Search results for "DISCOVERY"
showing 10 items of 4119 documents
Studies on the Stereoselective Selenolactonization, Hydroxy and Methoxy Selenenylation of α- and β-Hydroxy Acids and Esters. Synthesis of δ- and γ-La…
2003
Abstract The diastereoselective synthesis of hydroxy substituted γ- and δ-lactones was accomplished following two approaches. A 5- or 6-endo cyclization promoted by electrophilic selenium reagents of α- or β-hydroxy acids and a 5- or 6-exo cyclization of hydroxy esters obtained through a diastereoselective hydroxy selenenylation reaction of α- or β-hydroxy esters. Moreover, the diastereoselective methoxy selenenylation of the above compounds was investigated showing a case in which the compound that was unreactive in the hydroxy selenenylation conditions gave, in the methoxy selenenylation conditions, the deprotected diol. The usefulness of the methoxy selenenylation procedure was proven by…
2-Chlor-4-(dihexylamino)-1,3,5-triazine Herbicides, IV: 2-Chloro-4-(dihexylamino)-1,3,5-triazines
1984
Synthese de derives alkylamino-6 des composes du titre par action d'alkylamines sur la dichloro-2,4 dihexylamino-6 s-triazine
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…
Synthesis and reactivity of β-amino-α,β-unsaturated oxa- and thiazolines
1992
Abstract A simple and efficient route to masked β-amino-α,β-unsaturated acids 3 by reaction of metalated oxa- and thiazolines with nitriles has been developed. The reactivity of 3 has also been explored.
The structure and stereochemistry of atractyligenin
1966
Abstract The structure of atractyligenin C19H28O4, the nor-diterpenoidic aglycone of atractyloside C30H44O16S2K2 has been substantiated as Ia. The absolute configuration shown in Ia proves it to be a derivative of (−)kaurene.
Synthesis of (+)-pechueloic acid and (+)-aciphyllene. Revision of the structure of (+)-aciphyllene
2007
Abstract 1α H ,7α H ,10α H -Guaia-4,11-dien-3-one and its 1β H ,10β H diastereomer, easily obtained from (+)-dihydrocarvone, are good starting materials for the synthesis of natural guaiane derivatives. Allylic oxidation of the 1α H ,10α H isomer gave as main product its 13-hydroxy derivative and a small amount of (+)-7β-hydroxy-1α H ,10α H -guaia-4,11-dien-3-one, whereas the 1β H ,10β H diastereomer afforded selectively the (−)-7α-hydroxy-1β H ,10β H enantiomer in excellent yield. From the 13-hydroxy derivative (+)-pechueloic acid and (+)-methyl pechueloate were synthesized. Deoxygenation at C 3 of the 1β H ,10β H guaiadienone afforded a guaiadiene with the reported structure for aciphylle…
Umsetzung von amino-aziminen mit basen
1980
Abstract Amino-azimines of type (1) react at room temperature with bases (ammonia, aliphatic amines, hydrazine and methyl-hydrazine, aqueous/ethanolic sodium hydroxide) by cleavage of the to the and the NNN moieties (azide).
Fluoro heterocycles. A photochemical methodology for the synthesis of 3-amino- and 3-(N-alkylamino)-5-perfluoroalkyl-1,2,4-oxadiazoles
2000
Abstract A photochemical methodology for the synthesis of perfluoroalkyl-1,2,4-oxadiazoles has been described. 3-Amino- and 3-( N -alkylamino)-5-perfluoroalkyl-1,2,4-oxadiazoles have been prepared by irradiation of 3-perfluoroalkanoylamino-4-phenyl-1,2,5-oxadiazoles (furazans) at λ =313 nm in methanol and in the presence of ammonia or primary aliphatic amines.
N-Substituierte Imidazole aus Aldehyden, 1,2-Diketonen, primären Aminen und flüssigem Ammoniak. 4. Mitt. über Imidazolsynthesen mit flüssigem Ammoniak
1974
N-substituierte Imidazole 5 konnen aus Aldehyden 1, 1,2-Diketonen 2 und primaren Aminen 3 in flussigem Ammoniak 4 dargestellt werden. N-substituted Imidazoles from Aldehydes, 1,2-Diketones, Primary Amines and Liquid Ammonia N-substituted imidazoles 5 can be synthesized from aldehydes 1, 1,2-diketones 2 and primary amines 3 in liquid ammonia 4.