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1.
5-Substituted and 5,5-disubstituted hydantoins are synthesised from the corresponding aldehydes or ketones, using a one-pot, gallium(III) triflate-catalysed procedure that is compatible with a range of substrates and solvents. 相似文献
2.
An efficient synthesis of 9,10-disubstituted phenanthrenes is described in this Letter. These novel useful building blocks were obtained in a one-pot reaction including Suzuki-Miyaura cross-coupling followed by a Dieckmann-Thorpe ring closure under microwave irradiation. The selection of the appropriate reagents and the optimal reaction conditions to isolate the intermediate biphenyl compound or the final substituted phenanthrenes in high yields will be discussed in this Letter. 相似文献
3.
《Tetrahedron: Asymmetry》1998,9(5):817-825
(4R)-3-Amino-4-trimethylsilyloxy-2-alkenoates (R)-3, obtained from O-trimethylsilyl protected optically active cyanohydrins (R)-1 via the Blaise reaction, are hydrolyzed under mildly acidic conditions to give optically active tetronic acids (R)-4 without racemization. From the follow-up reactions of (R)-4 investigated, only methylation with diazomethane afforded the biologically active tetronic acid derivative (R)-5a without racemization whereas acylation and reductive alkylation, respectively, resulted in partial racemization or failed on the whole. 相似文献
4.
Novel 7- and 8-alkyl and aryl substituted 5-phenylmorphans were synthesized from substituted allyl halides and N-benzyl-4-aryl-1,2,3,6-tetrahydropyridine by a highly efficient and diastereoselective reaction series, "one-pot" alkylation and ene-imine cyclization followed by sodium borohydride reduction. Mild cyclization conditions gave the desired substituted 5-phenylmorphans in good yield as a single diastereomer. 相似文献
5.
6.
Several vulpinic acids were synthesized in a few steps from a single precursor, the tetronic acid. This commercial compound was converted in a few steps to an iodide. Suzuki-Miyaura cross-couplings involving this common intermediate and various arylboronates allowed to gain access to several vulpinic acids (or methyl pulvinates). Among them, two natural products, vulpinic acid and pinastric acid, were prepared. 相似文献
7.
This Letter reports an environmentally-friendly one-pot SNAr reaction of thiols to 4-halobenzoic acid methyl esters to provide 4-substituted sulfone benzoic acids and picolinic acids after bleach-mediated oxidative workup. These acid intermediates were synthesized on gram scale, are perfect partners for library synthesis, and have good physical chemical properties useful for drug discovery. 相似文献
8.
Condensation of the dianions derived from simple α-hydroxyketones and 1,2-diketones with 1,1′-carbonyldiimidazole provides a facile one step synthesis of tetronic acids and pulvinones. 相似文献
9.
Razieh Doostmohammadi Malek Taher Maghsoodlou Nourallah Hazeri Sayyed Mostafa Habibi-Khorassani 《中国化学快报》2013,24(10):901-903
A facile one-pot synthesis of 3,4,5-substituted furan-2(5H)-one derivatives from a three-component reaction of aniline derivatives, dialkylacetylenedicarboxylates and aromatic aldehydes under mild conditions using tetra-n-butylammonium bisulfate as a catalyst has been developed. 相似文献
10.
Hong-Jun Wang William G. Earley Robert M. Lewis Rajiv R. Srivastava Andrew J. Zych David M. Jenkins David J. Fairfax 《Tetrahedron letters》2007,48(17):3043-3046
A highly efficient one-pot, two-step microwave procedure has been developed for the synthesis of 4-substituted 1-heteroarylpiperazines. Microwave heating of heteroaryl chlorides with 1,4-diazabicyclo[2.2.2]octane (DABCO) at 160 °C for 15 min yielded 1-heteroaryl-4-(2-chloroethyl)piperazines, which could be further reacted with various nucleophiles, again under microwave irradiation conditions, to give an array of 4-substituted 1-heteroarylpiperazines in good to excellent yields. 相似文献
11.
12.
A new approach to the synthesis of 5-substituted 2-methyl-1,3,4-oxadiazoles was developed. 相似文献
13.
The tautomeric structures of some acetyl tetronic acids are studied by NMR analysis. 相似文献
14.
A general approach to the formation of 2-substituted benzoselenazoles from the three-component reactions of 2-iodoanilines, selenium powder, arylacetic acids or benzyl chlorides is described. The use of copper salt as catalyst and dimethyl sulfoxide (DMSO) as solvent are crucial to afford the title compounds in moderate to good yields (45–88%) with good functional group tolerance on the aromatic and heteroaromatic substrates. 相似文献
15.
A biocatalytic cascade reaction was designed for the stereoselective synthesis of optically pure 2-alkyl-1,3-diols employing two enzymes. The cascade process consists of two consecutive steps: a stereoselective diketone reduction and a hydroxy ketone reduction. Chiral diols were formed by the addition of ketoreductases in the same vessel, in high stereoselectivity and chemical yield, without the isolation of the intermediate β-hydroxy ketones. 相似文献
16.
Various 2-substituted indolizines can be directly and selectively lithiated in the 5 position and subsequent reactions with different electrophiles lead to some novel classes of indolizines. In particular, previously unknown 5-formyl- and 5-iodoindolizine have been prepared by this way and the molecular structure of 5-formyl-2- phenylindolizine was confirmed by X-Ray analysis. The reactivity of the 5-CHO- and 5- COPh groups toward some nucleophiles has been examined, and some additional classes of derivatives (oximes and alcohols) have been obtained. The possibility of Suzuki cross- coupling of 5-iodoindolizines and boronic acids was proven. 相似文献
17.
Li AH Ahmed E Chen X Cox M Crew AP Dong HQ Jin M Ma L Panicker B Siu KW Steinig AG Stolz KM Tavares PA Volk B Weng Q Werner D Mulvihill MJ 《Organic & biomolecular chemistry》2007,5(1):61-64
A highly effective one-pot Friedl?nder quinoline synthesis using inexpensive reagents has been developed. o-Nitroarylcarbaldehydes were reduced to o-aminoarylcarbaldehydes with iron in the presence of catalytic HCl (aq.) and subsequently condensed in situ with aldehydes or ketones to form mono- or di-substituted quinolines in high yields (66-100%). 相似文献
18.
The lactone of 5 - -hydroxyethylorotic acid, the thiolactone of 5-(-mercaptoethyl)orotic acid, and 5-(-benzamidobutyl)orotic acid were synthesized from substituted 5-carb-ethoxymethylenehydantoins obtained by the condensation of urea with -ethoxalyl derivatives of -butyrolactone, -thiobutyrolactone, and ethyl -benzamidocaproate. The lactam of 5-(-aminoethyl)orotic acid was synthesized by the ammonolysis of the lactone of 5 -(-hydroxyethyl)orotic acid. The acid hydrolysis of 5-(-benzamidobutyl)orotic acid gave 5-(-aminobutyl)orotic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1280–1282, September, 1971. 相似文献
19.
Peri-metalation of 4-(dimethylamino)-1-tert-butyldimethylsilyloxynaphthalene (5) followed by reaction with an electrophile and Jones' oxidation affords 5-substituted naphthoquinones. 相似文献
20.
Porntip Charoonniyomporn Suteera Witayakran Karen E.S. Phillips 《Tetrahedron letters》2004,45(3):457-459
Bisalkylthioarenes can be prepared efficiently from reactions between dihydroxyarenes and thiols under acidic conditions. 相似文献