Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. V . Reaktionen β,γ-ungesättigter Carbamidsäureester mit Sulfenylchloriden - Synthese von 3,5,5-trisubstituierten Oxazolidin-2-onen

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. V. Reactions of β,γ-Unsaturated Carbamic Acid Esters with Sulfenyl Chlorides — Synthesis of 3,5,5-Trisubstituted Oxazolidine-2-ones N,N-Disubstituted β,γ-Unsaturated urethanes 1 have been cyclized to 3,5,5-trisubstituted oxazolidine-2-ones 3 by aromatic sulfenyl chlorides in methylene chloride. The same oxazolidine-2-ones 3 were obtained by reaction of 5-bromomethyloxazolidine-2-ones 8 with thiophenols.     

Cyclisierungsreaktionen β, γ-ungesättigter Kohlensäurederivate. IV [1]. Synthese von N-substituierten Thiazolidin-2-onen und 2-Alkoxy-2-thiazolinen aus β,γ-ungesättigten Thiocarbamidsäureestern

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. IV. Synthesis of N-Substituted Thiazolidine-2-ones and 2-Alkoxy-2-thiazolines from β,γ-Unsaturated Thiocarbamic Acid Esters The reaction between N-substituted β,γ-unsaturated thiourethans and dry hydrogen chloride or bromine occurs in methylene chloride at room temperature. The thiourethans 1 a–4 a react with hydrogen chloride to give mixtures of corresponding 2-alkoxy-2-thiazolines 6–9 and the thiazolidine-2-one 11 a . A useful synthetic route to N-substituted thiazolidine-2-ones 11 is demonstrated by the reaction of N,N-disubstituted β,γ-unsaturated thiourethans with hydrogen chloride and bromine. The i.r. and H-n.m.r.-data of the compounds are described.     

Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. IX. Regiochemie der elektrophilen Cyclofunktionalisierung β,γ-ungesättigter Carbamidsäureester mit Brom – Synthese von Oxazolidin-2-onen und Tetrahydro-2H-1,3-oxazin-2-onen

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. IX. Regiochemistry of Electrophilic Cyclofunctionalization of β,γ-Unsaturated Carbamic Acid Esters with Bromine – Synthesis of Oxazolidine-2-ones and Tetrahydro-2H-1,3-oxazine-2-ones N,N-Disubstituted β,γ-unsaturated urethanes ( 1 ) and bromine react in methylene chloride at room temperature. The crotyl urethanes ( 1a – 1c and 1e ) and bromine give mixtures of corresponding saturated urethanes (dibromine adducts) ( 2a – 2c and 2e ), the oxazolidine-2-ones ( 3a – 3c and 3e ), and the tetrahydro-2H-1,3-oxazine-2-ones ( 4a – 4c and 4e ). The reaction of γ,γ-dimethylallyl urethanes ( 1f – 1h ) with bromine gives similar results. A useful synthetic route to N-substituted tetrahydro-2H-1,3-oxazine-2-ones ( 4l – 4q ) is demonstrated by the reaction of cinnamyl urethanes ( 1l – 1q ) with bromine.     

Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. XI [1] Untersuchungen zur Stereochemie der Cyclofunktionalisierung β,γ-ungesättigter Carbamidsäureester

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. XI. Investigation of Stereochemistry of the Cyclofunctionalization of β,γ-Unsaturated Carbamic Acid Esters N, N-Disubstituted β,γ-unsaturated urethanes 1 have been cyclized to 3,5-disubstituted oxazolidine-2-ones 3 by aromatic sulfenyl chlorides 2 . The stereochemistry of the products and the cyclofunctionalization reaction were investigated.     

Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. VII. Synthese eindeutig N-acylierter Thiazolidin-2-one und Oxazolidin-2-one

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. VII. Synthesis of Unequivocal N-Acylated Thiazolidine-2-ones and Oxazolidine-2-ones A new synthetic route to N-acylated thiazolidine-2-ones and oxazolidine-2-ones is reported: The reaction of carboxylic acid chlorides with 2-alkoxy-2-thiazolines ( 1, 2 ) or -2-oxazolines ( 3 ) yields unequivocal N-acylated thiazolidine-2-ones ( 4–6 ) or oxazolidine-2-ones ( 7 ). Bifunctional acid chlorides, e.g. oxalyl chloride or thiophosgene yield compounds 11 and 12 .     

Partialsynthesen von Cardenoliden und Cardenolid-Analogen. I. α,β- und β,γ-ungesättigte Lactonring-methylierte Cardenolide

Partial Syntheses of Cardenolides and Cardenolide Analogues. I. α,β- and β,γ-Unsaturated Lactone Ring-Methylated Cardenolides Base-catalyzed methylation of digitoxigenin 1a with methyl iodide and sodium hydride in DMF leads to the α,β-unsaturated cardenolides 2–5 and, after rearrangement of the CC-double bond, to the β,γ-unsaturated cardenolides 6 and 7 . Opening of the lactone ring results in the formation of 8 . Allylic oxidation of 4b affords the 14,21-epoxide 10 . Only the 22-methyl derivative 4a and its 3-O-tridigitoxoside 4d show strong biological effectivity, whereas methylation at 21R- or 21S-position results in considerable loss in activity.     

Die UV-Spektren α,β-ungesättigter Ester und ihre Beeinflussung durch Lösungsmittel und Komplexbildung

UV Spectra of α,β-Unsaturated Esters and the Influence of Solvents and Complex Formation Positions and intensities of partially overlapped π-π* and n-π* transitions in spectra of methyl and ethyl esters of acrylic, methacrylic and crotonic acid are discussed. Reproducible values were determined by graphical and mathematical band-separations. n-π* bands in gaseous methyl acrylate show vibrationally fine structures. These are compared with fine structures in the spectra of α-methylene-γ-butyrolactone and α, β-dehydrobutyrolactone. In solutions with C_ester lt; 0,1 m self-associations are negligible. The transition-displacements Δv _max due to solvent effects closely correlate with the solvent parameters of KOSOWER . These correlations allow to calculate λ_max-values at which solvents absorb strongly. Equilibrium constants K of EDA-complexes with TCNE and chloranile were determined. With a competition method K was found in the range of 0.9 to 10.3 l · mol⁻¹.     

Furylvinylhalogenide. X [1]. Reaktionen von β-Fur-2-yl-β-chlor-α-cyanacrylsäurederivaten mit Hydrazinen

Furylvinylhalides. X. Reactions of β-Fur-2-yl-β-chloro-α-cyanoacrylic Acid Derivatives with Hydrazines β-Fur-2-yl-β-chloro-α-cyanoacrylic acid derivatives 3 react with hydrazines yielding 3-fur-2-yl-5-aminopyrazoles 5 or 3-fur-2-yl-4-cyanpyrazolin-5-ones 6 . In some cases the β-hydrazino-α-cyanoacrylic acid derivatives 4 , could be isolated.     

2-Arylamino-thiophen-3-carbonsäurederivate

2-Arylamino-thiophene-3-carboxylic Acid Derivatives The title compounds 3 are synthesized by reaction of 2-amino-thiophene-3-carboxylic acid derivatives 1 with anilines. The nucleophilic 5-position in 3 allowed the synthesis of 5-aryliden-Δ³-thiolen-2-one-imines 5 , 6 and the oxidative coupling to yield the azo compound 7 . 1-Aryl-thieno-[2,3-d]pyrimid-4-ones 9 , the thieno[2,3-b]chinolin-4-one 10 and the 4-chloro thieno[2,3-b]chinolines 10 , 11 can be obtained from 3 .     

Trans- α, β-ungesättigte Fettsäuren und deren Reduktionsprodukte mit Lithium-Aluminium-Hydrid und Diisobutyl-Aluminium-Hydrid

Trans-α,β-Unsaturated Fatty Acids and Products formed by their Reduction with Lithium-Aluminium-Hydride and Di-isobutyl-Aluminium-Hydride A method for the preparation of pure methyl esters of α,β-unsaturated fatty acids is described. The reduction of these esters with LiAlH₄ led to poor yields of α,β-unsaturated alcohols. Saturated alkanols and aldehydes were mainly formed. Di-isobutyl aluminium hydride gave near quantitative yields of α,β-unsaturated alcohols. The reaction was studied with the help of gas chromatography using strongly polar stationary phases.     

α-Substituierte Phosphonate. 37. α-Pyrrolomethanphosphonsäurederivate und N-Vinylpyrrole

α-Substituted Phosphonates. 37. Derivatives of α-Pyrrolomethanephosphonic Acid and N-Vinylpyrroles Diethyl α-aminomethanephosphonate 5a and its α-aryl derivatives 5b–d react with 2,5-diethoxytetrahydrofuran 1 to give diethyl α-pyrrolomethanephosphonate 9a and the α-aryl derivatives 9b–d , respectively. The pyrrolo derivatives 9 can be converted into the lithium salts 15 and 16 , respectively, which with carbonyl compounds undergo the HORNER reaction yielding E/Z-mixtures of N-vinylpyrroles 18 . In certain cases the intermediate of the HORNER reaction, the β-hydroxyphosphonate 17 , can be isolated. The pyrrolo-analogue of stilbene, 18a , is formed only as E-isomer. On treating the lithium salts 15 and 16 with 9 or with alkyl halides α-C-alkylated pyrrolo-phosphonates 22 and 23 , respectively, are obtained.     

Furylvinylhalogenide. IX. Reaktionen von β-Fur-2-yl-β-chlor-α-cyanacrylsäureestern mit Aminen

Furylvinylhalides. IX. Reactions of β-fur-2-yl-β-chloro-α-cyanoacrylates with amines β-Fur-2-yl-β-chloro-α-cyanoacrylates 4 react with amines to yield β-Fur-2-yl-β-amino-α-cyanoacrylates 5 . The ¹H-n.m.r. spectra of 5 are discussed.     

β-Fur-2-yl-α-halogenacrylonitrile. IV. Reaktionen von β-Fur-2-yl-α-halogenacrylonitrilen mit Alkoholen und Phenolen

β-Fur-2-yl-α-halogenacrylonitriles. IV. Reactions of β-Fur-2-yl-α-halogenacrylonitriles with Alcohols and Phenols β-Fur-2-yl-α-halogenacrylonitriles 1a – c react with alcohols and phenols to yield β-fur-2-yl-β-alkoxyacrylonitriles and β-fur-2-yl-β-aroxyacrylonitriles 2a – k respectively. With ethylene glycol α-[2-(fur-2-yl)-1, 3-dioxolan-2-yl]acetonitriles 3a, b are formed.     

Iron‐Catalyzed Regio‐ and Stereoselective Conjugate Addition of Aryl‐Grignard Reagents to α,β,γ,δ‐Unsaturated Sulfones and its Synthetic Application

The iron‐catalyzed δ‐addition of aryl‐Grignard reagents to α,β,γ,δ‐unsaturated sulfones proceeded in a regio‐ and stereoselective manner to give cis‐4‐aryl‐2‐alkenyl sulfones. Allylic alkylation of the resultant products was performed without isomerization of the cis‐olefin to give cis‐4‐aryl‐1,1‐dialkyl‐2‐alkenyl sulfones, which upon intramolecular Friedel–Crafts reaction with aluminum chloride gave 1,4‐dihydronaphthalenes having a quaternary carbon center.     

HPLC-Trennung mono-ungesättigter Triglyceride hinsichtlich der α- oder β-Position der Ölsäure in einigen vegetabilischen Fetten

HPLC-Separation of Mono-Unsaturated Triglycerides with Respect to α- or β-Position of Oleic Acid in Some Vegetable Fats A method is described for the half-quantitative determination of the oleic acid distribution between α- and β-positions in the mono-unsaturated triglycerides. The method requires only about 60 μg sample (1–3 fractionations by HPLC), while the classical lipase hydrolysis requires about 10 mg. The procedure is therefore suitable for further examination of the fractions from chromatographic separations. The method is based on the increased polarity of the unsaturated triglycerides after halogen-addition to the double bonds. The effect of this addition is stronger at the mono-unsaturated isomer containing the oleic acid in the β-position. Therefore this isomer eluates earlier than the other possible isomer. Results of the examination of the method and measurements of some vegetable oil mono-unsaturated fractions are described.     

β-Fur-2-yl-α-halogenacrylonitrile. VII. Reaktionen von β-(5-Brom-fur-2-yl)-α-bromacrylonitril mit Mercaptan,Thioharnstoff und Thioharnstoffderivaten

β-Fur-2-yl-α-halogenacrylonitriles. VII. Reactions of β-(5-Bromo-fur-2-yl)-α-bromoacrylonitriles with Mercaptans, Thiourea and Thiourea Derivatives β-(5-Bromo-fur-2-yl)-α-bromoacrylonitrile 1 reacts with ethylmercaptan to yield β-(5-bromo-fur-2-yl) β-ethylthioacrylonitrile 3 . With thiourea β,β′-thio-bis[β-(5-bromo-fur-2-yl)]-acrylonitrile 2 is formed. The pyrimidines 4 and 5 have been prepared by the reaction of 1 with s-methylthiourea and 2-aminothiazole, respectively. The structure of the new compounds were determined by means of x-ray analysis, ¹H-n.m.r., ¹³C-n.m.r. and mass-spectroscopy.     

An efficient Synthesis of Acetylenic γ- and δ-Hydroxy Ketones, γ- and δ-keto acids,and γ- diketones via addition of 1-alkinyllithium compounds to γ- and δ-lactones

2-Hydroxy-6-alkyn-5-ones 3 , 1-hydroxy-5-alkyn-4-ones 4 , and 1-hydroxy-6-alkyn-5-ones 5 are conveniently obtained in excellent yields through a highly selective monoaddition of an 1-alkynyllithium compound 2 to γ-valerolactone (1a) , γ-butyrolactone (1b) or δ-valerolactone (1c) . They are oxidized by pyridinium dichromate or Jones reagent to the corresponding acetylenic 1,4-diketones 6 , 4-oxo carboxylic acids 7 , and 5-oxo carboxylic acids 8 , respectively.     

Synthesen von β-Fur-2-yl-α-halogenacrylonitrilen

Syntheses of β-Fur-2-yl-α-halogenacrylonitriles Syntheses of β-fur-2-yl-α-halogenacrylonitriles 2a–f by Wittig-olefination of furfurales, Hunsdiecker-reaction of β-(5-nitro-fur-2-yl)-α-cyanoacrylic acid 3 , halogenation of β-fur-2-yl acrylonitriles and reaction of furfurales with β-azido-α-halogen-γ-methoxy-Δ^α,β-crotonolactones 9 are described.