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2-Alkoxy-3-nitro-2H-chromenes have been obtained by the reaction of β-nitroacetaldehyde dialkyl acetals with some salicylic aldehydes in the presence of triethylamine p-toluene sulfonate. 相似文献
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The partial synthesis of pollinastanol (14) from cycloartanol (3) is reported. The transformation proceeds through the methylenic intermediate 12; the ring enlargement with cyanogen azide affords pollinastanone (13) further reduced to 14, The 4-keto isomer of pollinastanone (17) as well as a series of 5-β isomeric compounds are also described. 相似文献
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Some furochromenes substituted at the 2-position by an electron-attracting group were obtained starting from ortho-hydroxyformyl derivatives of 2,2-dimethyl-2H-chromene following various processes which are indicated. These new furochromenes are pharmacochemical analogues of some natural pyranocoumarins, and as such they are potential photosensitizers. 相似文献
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Jean Guillaumel Pierre Demerseman Jean-Marc Clavel Ren Royer 《Journal of heterocyclic chemistry》1980,17(7):1531-1536
When treated with acetyl chloride and ferric chloride in methylene chloride, at 0°, monosubstituted β-nitrostyrene derivatives such as 2,3 or 4-methyl, -chloro or -fluoro and 3-nitro-β-nitrostyrenes cyclize into the new corresponding 3-chloro-1,3-dihydro-2H-indol-2-one. Reaction with other metal chlorides such as aluminum chloride and titanium tetrachloride does not lead to these heterocyclic derivatives but only produces N-acetyl-N-hydroxy-α-chlorobenzeneacetamides and/or N-(acetyloxy)-α-chlorobenzeneethanimidoyl chlorides. 相似文献
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Condensed 2-pyridones have been prepared by thermal cyclization of vinyl isocyanates substituted in β-position with aromatic heterocyclic radicals. 相似文献
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Axel Couture Pierre Grandclaudon Eric Huguerre 《Journal of heterocyclic chemistry》1987,24(6):1765-1769
It has been established that the direct condensation between aromatic and aliphatic thioesters and the variously generated anion of amino-chloropyridines represents the best method for the synthesis of thiazolo-pyridines. The transient thioamides, sometimes isolated, can be easily converted chemically or photochemically into the desired fused heterocycles. 相似文献
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Triphenyl and tributyltin hydrides have been found to add to the terminal double bond of unsaturated ethyl malonates to give organotin substituted ethyl malonates. Attempted cyclisation of the latter into barbituric compounds failed. 相似文献
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A general synthetic route to new 3-acyl-5-ylidenetetronic acids by rearrangement in the presence of bases of 4-carbethoxy-2-ylidene[2H]-3-furanones is described. 相似文献
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A General Synthesis for Mono-C-Functionalized Tetrazamacrocycles A new synthesis, under usual conditions of concentration, medium, and temperature, of a series of mono-C-functionalized tetraazamacrocycles is given. The method may easily be generalized. The new procedure allows the modification of the length of the side-chain or the size of the cavity by choosing fitted staring materials. The key intermediate has a tosylated linear side-chain susceptible to be transformed into a large variety of functional groups. 相似文献
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Synthesis of amino-sugars using reductive amination reactions. Preliminary communication Treatment of aldehydo- or keto-sugars with primary or secondary amines and hydrogen in the presence of a catalyst (Pd/C) gave with good to excellent yields (67–96%) the expected secondary or tertiary amines. Primary amines can be obtained by using benzylamine, a hydrogenolysis taking place during the reaction. 相似文献
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Three new zinc bis(dipyrromethene) complexes have been isolated in the preparation of meso-tetramesitylporphyrin by the Rothemund zinc template based condensation process. 相似文献
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Synthesis of Novel Types of C-Glycosyl-derivatives from Acetylenic Sugars or Partial Synthetic Equivalents thereof The concept of synthetic equivalent is not unequivocal and, for example, α-fluoroenamines may behave in some cases as synthetic equivalents of ynamines and, in other situations, quite differently. Some uses of these α-fluoroenamines, ‘partial synthetic equivalents’ of ynamines, for the synthesis of C-glycosyl derivatives of coumarins, chromones, quinolines, quinolones, thietenes and isoxazoles are described. We also report the preparation of a series of mono- and diglycosylthiophenes by reacting HS? with mono- and diglycosylbutadiynes. Acetylenic sugar derivatives have also been used for the synthesis of a diglycosylazaphosphorine and a spirooxolenone. 相似文献
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R. Buyle 《Helvetica chimica acta》1966,49(4):1425-1429
By reacting an α-amino acid N-carboxyanhydride with an amidoxime the dioxopiperazine derived from the parent amino acid is formed in quantitative yield. In this way the dioxopiperazine of glutamic acid, which is not otherwise accessible, has been prepared. 相似文献