α-Alkylmercapto- und α-Arylmercapto-alkylisocyanate

α-Alkylmercapto- and α-Arylmercapto-alkylisocyanates α-Alkylmercapto- and α-arylmercapto-alkylisocyanates 2 were prepared from α-halosulfides 1 by reaction with silver cyanate. With ammonia, primary or secondary amines they give the corresponding α-mercaptoalkyl-ureas 4 ; with alcohols, the α-mercaptoalkylurethans 3.     

Neue Reaktionen an Phthalidisochinolinalkaloiden. Alkoxytauschreaktionen und Isomerisierungen an α- und β-Narcotin

New Reactions of Phthalidoisoquinoline Alkaloids. Alkoxy Exchange Reactions and Isomerisations of α- and β-Narcotine Substitution of the 7-methoxy group in α- and β-narcotine by other alkoxy groups occurs in an anhydrous ROH/RONa system. It is accompanied by isomerisation in position 3 with preference for the α-configuration (5R, 3S). In an alkaline aqueous system (ROH/KOH or 1N KOH only isomerisation in position 3 with preference for the β-configuration (5R, 3R) was observed. Some of the new 7-alkoxynarcotines were evaluated for their antitussive activity.     

Separation of δ-, γ- and α-tocopherols by CEC

In this study capillary electrochromatography (CEC) was used for the separation of three tocopherols (TOHs), namely delta-, gamma- and alpha-TOH and the antioxidant compound, butylated hydroxytoluene (BHT). The CEC experiments were carried out using an octadecylsilica (ODS) stationary phase packed, in our laboratory, in a fused-silica capillary (100 microm I.D., 365 microm O.D. x 33 cm of total length and 24.6 or 8.4 cm effective length). The mobile phase was composed by a mixture of methanol (MeOH) and acetonitrile (ACN), at different concentrations and 0.01% (w/v) of ammonium acetate. Retention time (t(R)), retention factor (k), resolution (R(s)) of the three TOHs were strongly influenced by the organic solvent composition of the run buffer and by the effective length of the capillary. Optimum experimental conditions were found even employing the short effective length of the capillary achieving the baseline separation of the studied analytes in a relatively short time (less than 5 min). The optimized method was applied to the qualitative analysis of vitamin E (alpha-TOH) present in a human serum extract.     

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 .     

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.     

Synthesis of α-, β- and cyclic spaglumic acids

A short, one-pot synthesis of α- and β-spaglumic acids (N-acetyl-L-aspartyl-L-glutamic acids, NAAGA) has been developed based on ultrasound-promoted acetylation of aspartic acid, followed by dehydration, condensation with glutamic acid dibenzyl ester and hydrogenolysis. The α- and β-peptides were separated by anion-exchange chromatography. The α-peptide shows a remarkable tendency to cyclize during methylation with diazomethane and yields cyclic N-acetylaspartylglutamic acid dimethyl ester, which could be hydrolysed to the hitherto unreported diketopiperazine dicarboxylic acid, cyclic spaglumic acid (cyclic NAAGA).     

N-Glykoside und Glykamine von Cyclopentylamin, 1.2.3.4-Tetrahydro-1-naphthylamin und 5α-Cholestan-3β-amin

N-Glycosides and Glycamines of Cyclopentylamine, 1,2,3,4-Tetrahydro-1-naphthylamine and 5α-Cholestan-3β-amine The galactosyl-, mannosyl- and lactosyl-N-glycosides of cyclopentylamine and the galactosyl- and glucosyl-N-glycosides of the other two title compounds are described. All N-glycosides are reduced by cyanoborohydride to the corresponding glycamines.     

Struktur-Wirkungs-Beziehungen bei Histaminanaloga, 23. Mitt. Absolute Konfiguration und histaminartige Wirkung der enantiomeren α-Chlormethylhistamine und Nα-Methyl-α-chlormethylhistamine

Structure-Activity Relationships of Histamine Analogues, XXIII: Absolute Configuration and Histamine-like Activity of the Enantiomeric α-Chloromethylhistamines and Nα-Methyl-α-chloromethylhistamines The histamine-like activities of the enantiomeric α-chloromethylhistamines (+)- 2a and (?)- 2a and of the Nα-methyl-α-chloromethylhistamines (+)- 2b and (?)- 2b on the guinea pig ileum (H₁) and atrium (H₂) are reported. The absolute configurations of the enantiomers were determined.     

Thion- und Dithioester, 48. Mitt. α,β-Ungesättigte Thioester in Diels-Alder-Reaktionen und Michael-Additionen

Thiono and Dithio Esters, XLVIII: α,β-Unsaturated Thio Esters in Diels-Alder Reactions and Michael Additions The reaction of cinnamic acid thio esters with different dienophiles leads to the formation of the Diels-Alder products 3 – 8 ; with lithium enolates the Michael adducts 11 and 13 were isolated.     

Imidazolsynthesen, 7. Mitt.: Imidazole aus Iminoestern, α-Amino- oder α-Acylaminoketonen und flüssigem Ammoniak

Imidazoles from Iminoesters and α-Amino-or α-Acylaminoketones and Liquid Ammonia Substituted imidazoles 4 are obtained from iminoesters 1 and α-amino- 2 or α-acylaminoketones 3 in liquid ammonia under pressure.     

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.     

Darstellung von γ- und δ-Laktoncarbonsäuren aus DL-3-(1′-Methoxymethylpropyl)-glutarsäure

Ether cleavage of DL -3-(1′-methyoxymethylpropyl)-glutaric acid with the protonic acid HBr leads to 4-carboxymethyl-5-methyl-5-ethyl-furanone-(2);ether cleavage with the Lewis acid BBr₃ to carboxymethyl-5-ethyl-pyranone-(2).     

Die Kondensation von γ-und δ-Oxo-carbonsäureester mit 1,2-, 1,3- und 1,4-Alkylendiaminen

Condensation of Esters of γ- and δ-Oxocarboxylic Acids with Alkylene-1,2,1,3- and 1,4-diamines. Esters of γ-and δ-Oxocarboxylic acids condense with alkylene-1,2-, 1,3-, and 1,4-diamines and yield bicyclic lactams (5) . The path of the reaction was studied by spectroscopic methods using ethyl levulinate and N-methyl-propylene-1,2-diamine. The first step is the formation of an “aminalester” by reaction of the CO-group of ethyl levulinate with alkylene diamine, followed by intramolecular ring closure.     

Über in α- und in β-Stellung durch aromatische oder heterocyclische Reste substituierte Enamine. 6. Mitt. über β-substituierte Enamine zugleich. 32. Mitt. über α-halogenierte Amine

Enamines with Aromatic or Heterocyclic Substituents in α- and β-Position Part VI on β-substituted enamines, Part XXXII on α-haloamines Treatment of trialkyl phosphites with carbimonium salts 1 , which are substituted in α-position by aromatic or heterocyclic groups, yields the corresponding dialkylaminomethyl phosphonic acid esters 2 . Reactions of carbonyl compounds with the carbanions 3 , which are accessible from 2 with base, give the tertiary enamines of type 4 or 6 .     

Synthese von γ,γ'-Dihydroxysulfonen und γ-Hydroxy-γ'-ketosulfonen

Syntheses of γ,γ'-Dihydroxysulfones and γ-Hydroxy-γ'-ketosulfones Reduction of γ,γ'-diketosulfones 1 with dimethylaminoborane leads to γ,γ'-dihydroxysulfones 3 via γ-hydroxy-γ'-ketosulfones 2 . The influence of substituents on the ratio of the yields of 2 and 3 is investigated.     

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.