共查询到20条相似文献,搜索用时 15 毫秒
1.
An innovative route for the synthesis of substituted naphtho[2,1-b]furan has been delineated through a ring transformation reaction of suitably functionalized 2H-pyran-2-ones by reaction with 6,7-dihydro-5H-benzofuran-4-one, in good yield. 相似文献
2.
A novel synthesis of highly functionalized alkylsulfanylmethyl arenes 8a-m through the ring transformation of 6-aryl-4-methyl/ethylsulfanyl-2H-pyran-2-one-3-carbonitriles 1a-j, by reaction with methyl vinyl ketone 2, is delineated and illustrated. To ascertain the course of reaction, 3-arylsulfanylmethyl-2-methyl-6-methylsulfanyl-4-phenylbenzonitriles 8k-m were also prepared from the reaction of 1 with 4-arylsulfanyl-butan-2-ones 7c,d. 相似文献
3.
Diptesh Sil 《Tetrahedron letters》2005,46(30):5013-5015
A one-pot efficient synthesis of highly functionalized 5,6-dihydronaphthalenes has been delineated through carbanion-induced ring transformation of 2H-pyran-2-ones by 2-cyclohexenone. 相似文献
4.
Vittorio Bertacche 《Tetrahedron》2007,63(39):9652-9662
A new synthesis of substituted 4-dialkylaminopyridines was developed, starting from 3-nitropyran-2-one N-functionalized amidines. Secondary amines were reacted with the amidines in a sealed tube and in ethanol as the solvent yielding exclusively 4-dialkylaminopyridine derivatives or a mixture with 4-methylpyridine derivative, depending on the C-α-linked substituents of the starting amidine. Structural elucidation of the 4-dialkylaminopyridines revealed their existence as two tautomeric forms, depending on the solvent. 相似文献
5.
Suitably functionalized 3-carbomethoxy/cyano-2H-pyran-2-ones are excellent synthons for the synthesis of arenes and heteroarenes of therapeutic importance. The compounds 6-aryl-3-cyano-4-methylsulfanyl-2H-pyran-2-ones have been transformed into bridgedhead azolopyrimidines and imidazothiazines through thermal and base-induced ring transformation reactions with aminoazoles and imidazolidin-2-thiones, respectively. 相似文献
6.
A concise approach to 5-arylamino-4H-pyran-4-ones is described via palladium-catalyzed amination reaction. The methodology involved in this Letter is based on protection/deprotection protocols and on manipulation of the 5-hydroxy group of readily available kojic acid. It would provide a new entry to a range of 5-arylamino-4H-pyran-4-ones via Buchwald-Hartwig-type amination reaction on 4H-pyran-4-one unit. 相似文献
7.
Diptesh Sil 《Tetrahedron letters》2004,45(44):8195-8197
An efficient synthesis of ethyl 7-aryl-2-methyl-4H,5H-pyrano[3,4-c]pyran-4,5-dione-1-carboxylate 5, and ethyl 6-aryl-3-cyano-2H-pyran-2-one-4-acetate 6 has been delineated by reaction of suitably functionalized 2H-pyran-2-ones 1 with ethyl acetoacetate 2. 相似文献
8.
Highly functionalized (E)-stilbenes 3a-m and 4-aryl-6-styryl-pyran-2-ylidineacetonitriles 4a-b have been prepared and delineated through the ring transformation of 6-aryl-3,4-disubstituted-2H-pyran-2-ones 1 with commercially available (E/Z)-4-phenyl-3-buten-2-one 2 without the use of any catalyst. 相似文献
9.
10.
Farhanullah 《Tetrahedron letters》2007,48(18):3187-3190
An innovative and efficient synthesis of highly congested 2-amino-3-aminomethyl-5-methylsulfanyl/sec-aminobiphenyl-4-carbonitriles 4 has been delineated through base catalyzed ring transformation of 6-aryl-4-methylsulfanyl/sec-amino-2H-pyran-2-one-3-carbonitriles 1 with Boc-protected 1,3-diamino-2-propanone 2, followed by TFA catalyzed hydrolysis of the intermediate [3-tert-butoxycarbonylaminomethyl-4-cyano-5-methylsulfanyl/sec-aminobiphenyl-2-yl]carbamic acid tert-butyl ester 3 in moderate yields as the TFA salts. 相似文献
11.
An innovative route for the synthesis of substituted dibenzofurans has been delineated through a ring transformation reaction of suitably functionalized 2H-pyran-2-ones by reaction with 7-methoxybenzofuran-3-one, in high yield. The novelty of the procedure lies in the creation of an aromatic ring from a 2H-pyran-2-one involving the -COCH2-moiety of the substrate. 相似文献
12.
Ludivine Jean-Gérard Sylvain Collet André Guingant Michel Evain 《Tetrahedron》2007,63(46):11250-11259
An investigation of the one-carbon homologation of some 1-tribromomethyl-isoquinoline and 2-tribromomethyl-quinoline derivatives was conducted. Under the influence of an aqueous solution of silver nitrate in the presence of a nucleophilic species (MeOH, H2O, EtNH2), these derivatives led to the respective expanded heterocycles, 2H-1- and 2H-3-benzazepin-2-one derivatives. A mechanism for this novel ring enlargement involving initial formation of an aziridinium, and its subsequent opening to form a stabilized benzylic carbocation, is proposed to explain the results. 相似文献
13.
A one-pot synthesis of 2,3,5-trisubstituted cyclopentadienones has been delineated through ring contraction of suitably functionalized 2H-pyran-2-ones using either cyanoacetamide or methyl cyanoacetate. 相似文献
14.
A concise synthesis of some new classes of heterocycles (4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a-diaza-cyclopenta[a]anthracen-6-carbonitriles and 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a-diazabenzo[a]anthracene-7-carbonitriles) has been developed by the ring transformation of suitably functionalized 2H-pyran-2-one with α-oxoketene cyclic aminals to intermediates (8-aroyl-5-aryl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-7-ylidene)-acetonitriles and (9-aroyl-6-aryl-1,2,3,4-tetrahydropyrido[1,2-a]pyrimidin-8-ylidene)-acetonitriles) followed by their photocyclization either in CHCl3 or acetonitrile. This reaction was further explored for the synthesis of methyl 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carboxylate, 4-aryl-11-oxo-1,2,3,11-tetrahydro-1,3a,9-triaza-cyclopenta[a]anthracene-6-carbonitriles, 5-aryl-12-oxo-1,3,4,12-tetrahydro-2H-1,4a,10-triazabenzo[a]anthracene-7-carbonitriles, 4-aryl-10-oxo-1,2,3,10-tetrahydro-9-thia-1,3a-diazadicyclopenta[a,g]naphthalene-6-carbonitriles and 5-aryl-11-oxo-1,3,4,11-tetrahydro-2H-10-thia-1,4a-diazacyclopenta[b]phenanthrene-7-carbonitriles from the similar reactions. 相似文献
15.
Ramendra Pratap 《Tetrahedron letters》2005,46(30):5025-5027
The one-pot substituent-directed regioselective synthesis of 1,7-diaryl-2-methyl-4H,5H-pyrano[3,4-c]pyran-4,5-diones 3 as the major and 3,4-diaryl-2-methyl-6-methylsulfanylbenzonitriles 4 as the minor products has been delineated through ring transformation of suitably functionalized 2H-pyran-2-ones 1 with aryl acetones 2. Under similar reaction conditions, 6-aryl-4-sec-amino-2H-pyran-2-ones 5 led, regioselectively, to 3,4-diaryl-2-methyl-6-sec-aminobenzonitriles 6. 相似文献
16.
Lewis acid promoted anomeric substitution reactions of a stereoselectively prepared hexahydro-2H,5H-pyrano[2,3-b]pyran-2-one derivative was studied as a model for diarylheptanoid synthesis. Aromatic nucleophiles consistently provided the expected thermodynamic C-aryl pyranoside product. 相似文献
17.
Sung Hwan KimSangku Lee Se Hee KimJin Woo Lim Jae Nyoung Kim 《Tetrahedron letters》2012,53(37):4979-4983
An indium-mediated Barbier type mono-allylation of 1,5-dicarbonyl compounds and a subsequent acid-catalyzed dehydrative cyclization afforded 2,3-dihydro-4H-pyran-4-ones and 3,4-dihydro-2H-[1,4]oxazines. 相似文献
18.
Anastasia A. Fesenko 《Tetrahedron》2009,65(11):2344-462
A general six-step approach to 6-tosyl-2,3,4,5-tetrahydro-1H-1,3-diazepin-2-ones has been developed. The key step involves a ring expansion reaction of 4-mesyloxymethyl- or 4-tosyloxymethyl-5-tosyl-1,2,3,4-tetrahydropyrimidin-2-one mediated by nucleophilic reagents. 相似文献
19.
Wen-Guo Zhao 《Tetrahedron》2007,63(48):11803-11808
The reaction of 1,3-dicarbonyl compounds such as acetoacetate, acetylacetone, dibenzoylmethane, and benzoylacetate with electron-deficient internal alkynes in the presence of catalytic amount of ReBr(CO)5 in toluene under neutral conditions resulted in the formation of 4,5,6-trisubstituted 2H-pyran-2-ones in moderate to high yield. The reaction took place via a two-step sequence including the rhenium(I)-catalyzed addition of the activated methylenes to alkynes to give enolic 2-alkenyl derivatives, and subsequently dealcoholic cyclization to form 2H-pyran-2-one derivatives. 相似文献
20.
A regioselective synthesis of aryl substituted arylacetates through ring transformation by ethyl levulinate 总被引:1,自引:0,他引:1
Ramendra Pratap 《Tetrahedron letters》2006,47(30):5389-5391
A regioselective synthesis of sterically hindered ethyl arylacetates in one step through ring transformation of suitably functionalized 6-aryl-3,4-disubstituted-2H-pyran-2-ones with ethyl levulinate at room temperature in excellent yields is described. 相似文献