Showing papers on "Pyran published in 2009"
TL;DR: Phosphine-catalyzed cycloaddition of ethyl-2,3-butadienoate with enone (S)-3b occurs with high levels of regio- and stereocontrol to deliver the cis-fused cyclopenta[c]pyran 4 characteristic of the iridoid family of natural products.
137 citations
TL;DR: The structure of five alkyl substituted variants of 1 that are also present in smoke are reported, and the analogue of 3,5-dimethyl-2H-furo[2,3-c]pyran-2-one was identified at levels that indicate that it is a contributor to the overall germination-promoting activity of crude smoke extracts.
Abstract: The butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one (1), is a major compound in smoke responsible for promoting the seed germination of a wide range of plant species. We now report the structure of five alkyl substituted variants of 1 that are also present in smoke. The concentrations of these analogues, as well as that of 1, in a typical smoke−water solution have been determined using high-performance liquid chromatography (HPLC) purification followed by gas chromatography−mass spectrometry (GC-MS) analysis. The analogue, 3,5-dimethyl-2H-furo[2,3-c]pyran-2-one (3), was identified at levels that indicate that it is a contributor to the overall germination-promoting activity of crude smoke extracts.
134 citations
TL;DR: The synthesis of spirocyclic oxindole pyran and oxepene frameworks using highly stereoselective Prins cyclizations of homoallylic and bis-homoallylic alcohols and isatin ketals is described.
89 citations
TL;DR: In this article, a three-component reaction of aldehydes, dimedone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature is described.
Abstract: An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, 1,3-diketone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol. An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, dimedone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol.
86 citations
TL;DR: Merocyanines where a polyenic spacer separates a 4H-pyran-4-ylidene moiety and different strong organic acceptors have been synthesized with weakly alternated structures and remarkably zwitterionic ground states, with a partial aromatic character that is compared to those of other pyran derivatives.
Abstract: Merocyanines where a polyenic spacer separates a 4H-pyran-4-ylidene moiety and different strong organic acceptors have been synthesized. According to NMR studies and X-ray diffraction data, these compounds have weakly alternated structures and remarkably zwitterionic ground states, with a partial aromatic character that is compared to those of other pyran derivatives. The proaromaticity of the 4H-pyran-4-ylidene donor lies behind the cyanine-like behavior and low (positive or negative) second-order optical nonlinearities of the shorter derivatives. On the other hand, lengthening the π-spacer gives rise to rapidly increasing μβ1907 values up to 17,400 × 10−48 esu.
84 citations
TL;DR: A series of novel chiral multifunctionalized 4H-pyran derivatives were easily accessed via the one-pot asymmetric Michael addition-cyclization reaction between malononitrile and beta,gamma-unsaturated alpha-keto esters catalyzed by chiral bifunctional thiourea-tertiary amine catalysts.
Abstract: A series of novel chiral multifunctionalized 4H-pyran derivatives were easily accessed via the one-pot asymmetric Michael addition-cyclization reaction between malononitrile and beta,gamma-unsaturated alpha-keto esters catalyzed by chiral bifunctional thiourea-tertiary amine catalysts. With the optimized reaction conditions, the desired products were obtained with 50-68% yields and 72-88% ees. (c) 2009 Elsevier Ltd. All rights reserved.
59 citations
TL;DR: An organocatalytic multicomponent reaction involving 3,4-dihydro-(2H)-pyran, aromatic aldehydes, and urea/thiourea as substrates and l -proline/TFA as catalyst afforded hexahydropyrano pyrimidinones (thiones) in good yields as mentioned in this paper.
51 citations
TL;DR: In this article, a simple, clean, and environmentally benign three-component process for the synthesis of 4H-benzo[b]pyran derivatives using basic ionic liquid N,N-dimethylaminoethylbenzyldimethylammonium chloride ([PhCH2Me2N+CH2CH2NMe2]Cl−) as an efficient catalyst under solvent-free condition is described.
Abstract: A simple, clean, and environmentally benign three-component process for the synthesis of 4H-benzo[b]pyran derivatives using basic ionic liquid N,N-dimethylaminoethylbenzyldimethylammonium chloride ([PhCH2Me2N+CH2CH2NMe2]Cl−) as an efficient catalyst under solvent-free condition is described. A wide range of aromatic aldehydes easily undergoes condensation with malononitrile and 5,5-dimethylcyclohexane-1,3-dione (dimedone) under solvent-free condition to afford the desired products of good purity in excellent yields. Taking into account environmental and economical considerations, the protocol presented here has the merits of environmentally benign, simple operation, convenient workup, and good yields. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:91–94, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20516
48 citations
TL;DR: The Sonogashira products and the tricyclic lactones obtained showed a high growth inhibitory effect on all the tested cell lines, with GI(50) values in the muM range.
43 citations
TL;DR: A convenient synthesis of the pyrano[2,3-e]isoindol-2-one ring system, an heteroanalogue of angelicin, is reported, using 5-dialkylamino- or 5-hydroxymethylene intermediates as building blocks.
42 citations
TL;DR: Anti-proliferative tests indicated that 2-naphthyl substituted (R)-5,6-dihydro-2H-pyran-2-one has slightly better cytotoxicity than (R-goniothalamin), and new analogues which may have less conformational changes compared to the lead compound are given.
TL;DR: In this paper, O'Neill et al. used prins and olefin cross-metathesis reactions as the key steps for the stereoselective total synthesis of (+)-strictifolione and (6R)-6-[(4R, 6R)-4, 6-dihydroxy-10-phenyldec-1-enyl]-5,6-dhydro-2H-pyran-2-one.
Abstract: Prins and olefin cross-metathesis reactions were used as the key steps for the stereoselective total synthesis of (+)-strictifolione and (6R)-6-[(4R,6R)-4,6-dihydroxy-10-phenyldec-1-enyl]-5,6-dihydro-2H-pyran-2-one. Removal of MOM protecting groups under neutral conditions using CeCl3·7H2O is an attractive addition to the present strategy.
TL;DR: In this article, an efficient and convenient approach to the synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5, 6, 7, 8- tetrahydro benzo[b]pyran derivatives using tetrabutylammonium bromide (TBABr) as the catalyst is described.
Abstract: An efficient and convenient approach to the synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5, 6, 7, 8- tetrahydro benzo[b]pyran derivatives using tetrabutylammonium bromide (TBABr) as the catalyst is described. This method provides several advantages such as neutral conditions, high yields and simple work procedure.
TL;DR: One important symbol of green chemistry is to diminish of the use of organic solvents because of the economical and environmental concerns associated with them as discussed by the authors, and water is a green and cheap solvent.
TL;DR: A variety of alpha,beta-unsaturated 1,3-diketones cyclize to 2, 3-dihydro-4H-pyran-4-ones in an acidic aqueous medium, with exceptions being alpha, beta-uns saturated 1,2-dicketones in which the beta carbon is substituted by a phenyl group.
Abstract: A variety of α,β-unsaturated 1,3-diketones cyclize to 2,3-dihydro-4H-pyran-4-ones in an acidic aqueous medium, with exceptions being α,β-unsaturated 1,3-diketones in which the β carbon is substituted by a phenyl group. Addition of 1-butanamine to the reaction medium results in the formation of 2,3-dihydro-4-pyridinones, which appear to arise via an initial 1,4-addition of the amine to the α,β-unsaturated 1,3-diketones.
TL;DR: A facile and efficient diastereoselective one-pot synthesis of polycyclic acetal-fused pyrano[3,2-c]pyrane-5(2H)-one and pyranopyrones demonstrated anticancer activities.
Abstract: A facile and efficient diastereoselective one-pot synthesis of polycyclic acetal-fused pyrano[3,2-c]pyrane-5(2H)-one was achieved through the annulation reaction of 2-C-formyl glycals with various 4-hydroxycoumarins and 4-hydroxy-6-methyl-2H-pyran-2-one. The asymmetric induction was significantly influenced by the C-4 stereogenic center of 2-C-formyl glycals. The resulting polycyclic acetal-fused pyranopyrones demonstrated anticancer activities.
TL;DR: In this paper, an unexpected four-component reaction of an alkyl isocyanide with Alkylidene-substituted Meldrum's acid in CH2Cl2 at room temperature produces imino-furopyranones in good yields.
TL;DR: In this article, Toluenesulfonic acid was used to catalyze the coupling of (Z)-hex-3-ene-1,6-diol with a series of aldehydes by means of intramolecular-Prins-cyclization to provide the corresponding hexahydro-2H-furo[3,2-c]pyran derivatives in good yields with complete cis-selectivity.
TL;DR: Synthesis of polyhydroxylated oxabicyclo[4,4,0]decanes, which constitute a new family of annulated carbasugars, has been accomplished in a stereoselective manner by employing readily available 1,2-anhydro-3, 4,6-tri-O-benzyl-alpha-d-glycopyranoses.
Patent•
15 Jul 2009TL;DR: In this article, solid forms of anhydrous (2S,3R,4R,5S,6R)-2-(4-chloro-3-4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol are disclosed, in addition to methods of their use in the treatment of various diseases and disorders.
Abstract: Solid forms of anhydrous (2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol are disclosed, in addition to methods of their use in the treatment of various diseases and disorders.
TL;DR: Seven new title compounds are produced from commercial dehydroacetic acid converted into 4-hydroxy-6-methylpyridin-2(1H)-one, which was then condensed with several aliphatic aldehydes to produce seven new titles compounds in variable yields.
Abstract: Commercial dehydroacetic acid was converted into 4-hydroxy-6-methylpyridin-2(1H)-one (3), which was then condensed with several aliphatic aldehydes to produce seven new title compounds in variable yields (35–92%). Reaction of 3 with α,β-unsaturated aldehydes resulted in the formation of condensed pyran derivatives 4g' and 4h'. A mechanism is proposed to explain the formation of such compounds. The effects of all methylpyridin-2(1H)-one derivatives on the development of the dicotyledonous species Ipomoea grandifolia and Cucumis sativus and the monocotyledonous species Sorghum bicolor were evaluated. At the dose of 6.7 × 10-8 mol a.i./g substrate the compounds showed some phytotoxic selectivity, being more active against the dicotyledonous species. These compounds can be used as lead structures for the development of more active phytotoxic products.
TL;DR: In this article, the synthesis, NMR and mass spectrometric characterisation of a several novel compounds of the naphthopyran family containing either halogen or phosphonate substituents are reported.
TL;DR: A practical stereoselective synthesis of (6S)-5,6,dihydro-6-[(2R)-2-hydroxy-6-phenyl hexyl]-2H-pyran-2-one, a potent natural antifungal compound, is described.
TL;DR: Tandem reactions of cis-2-acyl- 1-alkynyl-1-aryl cyclopropanes tuned by gold(i) and silver( i) catalysts are described, which afford selectively the key pyran-fused indene cores and the 2,4,6-trisubstituted phenols in good yields.
TL;DR: In this article, a total synthesis of α,β-unsaturated lactone from Ravensara crassifolia was achieved efficiently starting from chiral 2,3-O-isopropylidene-d -glyceraldehyde (3) followed by asymmetric allylation and ring-closing metathesis.
TL;DR: In this paper, a sequential and efficient catalytic preparation of polycyclic heterocycles, including tetrahydro furo- or cyclopenta- pyran, hexahydropyrano pyrrolidine, and tetrahedroisochromene derivatives is described based on a gold-catalyzed cycloisomerization reaction followed by a Ru-calyzed ring-closing metathesis.
TL;DR: In this paper, polysubstituted 2H-pyran-2-ones and 5,6-dihydro-2H-polypyrans 2-ones were synthesized via the MCRs initiated by the hydroalkylation of alkynoates with activated methylenes.
TL;DR: In this paper, a review of nitrogen and carbon-nucleophile-induced ring transformations of selected pyran-2-one derivatives is presented, which provide convenient routes for the synthesis of different heterocycles and carbocycles as well as β-heteroaryl-α,β-didehydroamino acid derivatives.
Abstract: In this review we report on several recently described nitrogen- and carbon-nucleophile-induced ring transformations of selected pyran-2-one derivatives. These reactions provide convenient routes for the synthesis of different heterocycles and carbocycles as well as β-heteroaryl-α,β-didehydroamino acid derivatives.
TL;DR: In this paper, a palladium-catalyzed amination reaction was proposed for 5-arylamino-4H-pyran-4-one units via Buchwald-Hartwig type amination.