Molecules

149 KiB

Open AccessArticle

Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl) Hydrazide and Amino Acid-(N'-Nicotinoyl) Hydrazide Derivatives

by Sherine N. Khattab

Molecules 2005, 10(9), 1218-1228; https://doi.org/10.3390/10091218 - 30 Sep 2005

Cited by 52 | Viewed by 15731

Abstract

The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl)- and N- Boc-amino acid-(N`-nicotinoyl) hydrazides 5a-5e and 6a-6e were prepared in very high [...] Read more.

The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl)- and N- Boc-amino acid-(N`-nicotinoyl) hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU) as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl) hydrazide hydrochloride salts (7a-7e) and amino acid-(N`- nicotinoyl) hydrazide hydrochloride salts (8a-8e). These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli. Full article

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235 KiB

Open AccessArticle

Synthesis, Tautomeric States and Crystal Structure of (Z)-Ethyl 2-Cyano-2-(3H-Quinazoline-4-ylidene) Acetate and (Z)-Ethyl 2-Cyano-2-(2-Methyl-3H-Quinazoline-4-ylidene) Acetate

by M. Tulyasheva, B. Rasulev, A. Tojiboev, K. Turgunov, B. Tashkhodjaev, N. Abdullaev and K Shakhidoyatov

Molecules 2005, 10(9), 1209-1217; https://doi.org/10.3390/10091209 - 30 Sep 2005

Cited by 4 | Viewed by 8768

Abstract

The new compounds (Z)-ethyl 2-cyano-2-(3H- and 2-methyl-3H-quinazoline-4-ylidene) acetate (1 and 2, respectively) were synthesized by multi-step reactions. Thestructures in a solution have been determined by ¹H-NMR spectroscopy and in the crystalform by X-ray analysis. Molecule 1 crystallized in a primitive monoclinic cell, [...] Read more.

The new compounds (Z)-ethyl 2-cyano-2-(3H- and 2-methyl-3H-quinazoline-4-ylidene) acetate (1 and 2, respectively) were synthesized by multi-step reactions. Thestructures in a solution have been determined by ¹H-NMR spectroscopy and in the crystalform by X-ray analysis. Molecule 1 crystallized in a primitive monoclinic cell, spacegroup Р2_1/c. The cell dimensions are a=7.970(6) å, b=7.061(2) å, c=20.537(7) å,β=97.69(5)°, V=1145.3(10) å³. Molecule 2 crystallized in a triclinic cell, space group P-1, the cell dimensions are a=8.196(5) å, b=8.997(6) å, c=9.435(4) å, α=74.22(4)°,β=89.75(4)°, γ=74.07(5)°, V=641.9(6) å³. In both compounds the presence of intra-molecular NH---O=C hydrogen bonding between the nitrogen atom in position 3 of thequinazoline ring and a carbonyl group of the ethyl cyanoacetate residue was proven byquantum-chemical, ¹H-NMR and X-ray methods. Full article

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161 KiB

Open AccessArticle

Relationship Between Physicochemical Properties and Herbicidal Activity of 1,2,5-Oxadiazole N-Oxide Derivatives

by L. Fernandez, M. Santo, M. Reta, L. Giacomelli, R. Cattana, J. Silber, M. Risso, H. Cerecetto, M. Gonzalez and C. Olea-Azar

Molecules 2005, 10(9), 1197-1208; https://doi.org/10.3390/10091197 - 30 Sep 2005

Cited by 11 | Viewed by 10110

Abstract

The relationship between the herbicidal activity of a number of novel 1,2,5-oxadiazole N-oxides and some physicochemical properties potentially related with thisbioactivity, such as polarity, molecular volume, proton acceptor ability, lipophilicity, andreduction potential were studied. The semiempirical molecular orbital method AM1 wasused to calculate [...] Read more.

The relationship between the herbicidal activity of a number of novel 1,2,5-oxadiazole N-oxides and some physicochemical properties potentially related with thisbioactivity, such as polarity, molecular volume, proton acceptor ability, lipophilicity, andreduction potential were studied. The semiempirical molecular orbital method AM1 wasused to calculate theoretical descriptors such as dipolar moment, molecular volume,Mulliken ́s charge and the octanol/water partition coefficients (log P_o/w). The values ofthe reduction potentials (E_r) were obtained by cyclic voltammetry. In addition, theretention factors (log _k’w) on a reversed-phase high-performance liquid chromatography(RP-HPLC) column in pure aqueous mobile phases were measured for several N-oxidederivatives. The log _k’w values show good correlation with the calculated values of logP_o/w, showing that the chromatographic parameter can be used as lipophilicity descriptorfor these compounds. The multiple regression analysis between the descriptors for the N-oxide derivatives and the herbicide activity indicate that the variance in the biologicalactivity can be explained by changes in the lipophilicity and in the reduction potential. Full article

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58 KiB

Open AccessArticle

Behavioural Response of Triatoma infestans (Klug) (Hemiptera: Reduviidae) to Quinazolines

by R. A. Alzogaray, A. Fontán, F. Camps, H. Masuh, P. Santo Orihuela, D. Fernández, A. Cork and E. Zerba

Molecules 2005, 10(9), 1190-1196; https://doi.org/10.3390/molecules10091190 - 30 Sep 2005

Cited by 10 | Viewed by 11367

Abstract

The behavioural responses of the haematophagous bug Triatoma infestans towards some previously identified components of its faeces: 4-methylquinazoline, 2,4- dimethylquinazoline and their mixtures were evaluated using a video tracking system. Fifth instar nymphs and females but not males were significantly attracted to polyethylene [...] Read more.

The behavioural responses of the haematophagous bug Triatoma infestans towards some previously identified components of its faeces: 4-methylquinazoline, 2,4- dimethylquinazoline and their mixtures were evaluated using a video tracking system. Fifth instar nymphs and females but not males were significantly attracted to polyethylene glycol formulations of 4-methyl + 2,4-dimethylquinazoline (50 μg each). Fifth instar nymphs were also attracted to 4-methylquinazoline alone (50 μg) but females were only attracted by the mixture of both methyl quinazolines (50 μg each). Syntheses of both methyl quinazolines were carried out starting from 2-aminoacetophenone by modifying the conditions of reported procedures. Full article

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140 KiB

Open AccessArticle

HPLC Analysis of Aliphatic Sulfonate Surfactants using Ion-Pair Detection

by M. Zahrobsky, D. Camporese, O. Rist and P. Carlsen

Molecules 2005, 10(9), 1179-1189; https://doi.org/10.3390/10091179 - 30 Sep 2005

Cited by 7 | Viewed by 11232

Abstract

A method was developed for the analysis of a number of surfactants which contained no UV-chromophores, using RP-HPLC with Indirect Photometric Detection, IPD. Pyridinium salts such as N-methylpyridinium iodide, N-methyl-2,2'-dipyridinium iodide and N,N'-dimethyl-2,2'-dipyridinium diiodide, were used as the visualization reagents, forming ion-pair complexes [...] Read more.

A method was developed for the analysis of a number of surfactants which contained no UV-chromophores, using RP-HPLC with Indirect Photometric Detection, IPD. Pyridinium salts such as N-methylpyridinium iodide, N-methyl-2,2'-dipyridinium iodide and N,N'-dimethyl-2,2'-dipyridinium diiodide, were used as the visualization reagents, forming ion-pair complexes with the sulfonate surfactants. This allowed ordinary UV-detection. N-methylpyridinium iodide proved to be a suitable reagent, both with respect to ease of preparation and response. The eluents consisted of mixtures of acetonitrile and water, being 0.1 - 0.25 mM with respect to pyridinium salt. The method was sensitive and exhibited good signal to noise ratios, as well as linear responses over a wide concentration range. All of the analyzed surfactants were separated, including the diastereomeric forms of some of the surfactants. Full article

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76 KiB

Open AccessArticle

Synthesis of Hydroxy Sulfonate Surfactants

by O. Rist and P. Carlsen

Molecules 2005, 10(9), 1169-1178; https://doi.org/10.3390/10091169 - 30 Sep 2005

Cited by 6 | Viewed by 13712

Abstract

The selective synthesis of sulfonate surfactants with side chains containing ether- and hydroxy groups was carried out using cyclic sulfates as epoxide analogues. The main chain was elaborated from 1,2-dodecane sulfate by the addition of various hydroxy/alkoxysulfonates. Ethyleneoxy- and 1,2-propyleneoxy- groups were introduced [...] Read more.

The selective synthesis of sulfonate surfactants with side chains containing ether- and hydroxy groups was carried out using cyclic sulfates as epoxide analogues. The main chain was elaborated from 1,2-dodecane sulfate by the addition of various hydroxy/alkoxysulfonates. Ethyleneoxy- and 1,2-propyleneoxy- groups were introduced using ethylene sulfate and 1,2-propylene sulfate, respectively. Full article

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137 KiB

Open AccessArticle

Synthesis of Oxadiazoles, Thiadiazoles and Triazoles Derived from Benzo[b]thiophene

by A. Sharba, R. Al-Bayati, M. Aouad and N. Rezki

Molecules 2005, 10(9), 1161-1168; https://doi.org/10.3390/10091161 - 30 Sep 2005

Cited by 27 | Viewed by 13195

Abstract

In this work 3-chloro-2-chlorocarbonylbenzo[b]thiophene (1) was prepared from cinnamic acid and then converted into the acid hydrazide 2. The azomethines 3a-e were prepared from the corresponding aryl aldehydes and the acid hydrazide 2. Treatment of compound 2 with formic acid gave the N-formyl [...] Read more.

In this work 3-chloro-2-chlorocarbonylbenzo[b]thiophene (1) was prepared from cinnamic acid and then converted into the acid hydrazide 2. The azomethines 3a-e were prepared from the corresponding aryl aldehydes and the acid hydrazide 2. Treatment of compound 2 with formic acid gave the N-formyl acid hydrazide 4, which upon refluxing with phosphorous pentoxide or phosphorous pentasulphide in xylene yielded the corresponding 2- (3-chloro-1-benzothien-2-yl)-1,3,4-oxadiazole (5) and 2-(3-chloro-1-benzo-thien-2-yl)-1,3,4- thiadiazole (6). Reaction of 1-thiosemicarbazide 7 with NaOH leads to ring closure giving 5- (3-chloro-1-benzothien-2- yl)-4H–triazole-3-thiol (8) which is converted into a number of derivatives 9-12 Reaction of 2 with phenyl isothiocyanate and NaOH afforded 5-(3-chloro- 1-benzothien-2-yl)-4-(phenyl)-4H-1,2,4-triazole-3-thiol (14). Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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198 KiB

Open AccessArticle

Synthesis of Thiadiazoles and 1,2,4-Triazoles Derived from Cyclopropane Dicarboxylic Acid

by A. Sharba, R. Al-Bayati, N. Rezki and M. Aouad

Molecules 2005, 10(9), 1153-1160; https://doi.org/10.3390/10091153 - 30 Sep 2005

Cited by 20 | Viewed by 10488

Abstract

New heterocyclic derivatives of cyclopropane dicarboxylic acid comprising thiadiazole and 1,2,4-triazole moieties are reported. Reaction of 1,1-cyclopropane dicarboxylic acid (1) with thiosemicarbazide and phosphorous oxychloride resulted in 1,1-bis (2-amino-1,3,4-thiadiazol-5- yl)cyclopropane (2). Cyclopropane dicarboxylic acid thiosemicarbazide (6) was converted into 1,1-bis(3-thio-4H-1,2,4-triazol-5-yl) cyclo- propane (7) [...] Read more.

New heterocyclic derivatives of cyclopropane dicarboxylic acid comprising thiadiazole and 1,2,4-triazole moieties are reported. Reaction of 1,1-cyclopropane dicarboxylic acid (1) with thiosemicarbazide and phosphorous oxychloride resulted in 1,1-bis (2-amino-1,3,4-thiadiazol-5- yl)cyclopropane (2). Cyclopropane dicarboxylic acid thiosemicarbazide (6) was converted into 1,1-bis(3-thio-4H-1,2,4-triazol-5-yl) cyclo- propane (7) by ring closure in an alkaline medium. The thiadiazole 2 and the triazole 7 were converted into a variety of derivatives. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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75 KiB

Open AccessArticle

Oxidative Stress, Lipid Profile and Liver Functions in Average Egyptian Long Term Depo Medroxy Progesterone Acetate (DMPA) Users

by L. Faddah, M. Al-Rehany, N. Abdel-Hamid and A. Bakeet

Molecules 2005, 10(9), 1145-1152; https://doi.org/10.3390/10091145 - 30 Sep 2005

Cited by 22 | Viewed by 15132

Abstract

Depo-medroxy progesterone acetate (DMPA, Depo-Provera^®) is used in morethan 80 countries as a long-acting contraceptive administered as a single intramuscular(i.m) injection of 150 mg/3 months. The present study was set up to investigate theeffects of DMPA on 80 average Egyptian women [...] Read more.

Depo-medroxy progesterone acetate (DMPA, Depo-Provera^®) is used in morethan 80 countries as a long-acting contraceptive administered as a single intramuscular(i.m) injection of 150 mg/3 months. The present study was set up to investigate theeffects of DMPA on 80 average Egyptian women classified into four groups comprisingthose using the drug for one, two, three and four years, respectively, compared to acontrol group (N = 20) of married non-hormonally – treated women of similar ages. Thedrug showed a transient significant elevation of alanine aminotransferase activity (ALT)without an apparent effect on other liver indices, namely total bilirubin (T.Bil) level,aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities. Only thelow density/high density lipoproteins cholesterol ratio (LDLC/HDLC) was gradually andnon-significantly (ns) increased in comparison to control group, however, neither totalcholesterol (TC) nor triglycerides (TG) were affected by the drug. The lipid peroxideproduct malondialdehyde (MDA) was significantly elevated in an gradual manner with acorresponding decrease in reduced glutathione (GSH), without any change in blood nitricoxide (NO) levels. It can be concluded that DMPA may be considered as a safecontraceptive medication for the studied group of women, but that special care should beexercised for cardiovascular, hepatic and other patients more sensitive to the harmfuleffects of free radicals. Alternatively, supportive medications are advisable for eachexposed case to secure against the possible irreversible adverse effects of the drug by continuous use. In addition, annual re-evaluation is much more advisable despite the proven safety of the drug. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

256 KiB

Open AccessArticle

Poly[3-(3,4-dihydroxyphenyl)glyceric Acid], A New Biologically Active Polymer from Symphytum Asperum Lepech. and S.Caucasicum Bieb. (Boraginaceae)

by V. Barbakadze, E. Kemertelidze, I. Targamadze, K. Mulkijanyan, A. Shashkov and A. Usov

Molecules 2005, 10(9), 1135-1144; https://doi.org/10.3390/10091135 - 30 Sep 2005

Cited by 24 | Viewed by 9661

Abstract

Two high-molecular water-soluble preparations with high anticomplementary, antioxidant, antilipoperoxidant and antiinflammatory activities were isolated from the roots of Symphytum asperum and S. caucasicum. Their main chemical constituent was found to be poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene], according to IR and NMR spectroscopy. The Symphytum high-molecular preparations can [...] Read more.

Two high-molecular water-soluble preparations with high anticomplementary, antioxidant, antilipoperoxidant and antiinflammatory activities were isolated from the roots of Symphytum asperum and S. caucasicum. Their main chemical constituent was found to be poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene], according to IR and NMR spectroscopy. The Symphytum high-molecular preparations can modulate in vitro B- chronic lymphocytic leukaemia (B-CLL) cells apoptosis and cell cycle progression. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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160 KiB

Open AccessArticle

New Multi-1,2,3-Selenadiazole Aromatic Derivatives

by M. Al-Smadi and S. Ratrout

Molecules 2005, 10(9), 1126-1134; https://doi.org/10.3390/10091126 - 30 Sep 2005

Cited by 12 | Viewed by 9165 | Retraction

Abstract

The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide [...] Read more.

The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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132 KiB

Open AccessArticle

A Facile Synthesis of Novel Herbicidal 1-Phenyl-piperazine-2,6-diones

by B. Li, D. Xiang, C. Hsu, Z. Liu, C. Wu and H. Yang

Molecules 2005, 10(9), 1119-1125; https://doi.org/10.3390/10091119 - 30 Sep 2005

Cited by 1 | Viewed by 8565

Abstract

Novel 1-phenyl-piperazine-2,6-diones were prepared by a new facile synthetic routeusing methyl N-substituted iminomonoacetate as starting material. The structures of thesecompounds were established by ¹H-NMR, ¹³C-NMR and GC/MS. 2-(4-Chloro-5-cyclo-pentyl-oxy-2-fluorophenyl)-tetrahydro-2H-pyrido-[1,2-a]-pyrazine-1,3-(4H,6H)-dione displayed thegreatest herbicidal activity. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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225 KiB

Open AccessArticle

The tert-Amino Effect in Heterocyclic Chemistry. Synthesis of Spiro Heterocycles

by E. D’yachenko, T. Glukhareva, L. Dyudya, O. Eltsov and Y. Morzherin

Molecules 2005, 10(9), 1101-1108; https://doi.org/10.3390/10091101 - 30 Sep 2005

Cited by 18 | Viewed by 10264

Abstract

The tert-amino reaction effect was examined. A new method to synthesize spiro heterocycles is presented. It was shown that the “tert-amino effect” could be applied to the formation of spiro-fused heterocycles. The formation of spiro compounds proceeds in most cases in good yields [...] Read more.

The tert-amino reaction effect was examined. A new method to synthesize spiro heterocycles is presented. It was shown that the “tert-amino effect” could be applied to the formation of spiro-fused heterocycles. The formation of spiro compounds proceeds in most cases in good yields in a one-pot reaction. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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265 KiB

Open AccessArticle

Studies Towards the Total Synthesis of Di- and Sesterterpenes with Dicyclopenta[a,d]cyclooctane Skeletons. Three-component Approach to the A/B Rings Building Block

by K. Michalak, M. Michalak and J. Wicha

Molecules 2005, 10(9), 1084-1100; https://doi.org/10.3390/10091084 - 30 Sep 2005

Cited by 23 | Viewed by 10715

Abstract

Sesqui- and sesterterpenes of ophiobolin and fusicoccin families are important synthetic targets because of complexity of structure and potentially useful physiological activities, including anti-tumor activity. A synthesis of versatile building blocks for these terpenoids is described. Cyclopenta[8]annulene rings system with properly dislocated substituents [...] Read more.

Sesqui- and sesterterpenes of ophiobolin and fusicoccin families are important synthetic targets because of complexity of structure and potentially useful physiological activities, including anti-tumor activity. A synthesis of versatile building blocks for these terpenoids is described. Cyclopenta[8]annulene rings system with properly dislocated substituents was constructed using as key steps ring closing metathesis reaction and Wagner - Meerwein rearrangement. Ring closing metathesis reaction leading to cyclopenta[8]annulene was studied in detail. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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175 KiB

Open AccessArticle

An Improved Synthesis of Some 5-Substituted Indolizines Using Regiospecific Lithiation

by Alexey G. Kuznetsov, Alexander A. Bush, Viktor B. Rybakov and Eugene V. Babaev

Molecules 2005, 10(9), 1074-1083; https://doi.org/10.3390/10091074 - 30 Sep 2005

Cited by 23 | Viewed by 9776

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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440 KiB

Open AccessArticle

The Preparation of New Phosphorus-Centered Functional Groups for Modified Oligonucleotides and Other Natural Phosphates

by A. Gautier, C. Lopin, G. Garipova, O. Dubert, I. Kalinina, C. Salcedo, S. Balieu, S. Glatigny, J. Valnot, G. Gouhier and S. Piettre

Molecules 2005, 10(9), 1048-1073; https://doi.org/10.3390/10091048 - 30 Sep 2005

Cited by 5 | Viewed by 10390

Abstract

Efforts to develop synthetic methodologies allowing the preparation of α,α– difluorophosphonothioates, α,α–difluorophosphonodithioates, α,α–difluorophosphono- trithioates, and α,α–difluorophosphinates are reviewed in the light of applications in the field of modified oligonucleotides and cyclitol phosphates. Two successful approaches have been developed, based either on the addition [...] Read more.

Efforts to develop synthetic methodologies allowing the preparation of α,α– difluorophosphonothioates, α,α–difluorophosphonodithioates, α,α–difluorophosphono- trithioates, and α,α–difluorophosphinates are reviewed in the light of applications in the field of modified oligonucleotides and cyclitol phosphates. Two successful approaches have been developed, based either on the addition of phosphorus-centered radicals onto gem–difluoroalkenes or on a process involving the addition of lithiodifluorophosphono- thioates 91 onto a ketone and the subsequent deoxygenation reaction of the adduct. The radical route successfully developed a practical route to α,α–difluoro–H–phosphinates which proved to be useful intermediates to a variety of phosphate isosters. The ionic route led to the first preparation of phosphonodifluoromethyl analogues of nucleoside– 3’–phosphates. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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460 KiB

Open AccessOther

Organic Synthesis in Pheromone Science

by Kenji Mori

Molecules 2005, 10(9), 1023-1047; https://doi.org/10.3390/10091023 - 30 Sep 2005

Cited by 5 | Viewed by 14059

Abstract

Examples are given to illustrate the use of chemical and/or enzymatic asymmetric reactions in the synthesis of the new pheromones of the broad-horned flour beetle, flea beetle, currant stem girdler and Colorado potato beetle. The relationships between stereochemistry and bioactivity among pheromones are [...] Read more.

Examples are given to illustrate the use of chemical and/or enzymatic asymmetric reactions in the synthesis of the new pheromones of the broad-horned flour beetle, flea beetle, currant stem girdler and Colorado potato beetle. The relationships between stereochemistry and bioactivity among pheromones are summarized to emphasize biodiversity as revealed in pheromone perception. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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101 KiB

Open AccessEditorial

Special Issue: Selected Papers from the 2nd International Conference on Natural Products and Physiologically Active Substances (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry” (EAHM-2004)

by Eugene V. Babaev and Alexey V. Tkachev

Molecules 2005, 10(9), 1021-1022; https://doi.org/10.3390/10091021 - 30 Sep 2005

Cited by 1 | Viewed by 5617

Abstract

Two meetings, ICNPAS-2004 and EAHM-2004, were jointly held on September 12-17, 2004 in Novosibirsk, Russia.[...] Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

251 KiB

Open AccessArticle

Dakin-West Trick in the Design of Novel 2-Alkyl(aralkyl) Derivatives of Oxazolo[3,2-a]pyridines

by Zeinul-Gabiden M. Kazhkenov, Alexander A. Bush and Eugene V. Babaev

Molecules 2005, 10(9), 1109-1118; https://doi.org/10.3390/10091109 - 1 Sep 2005

Cited by 9 | Viewed by 8729

Abstract

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic [...] Read more.

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of further utilization of this strategy is illustrated by preparation of unknown 2-benzylimidazo[1,2-a]pyridine from the salt I and ammonia. Full article

(This article belongs to the Special Issue Selected Papers from the “2nd International Conference on Natural Products and Physiologically Active Substances” (ICNPAS-2004) and the 3rd EuroAsian Heterocyclic Meeting “Heterocycles in Organic and Combinatorial Chemistry”)

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Molecules, Volume 10, Issue 9 (September 2005) – 19 articles , Pages 1021-1228

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