Epimeric sulfoxides derived from 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one

Russian Journal of Organic Chemistry - Epimeric mono- and bis-sulfoxides synthesized by oxidation of 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one were separated by silica...     

Condensation of acetylacetone with formaldehyde and thiols

Acetylacetone reacted with formaldehyde and thiols in aqueous medium or in the presence of 0.1 equiv of sodium hydroxide to give the corresponding 3-[(alkylsulfanyl)methyl]pentane-2,4-diones which exist in solution as mixtures of diketone and enol tautomers. Four-component condensation of acetylacetone with formaldehyde, methanethiol, and sodium sulfide, depending on the reaction time, led to the formation of a mixture of 1,1-bis(methylsulfanylmethyl)propan-2-one with 1,1′-{3-[(methylsulfanyl)methyl]tetrahydro-2H-thiopyran-3,5-diyl}diethanone or with 8-methyl-5-(methylsulfanylmethyl)-3-thiabicyclo[3.3.1]non-7-en-6-one.     

Synthesis of thiamono- and thiabicyclanes from sodium sulfide and methanethiolate

1-[5-Acetyl-3-(methylthiomethyl)tetrahydro-3-thiopyranyl]-1-ethanone was obtained by the interaction of sodium sulfide and sodium methanethiolate with formaldehyde and acetone. The intramolecular crotonate condensation of the product leads to 4-methyl-1-methylthiomethyl-7-thiabicyclo[3.3.1]non-3-en-2-one. The participation of 3-methylthiomethyl-3-buten-2-one in the formation of a thiamono-cyclane is clarified. A probable scheme for the conversions is proposed.     

Synthesis and Structure of Derivatives of 9-(2-Oxopropyl)-1,5-dinitro-7,8-benzo-3-azabicylo[3.3.1]non-7-en-6-ones

A number of 3-R-9-(2-oxopropyl)-1,5-dinitro-7,8-benzo-3-azsbicyclo[3.3.1]non-7-en-6-ones was synthesized by Mannich reaction involving Yanovsky adduct of 2,4-dinitronaphthol. It was established by molecular spectroscopy and X-ray diffraction analysis that the piperidine ring in these compounds was in the chairconformation with a diequatorial position of the substituent attached to the heteroatom and 2-oxo-propyl group, and the cyclohexenone fragment was in sofaform. By an example of 3-methyl-9-(2-oxopropyl)-1,5-dinitro-7,8-benzo-3-azsbicyclo[3.3.1]non-7-en-6-one the dissociative ionization of bicyclononanes under the electron impact was investigated.     

3-Azabicyclo[3.3.1]nonane Derivatives: III. Synthesis of 3-Substituted 9-Acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]-non-6-en-8-ones by Mannich Condensation of the Janovsky σ-Adduct of 2,4-Dinitrophenol with Acetonide Ion

A number of 9-acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-8-one derivatives were synthesized by Mannich condensation of 3-acetonyl-2,4-bis(aci-nitro)cyclohex-5-en-1-one disodium salt with formaldehyde and primary amines.     

A Chemical Study of Burley Tobacco Flavour (Nicotiana tabacum L.) VII. Identification and synthesis of twelve irregular terpenoids,related to solanone,including 7,8-dioxabicyclo[3.2.1]octane and 4,9-dioxabicyclo[3.3.1]nonane derivatives

Twelve novel constituents isolated from Burley tobacco condensate by semi-preparative GLC. have been identified as (E)-3,4-epoxy-5-isopropyl-nonane-2,8-dione ( A ), exo-(1-methyl-4-isopropyl-7,8-dioxabicyclo[3.2.1]oct-6-yl)methyl ketone ( B ), exo-1-(1-methyl-4-isopropyl-7,8-dioxabicyclo[3.2.1]oct-6-yl)-ethanol ( C ), (E)-5-isopropyl-8-hydroxy-8-methyl-non-6-en-2-one ( D ), (E)-5-isopropyl-6,7-epoxy-8-hydroxy-8-methyl-nonan-2-one ( E ), endo-2-(1-methyl-4-isopropyl-7,8-dioxabicyclo[3.2.1]oct-6-yl)-propan-2-ol ( F ), 3,3,5-trimethyl-8-isopropyl-4,9-dioxabicyclo[3.3.1]nonan-2-ol ( G ), (E)-5-isopropyl-non-3-ene-2,8-diol ( H ), 5-isopropyl-nonane-2,8-diol ( I ), (E)-5-isopropyl-8-hydroxy-non-6-en-2-one ( J ), 5-isopropyl-8-hydroxy-nonan-2-one ( K ), and (E)-3-isopropyl-6-methyl-hepta-4,6-dien-1-ol ( L ). Compounds A–K were synthesized from norsolanadione ( 2 ), and compound L from 2-isopropyl-5-oxo-hexanal ( 15 ). The relative configuration of the bicyclic internal acetals B, C, F, G and their δ-keto-epoxide precursors A and E is discussed. All these Burley tobacco flavour components belong to a growing family of metabolites structurally related to solanone ( 1 ). They are believed to arise from the breakdown of cembrene-type precursors.     

Aminomethylation by Formaldehyde and Primary Amines of Anionic σσ-Adduct Obtained from 2,4-Dinitrophenol and Acetophenone Carbanion

By condensation of 2,4-bis(aci-nitro)-3-(2-phenyl-2-oxoethyl)cyclohex-5-en-1-one with formaldehyde and primary amines a series of N-substituted 9-(2-phenyl-2-oxoethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-7-en-6-ones was synthesized. With the use of X-ray analysis the cyclohexenone fragment in the 3-(2-bromoethyl)-1,5-dinitro-9-(2-phenyl-2-oxoethyl)-3-azabicyclo[3.3.1]non-7-en-6-ones was established to exist in sofa conformation, and the nitrogen-containing ring to have the chair conformation with equatorial orientation of substituents in 3 and 9 positions. The regio- and stereoselectivity of the reaction under study was interpreted relying on the quantum-chemical calculations by AM1 and PM3 procedures.     

Isoswerosid,ein neues Secoiridoidglycosid aus den Wurzeln des Zwergholunders Sambucus ebulus L. (Caprifoliaceae). 2. Mitteilung über die Inhaltsstoffe der Zwergholunderwurzel

Isosweroside, a New Secoiridoid Glycoside from the Roots of Sambucus ebulus L. (Caprifoliaceae) The paper describes the isolation and structure elucidation of isosweroside (6-(β-D - glucopyranosyloxy)-methyl-9-vinyl-2,8-dioxabicyclo[3.3.1]non-6-en-3-one), the first Valeriana-type secoiridoid glycoside from the roots of Sambucus ebulus L. along with the two known glycosides ebuloside and morroniside.     

3-Azabicyclo[3.3.1]nonane Derivatives: IV. Synthesis of Amino Acids with 3-Azabicyclo[3.3.1]nonane Fragment

A series of 1.5-dinitro-3-azabicyclo[3.3.1]non-6-enes was prepared by reduction of 1-R-2,4- and 1-R-3,5-dinitrobenzenes with potassium borohydride followed by Mannich reaction with formaldehyde and amino acids. The molecular structure of (6-bromo-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid was studied by X-ray diffraction analysis. The mechanism of decomposition under electron impact was determined for (7-methoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid.     

Skeletal rearrangements of <Emphasis Type="Italic">cis</Emphasis>-(-)-7,8-epoxycarveol derivatives promoted by triethylsilyl trifluoromethanesulfonate

Diastereoisomeric couples of (1R,5R,6RS)-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-en-6-ylmethanols and their epoxide precursors, (5R,2′RS)-2-methyl-5-(2-methyloxiran-2-yl)cyclohex-2-en-1-ols, in the presence of triethylsilyl trifluoromethanesulfonate underwent [3.2.1]→[3.3.1] skeletal rearrangement with formation of scalemic mixtures of (1R,5R,6R)- and (1R,5R,6S)-2,6-dimethyl-6-triethylsiloxy-8-oxabicyclo[3.3.1]non-2-enes; the (6R)-stereoisomer was isolated as individual substance.     

Proximity Effects in Acid and Base-Catalysed Ether Formation

When heated with sodium ethoxide in ethanol 7-methylidenebicyclo[3.3.1]nonan-3-endo-ol (endo- 1 ) is converted into 1-methyl-2-oxa-adamantane ( 3 ). This reaction involves nucleophilic addition of a hydroxy group to an unactivated olefinic bond. Formation of the cyclic ether 3 also takes place when endo- 1 is heated in aqueous ethanol. This electrophilic addition is strongly catalysed by weak acids and suppressed by weak bases. These unusual reactions proceed more slowly with 7-methylbicyclo[3.3.1]non-6-en-3-endo-ol (endo- 2 ) and can be ascribed to a proximity effect. This follows from the IR . and NMR . spectra of endo- 1 and endo- 2 which show strong intramolecular hydrogen (OH-π) bonding. The unsaturated endo- and exo-alcohols 1 and 2 , respectively, undergo only exo-complexation with silver ion.     

The Homoconjugated Electron-Releasing Carbonyl Group of 1-Methylbicyclo[2.2.1]hept-5-en-2-one. Regioselective syntheses of 5-chloro- and 6-chloro-1-methylbicyclo[2.2.1]hept-5-en-2-one

Syntheses of (±)-2-exo-cyano-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl acetate ( 1 ) and of (±)-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 2 ) are reported. The additon of PhSeCl to 1 afforded (±)-5-endo-chloro-2-exo-cyano-1-methyl-6-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1]hept-2-endo-yl acetate ( 6 ), whereas 2 added to PhSeCl with the opposite regioselectivity giving (±)-6-endo-chloro-1-methyl-5-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1]heptan-2-one ( 7 ). These adducts were converted into 5-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 9 ) and 6-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 10 ), respectively.     

Intramolecular cyclization of cycloalkene carboxylic acid chlorides

Thermal cyclization of cyclooctene-4-yl-carboxylic acid chloride (5) and cycloheptene-4-yl-carboxylic acid chloride (10) yielded mixtures of mainly endo and exo 2-chlorobicyclo[3.3.1]nonane-9-one (7 and 8), and mixtures of endo and exo 2-chlorobicyclo[3.2.1]octane-8-one (12 and 13), respectively. AlCl₃-catalyzed cyclization of 10 gave the same product composition as the uncatalyzed reaction. In the AlCl₃-catalyzed cyclization of 5 considerable amounts of bicyclo[3.3.1]non-2-en-9-one (6) and exo 3-chlorobicyclo[3.3.1]nonane-9-one (9) were obtained in addition to 7 and 8.     

The preparation and reactions of 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-enyl ether: Formation of 1,3,4,5,6,7,8-heptafluoro-1-(prop-2-enyl)naphthalen-2-one and the photolysis and pyrolysis of this ketone [1].

1,3,4,5,6,7,8-Heptafluoro-2-naphthyl prop-2-enyl ether (8) was isomerised in boiling xylene to 1,3,4,5,6,7,8-heptafluoro- 1-(prop-2-enyl)naphthalen-2-one (9). Photolysis of (9) gave 2,5,7-trifluoro-3,4-(tetrafluorobenzo)tricyclo[3.3.1.O^2,7]non-3- en-6-one (11) (by a [2 + 2] addition) and 1,2,7-trifluoro-3,4- (tetrafluorobenzo) tricyclo [3.3.1.O^2,7]non-3-en-8-one (12) (via an initial [3,5] photochemically-allowed sigmatropic shift). Pyrolysis of (9) at 455° also gave (11), while at 490°, both (9) and (11) gave 1-fluorovinyl 4,5,6,7,8-pentafluoro-1-naphthyl ketone (19).     

Stereoselective 1,3-Dipolar Cycloadditions to (S)-1-Benzoyl-3-(cyanomethylidene)-5-(methoxycarbonyl)pyrrolidin-2-one

(5S)-1-Benzoyl-3-[(E)-cyanomethylidene]-5-(methoxycarbonyl)pyrrolidin-2-one ( 5 ) was prepared in four steps from L -pyroglutamic acid ( 1 ). 1,3-Dipolar cycloadditions of diazomethane ( 6 ) and 2,4,6-trimethoxybenzonitrile oxide ( 7 ) gave substituted 1,2,7-triazaspiro[4.4]non-1-en-6-one 12 and 1-oxa-2,7-diazaspiro[4,4]non-1-en-6-one 13 in 38 and 20% de, respectively. On the other hand, reaction of 5 with N-phenylbenzonitrile imines 8 and 9 , generated in situ from the corresponding hydrazonoyl chlorides 10 and 11 , respectively, and Et₃N, furnished racemic pyrrolo[3,4-c]pyrazoles 14 and 15 in 61 and 56% de, respectively. Cycloaddition of nitrile oxide 7 , when performed in the presence of Et₃N, led to pyrrolo[3,4-d]isoxazole 16 in 85% de.     

Reduction studies on benzaza[3.3.3]propellanc derivatives

Sodium borohydride reduction of 3-methyl-2,3-dioxo-7,8-benzo-3-aza[3.3.3]propellan-6-one (1b) gave 2,4-dioxo-3-methyl-7,8-benzo-3-aza[3.3.3]propellan-6-ol, while lithium aluminum hydride reduction gave 3-methyl-7,8-benzo-3-aza[3.3.3]propellan-6-ol, which on oxidation, gave the corresponding ketone. This ketone formed the corresponding thioketal upon reaction with 1,2-ethanedithiol. Raney nickel desulfurization of the thioketal provided 3-methyl-6,7-benzo-3-aza[3.3.3]propellane. The same compound was also obtained in poor yield by forming the thioketal of Ib followed by lithium aluminum hydride reduction and Raney nickel desulfurization of the product. Desulfurization of the thioketal of Ib gave 2,4-dioxo-6,7-Benzo-3-aza[3.3.3]propellane.     

Synthesis,structure, and transformations of 1-aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one

1-Aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one was obtained by reduction of 3,4-dimethoxycarbonyltetrahydro-1,4-thiazine. The reduction of this product with lithium aluminum hydride led to 3-hydroxymethyl-4-methyltetrahydro-1,4-thiazine. The molecular and crystal structures of 1-aza-3-oxa-7-thiabicyclo[3.4.0]nonan-2-one were investigated by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1280–1285, September, 1986.     

Synthesis of N-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicyclo[3.3.1]non-7-en-6-ones

Aminomethylation has been accomplished of the anionic Yanovskii adduct of 2,4-dinitronaphthol and 3,4-dimethylenedioxyacetophenone. The structure of the 3-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicylo[3.3.1]non-7-en-6-one was determined by two-dimensional homo-and heteronuclear correlation spectroscopy. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1382–1389, September 2007.     

Heterotricyclodecane XI,Sulfoxide und Sulfone von 2-Oxa-7-thia-isotwistan und 2-Oxa-7-thia-twistan sowie Derivaten

The synthesis of sulfoxides and sulfones of 2-oxa-7-thia-isotwistane ( 24 ) and 2-oxa-7-thia-twistane ( 35 ) as well as of several of their derivatives is described. endo-2-Hydroxy-9-thiabicyclo[3.3.1]non-6-ene ( 5 ) was used as starting material. During the course of the reactions special attention was given to intramolecular hydroxy-mercuration and jododemercuration reactions, spectroscopic features, molecular rearrangements and stereospecificity of oxidations of sulfides to sulfoxides.     

Synthesis of key intermediates for a concise and convergent approach to the marine natural product eleutherobin

Synthesis of 1,6-syn-5,6-anti-2-methyl-5-isopropyl-bicyclo[4.3.0]-non-2-en-8-one in three steps from (rac)-phellandrene; and 1,6-syn-1-methyl-6-methoxy-3-aza-9-oxabicyclo[4.2.1]-non-7-en-4-one in five steps from 2-methoxy-5-methylfuran and tetrabromoacetone, provided these key intermediates for the construction of the skeleton of eleutherobin.