Research

110 KiB

Open AccessArticle

Radical-scavenging Activity of Natural Methoxyphenols vs. Synthetic Ones using the Induction Period Method

by Yoshinori Kadoma, Toshiko Atsumi, Norihisa Okada, Mariko Ishihara, Ichiro Yokoe and Seiichiro Fujisawa

Molecules 2007, 12(2), 130-138; https://doi.org/10.3390/12020130 - 03 Feb 2007

Cited by 16 | Viewed by 11728

Abstract

The radical-scavenging activities of the synthetic antioxidants 2-allyl-4-X-phenol (X=NO₂, Cl, Br, OCH₃, COCH₃, CH₃, t-(CH₃)₃, C₆H₅) and 2,4-dimethoxyphenol, and the natural antioxidants eugenol and isoeugenol, were [...] Read more.

The radical-scavenging activities of the synthetic antioxidants 2-allyl-4-X-phenol (X=NO₂, Cl, Br, OCH₃, COCH₃, CH₃, t-(CH₃)₃, C₆H₅) and 2,4-dimethoxyphenol, and the natural antioxidants eugenol and isoeugenol, were investigated using differential scanning calorimetry (DSC) by measuring their anti-1,1-diphenyl-2-picrylhydrazyl (DPPH) radical activity and the induction period for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO). 2-Allyl-4-methoxyphenol and 2,4-dimethoxy-phenol scavenged not only oxygen-centered radicals (PhCOO^.) derived from BPO, but also carbon-centered radicals (R^.) derived from the AIBN and DPPH radical much more efficiently, in comparison with eugenol and isoeugenol. 2-Allyl-4-methoxyphenol may be useful for its lower prooxidative activity. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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99 KiB

Open AccessArticle

Antibacterial Activity of Long-Chain Fatty Alcohols against Staphylococcus aureus

by Naoko Togashi, Akiko Shiraishi, Miki Nishizaka, Keisuke Matsuoka, Kazutoyo Endo, Hajime Hamashima and Yoshihiro Inoue

Molecules 2007, 12(2), 139-148; https://doi.org/10.3390/12020139 - 05 Feb 2007

Cited by 132 | Viewed by 13280

Abstract

The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal [...] Read more.

The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal activity and membrane-damaging activity. 1-Dodecanol and 1-tridecanol had the highest antibacterial activity among the long-chain fatty alcohols tested, but had no membrane-damaging activity. Consequently, it appears that not only the antibacterial activity but also the mode of action of long-chain fatty alcohols might be determined by the length of the aliphatic carbon chain. Full article

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42 KiB

Open AccessCommunication

Comparative Chemical Analysis of the Essential Oil Constituents in the Bark, Heartwood and Fruits of Cryptocarya massoy (Oken) Kosterm. (Lauraceae) from Papua New Guinea

by Topul Rali, Stewart W. Wossa and David N. Leach

Molecules 2007, 12(2), 149-154; https://doi.org/10.3390/12020149 - 05 Feb 2007

Cited by 58 | Viewed by 12205

Abstract

Exhaustive hydro-distillation of the bark, heartwood and fruits of Cryptocarya massoy (Lauraceae) afforded pale yellow-coloured oils in 0.7, 1.2 and 1.0 % yields, respectively. Detailed chemical evaluation of these distillates using GC/MS revealed the major components in the bark and the heartwood oils [...] Read more.

Exhaustive hydro-distillation of the bark, heartwood and fruits of Cryptocarya massoy (Lauraceae) afforded pale yellow-coloured oils in 0.7, 1.2 and 1.0 % yields, respectively. Detailed chemical evaluation of these distillates using GC/MS revealed the major components in the bark and the heartwood oils to be the C-10 (5,6-dihydro-6-pentyl-2H-pyran-2-one) and C-12 (5,6-dihydro-6-heptyl-2H-pyran-2-one) massoia lactones, while the major fruit oil constituent was benzyl benzoate (68.3 %). The heartwood also contained trace amounts of the C-14 (5,6-dihydro-6-nonyl-2H-pyran-2-one) massoia lactone (1.4 %) and the saturated C-10 derivative d-decalactone (2.5 %). Full article

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90 KiB

Open AccessArticle

Isatinones A and B, New Antifungal Oxindole Alkaloids from Isatis costata

by Itrat Fatima, Ijaz Ahmad, Itrat Anis, Abdul Malik and Nighat Afza

Molecules 2007, 12(2), 155-162; https://doi.org/10.3390/12020155 - 06 Feb 2007

Cited by 43 | Viewed by 8897

Abstract

Two new oxindole alkaloids isatinone A (1) and B (2) have been isolated from Isatis costata, along with the known trisindoline. Their structures have been assigned on the basis of spectroscopic techniques and chemical studies. Both new compounds showed significant antifungal activity. Full article

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175 KiB

Open AccessArticle

One Pot Synthesis of α-Aminophosphonates Containing Bromo and 3,4,5-Trimethoxybenzyl Groups under Solvent-free Conditions

by Caihong Li, Baoan Song, Kai Yan, Gangfang Xu, Deyu Hu, Song Yang, Linhong Jin, Wei Xue and Ping Lu

Molecules 2007, 12(2), 163-172; https://doi.org/10.3390/12020163 - 07 Feb 2007

Cited by 25 | Viewed by 11883

Abstract

New α-aminophosphonates were synthesized by the Kabachnik-Fields reactionof 3,4,5-trimethoxybenzaldehyde (TMB) with p- or m-bromoaniline and a dialkylphosphite under solvent-free conditions. TMB was prepared from gallic acid via a fourstep synthetic sequence involving etherification, esterification, hydrazidation andpotassium ferricyanide oxidation. The structures of all synthesized [...] Read more.

New α-aminophosphonates were synthesized by the Kabachnik-Fields reactionof 3,4,5-trimethoxybenzaldehyde (TMB) with p- or m-bromoaniline and a dialkylphosphite under solvent-free conditions. TMB was prepared from gallic acid via a fourstep synthetic sequence involving etherification, esterification, hydrazidation andpotassium ferricyanide oxidation. The structures of all synthesized compounds wereconfirmed by elemental analysis, IR, ¹H-, ¹³C- and ³¹P-NMR spectral data. Compound 7gwas also characterized by X-ray crystallography. A half-leaf method was used todetermine the in vivo curative efficacy of the eight title products against tobacco mosaicvirus (TMV). It was found that compounds 7g and 7h possess good in vivo curativeeffects against TMV. Full article

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107 KiB

Open AccessArticle

Synthesis, NMR and Crystallographic Studies of 2-Substituted Dihydroquinazolinones Derived from (S)-Phenylethylamine

by Jaime Escalante, Claudia Ortíz-Nava, Patricia Flores, Jaime M. Priego and Cirilo García-Martínez

Molecules 2007, 12(2), 173-182; https://doi.org/10.3390/12020173 - 12 Feb 2007

Cited by 6 | Viewed by 11846

Abstract

2,3-Dihydro-3-[(S)-1-phenethyl]quinazolinone and some new 2-substitutedderivatives bearing isopropyl, o-nitrophenyl and p-nitrophenyl groups were prepared in40-90% yield by amidation of isatoic anhydride with (S)-phenylethylamine, followed bycondensation with triethyl orthoformate, isopropylaldehyde, o-nitro- and p-nitro-benzaldehyde, respectively. The two 2-subtituted dihydroquinazolinones obtained eitherby using isopropylaldehyde, o-nitro- or p-nitrobenzaldehyde, [...] Read more.

2,3-Dihydro-3-[(S)-1-phenethyl]quinazolinone and some new 2-substitutedderivatives bearing isopropyl, o-nitrophenyl and p-nitrophenyl groups were prepared in40-90% yield by amidation of isatoic anhydride with (S)-phenylethylamine, followed bycondensation with triethyl orthoformate, isopropylaldehyde, o-nitro- and p-nitro-benzaldehyde, respectively. The two 2-subtituted dihydroquinazolinones obtained eitherby using isopropylaldehyde, o-nitro- or p-nitrobenzaldehyde, were separated and purifiedbefore their NMR spectra in CDCl₃ solutions were recorded. The detection of the lowenergy conformation of O=C-N-phenethyl segment in solution allowed the correlation ofthe NMR data with the configuration of newly stereogenic carbon C-2; thus, onediastereomer was labeled SS while the other was RS. Configurations determined by theNMR method were corroborated by X-ray diffraction analysis. X-ray structures of eachdiastereomeric series showed characteristic conformational types: a propeller-like for theSS and a hairpin for the RS series. Interatomic distances of the hairpin conformationsuggest the existence of intramolecular face-to-face interactions between two aromaticrings. Full article

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47 KiB

Open AccessArticle

Synthesis of 3,4,7,8-Tetrahydronaphthalene-1,5(2H,6H)-dione

by Garrett B. Minne and Pierre J. De Clercq

Molecules 2007, 12(2), 183-187; https://doi.org/10.3390/12020183 - 13 Feb 2007

Cited by 3 | Viewed by 7501

Abstract

A short and high yielding route for thepreparation of the title compound, starting from commercially available1,5-dihydroxynaphthalene, is described. The key step in the sequence is the airoxidation of a bis(trimethylsilyloxy)diene precursor. Full article

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413 KiB

Open AccessArticle

Synthesis and Photochemistry of 1-Iodocyclohexene:Influence of Ultrasound on Ionic vs. Radical Behaviour

by Marika Blaskovicova, Anton Gaplovsky and Jaroslav Blasko

Molecules 2007, 12(2), 188-193; https://doi.org/10.3390/12020188 - 16 Feb 2007

Cited by 14 | Viewed by 8833

Abstract

Simultaneous application of UV light and ultrasonic irradiation to a reaction mixture containing 1-iodocyclohexene is reported. The irradiation of 1-iodocyclohexene in methanol was carried out with or without addition of zinc. The effect of ultrasound or mechanical stirring on this solid-liquid system was [...] Read more.

Simultaneous application of UV light and ultrasonic irradiation to a reaction mixture containing 1-iodocyclohexene is reported. The irradiation of 1-iodocyclohexene in methanol was carried out with or without addition of zinc. The effect of ultrasound or mechanical stirring on this solid-liquid system was also compared. The irradiation of 1-iodocyclohexene in methanol in the presence of zinc increases the yield of the nucleophilic trapping product, compared with the yield after irradiation in the absence of zinc. The photodegradation of 1-iodocyclohexene was slightly accelerated after addition of zinc. A rapid formation of radical product was accompanied by substantial decrease of 1-iodocyclohexene after application of ultrasound and irradiation without the zinc. The ultrasound significantly affects the photobehaviour of this reaction, predominantly its radical route. The joint application of ultrasound and zinc contributes positively to the production of radical and ionic products. The sonochemical stirring is more effective than mechanical stirring. Full article

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79 KiB

Open AccessArticle

Synthesis of 2,5-Disubstituted Octahydroquinolin-4-ones via anIntramolecular Hetero Diels-Alder Reaction

by Juan M. Ruiz, Maria M. Afonso and J. Antonio Palenzuela

Molecules 2007, 12(2), 194-204; https://doi.org/10.3390/12020194 - 19 Feb 2007

Cited by 3 | Viewed by 8570

Abstract

A route for the preparation of 2,5-disubstituted octahydroquinolin-4-ones, synthetic precursors of the decahydroquinoline-type toxins, is presented. The key steps are an asymmetric epoxidation and an intramolecular hetero Diels-Alder reaction between an activated diene and an imine. The presence of an allylic stereogenic center [...] Read more.

A route for the preparation of 2,5-disubstituted octahydroquinolin-4-ones, synthetic precursors of the decahydroquinoline-type toxins, is presented. The key steps are an asymmetric epoxidation and an intramolecular hetero Diels-Alder reaction between an activated diene and an imine. The presence of an allylic stereogenic center induces some selectivity and thus only two cycloadducts are obtained in 70:30 ratio and good yield. Full article

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157 KiB

Open AccessArticle

A Novel Antioxidant Phenyl Disaccharide from Populus tremula Knotwood

by Madalina Neacsu, Vicente Micol, Laura Pérez-Fons, Stefan Willför, Bjarne Holmbom and Ricardo Mallavia

Molecules 2007, 12(2), 205-217; https://doi.org/10.3390/12020205 - 19 Feb 2007

Cited by 6 | Viewed by 11962

Abstract

The complete characterization of two compounds obtained from the acetoneextract of Populus tremula knotwood has been was achieved using LC-DAD-MS,MS/MS, IR and NMR. The new compounds were unequivocally identified as a mixtureof the ester isomers of the (E) and (Z) p-coumarate of 1-O-rutinose. [...] Read more.

The complete characterization of two compounds obtained from the acetoneextract of Populus tremula knotwood has been was achieved using LC-DAD-MS,MS/MS, IR and NMR. The new compounds were unequivocally identified as a mixtureof the ester isomers of the (E) and (Z) p-coumarate of 1-O-rutinose. The isomers showedthe capacity to inhibit lipid peroxidation induced by tert-butylhydroperoxide and to trapperoxyl radicals, as determined by a chemiluminescence method. These new phenyldisaccharides also showed a significant ORAC (oxygen radical absorbance capacity)value, i.e. 11.7 μM TE (Trolox Equivalents). Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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127 KiB

Open AccessArticle

Novel 2-Chloro-8-arylthiomethyldipyridodiazepinone Derivatives with Activity against HIV-1 Reverse Transcriptase

by Nisachon Khunnawutmanotham, Nitirat Chimnoi, Patchareenart Saparpakorn, Pornpan Pungpo, Suda Louisirirotchanakul, Supa Hannongbua and Supanna Techasakul

Molecules 2007, 12(2), 218-230; https://doi.org/10.3390/12020218 - 20 Feb 2007

Cited by 7 | Viewed by 7694

Abstract

Based on the molecular modeling analysis against Y181CHIV-1 RT, dipyridodiazepinone derivatives containing an unsubstituted lactamnitrogen and 2-chloro-8-arylthiomethyl were synthesized via an efficientroute. Some of them were evaluated for their antiviral activity against HIV-1RT subtype E and were found to exhibit virustatic activity comparable [...] Read more.

Based on the molecular modeling analysis against Y181CHIV-1 RT, dipyridodiazepinone derivatives containing an unsubstituted lactamnitrogen and 2-chloro-8-arylthiomethyl were synthesized via an efficientroute. Some of them were evaluated for their antiviral activity against HIV-1RT subtype E and were found to exhibit virustatic activity comparable to some clinically usedtherapeutic agents. Full article

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47 KiB

Open AccessCommunication

Efficient Preparation of Aldoximes from Arylaldehydes, Ethylenediamine and Oxone® in Water

by Jing-Jing Xia and Guan-Wu Wang

Molecules 2007, 12(2), 231-236; https://doi.org/10.3390/12020231 - 21 Feb 2007

Cited by 24 | Viewed by 9319

Abstract

The one-pot reaction of aromatic aldehydes, ethylenediamine and Oxone® (2KHSO₅·KHSO₄·K₂SO₄) in pure water was found to unexpectedly afford aldoximes in excellent yields. Full article

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80 KiB

Open AccessArticle

Asymmetric Synthesis of the Epimeric (3S)-3-((E)-Hex-1-enyl)-2-methylcyclohexanones

by Freek A. Vrielynck and Pierre J. De Clercq

Molecules 2007, 12(2), 237-244; https://doi.org/10.3390/12020237 - 21 Feb 2007

Cited by 3 | Viewed by 8421

Abstract

The asymmetric rhodium-catalysed 1,4-addition of alkenylzirconium reagents to 2-cyclohexenone can be useful in the synthesis of 3-alkenyl-2-methylcyclohexanones, provided that formaldehyde is used in trapping the intermediate zirconium enolates. In this manner a four-step sequence leading to the two epimeric 3-hexenyl-2-methylcyclohexanones in enantiomeric form [...] Read more.

The asymmetric rhodium-catalysed 1,4-addition of alkenylzirconium reagents to 2-cyclohexenone can be useful in the synthesis of 3-alkenyl-2-methylcyclohexanones, provided that formaldehyde is used in trapping the intermediate zirconium enolates. In this manner a four-step sequence leading to the two epimeric 3-hexenyl-2-methylcyclohexanones in enantiomeric form was developed. Full article

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91 KiB

Open AccessArticle

Synthesis, Characterization and AntibacterialActivity of Azomethine Derivatives Derived from 2-Formylphenoxyacetic Acid

by Amjid Iqbal, Hamid Latif Siddiqui, C. M. Ashraf, Matloob Ahmad and George W. Weaver

Molecules 2007, 12(2), 245-254; https://doi.org/10.3390/12020245 - 22 Feb 2007

Cited by 43 | Viewed by 12094

Abstract

A series of eight new azomethine derivatives were synthesized by reacting 2-formylphenoxyacetic acid with aromatic amines. The chemical structures of these compounds were confirmed by means of ¹H-NMR, ¹³C-NMR, MS and elemental analysis. The compounds were assayed by the disc diffusion [...] Read more.

A series of eight new azomethine derivatives were synthesized by reacting 2-formylphenoxyacetic acid with aromatic amines. The chemical structures of these compounds were confirmed by means of ¹H-NMR, ¹³C-NMR, MS and elemental analysis. The compounds were assayed by the disc diffusion method for antibacterial against Staphylococcus aureus and Escherichia coli. Among the compounds tested, 2a, 2b, 2e, 2g and 2h exhibited good antibacterial activity, almost equal to that of Ciprofloxacin used as standard. Full article

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73 KiB

Open AccessArticle

Heteropolyacids as Green and Reusable Catalysts for the Synthesis of 3,1,5-Benzoxadiazepines

by Majid M. Heravi, Samaheh Sadjadi, Hossein A. Oskooie, Rahim Hekmat Shoar and Fatemeh F. Bamoharram

Molecules 2007, 12(2), 255-262; https://doi.org/10.3390/12020255 - 26 Feb 2007

Cited by 35 | Viewed by 9827

Abstract

Synthesis of 3,1,5-benzoxadiazepines from the condensation of o-phenylenediamine (o-PDA) and acyl chlorides in the presence of a catalytic amount of various heteropolyacids (HPAs) is reported. Full article

(This article belongs to the Special Issue Heterocycles)

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78 KiB

Open AccessArticle

Reactive Oxygen Species Scavenging Activity of Flavone Glycosides from Melilotus neapolitana

by Antonio Fiorentino, Brigida D'Abrosca, Severina Pacifico, Annunziata Golino, Claudio Mastellone, Palma Oriano and Pietro Monaco

Molecules 2007, 12(2), 263-270; https://doi.org/10.3390/12020263 - 28 Feb 2007

Cited by 27 | Viewed by 13572

Abstract

One new and six known flavone glycosides were isolated from the MeOH extract of Melilotus neapolitana Ten. The new compound, identified as 7-O-β-D-gluco-pyranosyloxy-4',5-dihydroxy-3-[O-α-L-rhamnopyranosyl-(1→6)-3-O-β-D-glucopyrano-syloxy]flavone (1) by 1D and 2D NMR techniques and mass spectra, was isolated along with kaempferol-3-O-rutinoside (2), kaempferol-3-O-glucoside (3), rutin (4), [...] Read more.

One new and six known flavone glycosides were isolated from the MeOH extract of Melilotus neapolitana Ten. The new compound, identified as 7-O-β-D-gluco-pyranosyloxy-4',5-dihydroxy-3-[O-α-L-rhamnopyranosyl-(1→6)-3-O-β-D-glucopyrano-syloxy]flavone (1) by 1D and 2D NMR techniques and mass spectra, was isolated along with kaempferol-3-O-rutinoside (2), kaempferol-3-O-glucoside (3), rutin (4), quercetin-3-O-glucoside (5), isorhamnetin-3-O-rutinoside (6), and isorhamnetin-3-O-glucoside (7). The antioxidant and radical scavenging activities of these compounds and the whole crude methanol extract were evaluated. The organic extract can inhibit MDA marker’s synthesis by 57%. All the metabolites displayed good reducing power, with the kaempferol (2,3) and isorhamnetin derivatives (6,7) being less active than the corresponding quercetin derivatives 4,5. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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88 KiB

Open AccessArticle

Synthesis and Biological Evaluation of Rigid Polycyclic Derivatives of the Diels-Alder Adduct Tricyclo[6.2.1.02,7]undeca-4,9-dien-3,6-dione

by Felicia Megumi Ito, Jacqueline Marques Petroni, Dênis Pires De Lima, Adilson Beatriz, Maria Rita Marques, Manoel Odorico De Moraes, Letícia Veras Costa-Lotufo, Raquel Carvalho Montenegro, Hemerson Iury Ferreira Magalhãe and Cláudia Do Ó Pessoa

Molecules 2007, 12(2), 271-282; https://doi.org/10.3390/12020271 - 27 Feb 2007

Cited by 29 | Viewed by 11713

Abstract

art of our research program concentrates on the discovery of new bioactivecompounds prepared either by total synthesis or molecular transformation of compoundswith bioactivity profiles. In this work we have focused our interest on chemicaltransformations of the Diels-Alder adduct tricyclo[6.2.1.0^2,7]undeca-4,9-dien-3,6-dione inorder to [...] Read more.

art of our research program concentrates on the discovery of new bioactivecompounds prepared either by total synthesis or molecular transformation of compoundswith bioactivity profiles. In this work we have focused our interest on chemicaltransformations of the Diels-Alder adduct tricyclo[6.2.1.0^2,7]undeca-4,9-dien-3,6-dione inorder to obtain cage-like compounds and derivatives, followed by an evaluation of theirbiological activity. Full article

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Molecules, Volume 12, Issue 2 (February 2007) – 17 articles , Pages 130-282

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