共查询到20条相似文献,搜索用时 46 毫秒
1.
Russian Journal of General Chemistry - A highly efficient one-pot three-component synthesis of 2-amino-3-cyano-4H-chromenes has been developed by annulation of aldehydes, malononitrile and dimedone... 相似文献
2.
The synthesis of substituted 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-2-hydroxy-2H-chromenes 2a-o was achieved in good yields by intramolecular cyclization of 3-(perfluoroalkyl)-3-phenoxypropenals 1 in the presence of aluminum chloride. Then a Lewis acid mediated nucleophilic reaction with silyl enol ethers 3 proceeded with complete regiospecificity to afford 4-functional 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-4H-chromenes 4a-p with high yields. 相似文献
3.
The preparation of substituted 2-amino-4H-chromenes by a Na2CO3-catalyzed reaction of malononitrile, benzaldehydes, and phloroglucinol or resorcinol in aqueous medium and at room temperature is reported. The merits of this procedure include limited use of organic solvents, easy workup technique, and high purity of products. The 2-amino-4H-chromenes were prepared in yields of 54–96%. 相似文献
4.
The treatment of substituted 2-hydroxybenzaldehydes by nitroethylene, prealably prepared or generated in situ within the reaction, in the presence of di-n-butylamine gave 3-nitro-2H-chromenes in fair to excellent yields. 相似文献
5.
A modular and highly efficient protocol for the synthesis of 2-aryl- and heteroaryl-2H-chromenes is described. Under base-free conditions, readily accessible 2-ethoxy-2H-chromenes undergo C(sp(3))-O activation and C(sp(3))-C bond formation in the presence of an inexpensive nickel catalyst and boronic acids. This new strategy enables broad access to 2-substituted-2H-chromenes and has been applied to the late-stage incorporation of complex molecules, including the pharmaceuticals loratidine and indomethacin methyl ester. 相似文献
6.
Treatment of 2-hydroxybenzaldehydes by potassium t-butoxide in THF at 0°C, followed by addition of β-nitroenones 1 affords 2-acyl-2-alkyl-4-hydroxy-3-nitrochromanes 3. Subsequent treatment of these nitro alcohols by silica gel at 50°C leads to the desired 2-acyl-2-alkyl-3-nitro-2H-chromenes 4 in good yields. 相似文献
7.
[reaction: see text] An unexpected tetrahydrothiophene-catalyzed ylide annulation reaction, via tandem Michael addition/elimination/substitution, for the controllable synthesis of 2H-chromenes and 4H-chromenes has been developed. 相似文献
8.
The antijuvenile hormones Precocene-I, Precocene-II and other bioactive 2, 2-dimethyl-2H-chromenes have been synthesised by intramolecular oxidative cyclisation of 2-isoprenyl phenols catalysed by a palla-dium(II) salt. 相似文献
9.
Osipov Dmitry V. Demidov Maxim R. Osyanin Vitaly А. Klimochkin Yuri N. 《Chemistry of Heterocyclic Compounds》2021,57(12):1170-1175
Chemistry of Heterocyclic Compounds - A two-step procedure was proposed for the synthesis of 2-aryl- and 2,4-diaryl-substituted 4H-chromenes by the formal [4+1] cycloaddition reaction of o-quinone... 相似文献
10.
The reaction of 2-tert-butyl-1-benzopyrilium perchlorate with various reducing agents leads to a mixture of 2H- and 4H-chromenes. The greatest selectivity (90% 2-tert-butyl-4H-chromene and 10% 2H-isomer) was achieved using 1,3-dimethylbenzimidazoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 313–315, March, 1989. 相似文献
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12.
The reactions of sodium bis(2-methoxyethoxy)aluminum hydride with 3-cyano-6-methylpyridine-2(1H)-thione and 3-cyano-6-methyl-2-methylthiopyridine afforded 3-aminomethyl-6-methylpyridine-2(1H)-thione and azomethine of the pyridine series, respectively. The corresponding reaction with 3-cyano-4,6-dimethyl-2-methylthiopyridine gave rise to azomethine, substituted 3-aminomethylpyridine, and substituted dipyridylmethane. 相似文献
13.
Some new azo sulfa drugs 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinone dyes (1-6) and 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinethione dyes (1′-6′) were synthesized by coupling of 4-(N-substituted)sulfamylbenzene diazonium salts with 3-cyano-4,6-diphenyl-2-pyridinone and/or with 3-cyano-4,6-diphenyl-2-pyridin-ethione. The corresponding iron (1a-6a, 1′a-6′a), copper (1b-6b, 1′b-6′b) and mercury (1c-6c, 1′c-6′c) chelates wvere also prepared. All synthesized compounds were screened in vitro for antibacterial and antifungal activities. 相似文献
14.
Condensation of propanal with cyanothioacetamide and morpholine gave 3-cyano-4-ethyl-5-methyl-6-morpholino-2-piperidone, the
structure of which was studied by X-ray analysis. Reaction of propanal with cyanothioacetamides and cycloalkanone enamines
gave 3-cyano-4-ethyl-2,5,6,7-tetrahydropyrindin-2(1H)-one and 3-cyano-4-ethyl-5,6-hexamethylenepyridine-2(1H)-thione. The
latter was used for the preparation of substituted 2-benzyloxycarbonylmethylthiopyridine and 3-amino-2-benzyloxycarbonylthieno[2,3-b]pyridine.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1053–1059, July, 2005. 相似文献
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16.
V. P. Litvinov Yu. A. Sharanin M. P. Goncharenko V. D. Dyachenko A. M. Shestopalov 《Russian Chemical Bulletin》1991,40(8):1675-1681
The reaction of 3-cyano-1,4-dihydropyridine-2-thiolates and the corresponding selenolates with allyl bromide gave 2-allylthio- and 2-allylseleno-3-cyano-1,4-dihydropyridines, which, upon heating in various solvents or in the solid state, undergo [3,3]-sigmatropic rearrangement to give 3-cyano-3-allyl-1,2,3,4-tetrahydropyridine-2-thiones and the corresponding selenones. The resultant pyridinethiones are alkylated by alkyl halides at the sulfur atom and are oxidized by iodine to give disulfides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1888–1895, August, 1991. 相似文献
17.
Jing Li Hong-Ru Tan Yu-Long An Zhi-Yu Shao Sheng-Yin Zhao 《Journal of heterocyclic chemistry》2020,57(1):486-496
An efficient method for synthesis and demethylation of 3-cyano-4-methoxy-2-pyridone derivatives has been developed. DABCO-induced demethylation can lead to 3-cyano-4-hydroxy-2-pyridones in DMF at 90°C with high yield. The protocol is applicable for the synthesis of 3-cyano-4-hydroxy-2-pyridone derivatives. The method is simple, efficient, and practical. 相似文献
18.
Ethyl 2-chloroacetoacetate and its 4-chloro isomer react with cyanoacetamide in the presence of the mild, nonnucleophilic base, triethylamine under stoichiometric conditions to give high yields of ethyl 4-cyano-2-hydroxy-2-methyl-5-oxopyrrolidine-3-carboxylate and ethyl (4-cyano-2-hydroxy-5-oxopyrrolidin-2-yl)acetate, respectively. These, under acid-catalyzed dehydration conditions, afforded ethyl 4-cyano-5-hydroxy-2-methyl-1H-pyrrole-3-carboxylate and ethyl (2Z)-(4-cyano-5-oxopyrrolidin-2-ylidene)ethanoate, respectively. Similarly, the 4-chloro isomer reacted with ethyl cyanoacetate to give the novel product, diethyl 2-cyano-4-oxohexanedioate. The use of triethylamine enables access to a whole new library of pyrrole derivatives from easily accessible, commercially available starting materials. The reactions described in this Letter enable access to libraries of important pyrrole systems in any of the isotopically enriched forms. 相似文献
19.
The excited states and electronic transitions of some 2H-chromenes (considered responsible for photochemical opening of photochromic spiropyrans) have been studied. The relative positions of nπ* and ππ* singlet and triplet energy levels of these compounds allow a satisfactory interpretation of their optical properties. Also highly localized electronic charge transfers are demonstrated in the case of 2H-chromenes substituted by a nitro group. 相似文献
20.
V. D. Dyachenko A. A. Nikishin I. E. Dyachenko 《Russian Journal of Organic Chemistry》2011,47(8):1214-1221
The reaction of ethyl isopropylidenecyanoacetate with ethyl 3-amino-3-thioxopropanoate gave rise to ethyl 4,4-dimethyl-6-oxo-2-thioxo-5-cyanopiperidine-3-carboxylate
whose alkylation provided ethyl 2-benzylsulfanyl-4,4-dimethyl-6-oxo-5-cyano-1,4,5,6-tetrahydropyridine-3-carboxylate, ethyl
5-benzyl-2-benzylsulfanyl-4,4-dimethyl-6-oxo-5-cyano-1,4,5,6-tetrahydropyridine-3-carboxylate, and ethyl 7,7-dimethyl-5-oxo-6-cyano-3,5,6,7-tetrahydro-2H-thiazolo[3,2-a]pyridine-8-carboxylate. 相似文献