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.     

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. I. Darstellung von β-Fur-2-yl-ß-aminoacrylonitrilen und β-Fur-2-yl-α-aminoacrylonitrilen

β-Fur-2-yl-α-halogenacrylonitriles. I. Preparation of β-Fur-2-yl-ß-aminoacrylonitriles and β-Fur-2-yl-α-aminoacrylonitriles β-Fur-2-yl-α-halogenacrylonitriles 1 react with secondary amines to yield β-fur-2-yl-ß-aminonitriles 2 and β-fur-2-yl-α-aminoacrylonitriles 3 . The ¹ H-n.m.r. spectra of the E/Z isomers 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.     

β-Fur-2-yl-α-halogenacrylonitrile. V [1] Darstellung von β-(5-Nitro-fur-2-yl)-α-azidoacrylonitril und β-(5-Nitro-fur-2-yl)-α-aminoacrylonitril

β-Fur-2-yl-α-halogenacrylonitriles. V. Preparation of β-(5-Nitro-fur-2-yl)-α-azidoacrylonitrile and β-(5-Nitro-fur-2-yl)-α-aminoacrylonitrile β-(5-Nitro-fur-2-yl)-α-chloroacrylonitrile ( 1 ) reacts with sodium azide to yield β-(5-nitro-fur-2-yl)-α-azidoacrylonitrile ( 2 ). By Staudinger-reaction β-(5-nitro-fur-2-yl)-α-aminoacrylonitrile ( 5 ) is formed. The ¹H- and ¹³C-n.m.r. spectra of E/Z isomers are discussed.     

Steroide. XLVI. Darstellung von 15.16.17-trisubstituierten Steroiden durch Ringöffnung von 17β-substituierten 15β.16β-Epoxy-östra-1.3.5(10)-trien-3-methyläthern

Steroids. XLVI. Preparation of 15,16,17-Trisubstituted Steroids by Ring Cleavage of 17β-Substituted 15β,16β-Epoxy-estra-1,3,5(10)-triene 3-Methylethers The ring cleavage of 15β.16β-epoxy-3-methoxy-estra-1-3,5(10)-triene-17β-ol 1a with strong nucleophiles occurs mainly at C-16, yielding 16α-substituted 15β,17β-diols 2a–f . Besides this, 1a is cleaved to a small extent at C-15, yielding the 15α-substituted 16β,17β-diols 3a—f and the Δ¹⁴-16,17β-diol 5a . The structures have been elucidated by means of i.r., H-n.m.r. and mass spectroscopy.     

r-5-(α-Halogenbenzyl)-3, t-4-diaryl-c-4-hydroxy-oxazolidin-2-one als Ringtautomere von α-(Arylaminocarbonyloxy)-β-halogen-dihydrochalkonen

r-5-(α-Halogenobenzyl)-3, t-4-diaryl-c-4-hydroxy-oxazolidin-2-ones as Ring Tautomers of α-(N-Arylaminocarbonyloxy)-β-halogeno-dihydrochalcones The reaction of chalcone halogenohydrins ( 1–3 ) with arylisocyanates does not stop at the stage of the α-arylaminocarbonyloxy-β-halogeno-dihydrochalcones ( 7 ), but the cyclic urethanes 4–6 are formed. Compound 7h was synthesized independently. The structure and stereochemistry of 4–6 and 7h were determined by ¹³C n.m.r. spectroscopy.     

Steroide. XLVIII. 16α-Heterosubstituierte Östradiol-3-methyläther

Steroids. XLVIII. 16 α-Heterosubstituted 3-Methoxy-estra-1,3,5(10)-triene-17β-ols The synthesis of 16α-heterosubstituted 3-methoxy-estra-1,3,5(10)-triene-17β-ols 2a—2e from 16β-bromo-3-methoxy-estra-1,3,5(10)-triene-17β-ol 1 by substitution with nucleophiles is described. Additional compounds of this class 2f—2h are obtained by transformation of the new 16α-substituents. Jones oxidation of 2b and 2c yields the 17-keto compounds 3b and 3c . The configuration of the new compounds is confirmed by i.r. and ¹H n.m.r. spectra.     

β-Fur-2-yl-α-halogenacrylonitrile. VIII. Konformationsuntersuchungen an substituierten β-Fur-2-yl-acrylonitrilen

β-Fur-2-yl-β-halogenacrylonitriles. VIII. Investigations of the Conformation of Substituted β-Fur-2-yl-acrylonitriles X-ray analysis, n.m.r.-investigations in the presence of Eu(FOD)₃ and NOE-measurement indicate, that the E-isomer of β-substituted β-fur-2-yl-acrylonitriles exist in the s-cis conformation, whereas the E-isomer of the α-substituted β-fur-2-yl-acrylonitriles prefer the s-trans-conformation. The influence of the configuration and conformation on the chemical shift of the H-3-furan protons is discussed.     

Reaktionen von β-Chlorvinylaldehyden. IV [1]. Synthesen von 2-Formylmethylen-2H-1-benzopyranen und Benzopyrylocyaninfarbstoffen aus β-Chlorvinylaldehyden

Reactions of β-Chlorovinylaldehydes. IV. Syntheses of 2-Formylmethylene-2H-1-benzopyranes and Benzopyrylocyaninedyes from β-Chlorovinylaldehydes α-Alkyl-β-chlorocrotonaldehydes react with salicylaldehyde in methanolic solution of potassium hydroxide forming 2-formyl-methylene-2H-1-benzopyranes 1 . The corresponding benzopyryliumsalts 2 which are easily available from 1 and strong acids, exist in the enolic form. They react at room temperature in alcoholic solution with elimination of ethyl formiate, yielding dark blue compounds which were identified as 2,2′-benzopyrylotrimethincyanindyes 3 . The structure of 3 has been elucidated by means of ¹H-n.m.r.-spectra.     

Reaktionen von β-Chlorvinylaldehyden. V [1]. Zur Bildung von 2,2′-Thiopyrylotrimethinfarbsalzen aus 2-(α-Formylalkyliden)-2H-thiopyranen

Reactions of β-Chlorovinylaldehydes. V. The Formation of 2,2′-Thiopyrylocyanine Dyes from 2-(α-Formylalkylidene)-2H-thipyranes Substituted β-chlorocrotonaldehydes react with Na₂S · 9H₂O to form 2-(α-formyl-alkylidene)-2H-thiopyranes 1 . The corresponding thiopyrylium salts 2 which are easily available from 1 and strong acids exist in the enolic form (2-β-hydroxyvinyl-thiopyrylium salts). They are converted at room temperature in methanol solution to dark green compounds, which are identified as 2,2′-thiopyrylotrimethincyanine dyes 3 . The mechanism of formation of compounds 3 is discussed.     

Die Reaktion von α,β-Dihalogen-propionitrilen mit monosubstituierten Hydrazinen - einfache Synthese 1-substituierter 3- bzw. 5-Amino-pyrazole

The Reaction of α,β-Dihalogeno-propionitriles with Monosubstituted Hydrazines — A Simple Synthesis of 1-Substituted 3- or 5-Amino-pyrazoles In methanol hydrazines 3 , and α,β-dihalogeno-propionitriles 1, 2 even at 0°C irreversibly yield 3 · HX, and α-halogenoacrylonitriles 4, 5 (A₁). Fast addition of alkyl- and aralkyl- hydrazines 3 to 4, 5 (C) gives 1-substituted 1-(2′-halogeno-2′-cyan-ethyl)-hydrazines 6 , the addition of arylhydrazines 3 to 4, 5 (D) 1-aryl-2-(2′-halogeno-2′-cyan-ethyl)-hydrazines 8 . In methanol 6 spontaneously cyclise (E) to hydrogen halides 7 · HX of 1-alkyl- and 1-aralkyl-3-amino-pyrazoles, 8 with 2 moles of acids (F) to salts 10 · 2HY of 1-aryl-4-halogeno-5-imino-pyrazolidines, and the free 10 spontaneously (G) to hydrogen halides 9 · HX of 1-aryl-5-amino-pyrazoles. Mechanisms (A₁), (C), (D), (E), (F), and (G) are proved by t.l.c., ¹H-n.m.r., and isolation of intermediates, the structures of 7 resp. 9 , using the significant ¹H-n.m.r.-parameter Δ. Simple general syntheses are described for 3-amino-pyrazoles 7 (R = H, alkyl, aralkyl) or 5-amino-pyrazoles 9 (R = aryl) starting with α,β-dihalogeno-propionitriles 1, 2 , and for α-bromo-acrylonitrile 5 .     

Ein effektives Verfahren zur Herstellung von 1α,25-Dihydroxy-cholecalciferol (Calcitriol) aus 1α3β,25-Trihydroxy-cholesta-5,7-dien (Procalcitriol)

An Effective Procedure for the Synthesis of 1α,25-Dihydroxy-cholecalciferol (Calcitriol) Starting with 1α,3β, 25-Trihydroxy-cholesta-5,7-diene (Pro-Calcitriol) In order to develop an effective synthesis of the important vitamin D metabolite 1α,25-(OH)₂-cholecalciferol (calcitriol) 5a starting with pro-calcitriol 1a the influence of reaction temperature and degree of turnover of 1a to the compositions of the photoproducts at irradiation in a 500 ml photoreactor were investigated. The combination of the highly photostable filter solution consisting of 2,7-dimethyl-3,6-diaza-cyclohepta-1,6-diene-tetrafluoroborate and biphenyl in ethanol realizes the double wavelength irradiation in the range of 290 to 300 nm and > 330 nm resulting in a highly amount of the desired pre-calcitriol 2a . The reversible photoisomers of pre-calcitriol 2a 1α,25-(OH)₂-lumisterol₃ 4a and 1α,25-(OH)₂-tachysterol₃ 3a were isolated from an irradiation mixture in pure form by means of an appropriate combination of flash-chromatography, MPLC and preparative HPLC, respectively. The isomers 2a, 3a and 4a were characterized chromatographically and spectroscopically. Photoisomerization of 1a at −45 °C using the filter solution mentioned above and recycling all reversible photoisomers resulted in highly pure 5a after thermally induced isomerization of 2a isolated from the irradiation mixture by means of flash-chromatography on Ag⁺- impregnated silica with a yield of 68%.     

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.     

β-Thiocyanatovinylcarbonylverbindungen. III. 1H-NMR-Untersuchungen an β-Thiocyanato-vinylaldehyden

β-Thiocyanato-vinyl-carbonyl Compounds. III ¹H-NMR Investigations of β-Thiocyanato-vinylaldehydes The ¹H-NMR spectra of some alkyl- and phenylsubstituted Z/E-isomeric β-thiocyanato-vinylaldehydes are represented. The assignment for Z/E-isomers is made using the chemical shifts of the CHO-protons and paramagnetic shift experiments. The discussion of the ΔEu-values allows to determine the conformation of the CHO-group. The main products in the case of the alkyl-substituted β-thiocyanato-vinylaldehydes are the Z-isomeric compounds which fact is attributed to mechanistic and electronic effects.     

HPLC and 13C-NMR study of carboxymethyl-β-(1 → 6)-D-gluco-β-(1 → 3)-D-glucan derived from saccharomyces cerevisiae

Sodium salt of carboxymethyl-β-(1 → 6)-D-gluco-β-(1 → 3)-D-glucan (CMG-Na) was prepared from β-D-glucan isolated from baker's yeast (Saccharomyces cerevisiae). Three samples, Fractions I, II, and III, were further separated from the crude CMG-Na derivative. For the physicochemical characterization of the separated fractions, the methods of high-performance liquid chromatography (HPLC) in the size-exclusion mode and carbon?13 nuclear magnetic resonance (¹³C-NMR) spectroscopy were applied. The HPLC method revealed that the molecular weights, M_n, M_w, and M_z averages, of Fraction II were 9.71 × 10⁴, 2.27 × 10⁵, and 3.59 × 10⁵ Da, respectively, whereas those of Fraction III were 1.52 × 10⁴, 2.13 × 10⁴, and 3.57 × 10⁴ Da, respectively. The ¹³C-NMR spectra of Fraction II showed a ratio of 3 : 1 for β?(1 → 3) / β?(1 → 6), whereas for Fraction III, the content of β-(1 → 3) units was smaller. © 1993 John Wiley & Sons, Inc.     

13C-NMR-Spektroskopie von bromierten 3-Keto- und 3β-Acetoxy-5α-cholestan-Verbindungen

¹³C-NMR Spectroscopic Investigations of Brominated 3-Keto- and 3β-Acetoxy-5α-cholestane Derivatives The chemical shifts of some brominated 3-keto- and 3β-acetoxy-5α-cholestane derivatives are determined. The substituent effects of bromine atoms on chemical shifts (SCS) and their additive behaviour, especially γ-SCS, are discussed.     

Herstellung und Charakterisierung der Sulfamate von Estra-3,17ξ-diolen. Schnelle Umsetzung von 16α-Fluorestradiol zum 16α-Fluorestradiol-3,17β-disulfamat

Estradiols are able to form two monosulphamates and one disulphamate. In the present work all the sulphamates of 17α-estradiol, 17β-estradiol and 16α-fluoroestradiol were synthesized and characterized. For characterization NMR spectroscopy was used first of all. Because of its high sulphatase inhibitory efficiency 16α-fluoroestradiol-3,17β-disulphamate found a special interest among the new sulphamates. Just the binding between sulphamate and sulphatase favoured 16α-[^18F]fluorestradiol-3,17β-disulphamate to a new radio-pharmaceutical which should be appropriate to image the active sites of sulphatase by positron emission tomography. The preparation of 16α-[¹⁸F]fluoro-estradiol-3,17β-disulphamate requires a simple and rapid procedure. The conditions for such a procedure were also elaborated using non-radioactive substances.     

Photochemie von Aminoketonen. IV [1]. Synthese von 3-Aryl-pyrrolidinolen-(3) durch Photocyclisierung von β-Amino-propiophenonen

Photochemistry of Aminoketones. IV. Synthesis of 3-Aryl-pyrrolidinols-(3) via Photocyclization of β-Amino-propiophenones Photolysis (λ_irr ≥ 300 nm) of N-benzyl-N-benzoyl-β-aminopropiophenones 6–9 in abs. ether affords a 47–50% yield of N-benzoyl-pyrrolidinols 12–18 . The relative configurations of the diastereomeric 12–18 are determined by ¹H-n.m.r. spectroscopy. The different behaviour of the N-acylated 6–9 in contrast to N,N-dialkyl-β-aminopropiophenones is explained by assumption of a dipol-dipol interaction between the keto and the amido carbonylgroups in the n,π*-excited state.     

1H- und 13C-NMR-spektroskopische Messungen und MO-Berechnungen zur π-Elektronenstruktur von p,p′-disubstituierten trans-Stilbenen und substituierten trans-β-Styryl-methyl-sulfonen

¹H and ¹³C n.m.r. Spectroscopical Measurements and HMO-π-Calculations to the π-Electronic Structure of p,p′-Disubstituted trans-Stilbenes and Substituted trans-β-Styryl-methyl-Sulfones The ¹H and ¹³C n.m.r. spectra have been measured for a series of donator-acceptor-disubstituted trans-stilbenes 1 and monosubstituted β-styryl-methyl-sulfones 2 . The ¹³C n.m.r.-signals have been identified by comparison with empirical calculated chemical shifts and quantum chemical determined HMO-π-electrons densities. The influence of substitutents to the experimental chemical shifts are discussed in detail. For 1 and 2 exist linear correlations between chemical shifts and HAMMETT values, and π-electron densities, respectively.