (DFT). Comparison of the results obtained for the Z-and E-isomers shows that in both cases the conformational equilibrium for both isomers is characterized by significant preference of the chair conformer having an equatorial methyl group, namely, − ΔH (chair a ⇌ chair e) = 1.98–2.12 and 1.36–1.54 kcal mole⁻¹ for the Z-and E-isomers, respectively. Distinctions in the non-planarity of the enone fragment and cyclohexanone ring in the Z-and E-isomers under study following from the results of mathematical modeling were confirmed by the experimental values of the geminal spin-spin coupling constants of protons of the methylene groups in α,α ′-positions with respect to the enone group. Quantum chemical calculations of the Z-isomer revealed the existence of intramolecular hydrogen bond between the carbonyl oxygen and the nearest aromatic proton in ortho-position of the benzene ring. Possible reasons for different helical twisting power of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone and the E-and Z-arylidene derivatives of 1R, 4R-isomenthone in the mesophase are discussed based on the results of molecular structure studies for these compounds. In the text below the unsaturated ketones under study will be called “arylidene cyclohexanone derivatives” for convenience of comparing the characteristics of methylcyclohexanone and isomenthone derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 962–972, June, 2006.     

Diastereoselective reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with aromatic aldehydes. Synthesis of (1R,2R,4S,5S,8S)-2,8-diaryl-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octanes

We have synthesized a series of (1R,2R,4S,5S,8S)-2,8-diaryl-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octanes as a result of reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with aromatic aldehydes. The structure of the compounds obtained was established on the basis of ¹H NMR data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 757–763, May, 2006.     

Reaction of 6-methoxybenzo[b]furan-3(2H)-one and benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes as a convenient synthetic route to substituted 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans and 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans

The reactions of 6-methoxybenzo[b]furan-3(2H)-one with 2-aryl-1,1-dicyanoethylenes and malononitrile or with aromatic aldehyde and two moles of malononitrile afford 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans. The reactions of benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes or with aromatic aldehyde and one mole of malononitrile produce 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans.     

A study of the Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one derivatives

Summary The Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 a) gave 7-hydroxy-8-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (3 a) and 2,3-dihydro-2,6-diphenyl-3-methyl-(7H)furo[2,3-h]-1-benzopyran-7-one (7 a). 2-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 b) afforded4 b and7 b. 8-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (12) gave only the alkali soluble product 7-hydroxy-8-methyl-6-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (13).3 a,4 b, and13 were further cyclized in acidic medium to9 a,10 b, and14 followed by dehydrogenation.This paper is dedicated to Dr. F. M. Dean, Department of Organic Chemistry, Robert Robinson Laboratories, University of Liverpool, Liverpool, U. K., on his retirement     

(R)-4-Menthenone in the synthesis of optically pure sex pheromone of the peach leafminer moth (Lyonetia clerkella)

The synthesis of (14S)-methyloctadec-1-ene, sex pheromone of the peach leafminer moth (Lyonetia clerkella), is described to demonstrate a new potential of the synthetic use of (R)-4-menthenone.     

Silver selective benzimidazol-2(1H)-one based,sulphur-containing podands

Podands based on benzimidazol-2(1H)-one, containing S and terminal NH₂ groups, selectively transport and extract silver picrate over Mg²⁺, Ca²⁺, Sr²⁺, Ph²⁺ and Tl⁺ picrates.     

The Reactions of 6-(tert-Butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with Carbonyl Compounds

The reaction of 6-(tert-butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with acetone and benzaldehyde yields the corresponding hydrazones. In the presence of thionyl chloride the benzaldehyde hydrazone is converted to 3-(tert-butyl)-6-phenyl-1,2,4-triazolo[4,3-b]-1,2,4-triazin-2(1H)-one and this can also be formed via the acylation of the starting hydrazinotriazinone using benzoyl chloride.     

Enantiospecific synthesis of (S)-(+)-3-methylheneicosan-2-one, an analog of the sex pheromone of the German cockroach (Blatella germanica L.) from (−)-(1R,4S)-menthone

An enantiospecific synthesis of (S)-(+)-3-methylheneicosan-2-one, an analog of the sex pheromone of the German cockroach (Blatella germanica L.), was carried out through selective transformations of (3R,6S)-3,7-dimethyloctane-6-olide obtained from (−)-menthonevia the Baeyer—Villiger reaction. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1071–1073, May, 1997.     

Crystal Structures of 5-Nitro- and 5-Ethoxycarbonyl-Substituted 6-Phenyl-4-(3-fluorophenyl)-3,4-dihydro-(1H)-pyrimidin-2-ones

The crystal structures of 5-nitro- and 5-ethoxycarbonyl-substituted 6-phenyl-4-(3-fluorophenyl)-3,4-dihydro-(1H)-pyrimidin-2-ones were determined by X-ray diffraction analysis. Conformational peculiarities of the structures have been revealed and compared with data for other biologically active dihydropyrimidinones.     

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     

The complete closed coexistence curves for 2H,3H,6H,7H,8H-5,8-(Dimethylmethano)-5(R)-methylquinoxaline with water and with deuterium oxide

The complete closed solubility curves for 2H, 3H, 6H, 7H, 8H-5,8-(dimethylmethano)-5(R)-methylquinoxaline with water and with deuterium oxide have been determined. With water the lower critical solution temperature (LCST) was found to be 51.4°C and the critical solution temperature (CST) was found to be 215.0°C. With deuterium oxide the values were 40.4°C for the LSCT and 221.7°C for the CST. The deuterium oxide curve completely encompassed the water curve. Solution compositions at the critical temperatures were also determined.     

Syntheses based on 2-ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one

2-Ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one containing the active methylene group reacts easily with carbon disulfide and phenyl isothiocyanate in the presence of sodium hydride. Further alkylation of the reaction product by alkyl halides results in the formation of the corresponding 1,3,4-thiadiazolo[3,2-a]pyrimidine derivatives containing a ketene dithioacetal fragment. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2371–2373, November, 1998.     

Reactions of 5-[3-(trifluoromethyl)-phenyl]furan-2-carbaldehyde

The Knoevenagel condensations of 5-[3-(trifluoromethyl)phenyl]furan-2-carbaldehyde with seven compounds containing an active methyl or methylene group have been studied. The compounds used were: methyl 2-cyanoacetate, malononitrile, 2-furylacetonitrile, acetophenone, 2-thioxo-1,3-thiazolidin-4-one (rhodanine), 5,5-dimethylcyclohexane-1,3-dione (dimedone), and methyl 2-azidoacetate. The effect of microwave irradiation on the condensation reactions was studied and compared with “’classical”’ conditions. Thermolysis of methyl 2-azido-3-{5-[3-(trifluoromethyl)phenyl]-2-furyl}propenoate afforded methyl 2-[3-(trifluoromethyl)phenyl)]-4H-furo[3,2-b]pyrrole-5-carboxylate. (2E)-3-{ 5-[3-(Trifluoromethyl)phenyl]-2-furyl}propenoic acid was converted to the corresponding azide, which was cyclized on heating into 2-[3-(trifluoromethyl)phenyl)]-4,5-dihydrofuro[3,2-c]pyridin-4-one. The latter after successive action of POCl₃ and NH₂NH₂-Pd/C gave 2-[3-(trifluoromethyl)-phenyl]furo[3,2-c]pyridine. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–831, June, 2006.     

Regioselective synthesis of cytotoxic 4-(1-alkynyl)-substituted 2-(5H)-furanones

4-(1-Alkynyl)-3-bromo- and 4-(1-alkynyl)-3-chloro-2(5H)-furanones have been regioselectively synthesized in moderate to good yields by a new version of the Pd/Cu-catalyzed Sonogashira reaction involving treatment of 1-alkynes with 3,4-dibromo- and 3,4-dichloro-2(5H)-furanone, respectively, in the presence of KF as a base. 4-(1-Alkynyl)-3-bromo-2(5H)-furanones have been found to be able to undergo Stille-type and Suzuki-type reactions with aryl(tributyl)tins and arylboronic acids, respectively, to give 4-(1-alkynyl)-3-aryl-2(5H)-furanones in modest to satisfactory yields. Some 4-(1-alkynyl)-substituted 2(5H)-furanones so prepared have been found to exhibit significant cytotoxic activities, especially against human leukemia cell lines.     

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.

     

Novel synthesis of (4<Emphasis Type="Italic">R</Emphasis>)-4-methylpentanolide from (L)-(−)-menthol

A novel synthesis of the promising optically pure chiral (4R)-4-methylpentanolide that is based on several regiospecific oxidative transformations of (4R)-2,4-dimethyl-1-(1-methylethyl)-1-cyclohexene, the product of addition of (–)-menthone and methylmagnesium iodide followed by acid dehydration, was proposed.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 451–453, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Biosynthesis of (R)-3-hydroxyalkanoic acids by metabolically engineered Escherichia coli

An efficient system for the production of (R)-hydroxyalkanoicacids (RHAs) was developed in natural polyhydroxyalkanoate (PHA)-producing bacteria and recombinant Escherichia coli. Acidic alcoholysis of purified PHA and in vivo depolymerization of PHA accumulated in the cells allowed the production of RHAs. In recombinant E. coli, RHA production was achieved by removing CoA from (R)-3-hydroxyacyl-CoA and by in vivo depolymerization of PHA. When the recombinant E. coli harboring the Ralstonia eutropha PHA biosynthesis genes and the depolymerase gene was cultured in a complex or a chemically defined medium containing glucose, (R)-3-hydroxybutyric acid (R3HB) was produced as monomers and dimers. R3HB dimers could be efficiently converted to monomers by mild alkaline heat treatment. A stable recombinant E. coli strain in which the R. eutropha PHA biosynthesis genes were integrated into the chromosome disrupting the pta gene was constructed and examined for the production of R3HB. When the R. eutropha intracellular depolymerase gene was expressed by using a stable plasmid containing the hok/sok locus of plasmid R1, R3HB could be efficiently produced.     

Thioureas from 3-aminoquinazolin-4(3H)-one. 2. Unusual alkaline recyclization of 3-(N",N",S-trialkylisothioureido)quinazolin-4(3H)-ones into new 1,3,4-oxadiazoles

3-(N",N",S-trialkylisothioureido)quinazolin-4(3H)-ones obtained by the reactions of 3-(N",N"-dialkylthioureido)quinazolin-4(3H)-ones with alkyl halides undergo unusual recyclization into 5-(2-aminophenyl)-2-dialkylamino-1,3,4-oxadiazoles under the action of aqueous solutions of alkali, hydrazine, and primary aliphatic amines. A plausible mechanism of the recyclization was proposed.     

4-Phosphoranylidene-5(4H)-oxazolones — A novel synthesis and properties

Summary 4-Phosphoranylidene-5(4H)-oxazolones (2), a hardly known class of phosphorus ylides, were readily prepared from 4-unsubstituted-5-(4H)-oxazolones (1) by treatment with Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄, or Ph₃P-CBr₄ adducts in the presence of triethylamine in CH₂Cl₂ at room temperature in a novel, efficient one-pot procedure. The spectroscopic properties of the ylides are reported and discussed.

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4-Phosphoranyliden-5(4H)-oxazolone — Eine neue Synthese und Eigenschaften

Zusammenfassung 4-Phosphoranyliden-5(4H)-oxazolone, eine sehr wenig bekannte Gruppe der Phosphor-ylide, wurden auf einfache Weise nach einem neuen Eintopfverfahren mit guten Ausbeuten hergestellt. Als Ausgangsverbindungen wurden 4-unsubtituierte-5-(4H)-Oxazolone (1) eingesetzt, die unter der Einwirkung von Addukten wie Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄ oder Ph₃P-CBr₄ in Anwesenheit von Triethylamin in CH₂Cl₂ bei Zimmertemperatur die Titelverbindungen liefern. Die spektroskopischen Eigenschaften der Ylide werden berichtet und diskutiert.