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1.
Preparation of Stilbenyl Derivatives of 1,2,4-Oxadiazoles Schiffs bases derived from 3- and 5-(p-formylphenyl)-phenyl-1,2,4-oxadiazoles and chloroanilines are reacted with various p-tolyl substituted aromatic heterocycles in the presence of dimethylformamide and potassium hydroxide to yield the corresponding heterocyclic substituted stilbenes (‘Anil synthesis’). The reactivity of 5-[4-(chlorophenylimino-methyl)phenyl]-3-phenyl-1,2,4-oxadiazoles is very low and side reactions will predominate. 相似文献
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Kurt Burdeska Hermann Fuhrer Guglielmo Kabas Adolf Emil Siegrist 《Helvetica chimica acta》1981,64(1):113-152
Preparation of Styryl and Stilbenyl Derivatives of Pyrimidines 2- and 4-(p-Tolyl)-substituted pyrimidines react with anils of hetero-aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide or potassium t-butoxide to yield the corresponding 2- and 4-[4″-(heteroaryl)stilben-4′-yl]pyrimidines or the 2- and 4-[a-(heteroaryl)-4′-styryl]pyrimidines respectively (‘Anil synthesis’). Furthermore, the Schiff′s bases derived from p-chloroaniline and 4-(pyrimidine-2-yl and 4-yl)benzaldehydes give, with methyl- and with p-tolyl-substituted heterocycles, the corresponding heterocyclic substituted styryl and stilbenyl derivatives. Alkyl-, alkoxy- or phenyl-substituted pyrimidines undergo also the ‘Anil synthesis’. 相似文献
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Adolf Emil Siegrist Gza Kormny Guglielmo Kabas Hans Schlpfer 《Helvetica chimica acta》1977,60(7):2334-2370
Preparation of heterocyclic substituted stilbenyl derivatives of 2H-1,2,3-triazole Schiff's bases derived from 2- and 4-(p-formylphenyl)-2H-1,2,3-triazoles and o- or p-chloroaniline are reacted with various p-tolyl substitued aromatic heterocycles in the presence of dimethylformamide and potassium hydroxide or potassium t-butoxide to yield the corresponding heterocyclic substituted stilbenes (“Anilsynthesis”). In order to avoid opening of the 2H-1,2,3-triazole ring, the reaction is carried out without external heating. In many cases an improvement in yield is obtained by irradiation with UV. light at the beginning of the reaction. 相似文献
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Preparation of Stilbenyl Derivatives of Pyrazoles Schiffs bases derived from 1-, 3- and 5-(p-formylphenyl)phenylpyrazoles and p-chloroaniline are reacted with various p-tolyl substituted aromatic heterocycles in the presence of dimethylformamide and potassium hydroxide or potassium t-butoxide to yield the corresponding heterocyclic substituted stilbenes (anil synthesis). Introduction of a chloro substituent in the 4- and 4,5-positions of the pyrazole system causes a decrease in yield and a hypsochromic shift in the absorption and fluorescence maxima of the title compounds. 相似文献
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Adolf Emil Siegrist 《Helvetica chimica acta》1981,64(3):662-680
Preparation of Styryl and Stilbenyl Derivatives of 1H-Benzotriazoles 1-(p-Tolyl)-substituted 1H-benzotriazoles react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding 1-(styr-4′-yl)-1H-benzotriazoles and 1-(stilben-4′-yl)-1H-benzotriazoles, respectively (‘anil synthesis’). Further, under the same reaction conditions, the Schiff's bases derived from p-chloroaniline and 4-(1′H-benzotriazol-1′-yl)benzaldehydes give, with p-tolyl-substituted heterocycles, the corresponding heterocyclic substituted stilbenyl derivatives. 相似文献
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Preparation of styryl derivatives of 3-phenyl-benzisoxazole 3-(p-Tolyl)-1,2-or 2, 1-benzisoxazoles and 6-methyl-3-phenyl-1,2-benzisoxazoles react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide or potassium t-butoxide to yield the corresponding 3-(stilben-4-yl)-1,2- or 2,1-benzisoxazoles and the 3-phenyl-6-styryl-1,2-benzisoxazoles respectively (‘Anil Synthesis’). Further, the Schiff's bases derived form chloroanilines and 3-(p-formylphenyl)-1,2-benzisoxazoles yield, with methyl-and p-tolyl substituted heterocyles the corresponding heterocyclic substitued styryl and stilbenyl derivatives. 相似文献
7.
Adolf Emil Siegrist Hans Rudolf Meyer Peter Gassmann Serge Moss 《Helvetica chimica acta》1980,63(5):1311-1334
Preparation of Styryl and Distyryl Derivatives of Pyridine 2,4-, 2,5- and 2,6-Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines (‘anil synthesis’). Under the same reaction conditions (4-methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines. Similarly, the Schiff's base derived from pyridine-3-carbaldehyde and p-chloroaniline on treatment with methyl- and p-tolyl-substituted aromatic heterocycles gives the corresponding (heteroaryl-styryl)pyridines, whereas with the Schiff's bases derived from pyridine-2- and -4-carbaldehyde side reactions, such as dimerization followed by disproportionation predominate. 相似文献
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Preparation of styryl derivatives of 2-phenyl-imidazo [1, 2-a]pyridine 2-(p-Tolyl)-imidazo [1, 2-a]pyridines and 7-methyl-2-phenyl-imidazo [1,2-a]-pyridines can be converted, in dimethylformamide, on reaction with anils of aromatic aldehydes in the presence of potassium hydroxide or potassium t-butoxide, into the corresponding 2-(stilben-4-yl)- and 2-phenyl-7-styry1-imidazo [1, 2-a]-pyridines (‘Anil-Synthesis’). The 2-(p-tolyl)-imidazo [1,2-a]pyridines react far less readily than the 7-methyl-2-phenyl-imidazo[1,2-a]pyridines. 相似文献
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Preparation of styryl derivatives of 2-phenyl-4H-1,2,4-triazolo [1,5-a]pyridine 7-Methyl-2-phenyl- and 2-(3-chloro-4-methylphenyl)-4H-1,2,4-triazolo[1,5-a]-pyridines react with anils of aromatic aldehydes in the presence of dimethyl-formamide and potassium hydroxide at 20–45° to yield the 2-phenyl-7-styryl- and 2-(2-chloro-stilben-4-yl)-4H-1,2,4-triazolo [1,5-a]pyridines respectively (‘Anil Synthesis’). Further, the Schiff's bases derived from o-chloroaniline and 2-(p-formyl-phenyl)- and 7-formyl-2-phenyl-4H-1,2,4-triazolo [1,5-a]pyridine yield, with methyl- and with p-tolyl-substituted heterocycles, the corresponding heterocyclic substituted styryl and stilbenyl derivatives. 相似文献
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Robert W. Gray Armin Guggisberg Klaus Peter Segebarth Manfred Hesse Hans Schmid 《Helvetica chimica acta》1976,59(2):645-649
The Constitution of Loroglossine. Loroglossine, a characteristic constituent of orchids, is shown to be bis-[4-(β-D -glucopyranosyloxy)-benzyl]-(2 R, 3 S)-2-isobutyl-tartrate ( 1 ). Hydrolysis and esterification gave 1 mol-equiv. of dimethyl (+)-2-isobutyl-erythro-tartrate ((+)-3) and 2 mol.-equiv. of a glucoside which, after acetylation, gave 4 , identical with a synthetic sample. The erythro configuration of (+)- 3 by oxidation of isobutyl-maleic acid with osmium tetroxide and subsequent esterification. The absolute configuration of (+)- 3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 7 and 8 with S (+)- and R (?)-α-phenylbutyric acid respectively. 相似文献
18.
Peter Wieland 《Helvetica chimica acta》1978,61(8):3068-3071
Preparation of Cortexon-Analogs with Conformatively Fixed Side Chain The synthesis of cortexon-analogs with a conformatively fixed side chain is described. The key step in the synthesis consists of an intramolecular displacement of bromine in position 21 by the oxygen of a 17α-hydroxymethyl group. 相似文献
19.
Peter Wieland 《Helvetica chimica acta》1976,59(4):1027-1034
New methods for the preparation of 21-fluoro-steroids. 21-Fluoro-20-oxosteroids are obtained either by reacting a 21-diazo-20-oxo-steroid with hydrofluoric acid or by subjecting a 21-mesyloxy-20-oxo-steroid to reduction with the radical anion derived from lithium and biphenyl, followed by treatment of the resulting enolate with perchloryl fluoride. 相似文献