Thion- und Dithioester, 38. Mitt. Zur Kondensation von 2-Amino-dithiooxalsäure-O-ester mit Cyanessigestern

Thiono- and Dithioesters, XXXVIII: Condensation of 2-Amino-dithio-O-oxalates with Cyanoacetic Esters By thiolysis of the cyano methanimidoates 2 cyano methanethioates 1 or 2-amino-2-thioxoethanethioates 3 are formed, depending on the reaction conditions. The thionoester group in 3 condenses with cyanoacetates in the presence of potassium methoxide to form the potassium salts 7 , which were S-alkylated to give the thioenol ethers 9 . Condensations of 9 with hydrazines lead to structurally different products 11–18 .     

Thion- und Dithioester, 41. Mitt. Zur Reaktion von Dithionmalonsäureestern mit Elektrophilen

Thiono and Dithio Esters, 41. - Reaction of Dithiono Malonic Esters with Electrophiles Dithiono malonic esters 1 react with alkali alkoxides to form the stable alkali salts 2 . According to an X-ray analysis for the N,N,N′,N′-tetramethylformamidinium salt 18 their anions adopt a trans,s-trans configuration in the crystalline state. By NOE experiments the same configuration is confirmed for solutions ([D₆]DMSO or D₂O). Alkylation of 2 , however, gives rise to the Z-configurated thiono acrylic esters 4 , By oxidation of 1a with tert.-butyl hypochlorite or iodine the 1,2-dithiolium salts 5 and 7 were obtained. The reaction of 1a with N,N-dimethylformamide diethylacetal ( 8 ) in ethanol leads to the formation of the dimethylaminomethylene compound 12 , in ether the formamidinium salt 18 precipitates. The latter decomposes to N,N-dimethyl thioformamide 20 and the thiono acrylic ester 21 .     

Thion- und Dithioester, 43. Mitt. Alkylierung und Acylierung von Tetrathiomalonestern

Thiono and Dithio Esters, 43.-Alkylation and Acylation of Tetrathiomalonates Diethyl tetrathiomalonate (3) has been obtained from dithiomalonic acid dipyrrolidide (1) via the bisimidium salt 2 by subsequent thiolysis. 3 reacts with alkyl and acyl halides to form the substituted dithioacrylic esters 4 as mixtures of E,Z-isomers. The methyl derivative 4a is also prepared from 3 and diazo methane or N,N-dimethylformamide dimethylacetal (5a) . The CH-acidic Z-isomers 4a-i have been cyclised in basic medium to give the thiophenes 8 or 9 . By Vilsmeier reagent 3 is chlorinated to form the 3-chloro-dithioacrylic ester 12 . The chelate complexes 14 have been isolated from 3 with nickel(II) or zinc acetate.     

Thion- und Dithioester, 39. Mitt. Zur Kondensation von 2-Morpholino-dithiooxalsäure-O-ester mit Malondinitril oder Cyanessigester

Thiono- and Dithioesters XXXIX: Condensation of 2-Morpholinodithiooxalic O-esters with Malonodinitrile or Cyanoacetate Condensation of 2-morpholino- or 2-piperidino-dithiooxalic O-esters 1 with malonodinitrile or cyanoacetate in the presence of potassium ethanolate leads to the formation of the potassium salts 3 , which are alkylated by alkyl iodides to give the thioenol ethers 4. With CH-acidic alkylating agents the thiophenes 6 are obtained directly. Compound 3a cyclises with hydroxylamine-O-sulfonic acid to form the isothiazole 8 ; compound 4 with hydrazine yields the pyrazoles 10. S-Alkylation of the thiophenes 6 at the thioamide sulfur followed by hydrazinolysis gives the thiopheno[2.3-d]pyridazines 13 and 14.     

Thion- und Dithioester, 36. Mitt. Tetrakis(alkylthio)-ethylene

Thiono- and Dithioesters, XXXVI: Tetrakis(alkylthio)ethylenes 4,5-Bis(benzoylthio)-1,3-dithiol-2-one (4b) reacts with 4 moles of NaOCH₃ to give the tetrasodium salt of ethenetetrathiole 6 , which can be alkylated to yield the tetrathioethylenes 7 (method A). With 2 moles of NaOCH₃, 4b is transformed into disodium 2-oxo-1,3-dithiol-4,5-dithiolate (8) , which can be converted into the tetrathioethylenes 11 with Z configuration via the intermediates 9 and 10 (method B). Reduction of dimethyl tetrathiooxalate (5a) with lithium sulfide or sodium bis(trimethylsily1)amide leads to the formation of the alkali salt 12, which can be alkylated to give the tetrathioethylenes 11 (method C).     

Thion- und Dithioester, 40. Mitt. Zur Reaktion von Dithionmalonsäureestern mit nucleophilen Stickstoffbasen

Thiono and Dithio Esters, 40. - Reactions of Dithionomalonic Esters with Nucleophilic Nitrogen Bases Dithionomalonic esters 1 , obtained from malonitrile via malonodiimidium salts 5 by thiolysis, react with amines under elimination of H₂S to form the 3-amino-thioacrylic O-esters 11 . The alkali salts of 1 condense with amines to give the malonodithiomides 12 by loss of 2 molecules of alcohol. Oxidative cyclization of 11 leads to the isothiazoles 16–18 . Reation of 1 with hydrazines gives rise to the pyrazoles 20–22 ; with amidines the pyrimidines 23 and 24 were obtained.     

Über Dialkyl-[β,β,β-trichlor-bzw. β,β,β-triphenyl-äthyl]-amine. 34. Mitt. über α-halogenierte Amine

Dialkyl-[β,β,β-trichloro- or β,β,β-triphenyl-ethyl]-amines Reactions of α-halo amines 2 with trichloromethyllithium give dialkyl-[β,β,β-triphenyl-ethyl]-amines 1 , with triphenylmethyllithium dialkyl-[β,β,β-triphenyl-ethyl]-amines 3 .     

Thion- und Dithioester, 52. Mitt.: Zur Reaktion von Dithionmalonestern mit N,N-Dimethylformamidacetalen

Thiono and Dithio Esters, LII¹⁾: Reaction of Dithiono Malonates with N,N-Dimethylformamide Acetals The reaction of the dithiono malonates 1 with the formamide acetals 2 leads to the 2-dialkylaminomethylene dithionomalonates 4 and the thiono acrylates 6 . The condensation of 4 with hydrazines gives rise to the pyrazoles 7 and 8 , with hydroxylamine sulfonic acid to the isothiazoles 10 , and with amidines to the pyrimidines 11 - 13 .     

Nitroketenaminale, 9. Mitt.: Zur Umsetzung von α,β-ungesättigten Aldehyden mit Nitroketenaminalen

Nitroketeneaminals, IX: Reaction of α,β-Unsaturated Aldehydes with Nitroketeneaminals Reaction of α,β-unsaturated aldehydes 1a , b with nitroketeneaminal 2a in boiling acetic acid leads to 2-amino-3-nitropyridines 4 unsubstituted at C-6. By refluxing 1a and 2a in alcohol/acetic acid or in alcohols, respectively, 2-alkoxy-1,2,3,4-tetrahydropyridines 7a and 8a are obtained. The reaction of 1a and 2b yields 5-alkoxy-2,3,4,5,6,7-hexahydroimidazo[1,2-a]pyridines 7b and 8b . By ¹H-NMR spectroscopy the relative configuration of 7aC, 7aT, 7bC , and 7bT can be determined.     

α-Thiotetronsäuren, 1. Mitt.: Synthese und Eigenschaften von γ-Alkyliden-α-thiotetronsäuren

α-Thiotetronic Acids, I: Synthesis and Properties of γ-Alkylidene α-Thiotetronic Acids We report on the synthesis of the alkylidene α-thiotetronic acids 11 and 12a and a variety of their derivatives, starting with 2,3-dimethoxysuccinic thioanhydride ( 4 ) or diethyl 3-thioxoglutarate. The rhodium(II)-catalysed decomposition of the diazoketone 26 furnishes the reductone 12p and the aminoreductone 12r with the thietanone 27 as one of the by-products.     

Massenspektrometrische Untersuchungen an isomeren α,β- und β, γ-ungesättigten Ketonen mit raumerfüllenden Substituenten

A Mass Spectrometric Study on Isomeric α,β- and β,γ-Unsaturated Ketones with Bulky Substituents The mass spectra of the α,β- and β,γ-unsaturated ketones 1-4 (scheme 1) are very different depending on the stereochemistry of the double bond. The E-configurated ketone 2 predominantly shows McLafferty fragmentation, whereas Z-configurated ketone 1 reveals ?-cleavage. In the β, γ-unsaturated ketones 3 and 4, mainly loss of the pertinent allyl radical by α-cleavage was observed.     

Ungesättigte und halogenierte γ-Hydroxysulfone; Darstellung und Reaktivität

Unsaturated and Halogenated γ-Hydroxysulfones: Syntheses and Reactivities α,β-Unsaturated γ-hydroxysulfones 2 and β-bromo-γ-hydroxysulfones 4 are prepared from the corresponding keto derivatives by reduction with dimethylaminoborane. Addition of p-toluenethiol to the double bond of 2 takes place in the position β to that of the sulfonyl group. With bases an isomerisation of 2 to γ-ketosulfones 10 is observed. With primary or secondary amines Mannich bases are formed. β-Bromo-γ-hydroxysulfones 4 are cleaved by bases to yield 2 .     

Dithio- und Thionester, 57. Mitt.: Synthese N-geschützter β- und γ-Aminosäuredithioester und -thionester

Dithio and Thiono Esters, LVII: Synthesis of Dithio and Thiono Esters of N-Protected β- and γ-Amino Acids The N-Protected β-aminonitriles 1 were transformed into the imidoester or thiolimidoester hydrochlorides 2 or 3 according to Pinner and sulfhydrolyzed with H₂S to give the N-protected β-amino thiono esters 4 or dithio esters 5 . Alkylation of the amides 6 and thioamides 7 yields the iminium salts 8/9 and their sulfhydrolysis again 4/5 . By the first approach N-protected γ-amino nitriles 11 were converted into the γ-amino thiono esters 14 and dithio esters 15 .     

Struktur-Wirkungs-Beziehungen bei Histaminanaloga, 22. Mitt. Absolute Konfiguration und histaminartige Wirkung der enantiomeren α, Nα-Dimethylhistamine

Structure-Activity Relationship of Histamine Analogues. XXII: Absolute Configuration and Histamine-like Activity of the Enantiomeric α, N^α-Dimethylhistamines The synthesis of the enantiomeric α, N^α-Dimethylhistamines (+)— 3 and (?)— 3 , the determination of the absolute configuration and the histamine-like activity of the enantiomers on the guinea-pig ileum (H₁) and atrium (H₂) are reported.     

α-Aminoalkylierungsreaktionen mit N-funktionellen Glyoxylsäurederivaten 5. Mitt.: α-Aminosäuren und Derivate

Aminoalkylation with Glyoxylic Acid Derivatives O.N- and N.N-Acetals as well as dialkylimoniumsalts of glyoxylic acid derivatives can be used for aminoalkylation of C-H-acid compounds, producing amides or esters of N.N-dialkylated α-aminoacids. The reaction is investigated on various examples.