Furanone Ring Research Articles

Iodocycloisomerization/Nucleophile Addition Cascade Transformations of 1,2-Alkynediones

A general electrophilic iodocyclization/nucleophile addition cascade transformation for 1,2-alkynediones for the synthesis of various oxygen heterocycles and access to regioselective alkyne hydroxylation is reported. Furan-tethered ynediones resulted in the construction of exo-enol ethers via carbonyl-alkyne cyclization-initiated heteroarene dearomatization, whereas other (hetero)arene-, alkenyl-, and alkyl-tethered ynediones resulted in the formation of highly functionalized 3(2H)-furanones. Importantly, the developed domino protocols involve the construction of important heterocyclic scaffolds and installation of two functional groups in a single operation. Moreover, the use of water as a nucleophile resulted in regioselective alkyne hydroxylation via furanone ring opening. The developed protocols are characterized by a wide substrate scope, and their utility has been demonstrated by a number of postsynthetic transformations.

Fungal polyketides from a rhizospheric soil-derived Penicillium sp. YUD17004 associated with Gastrodia elata

Five unprecedented polyketide metabolites were isolated and characterized from a rhizospheric soil-derived Penicillium sp. YUD17004. Their diverse structures included two indanone-type polyketides penicillyketides A and B, a phthalide-like polyketides penicillyketide C, a symmetrical chromone dimer penicillyketide D, along with a pyrone derivative pyranlyketide, which were elucidated by spectroscopic data interpretation and quantum chemical electronic circular dichroism calculation. Notably, the structures of penicillyketides A and B feature a highly functionalized indanone ring nucleus, but differ from other indanone-containing polyketides by the alkyl substitution pattern. The structure of penicillyketide C comprises a furanone ring instead of the hydroxycyclopentenone ring characteristic for penicillyketides A and B, and represents an undescribed arrangement within C17 polyketides. Penicillyketide D represented the first example of a chromone homodimer with the bridge at C-2/2′. Penicillyketide B exhibited weak anti-inflammatory activity with an IC50 value of 32 ± 1.0 μM. Penicillyketide D displayed weak cytotoxicity against MCF-7 cell line with an IC50 value of 25 ± 0.9 μM.

Ultrasonic-Assisted Synthesis and Quantum Chemical Analysis of Spiro[Indoline-3,3′-Pyrazol]-2-One Derivatives as Effective Bactericidal and Viricidal Agents

The present work described a novel synthesis of spiro[indoline-3,3′-pyrazol]-2-one derivatives 2, 4, 5, and 7 via a one-pot reaction of chalcones or β-aroyl acrylic acid 1a–c, isatin, and hydrazine derivatives e.g. hydrazine hydrate, methyl hydrazine, phenylhydrazine or acetohydrazide in sonicated reaction condition. The unexpected product 1,3-oxazino[3,2-a]indol-10-yl-ethanone derivative 6 can be generated instead of N-acetyl spiro[indoline-3,3′-pyrazol]-2-one as desired. Also, the Spiropyrazole-fused furanone and pyridazinone ring can be made. Owing to their unique 3-dimensional structures, spirooxindoles have been found as lucky chemotypes for antiviral drug enhancement in an attempt to achieve these spiropyrazole derivatives 2–10 with hydrophobic groups. Furthermore, the density functional theory (DFT) was used to elucidate the electronic and structural features of spiropyrazole derivatives and their reactive species, which supports the proposed mechanism of antibacterial and antiviral capabilities.

Experimental and theoretical insights into the enhanced intramolecular charge transfer fluorescence of a 3(2H)-furanone based d-π-A compounds tailored with dialkyl chains

As a continuance of our search for novel derivatization reagents, two new compounds possessing di-methyl and di-ethyl group at the phenyl ring of 3(2H)-furanone ring system have been designed and synthesized. The influences of different factors modulating the solvatochromic fluorescence responses of both dyes are discussed in detail. The maximum wavelengths at absorption and emission spectra, Stokes shift, quantum yields, mean fluorescence decay times, radiative and nonradiative decay constants have been determined. It is shown that the expansion of d-π-A architecture with di-alkyl groups substantially increases+ the optical properties of title compounds than the unsubstituted ones, which was synthesized previously via our research. Further, using time-dependent density functional theory (TD-DFT) calculations it turned out that the donor - acceptor groups at both ends and -C = C- linker imposes a hybridized local excitation charge transfer (HLCT) with the terminal –COOH group could serve to bind targeted analytes having –NH2 or –OH group.

Studies on analogs of DAMASCENOLIDETM: Part 3. Synthesis and odor evaluation of dimethylated, cyclopropanated, and other analogs of DAMASCENOLIDETM.

DAMASCENOLIDETM [1, 4-(4-methylpent-3-en-1-yl)furan-2(5H)-one], which has a citrus-like odor, is an important aroma component of roses. We have previously reported on the synthesis and odor evaluation of 24 analogs of 1 as part of our new aroma compound developing project. To accumulate more information on structure-odor relationships, 10 more promising analogs such as dimethylated and cyclopropanated analogs were synthesized and subjected to odor evaluation. As a result, it was found that dimethylation of the furanone ring affected the odor. It was also found that cyclopropanation of 1 affected the odor, whereas cyclopropanation of the double bond isomer of 1 did not significantly affect the odor. The effects on the odor caused by ring size expansion and replacement of the side chain were also investigated.

Analog synthesis of DAMASCENOLIDETM, an important aroma component of roses, and their odor properties.

DAMASCENOLIDETM [1, 4-(4-methylpent-3-en-1-yl)furan-2(5H)-one], which has a citrus-like odor, is an important aroma component of roses. We have previously reported on the synthesis and odor evaluation of double-bond isomers of 1 and concluded that the position and the geometric isomerism of the double-bond had a significant effect on the odor. For the purpose of deepening knowledge about structure-odor relationships, we synthesized 13 analogs of compound 1 and evaluated their odors. As a result, it was found that the presence of two double-bonds and branched methyl group at the terminal position in the side chain was essential in order to have a citrus-like odor. Substitution of the side chain with appropriate length at the appropriate 4-position of the 2(5H)-furanone ring was also an important factor in determining the quality of the odor.

Molecular and Crystal Structures of 4-Cyano-3(2H)-Furanones and Structural Effects in 1H NMR Spectra

Features of the molecular structure in crystals of a series of functionalized 4-cyano-3(2H)-furanones with a spiro-cyclohexane substituent or two methyl groups at position 2 of the furanone ring and also an aryl or heteroaryl substituent at position 5 are analyzed in comparison with the literature data. Effects appearing in 1H NMR spectra, which are caused by the features of the molecular structures of these compounds are interpreted. Their crystal structure is considered and intermolecular interactions responsible for the supramolecular architecture of the crystals formed are revealed.

Unraveling the sequence of the electronic flow along the water-assisted ring-opening reaction in mutagen MX

The ring-opening reaction of 3-chloro-4-(dichloromethyl)-5-hydroxy-5H-furan-2-one (mutagen X or MX) remains an intriguing subject of both theoretical and experimental interest. This relies on the fact of uncertainty concerning which structure acts as the real mutagen. Challenging the current accepted idea of a direct tautomeric process transforming the furanone ring to the oxobutenoic acid chain structure, a water-assisted process via a six-membered transition structure (TS) is revealed to proceed with activation energy of 24.5 kcal/mol (i.e., 26.8 kcal/mol lower than the conventional tautomeric process). An analysis based on the application of catastrophe theory to the evolution of the electron localization function topology along the intrinsic reaction coordinate reveals that the process can be explained, using a Lewis-like chemical language, as a result of the electronic activation of the furanone specie by the water molecule: on the activation pathway (i.e., before TS is reached), the electronic perturbation introduced by the water reagent is first observed on the valence shell of the ring oxygen and then on that of the hydroxylic one. Thereafter, the release of the hydroxylic hydrogen and the breaking of the C–O bond in the furanone ring follow the electronic rearrangement. On the de-activation pathway, the water molecule first captures the hydroxylic proton. Then, a hydronium-like structure transfers a proton to the oxygen of the furanone moiety contributing to stabilize the open ring structure. The above description of such a favorable ring-opening process become thus associated with nine topological structural stability domains, featuring the following sequence of catastrophes: C5H3O3Cl3 + H2O: 10-C†F†[FU]UC[C†C†]CC-0: C5H3O3Cl3 + H2O.

Synthesis of Substituted Pyridazin-3-ones, 1,2-Oxazin-3-ones, and Furopyrimidines from (Arylmethylidene)furan-2(3H)-ones

Reactions of 5-substituted 3-(arylmethylidene)furan-2(3H)-ones with hydrazine hydrate, hydroxylamine, and guanidine involved opening of the furanone ring. Their hydrazinolysis under mild conditions afforded acyclic 4-oxoalkanoic acid hydrazides which underwent heterocyclization to substituted pyridazinones in boiling ethanol. The presence of an alkyl substituent in the 5-position of the initial furanone favored heterocyclization with the formation of pyrazolidinone derivatives. The reactions of 3-(arylmethylidene)furan-2(3H)-ones with hydroxylamine and guanidine also produced new six-membered heterocycles, 2H-1,2-oxazin-3(4H)-ones and 4,6-disubstituted 3,4-dihydrofuro[2,3-d]pyrimidin-2-amines, respectively.

Simple 2(5H)-furanone derivatives with selective cytotoxicity towards non-small cell lung cancer cell line A549 – Synthesis, structure-activity relationship and biological evaluation

A series of 5-alkoxy derivatives of 3,4-dichloro-5-hydroxyfuran-2-(5H)-one (mucochloric acid, MCA) were obtained and subsequently subjected to modification in the C-4 position of 2(5H)-furanone ring. The cytotoxicity of newly synthesized compounds was evaluated in MTT assay against non-small cell lung cancer (A549) and healthy lung epithelial cell line (BEAS-2B). The derivatives containing a branched alkoxy substituent in the C-5 position demonstrated the highest anticancer properties, whereas modification of compounds in the C-4 position of 2(5H)-furanone ring only slightly improve their antiproliferative properties. Compounds 12 and 15 exhibited the best selectivity towards A549 cells and were also evaluated in a panel of cancer cell lines of different origin. Further investigation revealed that treatment of A549 cell line with compounds 12 and 15 led to G2 phase cell cycle arrest and induction of caspase-independent cell death. Moreover, compound 12 was found to act synergistically with erlotinib.

Deamidation of Protonated Asparagine-Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study.

Peptide deamidation of asparaginyl residues is a spontaneous post-translational modification that is believed to play a role in aging and several diseases. It is also a well-known small-molecule loss channel in the MS/MS spectra of protonated peptides. Here we investigate the deamidation reaction, as well as other decomposition pathways, of the protonated dipeptide asparagine–valine ([AsnVal + H]+) upon low-energy activation in a mass spectrometer. Using a combination of infrared ion spectroscopy, guided ion beam tandem mass spectrometry, and theoretical calculations, we have been able to identify product ion structures and determine the energetics and mechanisms for decomposition. Deamidation proceeds via ammonia loss from the asparagine side chain, initiated by a nucleophilic attack of the peptide bond oxygen on the γ-carbon of the Asn side chain. This leads to the formation of a furanone ring containing product ion characterized by a threshold energy of 129 ± 5 kJ/mol (15 kJ/mol higher in energy than dehydration of [AsnVal + H]+, the lowest energy dissociation channel available to the system). Competing formation of a succinimide ring containing product, as has been observed for protonated asparagine–glycine ([AsnGly + H]+) and asparagine–alanine ([AsnAla + H]+), was not observed here. Quantum-chemical modeling of the reaction pathways confirms these subtle differences in dissociation behavior. Measured reaction thresholds are in agreement with predicted theoretical reaction energies computed at several levels of theory.

Synthesis of Compounds of the Pyrimidine Series Based on the Reactions of 3-Arylmethylidenefuran-2(3H)-ones with N,N-Binucleophilic Reagents.

The arylmethylidene derivatives of furan-2(3H)-ones are important building blocks for the synthesis of various heterocyclic compounds containing pyrimidine and pyridazine structural fragments, analogues of nitrogen-containing bases of pyrimidine series. In order to continue the development of constructing of molecules containing pyridine and pyridazine fragments, this article is devoted to the synthesis of new biologically active compounds with these moieties. The introduction of a heterocyclic chromenone fragment changes the previously observed 5-R-3-arylmethylidenefuran-2(3H)-ones route of reaction with guanidine carbonate and leads to 3-[(2-amino-4-(2-hydroxyphenyl)pyrimidin-5-yl)methylene]-5-phenylfuran-2(3H)-ones (2a–d). The structure of the reaction products depends on the nature of the aromatic substituent at the C-3 position of the furanone ring. The interaction of 5-aryl-3-arylmethylidenefuran-2(3H)-ones (1e–h) with thiourea in the basic medium leads to the isolation of 5-(2-oxo-2-phenylethyl)-6-aryl-2-thioxotetrahydropyrimidine-4(1H)-ones (3a–d), demonstrating pronounced plant-growth regulatory activity. Optimal conditions for all discussed processes were developed.

Study of metal complexation of cardenolides with divalent metal ions by Electrospray Ionization Mass Spectrometry

Cardenolides are natural products with positive inotropic and cytotoxic activity that are able to interact with metals, although the possible role that these interactions may play in their biological activity is not known. Mixtures of the following cardenolides: digoxigenin (DgG), gitoxigenin (GxG), digitoxigenin (DxG), uzarigenin (UzG) and a butenolide, 2(5H)-furanone (Fur), with different metal cations, namely Ca2+, Mg2+, Cu2+, Co2+ and Zn2+,were studied by Electrospray Ionization Mass Spectrometry in a Quadrupole-Time of Flight. The relative stability of the most important adducts was studied by threshold collision induced dissociation, E1/2. Computational modeling of the observed complexes with calcium was performed using DFT B3LYP/6-31G+(d,p) level of theory.Complexes of stoichiometry [nM+Me]2+, with n=4 to 6 ligands and Me a metal cation, were observed for all studied compounds. The adducts [4M+Me]2+ corresponded to the most intense peaks in most of the mass spectra and showed the highest E1/2. GxG showed a higher tendency to form complexes with low coordination numbers. Calculations showed that the carbonyl oxygen of the butenolide moiety is the most important site of coordination and allowed the proposal of different binding modes to explain the differences observed in the GxG MS spectra.A direct relationship was observed between experimental and computational data, which allowed to predict the MS behavior of these or similar compounds. The analysis can be extrapolated to other compounds with a furanone ring, and used as an analytical tool to characterize furanone compounds, or for the differentiation of DgG and GxG.

Novel 4-(4-substituted amidobenzyl)furan-2(5H)-one derivatives as topoisomerase I inhibitors

In this study, two series of novel 4-(4-substituted amidobenzyl)furan-2(5H)-one derivatives containing an α,β-unsaturated lactone fragment were synthesized and screened for Topo I inhibition and antitumor activity. The topoisomerase I inhibitory activities and cytotoxicities against three human cancer cell lines (MCF-7,Hela,A549) were evaluated. The results revealed that series 2, compounds bearing an exocyclic double bond on the furanone ring, generally showed more potent activity than series 1, compounds lacking an exocyclic double bond. Several compounds of series 2 possess significant Topo I inhibitory activity and potent antiproliferative activity against cancer cell lines. Further mechanism studies of the most active compound of series 2 (B-15) indicated that synthetic compounds can not only stabilize the drug-enzyme-DNA covalent ternary complex as well as camptothecin, but also interfere with the binding between Topo I and DNA. The binding patterns of these compounds with Topo I and structure-activity relationships are discussed.

Natural and Synthetic Furanones with Anticancer Activity

This paper describes the enantioselective synthesis of analogues of sapinofuranones A and B, namely 5-substitutes dihydro- and 5H-furan-ones, and their in vitro growth inhibitory activity against six cancer cell lines in comparison with fungal furanones such as diplofuranone A, diplobifuranylones A and B, as well as (S,S)-enantiomer of sapinofuranone B. The compounds under study displayed weak if any in vitro growth inhibitory activity against the analysed cancer cell lines. -However, it seems that among dihydro- and 5H-furan-ones bearing a 1-hydroxypentyl side chain, the stereochemistry of the furanone ring and that of hydroxylated methine could modify the in vitro growth activity of these compounds. The natural furanones that showed a different unsaturated chain at C-4 or rearranged into a dihydrofuran ring appeared to be inactive in terms of growth inhibitory activity, e.g. displaying growth inhibitory concentration at 50% (GIs) > 100 ptM in all six cancer cell lines analysed.

Rational Design and Synthesis of Biologically Active Disubstituted 2(3H) Furanones and Pyrrolone Derivatives as Potent and Safer Non Steroidal Anti-inflammatory Agents.

Furanone and pyrrolone heterocyclic ring system represent important and interesting classes of bioactive compounds. Medicinal chemists use these heterocycyclic moieties as scaffolds in drug design and discovery. A series of 3-arylidene-5-(naphthalene-2-yl)-furan-2(3H)-ones (2a-j) were synthesized by incorporating pharmacophore of COX-2 inhibitor rofecoxib and naphthyl ring of naproxen as potential non steroidal anti-inflammatory agents. These furanone derivatives were subsequently reacted with dry ammonia gas and benzylamine to furnish corresponding 3-arylidene-5-(naphthlen-2-yl)-1H-pyrrol-2(3H)-ones (3a-e) and 3-arylidene-1-benzyl-5- (naphthalene-2-yl)-1H-pyrrol-2(3H)-ones (4a-e), respectively. The newly prepared heterocyclics were screened for their expected in-vivo biological activities including anti-inflammatory, analgesic and ulcerogenic actions in rodents. The COX-2 inhibitory behavior of synthesized compounds was also assessed via automated docking studies. The chemical structure of the synthesized compounds was characterized by using modern spectroscopic techniques. Result of in-vivo pharmacological studies demonstrated that almost all N-Benzyl-pyrrol-2(3H)-ones (4a-e) showed better anti-inflammatory and analgesic activities in comparison with the other two series of furan-2(3H)-ones and pyrrol- 2(3H)-ones. The moldock score value of the tested compounds was found in the range of -116.66 to -170.328 and was better than the standard drug. Among all the synthesized compounds, only nine compounds (2d, 2g, 2h, 3d, 4a, 4b, 4c, 4d and 4e) exhibited potent anti-inflammatory and analgesic activities with significantly reduced gastrointestinal toxicity in various animal models in comparison to standard drug, diclofenac. Therefore, it is recommended to explore the potential of the synthesized compounds as lead candidates for the development of new therapeutic agents.

A novel domino approach for synthesis of indolyl tetrahydropyrano[4,3-c]pyrazole derivatives as anticancer agents

A series of indolyl substituted 1,4,6,7-tetrahydropyrano[4,3-c]pyrazole derivatives were synthesized via a domino method based on the 1,4:3,6-Dianhydrofructose. The mechanism was proposed and proved by calculation with a density functional theory (DFT), which includes formation of phenylhydrazone, furanone ring opening, Fischer indole synthesis, pyrazole ring closing and a furan ring expansion. In vitro antitumor activity of all synthesized compounds against four human cancer cell lines (MCF-7, EC-109, HGC-27, and PC-3 cell lines) were then evaluated, using MTT assay. We found that most of the compounds were more potent than the positive control 5-fluorouracil. Particularly, compound 4i against HGC-27 and PC-3, 4j against EC-109 cell lines showed three fold greater activity than 5-fluorouracil, respectively. The activity of compounds 4c and 4d against MCF-7 cell line was close to that of doxorubicin.

Synthetic studies on Stemona alkaloids. Construction of the sessilifoliamides B and C and 1,12-secostenine skeleton

An original synthetic approach to the Stemona alkaloids stenine and sessilifoliamides B and C has been explored. The strategy relies on the early construction of the pyrroloazepine core (rings A and B) and latter addition of the furanone (ring D) and ethyl chain at C-10, which are the common structural features of the three alkaloids. The formation of the azabicyclic nucleus through an intramolecular Morita–Baylis–Hillman reaction of a properly substituted pyrrolidone has been extensively investigated by modifications on the substrate and all the parameters involved in the process and an efficient protocol in terms of yield and stereoselectivity has been developed. Despite many alternative tactics were explored, insurmountable difficulties found in the last synthetic steps have frustrated the completion of the syntheses. However, along the way, a plethora of new compounds was prepared, some of them containing the full skeleton of the targeted alkaloids, which can be useful for future synthetic applications.

Reassignment of the absolute configuration of plakinidone from the sponge consortium Plakortis halichondrioides–Xestospongia deweerdtae using a combination of synthesis and a chiroptical approach

Recent work by Wu et al. in connection with the first synthesis of the marine natural product plakinidone revealed that the most salient feature of its purported structure, a six-membered perlactone moiety, was in fact a five-membered lactone, i.e. a 3-methyl-4-hydroxy-2(5H)-furanone or tetronic acid ring. With the planar structure of plakinidone confidently revised, we undertook a new investigation to unambiguously establish its absolute configuration. Upon preparing two stable derivatives 1 and 5 from a sample of naturally occurring plakinidone extracted from the sponge association Plakortis halichondrioides–Xestospongia deweerdtae, the absolute configuration was assigned by synthesis and vibrational and electronic circular dichroism (VCD and ECD) measurements in combination with density functional theory calculations at the B3LYP/aug-cc-pVDZ/PCM(CH3CN) level of theory. Our combined efforts and the agreement between the experimental and calculated VCD/ECD spectra of 1 revealed that the absolute configuration of plakinidone was in fact (11S,17R) and not the formerly reported (11S,17S) diastereomer assigned by Wu et al. Therefore, we propose that natural plakinidone is accurately represented by structure 12.

ChemInform Abstract: Expedient Access to Functionalized Furan/3(2H)‐furanone Ensembles via Microwave‐Assisted Domino Reactions.

AbstractA one-pot linkage between furan and 3(2H)-furanone rings has been effected via the microwave-assisted Et3N-catalyzed domino condensation of the furan and benzofuran carboxylic acids with available cyanopropargylic alcohols (MeCN, 100 °C, 1.2 atm, 2–17 h). Despite involving a number of C-H-forming/breaking steps, the assembly is chemoselective and the final products, 5-(2-furyl)-3(2H)-furanones, are formed in 59–96% yields.