Pyryliumverbindungen. 36. Substituierte Benzoesäureester aus 2,4,6-Triaryl-pyryliumsalzen und α-Ketocarbonsäureestern

Pyrylium Compounds. 36. Substituted Benzoic Acid Esters from 2,4,6-Triarylpyrylium Salts and α-Ketocarboxylic Acid Esters 2,4,6-Triarylpyrylium salts 1 react with α-ketocarboxylic acid esters 2 in the presence of two equivalents of an appropriate condensing agent (e.g. dialkylamine salts of weak acids, triethylamine/acetic acid, or sodium acetate) to give 2-aroyl-3,5-diarylbenzoic acid esters 3 . However, using only one equivalent of the condensing agent, the formation of 3,5-diarylbenzoic acid esters 5 predominates. Alkaline saponification of the new esters 3 and 5 yields the corresponding substituted benzoic acids 4 and 6 , respectively. – I.r., u.v., n.m.r. and mass spectroscopic data of the novel products 3 – 6 are reported.     

Funktionell substituierte zinnorganische Verbindungen. I. ω-Triäthylstannylalkylphosphon- und -phosphinsäureester

Functionally Substituted Organotin Compounds. I ω-Triethylstannylalkylphosphonic- and -phosphinic Esters ω-Triethylstannylalkylphosphonic- and -phosphinic esters 1 can be synthesized by radical addition of triethylstannane to alkenylphosphonic- and -phosphinic esters. Their reaction with bromine or hydrochloric acid causes a substitution of an ethyl group forming organotin halides 2 and 3 . On alkaline hydrolysis of stannylsubstituted phosphinic esters, the acids 4 were obtained which can be transformed into the cyclic organotin phosphinates 5 . Lithium aluminium hydride reduces ω-triethylstannylalkylphosphonic- and -phosphinic esters to ω-triethylstannyl-alkylphosphines 6 . The P-phenylsubstituted compounds 6 are oxidized by sulfur via the dithioacids 8 to 1-diethyl-3-phenyl-1,2,3-stannathiaphospholane- and -phosphorinane-P-sulfid 9 , respectively.     

α-Substituierte Phosphonate. 39. Methandiphosphonsäureester durch UV-induzierte Michaelis-Becker-Reaktion

α-Substituted Phosphonates. 39. Methane-diphosphonic Esters by U.V.-Induced Michaelis-Becker-Reaction Dibromomethane resp. chlorbromomethane reacts with sodium dialkyl phosphite in heptane-/liq.NH₃ or in liq. NH₃ by u.v. irradiation at low temperatures to give in good yields methane diphosphonic acid tetraalkylesters 1 . In the same manner with sodium diethyl thionophosphite the corresponding methane-bis-thiophosphonic acid tetraethylester 4 is obtained.     

Über die Lichtschutzwirkung oxalkylierter p-Amino-benzoesäureester

Light Protecting Action of Oxalkylated p-Amino-Benzoic Acid Esters The oxethylation or oxpropylation of esters of p-amino-benzoic acid in the presence of catalytic amounts of alkali leads to the formation of water soluble and oil soluble light protecting agents respectively, having the maximum absorption in the region of about 305 to 308 mμ. The absorptive behaviour of these substances, which have a very minute phase difference of only 8 mμ, lies very close to the mean erythema activity curve having the maximum of absorption at 297 mμ, as suggested by IBK. Oxethylated p-amino-benzoic acid esters are practically non-toxic and affable to skin.     

Cyansäureester. 25 [1]. Umsetzung von Mercapto-N-heterocyclen mit Arylcyanaten

Cyanic Acid Esters. 25 The Reaction of Mercapto-N-heterocycles with Aryl Cyanates Unsaturated N-heterocycles containing a cyclic thio urea structure and aryl cyanates (molar ratio 1:2), react to form azolo(1,2-d) (1,2,4)thiadiazoles. This reaction has a wide scope concerning starting materials and gives good yields. Under the same conditions 2-thione-benzthiazolin is transformed to the corresponding disulfide. 4,5-Bis-mercaptomethylene-o-xylene and aryl cyanates give 2,3-dithia-6, 7-dimethyl-tetraline.     

Über die Struktur cyclisierter Fettsäureester

The Structure of Cyclised Fatty Acid Esters It is proved that the cyclic fatty acids which are obtained from tung and linseed oils by alkali-treatment contain mainly two types of products. Approximately 30% of these consist of 1,2-disubstituted cyclohexadiens, whose one double bond of the ring is in the 1-position and the other one is conjugated to the former. Approximately 60% of the mixture is comprised of ω-(2-alkyliden-cyclohexenyl)-fatty acid esters. The double bond in the ring is predominantly in the 3-position. As a result of the rearrangement of double bonds before cyclisation, R′varies from C₂ to C₁₁ and R″ from C₀ to C₉.     

Cyansäureester, 27 [1]. Triazino-benzimidazole aus 2-Amino-benzimidazol-1-imidsäureestern und carbonylanalogen Verbindungen

Cyanic Acid Esters. 27. Triazino-benzimidazoles from 2-Amino-benzimidazole-1-imid-esters and Carbonyl Analogic Compounds The Cyclocondensation of 2-amino-benzimidazole-1-imid-esters with aldehydes, carbonic acid anhydrides and isocyanates has been investigated. With aldehydes in the presence of piperidine 4-aryloxy-1,2-dihydro-1,3,5-triazino[1,2-a]benzimidazoles 3 and with carbonic acid anhydrides 4-aryloxy-1,3,5-triazino[1,2-a]benzimidazoles 5 are formed. Isocyanates react with the imid esters to the corresponding 3-substituted ureas 8 which on heating undergo acyl migration of the carbamoyl group followed by cyclocondensation to 4-imino-2-oxo-1,2,3,4-tetrahydro-1,3,5-triazino[1,2-a]benzimidazoles 12 .     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern II Trimethylolpropantrifettsäureester

Mass Spectrometric Fragmentation of Neopentylpolyolesters, Part II: Fatty Acid Triesters of Trimethylolpropane The fragmentation of the homologous fatty acid triesters of trimethylolpropane (C₂ to C₁₄) upon electron impact was investigated. Main fragments arise by M–RCOO and M–RCOOH. Cyclic acetal structures for these ions are postulated. Subsequent fragmentation was elucidated by DADI-measurements and high resolution measurements. The influence of the length of the fatty acid chain upon the fragmentation is discussed. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions.     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern III Neopentylglycoldifettsäureester

Mass Spectrometric Fragmentation of Neopentylpolyolesters, Part III: Fatty Acid Diesters of Neopentylglycole The fragmentation of the homologous fatty acid diesters of neopentylglycole (C₂ to C₁₈) upon electron impact was investigated. Main fragments arise by M-RCOO and M-RCOOH. Cyclic acetal structures for these ions are postulated. Subsequent fragmentation was elucidated by DADI-measurements and high resolution measurements. The influence of the length of the fatty acid chain upon the fragmentation is discussed. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions.     

Dithiocarbonsäuren,Dithiocarbonsäureester oder Thiocarbonsäureamide aus methylenaktiven Chlormethylverbindungen und Schwefel

Dithiocarboxylic Acids, Dithiocarboxylic Esters, or Thiocarboxylic Amides by Reaction of Methylene-active Chloromethyl Compounds with Sulfur With a mixture of sulfur and amine in DMF at room temperature halomethyl compounds ( 1 , 5 – 10 ) can be oxidized to give thiocarboxylic acids ( 2 , 11 – 16 ) and their derivatives ( 3 , 4 , 17 – 35 ). We studied this reaction in detail especially with chloroacetic derivatives ( 11 – 15 ) or chloromethyl heterocycles ( 16 ) formally derived from chloroacetic acid. The resulting thiooxalic acid derivatives ( 11 – 27 ) represent activated acids and very useful C₂-synthons, especially for the synthesis of heterocycles. Oxidation in the presence of triethyl amine leads to dithiocarboxylates ( 11 – 16 ) which can be alkylated to dithioesters ( 17 – 27 ) in high yields. As a rule, with different primary and secondary amines instead of tertiary amines these dithiocarboxylates or dithiocarboxylic esters can be transformed already at low temperatures to thioamides ( 28 – 35 ).     

Beitrag zur analytischen Erfassung der Cholesterylfettsäureester in biologischem Material

Contribution to Analytical Determination of Cholesterol Fatty Acid Esters in Biological Material A method for analysis of cholesterol esters in biological material is described. The methodology is devided into sample preparation, lipid extraction with methylene chloride/methanol, subsequent isolation of the cholesterol ester fraction with column chromatography on water containing silica gel and the determination with nonaqueous reverse phase h.p.l.c. Each step of the procedure is discussed in detail. Finally we report about application of the method to biological samples.     

Cyansäureester. 35. Über Bildung und Folgereaktionen von N-Cyanatophthalimid. Neue spezifisch aktivierte und blockierte Isatosäurederivate

Cyanic Acid Esters. 35. On Formation and Consecutive Reactions of N-Cyanato Phthalimide. New Specifically Activated and Blocked Isatoic Acid Derivatives Depending on the reaction conditions N-hydroxy-phthalimide affords on treatment with cyanogen bromide via N-cyanato phthalimide 2 the iminocarbonate 3 and isatoic acid derivatives 7 and 16 . Both the latter react with nucleophiles as isatoic acid derivatives activated on the carboxylic group and protected on the carbamic group or vice versa, furnishing N,N-bis alkoxycarbonyl anthranilic acid amides 9 , N-alkoxycarbonyl anthranilic acid amides 12 , o-alkoxycarbonyl phenyl ureas 17 and the benzotriazepin-2,5-dione 14 . The structures of the new compounds are proved by ¹H-n.m.r. and ¹³C-n.m.r. measurements as well as independent synthesis.     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern IV Di- und Tripentaerythritfettsäureester

Mass Spectrometric Fragmentation of Neopentylpolyolesters, Part IV: Fatty Acid Esters of Dipentaerythritol and Tripentaerythritol The fragmentation of some fatty acid esters of dipentaerythritol and tripentaerythritol upon electron impact ionisation was investigated. Main fragments in the spectra of dipentaerythritol ester arise by M-RCOO and cleavage of the ether bond. These ions are also formed in the spectra of tripentaerythritol ester by ether bond cleavage. Cyclic acetal structures for this ions are postulated. Their subsequent fragmentation, which was elucidated by DADI-measurements, leads to a striking similarity of the mass spectra of both ester types. Problems concerning the mass spectrometric identification of ester components formed by esterification of dipentaerythritol with mixtures of fatty acids is discussed. It is shown, that by GC-MS and calculation of the possible ester components using the known fatty acid composition, a detailed characterisation of these complex ester systems is possible.     

Desaktivierung angeregter Singulettzustände von N-Arylurethanen durch intra- und intermolekulare Energieübertragung auf Salicylsäureester und -amide

Quenching of Excited Singlet States of N-Arylurethanes by Intra- and Intermolecular Resonance Energy Transfer to Salicylic Acid Esters and Amides Fluorescence and photo-Fries reactions of N-arylurethanes are quenched by energy transfer to salicylic acid esters and amides. Quenching of photo reaction and fluorescence obeys the Stern-Volmer equation and is accompanied by sensitization of salicylic acid ester fluorescence. The rate constants of energy transfer are greater than the diffusion rate constants and show that resonance energy transfer occurs. The influence of solvent viscosity, donor lifetime, and spectral overlap is discussed. The rate constants of energy transfer are slightly decreased by increasing the solvent viscosity. The results are in good agreement with the treatment of POVINELLI .     

Metathese ungesättigter Fettsäureester – ein einfacher Zugang zu langkettigen Dicarbonsäuren

Metathesis of Unsaturated Fatty Acid Esters – a Simple Approach to Long-Chained Dicarboxylic Acids Long-chained, symmetric unsaturated C₁₈-, C₂₀- und C₂₆-dicarboxylic acid esters are easily accessible from natural fatty acid esters by metathesis in a two-step procedure. In the first step unsaturated fatty acid esters are cleaved by metathesis with ethylene. Pure oleic acid ester or fatty acid methylesters, produced from high-oleic sunflower oil or from rapeseed oil by transesterification with methanol, are converted to 1-decene and 9-decenoic acid methylester. From erucic acid methylester 1-decene and 13-tetradecenoic acid methylester are achieved. Using our newly developed high efficient catalytic system B₂O₃-Re₂O₇/Al₂O₃-SiO₂ + SnBu₄ conversion rates of 86 – 96% are obtained and the terminally unsaturated fatty acid esters are isolated in yields of 61 – 83%. In the second step 9-decenoic and 13-tetradecenoic acid methylester as well as 10-undecenoic methylester, which is commercially obtained by pyrolysis of ricinoleic acid ester, are converted to 9-octadecenedioic-, 13-hexacosenedioic- and 10-eicosenedioic acid dimethylester, by which process ethylene is eliminated. The conversion rates are 89 – 99% and the dicarboxylic acid dimethylesters are isolated in yields of 77 – 84%.     

Tumorpromovierende Diterpen-Fettsäureester aus Euphorbia triangularis und Euphorbia cooperi

Tumor-Promoting Diterpenyl Fatty Acid Esters from Euphorbia triangularis and Euphorbia cooperi Three diterpenic diesters were isolated from milk-juice of Euphorbia triangularis and they were identified as 13-isobutyrate (T₁), 13-tiglate (T₂) and 13-(2-methyl-butyrate) (T₃) of the new diterpene 12-desoxyphorbol. Apart from these, a mixture of corresponding 20-acetates (T₁–T₃) could be isolated and characterized. The known crotophorbolon is obtained by alkali-treatment of 12-desoxyphorbol-13-tiglate under energetic conditions. A diterpene-diester and a diterpene-triester were isolated from milk-juice of Euphorbia cooperi and they were characterized as 13-O-isobutyroyl-16-tiglate and ?20-acetate respectively of the new diterpene 12-desoxyphorbol-16-hydroxyphorbol. All the isolated diterpene esters showed more or less pronounced irritation on mice ear. In general, the 20-esters are less effective than the corresponding esters having the free 20-hydroxyl group. Exact knowledge of the isolated esters is significant from the viewpoint of environmental protection, since some of these compounds might possess co-carcinogenic properties as well.     

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. 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.     

Zur Charakterisierung der Reaktionsprodukte bei der Umsetzung höhermolekularer ungesättigter Fettsäureester mit Schwefelwasserstoff bei Anwesenheit von elementarem Schwefel

Identification of the Reaction Products by the Reaction of High Molecular Unsaturated Fatty Acid Esters with Hydrogen Sulfide by the Presence of Elementary Sulfur The use of preparatory High Performance Liquid Chromatography (HPLC), Field Desorption Mass Spectroscopy (FDMS) and Raman Spectroscopy (RS) gives a view over the reaction of unsaturated fatty acid esters with hydrogen sulfide by the presence of elementary sulfur. The reaction products were isolated by HPLC and identified by FDMS. The represented reaction of methyl oleat with hydrogen sulfide and elementary sulfur yields di-stearylmolecules with sulfur chains from 1 to 6 sulfur atoms between the stearyl groups. The length of the sulfur chains is a function of the reaction time.     

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.