Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 2009"

Synthesis and Anticancer Activity of Novel Nonfused Bicyclic Thiazolidinone Derivatives

Abstract: A series of new 2-{4-oxo-2-[(4-oxothiazolidin-2-ylidene)-hydrazono]-thiazolidin-5-yl}-N-arylacetamides ( 4a–e ), 5-(2-oxo-2-aryl-ethyl)-2-[(4-oxothiazolidin-2-ylidene)-hydrazono]-thiazolidine-4-ones ( 5a–d ), 2-(4-oxo-2-[(2-oxothiazolidin-4-ylidene)-hydrazono]-thiazolidin-5-yl)-N-arylacetamides ( 7a–e ), and 5-(2-oxo-2-aryl-ethyl)-2-[(2-oxothiazolidin-4-ylidene)-hydrazono]-thiazolidine-4-ones ( 8a–d ) have been synthesized starting from 2-thioxothiazolidin-4-one and 4-thioxothiazolidin-2-one through a multistep reaction sequence. 2-Thioxothiazolidin-4-one was alkylated via the intermediate formation of the triethylammonium salt 1 by ethyl chloroacetate. Compound 2 and 4-thioxothiazolidin-2-one reacted with thiosemicarbazides to give the 1-(4-thiazolidinone-2-ylidene)-4-R-thiosemicarbazones ( 3a,b ) and 1-(2-thiazolidinone-4-ylidene)thiosemicarbazones ( 6a,b ), respectively. Following [2+3]-cyclization of thiazolidinone-substituted thiosemicarbazones ( 3a,b and 6a,b) with N-arylmaleimides and aroylacrylic ...

(N-Isocyanimino)triphenylphosphorane as an Efficient Reagent for the Synthesis of 1,3,4-Oxadiazoles from 3-Substituted Benzoic Acid Derivatives

Abstract: The reaction of 3-substituted benzoic acid derivatives with (N-isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford corresponding 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions.

The Reaction of (N-Isocyanimino)triphenylphosphorane with Anthranilic Acid Derivatives: One-Pot Synthesis of 2-Substituted 1,3,4-Oxadiazoles via Intramolecular Aza-Wittig Reaction

Abstract: The reaction of anthranilic acid derivatives with (N-isocyanimino)triphenylphosphorane proceeds smoothly at room temperature to afford 2-substituted 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions. The structures of the products were deduced from their IR, 1H NMR, and 13C NMR spectra and mass spectrometry.

Melamine Hydrogen Peroxide (MHP): Novel and Efficient Reagent for the Chemo- and Homoselective and Transition Metal–Free Oxidation of Thiols and Sulfides

Abstract: Melamine hydrogen peroxide (MHP) as a novel hydrogen peroxide adduct was easily prepared. Both chemo- and homoselective oxidation of thiols and sulfides to their corresponding disulfides and sulfoxides occurred by using MHP in moderate to excellent yields. AlCl3 acts as a suitable activator in the oxidation of sulfides with MHP.

Diphosphine Compounds, Part III: UV/Visible Spectroscopy and Novel Routes to Functionalized Diphosphine-M(CO)6 Complexes (M = W, Mo, or Cr)

Abstract: Reaction of coordinated (diphenylphosphino)methane and ketones or aldehydes have been characterized by 31P{H1}-NMR, 1H{31P}-NMR, and UV/vis spectroscopy in dichloromethane. Group VI metals hexacarbonyl [M(CO)6 where M = Cr, Mo, and W] reacted with (diphenylphosphino)methane, [(Ph2P)2CH2], to give [(OC)4M{(Ph2P)2CH2}] depending upon the reaction conditions. Condensation of [(CO)4M{(Ph2P)2CH2}] with different ketones or aldehydes forms [(CO)4M{(Ph2P)2C = CR1R2}]. Complexes of the types [(OC)4M{(Ph2P)2C = CR1R2}] reacted with hydrazine in a Michael addition to give [(CO)4M{(Ph2P)2CHC(R1R2)NHNH2}](1.3a–e), which condensed with different ketones and aldehydes to give complex of the type [(CO)4M{(Ph2P)2CHC(R1R2)NHN = C(R3)] (1.4a–e). The structures of the complexes are discussed on the basis of elemental analysis (EA), IR,1H-NMR, 31P-NMR spectroscopic data, and FAB mass spectra. The UV/vis spectra show two absorption bands with the low energy band moving to lower energy with increasing substitution on the (diph...

An Efficient Synthesis and Antibacterial Screening of Novel Oxazepine α-Aminophosphonates by Ultrasound Approach

Abstract: An efficient synthesis of novel α-aminophosphonates by the reaction of quino[2,3-b][1,5]benzoxazepines with triethyl phosphite in the presence of the easily available, inexpensive, and nontoxic catalyst p-toluene sulphonic acid (p-TSA). This method affords the α-aminophosphonates under the influence of ultrasound irradiation in solvent-free conditions, in short reaction times (4–6 min), high yields (80–90%), with improved purity. The synthesized α-aminophosphonates show antibacterial activity against Gram-positive and Gram-negative bacteria. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

(N-Isocyanimino)triphenylphosphorane-Catalyzed Stereoselective O-Vinylation of N-Hydroxyimides

Abstract: Protonation of the highly reactive 1:1 intermediates, produced in the reaction between (N-isocyanimino)triphenylphosphorane and dialkyl acetylenecarboxylates, by N-hydroxyimides leads to iminotriphenylphosphorane-containing salts, which undergo a reaction sequence including an addition, a proton transfer, and an elimination to produce the corresponding electron-poor O-vinyl derivatives in high yields under neutral conditions. The reaction is completely stereoselective.

Synthesis of Thiazolidine and Thiophene Derivatives for Evaluation as Anticancer Agents

Abstract: The non-isolated adducts (3a,b) were used as key intermediates to synthesize some novel thiazolidine and thiophene derivatives. Compound (4) exhibited a remarkable antitumor activity against EAC ce...

A Molecular Approach for the Prediction of Sulfur Compound Solubility Parameters

Abstract: A quantitative structure–property relationship (QSPR) study was performed to construct a multivariate linear model and a three-layer feed-forward neural network model. This model relates the solubility parameters of 82 sulfur compounds to their structures. Molecular descriptors, which are extracted from the molecular structure of compounds, have been used as model parameters. The multivariate linear model was gained by a genetic algorithm–based multivariate linear regression; the results showed that the squared correlation coefficient (R2) between predicted and experimental values was 0.964. Next, a three-layer feed-forward neural network model with optimized structure was employed; the results showed that the squared correlation coefficient (R2) is 0.9874, and with this model we can predict the solubility parameter more accurately than the linear model. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements t...

Synthesis and Antimicrobial Activity of Some New Heterocyclic Schiff Bases Derived from 2-Amino-3-formylchromone

Abstract: Some new hydrazone derivatives 3a–e have been obtained from 2-amino-3-formylchromone (1). Heterocyclization of thiocarbohydrazone derivative 3e via reaction with some electrophilic reagents afforded 1,2,4-triazoles 6–8 and 1,2,4-triazines 9–13. Condensation reactions of aldehyde 1 with o-aminoaldehydes and/or ketones afforded some new isolated and condensed heterocyclic systems 17, 19, and 20. The newly synthesized compounds were screened for their antimicrobial activity.

One-Pot, Multicomponent Condensation Reaction in Neutral Conditions: Synthesis, Characterization, and Biological Studies of Fused Thiazolo[2,3-b]quinazolinone Derivatives

Abstract: A new series of 12-(2-chloro-6-quinoline-3-yl)-3,3,8-substituted-2,3,4,12-tetrahydro-benzo[4,5]thiazolo[2,3-b]quinazolin-1-ones 4 was synthesized in one pot by condensing various 2-chloro-3-formylquinolines 1, 2-amino-6-substituted-benzothiazoles 2, and 1,3-cyclohexanedione 3 in ethanol. All the compounds were characterized by IR, 1H NMR, 13C NMR spectra and elemental analysis. All the synthesized compounds were screened for their antibacterial activity against Grampositive bacterial species Bacillus cereus and Bacillus substilus, Gram-negative bacterial species Escherichia coli, and their fungicidal activity against Aspergillus niger, Fuserium oxisporum, and Rhizopus species.

Synthesis of Some New 1,3,2-Oxazaphosphinine, 1,3,2-Diazaphosphinine, Acyclic, and/or Cyclic α-Aminophosphonate Derivatives Containing the Chromone Moiety

Abstract: The synthesis of some new 1,3,2-oxazaphosphinine 18, 1,3,2-diazaphosphinine 19, acyclic, and cyclic α-aminophosphonate derivatives 3–17 containing the chromone moiety have been achieved via reaction of 3-(phenyliminomethyl)chromone (1), 3-(phenylaminomethylene)-2-hydroxychromanone (4), and/or 3-(phenylamino-methylene)-2-(phenylamino)chromanone (5) with diethyl phosphite, tris(2-chloroethyl)phosphite, and phenylphosphonic dichloride. Structures of the products were verified on the basis of their elemental analyses, IR, 1H, and 31P NMR spectral data.

A Simple, Microwave-Assisted, and Solvent-Free Synthesis of 2-Arylbenzothiazoles by Acetic Acid–Promoted Condensation of Aldehydes with 2-Aminothiophenol in Air

Abstract: An efficient and simple procedure has been developed for the synthesis of various 2-arylbenzothiazoles by acetic acid–promoted condensation of 2 -aminothiophenol with aromatic aldehydes under microwave irradiation and solvent-free conditions in high yields.

Perchloric Acid–Doped Polyaniline as an Efficient and Reusable Catalyst for the Synthesis of 2-Substituted Benzothiazoles

Abstract: 2-Substituted benzothiazoles have been efficiently synthesized in good yields by the condensation reaction of o-aminothiophenol with aldehydes in the presence of a catalytic amount of perchloric acid–doped polyaniline (HClO4/PANI). The low cost, simple recovery, and efficient reusability are remarkable characteristics of this catalyst.

Synthesis of Phosphonic Acids Possessing Isoindolin-1-one Moiety: Unexpected Acid-Catalyzed C-P-Bond Cleavage

Abstract: Phosphonic acids bearing isoindolin-1-one moiety were synthesized by dehydrative aromatization of the corresponding epoxyisoindolyl phosphonates. A mechanism for the unexpected acid catalyzed dephosphorylation was proposed.

Synthetic Utility of Enaminonitrile Moiety in Heterocyclic Synthesis: Synthesis of Some New Thienopyrimidines

Abstract: The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile ( 4 ) was condensed with p-anisaldehyde affording the Schiff base ( 5 ). Acylation of the thienopyridine derivative ( 4 ) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives ( 6 ) and ( 7 ). Condensation of ( 4 ) with triethylorthoformate yielded the ethoxymethyleneamino derivative ( 8 ), which was treated with hydrazine hydrate to give the hydrazide derivative ( 9 ), which in turn was converted to a triazolopyrimidine derivative ( 10 ) upon treatment with freshly distilled acetic anhydride. Thiation of ( 4 ) with carbon disulfide afforded the pyrimidine dithione derivative ( 11 ), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative ( 12 ).On the other hand, treatment of ( 4 ) with formamide yielded the aminopyrimidine derivative ( 13 ), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1 4 ). Chlorination of (1 4 ) with...

Synthesis and Anticancer Activities of Some Thiazole Derivatives

Abstract: In this study, 2-substituted 4-[3/4-(4-arylthiazole-2-yl)aminophenyl]thiazole derivatives and 2-[4-[2-substituted 4-methylthiazole-5-yl]thiazole-2-yl]amino-5-arylidenethiazoline-4-one derivatives have been synthesized. The cytotoxic and/or growth inhibitory effects of the 16 selected compounds were evaluated in vitro against approximately 66 human tumor cell lines derived from nine neoplastic diseases. Some of the compounds were found to act as anticancer agents.

Ce(SO4)2·4H2O as a Recyclable Catalyst for an Efficient, Simple, and Clean Synthesis of 4H-Benzo[b]pyrans

Abstract: An efficient method for the synthesis of 4H-benzo[b]pyrans has been developed by the use of Ce(SO4)2·4H2O (2.5 mol%) as a catalyst. Heating the mixture of an appropriate aldehyde, malononitrile, and dimedone in the presence of the catalyst at 45°C in a mixture of water:ethanol (1:1) as solvent for about 9–55 min resulted excellent yields of the corresponding products. Short experimental time of the reaction, excellent yields, simple workup, not using cumbersome apparatus for purification of the products, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.

A Facile Synthesis of Stable Phosphorus Ylides Containing Chlorine and Sulfur Derived from 6-Chloro-2-benzoxazolethiol and 2-Chloro-phenothiazine

Abstract: Stable crystalline phosphorus ylides containing chlorine and sulfur were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylene-dicarboxylates in the presence of 6-chloro-2-benzoxazolethiol and 2-chloro-phenothiazine. These stable ylides exist in solution as a mixture of two geometrical isomers. This is caused by the conjugation of the ylide moiety with the adjacent carbonyl group, which results in a restricted rotation around the respective carbon-carbon bond.

Anti-Alzheimer and Anti-Cox-2 Activities of the Newly Synthesized 2,3′-Bipyridine Derivatives (I)

Abstract: 3-Aryl-1-pyridin-3-ylprop-2-en-1-ones 1a,b reacted with 2-cyanoethane-thioamide (2) to afford the corresponding 4-aryl-6-thioxo-1,6-dihydro-2,3′-bipyridine-5-carbonitriles 6a,b. The synthetic potentiality of compounds 6a,b were investigated in the present study via their reactions with several active-hydrogen containing compounds 8a–g aiming to synthesize 4-aryl-6-pyridin-3-ylthieno[2,3-b]pyridin-3-amines 10a–n via 6-(alkylthio)-4-aryl-2,3′-bipyridine-5-carbonitriles 9a–n. The structures of all newly synthesized heterocyclic compounds were elucidated by considering the data of IR, 1H NMR, and mass spectra, as well as that of elemental analyses. Anti-Alzheimer and anti-COX-2 activities for all newly synthesized heterocyclic compounds were investigated. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Diastereoselective Synthesis of New Dialkylphosphorylhydrazones

Abstract: A series of 22 dialkylphosphorylydrazones (dialkyl ester, N′-[(1E)-(R1 phenyl)methylene]-phosphorohydrazidic acid), 20 of them new, along with three new N,N′-bis (diisobutylphosphorylthioamide)diamines (bis-[diisobutyl ester), N-thioxomethylene]-, diamine)phosphora-midic acid, were prepared and characterized by IR, 1H NMR, 13C NMR, 31P NMR, and mass spectrometry. The analysis of 1H NMR, 13C NMR, 31P NMR, and NOE spectra confirmed the observation of the single diastereoisomer E in the synthesis of dialkylphosphorylydrazones. The results of a molecular modeling study performed in order to investigate the mechanism of the synthesis of dialkylphosphorylydrazones are in agreement with the experimental results, i.e., the favored formation of diastereoisomer E over Z.

One-Pot Stereoselective Synthesis of Alkyl (Z)-2-[4-Oxo-3-phenyl-2-(phenylimino)-1,3-thiazolan-5-yliden]acetates from Acetylenic Esters and N, N′ -Diphenylthiourea

Abstract: N, N′ -diphenylthiourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl (Z)-2-[4-oxo-3-phenyl-2-(phenylimino)-1,3-thiazolan-5-yliden]acetates in fairly good yields. NMR spectra indicated that the reaction is completely stereoselective.

Spectral, BVS, and Thermal Studies on Bisdithiocarbamates of Divalent Zn, Cd, and Their Adducts: Single Crystal X-Ray Structure Redetermination of (Diiodo) (Tetraethylthiuramdisulfide)mercury(II), [Hg(tetds)I2]

Abstract: The current article describes the TG and DT analyses of divalent Zn, Cd, and Hg dithiocarbamato (dtc) complexes and their adducts (dchdtc = N,N-dicyclohexyldithiocarbamate anion, 4-mpzdtc = 4-methylpiperazinecarbodithioato anion, padtc = N,N′-(iminodiethylene)bisphthalimidedithiocarbamate anion, pipdtc = piperidinecarbodithioate anion, 1,10-phen = 1,10-phenanthroline, and 2,2′-bipy = 2,2′-bipyridine) along with the structural reinvestigation of [Hg(tetds)I 2 ], where tetds = tetraethylthiuramdisulfide. In the case of Zn(II) and Cd(II) dithiocarbamates and their nitrogenous adducts, thermal decomposition of the nitrogenous bases is followed by the decay of dithiocarbamate leading to the formation of ZnS or CdS as residue. The interaction of iodine with [Hg(dedtc) 2 ] in CHCl 3 results in the oxidation of diethyldithiocarbamate leading to the formation of [Hg(tetds)I 2 ], and the structure was redetermined because the earlier determination was by a Polaroid crystallographic technique with a higher R value. ...

Chemoselective Synthesis of Stable Phosphorus Ylides from 6-Azauracil and Mechanistic Investigation of the Reaction by UV Spectrophotometry

Abstract: Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, in the presence of NH-acids such as 6-azauracil. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometry. The second order fits were automatically drawn, and the values of the second order rate constants (k2) were automatically calculated using standard equations. At the temperature range studied, the dependence of the second order rate constant (Ln k2) on reciprocal temperature was in agreement with the Arrhenius equation. This provided the relevant plots to calculate the activation energy of all the reactions. Furthermore, useful information was obtained from studies of the effect of solvent, structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates), and also concentration of reactants on the rate of reactions. The proposed mechanism was confirmed according to the obtained results, and a steady-state approximation and first step (k2) of the reaction was recognized as a rate-determining step on the basis of experimental data.

A Facile Synthesis of Bromo-Substituted Benzofuran Containing Thiazolidinone Nucleus Bridged with Quinoline Derivatives: Potent Analgesic and Antimicrobial Agents

Abstract: Treatment of 5-bromo-2-acetyl benzofuran with hydrazine followed by condensation of the resulting hydrazone with different quinoline derivatives gave the corresponding Schiff bases. Reaction of these Schiff bases with thioacetic acid furnished the target thiazolidinone molecule. Some of the newly synthesized compounds show promising analgesic and antimicrobial activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

A Green Protocol for Solvent-Free Conversion of Epoxides to Thiiranes with Dowex-50WX8–Supported Thiourea

Abstract: Structurally different epoxides were efficiently converted to the corresponding thiiranes by Dowex-50WX8–supported thiourea under solvent-free conditions. The reactions were carried out either in an oil bath or under microwave irradiation to give the thiiranes in 75–98% yields within 30 sec–120 min.

An Efficient Synthesis of New 3,4-Dihydropyrimidin- 2(1H)-ones Incorporating a Phenyl Moiety at C-5 and C-6 Catalyzed by TMSCl and Co(OAc)2.4H2O

Abstract: New 3,4-dihydropyrimidin-2-ones having a phenyl moiety at C-5 and C-6 have been prepared by a microwave-assisted Biginelli–like reaction by a three-component, one-pot condensation of an aromatic aldehyde, deoxybenzoin and urea, or thiourea using TMSCl and Co(OAc) 2 .4H 2 O as an efficient Lewis acid catalyst.

Synthesis and Biological Activity of O,O-Dimethyl-2,6-Pyridinyl Diformyloxy Alkyl Phosphonates

Abstract: In an attempt to discover novel compounds with high activity and low toxicity, a series of new O,O-dimethyl-2,6-pyridinyl diformyloxy alkyl phosphonates 4a–4p has been designed and synthesized by the reaction of 2,6-pyridinyl diformyloxy chloride with α-hydroxyalkyl phosphonate. The structures of all new compounds were characterized by elementary analysis, IR, 1H NMR, and MS spectroscopies. The results of a preliminary bioassay indicate that some of the target compounds have obviously promotive action for plant growth against the stalk of barnyard grass.

Synthesis of Some Pyridothienopyrazolopyrimidopyrimidine and Mercaptomethylpyrazolopyrimidine Derivatives

Abstract: Mercaptomethylpyrazolopyrimidine (2) was synthesized and reacted with ethyl chloroacetate to afford ethyl pyrazolpyrimidinylmethylmercapto acetate ( 3) , which in turn was converted into the corresponding carbohydrazide 4 . Carbohydrazide 4 reacts with a variety of reagents to give different pyrazolopyrimidines ( 5–12 ). Chloromethyl-pyrazolopyrimidine (1) reacts with chloropyridine to give compound 13 , which was subjected in a series of reactions to give new compounds 14–20 .

Synthesis and Pesticidal Properties of Thio and Seleno Analogs of Some Common Urea Herbicides

Abstract: Thio and seleno analogs of fenuron, isoproturon, chlorotoluron, metoxuron, monuron, and diuron were synthesized from the corresponding aryl amines. Their reaction with thiophosgene leads to isothiocyanates. Aryl amines were also converted (via isocyanides) to isoselenocyanates. The reaction of both isothio- and isoselenocyanates with dimethylamine affords the corresponding thio and seleno analogs of the above-mentioned urea herbicides. Herbicidal activity of the synthesized compounds was slightly lower than the activity of the parent urea herbicides. The thio and seleno analogs as well as the parent ureas showed good fungicidal activity at a concentration of 200 ppm against selected fungi.