Search results for "medicinal"
showing 10 items of 2966 documents
Iron(III) Chloride as a Mild Catalyst for the Dearomatizing Cyclization of N-Acylindoles
2020
A catalytic approach for the preparation of indolines by dearomatizing cyclization is presented. FeCl3 acts as a catalyst to afford tetracyclic 5a,6-dihydro-12H-indolo[2,1-b][1,3]benzoxazin-12-ones in good yields. The cyclization also proceeds with tosylamides forming C-N bonds in 53% yield.
Erweiterte Konjugation in unsymmetrischen Stilbenylsquarainen
1998
Extended Conjugation in Stilbenylsquaraines Unsymmetrical 1-aryl-3-stilbenylsquaraines 2a–e and 1,3-bis(stilbenyl)squaraines 3a–c were prepared by CC coupling reactions of the corresponding substituted arenes with derivatives of squaric acid (Schemes 2 and 3). Dialkylamino and alkoxy groups enhance the solubility of these dyes and enlarge the intramolecular charge transfer of these donor–acceptor–donor systems. The extended conjugation of the stilbene units – in comparison with arene building blocks – leads to significant bathochromic shifts in the Vis/NIR absorption spectra.
New synthesis of condensed heterocycles from isoxazole derivatives VI. 2,5-Dimethyl-3-aeetyl-7-amino-1H-pyrrolo[3,2-b] pyridine
1978
A new synthesis of pyrrolo[3,2-b] pyridine starting with pyrrole ring is described. The procedure allows the synthesis of 4-azaindoles bearing a sensitive group at C-7. The nitration of 4b with nitric acid and acetic anhydride at −15° gave 5. The hydrogenation of 5 led to simultaneous reduction of N-hydroxy and nitro groups and to hydrogenolysis of the isoxazole nucleus, affording an appropriate chain of atoms to building up the pyrrolo[3,2-b] pyridine ring.
An Unexpected Three-Component Condensation Leading to Amino- (3-oxo-2,3-dihydro-1H-isoindol-1-ylidene)- acetonitriles
2004
The reaction of 2-carboxybenzaldehyde with primary amines in the presence of cyanide leads to the formation of 2-substituted amino(3-oxo-2,3-dihydro-1H-isoindol-1-ylidene)acetonitriles. These compounds originate from the condensation of 2-carboxybenzaldehyde with the amine and two molecules of hydrogen cyanide and represent a novel class of isoindolinones.
Über Dipyridyl-acetylene undcis-1.2-Dipyridyl-äthylene
1959
Die Darstellung von Di-[pyridyl-(2)]-acetylen, [Pyridyl]-(2)]-[pyridyl-(3)]-acetylen und [Pyridyl-(2)]-[pyridyl-(4)]-acetylen wird beschrieben. Durch Hydrierung dieser Verbindungen mit Lindlar-Katalysator in Methanol lassen sich cis-Dipyridyl-athylene gewinnen.
Über die Synthese von o-Acylamino-ß-dimethylamino-propiophenonen 1. Mitt.: Verhalten von o-Nitro- und o-Carbäthoxyamino-acetophenon bei der Mannich-R…
1970
Das bei der Mannich-Reaktion von o-Carbathoxyamino-acetophenon mit Paraformaldehyd und Dimethylamin-hydrochlorid erhaltene Kondensationsprodukt wurde als ein Gemisch von o-Carbathoxyamino-β-dimethylamino-propiophenon und o-Carbathoxyamino-α-dimethylaminomethyl-acrylophenon identifiziert. Durch Variation der Versuchsbedingungen konnte das Acrylophenonderivat als Hauptprodukt erhalten werden. Es war durch Saurekatalyse in 1-N-Carbathoxy-3-dimethylaminomethyl-4-oxo-1,2,3,4-tetrahydrochinolin uberfuhrbar. Synthesis of o-Acylamino-β-dimethylamino-propiophenones The aminomethylation product of o-carbethoxyamino-acetophenone, paraformaldehyde and dimethylamine-hydrochloride was identified as a mix…
Über die Synthese von o-Acylamino-β-dimethylamino-propiophenonen 2. Mitt.: Aminomethylierung von o-Carbäthoxyamino- und o-Nitro-acetophenon1)
1970
Die bei der Mannich-Reaktion mit o-Carbathoxyamino- und o-Nitro-acetophenon zu Acrylophenonderivaten fuhrende Sekundarreaktion zwischen den Aminomethylierungsprodukten und Formaldehyd konnte auf folgende Weise nahezu vollstandig vermieden werden: durch Verhindern des Zerfalls von intermediar entstehendem Dimethylaminomethylol in seine Komponenten wird die Bildung des Carbonium-Imonium-Kations derart beschleunigt, das fur die Nebenreaktion erforderlicher freier Formaldehyd rasch aus dem Reaktionsmedium verschwindet. — Die Synthese von o-Carbathoxyamino-, o-Nitro- und o-Amino-β-dimethylamino-propiophenon sowie seines Formyl- und Acetylderivates wird beschrieben. Synthesis of o-Acylamino-β-dim…
ChemInform Abstract: Enantioselective LaIII-pyBOX-Catalyzed Nitro-Michael Addition to (E)-2-Azachalcones.
2013
A [La(OTf)3] complex with a new pyBOX ligand bearing a bulky 1-naphthylmethyl substituent at the 4′-position of the oxazoline ring catalyzes the conjugate addition of nitroalkanes to a broad range of (E)-2-azachalcones, providing the expected nitro-Michael products with good yields and enantiomeric excesses up to 87 %. The optical purity of the products can be increased by a single crystallization. A plausible stereochemical model to account for the observed stereochemistry has been proposed.
ChemInform Abstract: Addition of Organolithium Reagents to Cinnamic Acids.
2010
Abstract Reaction of tert -butyllithium with p - and m -substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
ChemInform Abstract: Trienediolates of Hexadienoic Acids in Synthesis. Synthesis of Retinoic and nor-Retinoic Acids.
2010
Abstract Double deprotonation of either (E,E)-3-methyl-2,4-hexadienoic acid 2, or 4,6-dimethyldihydro-2-pyrone 3 generates apparently the same lithium trienediolate, which affords ω-hydroxy acids 9 on reaction with ketones 7. Hydroxy acids 9 are easily dehydrated to octatrienoic acids 5, which are structurally related to retinoic acid. Similarly, sorbic acid 1 leads to nor-retinoic acid analogs 6.