Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 2012"
TL;DR: In this paper, the isolated HAP has been characterized using thermo gravimetric analysis (TG) and differential thermal analysis (DTA), Fourier Transformed Infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission electron microscope (FE-SEM), and energy dispersive x-ray (EDX).
Abstract: Natural hydroxyapatite (HAP) is isolated from waste chicken bone by thermal calcinations at different temperatures in the range of 200 °C to 1000 °C. The isolated HAP has been characterized using thermo gravimetric analysis (TG) and differential thermal analysis (DTA), Fourier Transformed Infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission electron microscope (FE-SEM), and energy dispersive X-ray (EDX). The XRD results showed that the enhanced crystallinity of HAP phase by thermal calcination above 600 °C and the crystal size has been found to increase with increasing temperature of thermal calcinations due to agglomeration. Value addition for the waste chicken bone is given by the isolation of useful bioceramics (HAP) and the optimum temperature for the thermal calcination is found to be 600 °C. The isolated HAP has been characterized as carbonated HAP of B type with the hexagonal structure. These results will not only make the chicken bone as an important bioresource for the HAP but wi...
64 citations
TL;DR: In this paper, 3-Methyl-4-arylmethylene-isoxazol-5(4H)-ones were synthesized by the convenient three-component reaction of ethyl acetoacetate, hydroxylamine hydrochloride, and aromatic aldehydes catalyzed by sodium sulfide.
Abstract: 3-Methyl-4-arylmethylene-isoxazol-5(4H)-ones were synthesized by the convenient three-component reaction of ethyl acetoacetate, hydroxylamine hydrochloride, and aromatic aldehydes catalyzed by sodium sulfide in the presence of ethanol at room temperature. The advantages of this procedure were mild reaction conditions, high yields, short reaction time, and operational simplicity.
45 citations
TL;DR: A new 1,2,3-thiadiazole compound, C18H18Cl2N4O2S, has been synthesized and the crystal structure was determined by single crystal X-ray diffraction study.
Abstract: A new 1,2,3-thiadiazole compound, C18H18Cl2N4O2S, has been synthesized and the crystal structure was determined by single crystal X-ray diffraction study. The fungicidal activity of the title compo...
34 citations
TL;DR: In this paper, a highly efficient heterogeneous catalytic thiocyanation of indoles, substituted anilines, and substituted aromatic amines in water under mild and green conditions is described.
Abstract: This article describes a highly efficient heterogeneous catalytic thiocyanation of indoles, substituted anilines (electron rich and electron deficient) and N-substituted aromatic amines in water under mild and green conditions The reaction of substrates with KSCN in the presence of silica sulfuric acid (SSA) and silica boron sulfonic acid (SBSA) as heterogeneous catalysts and H2O2 or UHP (urea hydrogen peroxide) as green oxidants produces aryl thiocyanates in short reaction times and high yields Moreover, in this article, some novel aryl thiocyanates were synthesized
30 citations
TL;DR: A green one-pot three-component synthesis for α-aminophosphonates by condensation of aldehydes, amines, and diethylphosphite by using nonionic surfactant Tween-20 as catalyst in aqueous media was developed in this paper.
Abstract: A green one-pot three-component synthesis has been developed for α-aminophosphonates by condensation of aldehydes, amines, and diethylphosphite by using nonionic surfactant Tween-20 as catalyst in aqueous media. The results showed that this synthetic route for α-aminophosphonates takes just 25–60 min for completion at 60 °C and affords 64%–91% yields depending on the nature of the amine substrates. The major advantages of this novel method are green reaction conditions with water as solvent, simple workup, less reaction times, and high to moderate yields.
30 citations
TL;DR: In this article, a one-pot, efficient three-component condensation of aldehydes, 2-naphthol, and 2-aminobenzothiazole in the presence of sodium hydrogen sulfate as an effective catalyst for the synthesis of 1-(benzothiazolylamino)methyl-2 naphtholic derivatives under thermal and solvent-free conditions is described.
Abstract: A one-pot, efficient three-component condensation of aldehydes, 2-naphthol, and 2-aminobenzothiazole in the presence of sodium hydrogen sulfate as an effective catalyst for the synthesis of 1-(benzothiazolylamino)methyl-2-naphthol derivatives under thermal and solvent-free conditions is described. These products involve two biologically active parts, Betti's base and benzothiazole. The present methodology offers several advantages, such as good yields, short reaction times, and easy work-up.
27 citations
TL;DR: In this article, a series of acetoxybenzoylthioureas derivatives with aryl and amino acid ester side chains were synthesized by reaction of acyloxy benzyl ester-based derivative of aspirin.
Abstract: A series of acetoxybenzoylthioureas derivatives with aryl and amino acid ester side chains were prepared by reaction of acetoxybenzoyl isothiocyanate, an acyloxy benzyl ester-based derivative of aspirin, with aryl amines or amino-functionalized amino acids with overall yields of 46–73%. The products that display a thiourea segment as a linker showed improved antibacterial properties in comparison with aspirin. The structures of the synthesized compounds were characterized by infra red spectroscopy, 13C nuclear magnetic resonance (NMR), and 1H NMR spectroscopy. The compounds were screened for their antibacterial activity by using gram-negative bacteria (E. coli ATCC 8739). [2-(phenylcarbamothioylcarbamoyl)phenyl] acetate showed the highest antibacterial activity against E. coli compared with other synthesized compounds. 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 supplementa...
23 citations
TL;DR: In this paper, an efficient and simple method for the facile synthesis of arylthiocyanates via diazotization-thIocyanation of primary aromatic amines using cross-linked poly (4-vinylpyridine) supported thiocynate ion is described.
Abstract: An efficient and simple method for the facile synthesis of arylthiocyanates via diazotization-thiocyanation of aryl amines using cross-linked poly (4-vinylpyridine) supported thiocyanate ion is described. Various primary aromatic amines, with electron-withdrawing and electron-donating groups, were transformed into aryl thiocyanates in high to excellent yields in a short reaction time. The present procedure offers advantages such as short reaction time, simple reaction work-up, and the polymeric reagents can also be regenerated and reused for several times without significant loss of their 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.
21 citations
TL;DR: In this article, the synergistic effect of a combination of (HOCH2)3P and Na2S2O4 for the bleaching of mechanical pulps was studied in aqueous media under Ar and in air.
Abstract: With the aim of learning about the synergistic effect of a combination of (HOCH2)3P and Na2S2O4 for the bleaching of mechanical pulps, reactions of (HOCH2)3P (and its associated precursor, (HOCH2)4P+Cl−) with Na2S2O4 were studied in aqueous media under Ar and in air. The secondary phosphine (HOCH2)2PH is the major product in a 1:1 reaction of (HOCH2)3P and Na2S2O4 under Ar, the formaldehyde being removed in the form of HOCH2SO3Na and HOCH2SO2Na; the latter is Rongalite, itself an industrial bleaching agent. Significant amounts of the primary phosphine HOCH2PH2 are also seen. When the reaction is performed in air, the oxide (HOCH2)2P(O)H is the main product. Reaction of (HOCH2)4P+Cl− with Na2S2O4 (even under Ar) leads to solely the oxidation products: (HOCH2)3PO, (HOCH2)3PS, and (HOCH2)2P(O)OH. 31P{1H} and 1H NMR spectral data for secondary and primary (hydroxymethyl)phosphines and their oxidation products are reported for the first time. The toxicity of the primary and secondary phosphines is lik...
21 citations
TL;DR: In this article, a series of novel α-aminophosphonate derivatives containing benzothiazole and thiourea moieties from substituted 2-aminobenzothiazoles and synthetic intermediates under microwave irradiation has been demonstrated.
Abstract: The synthesis of a series of novel α-aminophosphonate derivatives containing benzothiazole and thiourea moieties from substituted 2-aminobenzothiazoles and synthetic intermediates O,O′-dialkylisothiocyanat-(phenyl)methylphosphonates under microwave irradiation has been demonstrated. Several salient features, such as good to excellent yields, shorter reaction times, milder reaction conditions, and simple purification procedures, make the present synthetic protocol highly attractive to access the title compounds. Bioassays indicated that most of the compounds possessed broad-spectrum insecticidal and antiviral activities against Tobacco Mosaic Virus (TMV) in vivo. Interestingly, in comparison with control insecticide Avermectin, two compounds displayed remarkably high in vitro insecticidal activities against Plutella xylostella. Furthermore, according to the results from preliminary bioassay, all were associated with moderate to good anti-TMV activities. [Supplemental materials are available for th...
21 citations
TL;DR: In this paper, a new series of modified α-amidophosphonates (or β-ketophosphonsonate) was synthesized by an efficient method, starting from aminoesters and chloroacetyl chloride.
Abstract: A new series of modified α-amidophosphonates (or β-ketophosphonate) was synthesized by an efficient method, starting from aminoesters and chloroacetyl chloride. We have established that chloroacetyl chloride is a suitable reagent allowing the introduction a halogen moiety for the Arbuzov reaction. The α-amidophosphonates were prepared in two steps (acetylation, phosphorylation). 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.
TL;DR: In this article, a general, facile, and efficient new synthetic path to thioesters was established by employing defined TFA-catalyzed reaction of carboxylic acid and thiol under mild conditions.
Abstract: A general, facile, and efficient new synthetic path to thioesters was established by employing defined TFA-catalyzed reaction of carboxylic acid and thiol under mild conditions. The structure of the newly synthesized compounds was determined by infrared spectroscopy, nuclear magnetic resonance, and a single crystal X-ray crystallographic analysis. Supplemental materials are available for this paper. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
TL;DR: In this article, the structures of the cyclized compounds have been established on the basis of elemental analysis and spectroscopic data, and the synthesized compounds were screened for antimicrobial activity.
Abstract: 8-Methoxy-4-phenyl-3,4,5,6-tetrahydrobenzo[h]quinazoline-2(1H)-thione, obtained by the condensation of 2-benzylidene-6-methoxy-3,4-dihydronapthalene-1(2H)-one with thiourea, on reaction with chloroacetic acid and 3-chloropropanoic acid in the presence of the ionic liquid N-methylpyridinium tosylate furnishes 3-methoxy-7-phenyl-7,10-dihydro-5H- benzo[h]thiazolo[2,3-b]quinazoline-9(6H)-one and 3-methoxy-7-phenyl-5,6,10,11-tetrahydro- benzo[h][1,3]thiazino[2,3-b]quinazoline-9(7H)-one. Further, condensation of the thione with 1,2-dibromoethane and 1,3-dibromopropane yields 3-methoxy-7-phenyl-6,7,9,10-tetrahydro-5 H-benzo[h]thiazolo[2,3-b]quinazoline and 3-methoxy-7-phenyl-5,6,7,9,10,11-hexahydrobenzo [h][1,3]thiazino[2,3-b]quinazoline respectively. Arylidene derivatives have been obtained by two routes. The structures of the cyclized compounds have been established on the basis of elemental analysis and spectroscopic data. The synthesized compounds were screened for antimicrobial activity. Some of th...
TL;DR: In this article, an efficient, simple and environmentally benign procedure for the one-pot synthesis of 3,4-dihydropyrimidine-2-(1H) thione derivatives that entails the three-component condensation of appropriate aryl aldehydes, β-dicarbonyls, and thiourea in the presence of catalytic amount of tungstate sulfuric acid under solvent-free conditions was reported.
Abstract: An efficient, simple, and environmentally benign procedure for the one-pot synthesis of 3,4-dihydropyrimidine-2-(1H) thione derivatives that entails the three-component condensation of appropriate aryl aldehydes, β-dicarbonyls, and thiourea in the presence of catalytic amount of tungstate sulfuric acid under solvent-free conditions was reported. This method has many advantages including excellent yields, short reaction time, and simple work-up procedure. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: 1H, 13C NMR and Mass Spectra for 5b, 5g, 5j, 5i, 5l (S2-S16). Additional Characterization Data (S17-18).
TL;DR: A series of novel diphenyl (arylamino), 1-phenyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)methylphosphonates have been synthesized in high yields.
Abstract: A series of novel diphenyl (arylamino)(1-phenyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl)methylphosphonates have been synthesized in high yields. They were screened for their antibacterial activities against Escherichia coli (NCIM2065) as a Gram-negative bacterium, Bacillus subtilis (PC1219) and Staphylococcus aureus (ATCC25292) as Gram-positive bacteria and Schccaromycies cerevisiae as a fungus. The minimum inhibitory concentrations (MICs) of the synthetic compounds showed moderate antibacterial and antifungal activities at low concentrations (10–1000 μg/mL).
TL;DR: Trichloroisocyanuric acid (TCCA) and N-chlorosuccinimide (NCS) were found to be mild and efficient reagents for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good-to-excellent yields through the oxidative chlorination as mentioned in this paper.
Abstract: Trichloroisocyanuric acid (TCCA) and N-chlorosuccinimide (NCS) were found to be mild and efficient reagents for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good-to-excellent yields through the oxidative chlorination. The overall process is simple and practical, and it provides convenient access to a variety of aryl or heteroarylsulfonyl chlorides. The mild reaction conditions and the broad substrate scope render this method attractive and complementary to existing syntheses of aryl or heteroarylsulfonyl chlorides.
TL;DR: In this paper, the reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC10H7)PPh2 (1) ligand.
Abstract: The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC10H7)PPh2 (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC10H7)P(S)Ph2 (2) and (1-NHC10H7)P(Se)Ph2 (3), respectively. Moreover, the byproduct {Ph2P(S)}2O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1–3 were identified and characterized by multinuclear (1H, 13C, 31P, 77Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out.
TL;DR: In this paper, a new (E)-pyrene-1-carbaldehyde O-tert-butyldimethylsilyl oxime 3 was synthesized for the detection of chemical warfare nerve agents, O-isopropyl methylphosphonofluoridate (GB) and O-pinacolyl methyl phosphonof fluorine (GD).
Abstract: A new (E)-pyrene-1-carbaldehyde O-tert-butyldimethylsilyl oxime 3 was synthesized for the detection of chemical warfare nerve agents, O-isopropyl methylphosphonofluoridate (GB) and O-pinacolyl methylphosphonofluoridate (GD). 1H NMR spectrum showed that the tert-butyldimethylsilyl (TBDMS) group was deprotected using TBAF and the oximate supernucleophile was made. Upon addition of chemical warfare agents (GB and GD) (50 mol%), the reaction was completely finished within 5 min and also the color change of reaction mixture was observed under a hand-held UV lamp with the naked eye.
TL;DR: In this article, the synthesis and antimicrobial evaluation of a new series of substituted 1,2,4-triazole and 1,3, 4-thiadiazole derivatives are presented.
Abstract: 1,2,4-triazole and 1,3,4-thiadiazole derivatives are still considered a viable lead structure for the synthesis of more efficient antimicrobial agents having a broad spectrum of activity. This study presents the synthesis and antimicrobial evaluation of a new series of substituted 1,2,4-triazole and 1,3,4-thiadiazole derivatives. Reaction of 4-phenyl-5-(pyridin-3-yl)-4H-1,2,4-triazole-3-thione with ethyl bromoacetate yields the corresponding ethyl acetate (1). In the subsequent reaction with 100% hydrazine hydrate, the hydrazide (2) was obtained, which was converted with isothiocyanates to new acyl derivatives of thiosemicarbazide (3a–l). The cyclization of these compounds in alkaline media resulted in the formation of new derivatives of 1,2,4-triazole (4a–i), whereas in acidic media new derivatives of 1,3,4-thiadiazole (5a,b,g) were obtained. All synthesized compounds were screened for their in vitro antimicrobial activities.
TL;DR: In this article, a series of new O,O-dimethyl-(3-phenacryloyloxy) alkyl phosphonates 4a-m have been designed and synthesized by the reaction of 3-phenACryl-oyl chloride with α-hydroxyalkyl phosphonate, and all new compounds were characterized by elemental analysis, IR, and 1H NMR spectroscopy as well as by mass spectrometry.
Abstract: In an attempt to discover novel compounds with high biological activity and low toxicity, a series of new O,O-dimethyl-(3-phenacryloyloxy) alkyl phosphonates 4a–m have been designed and synthesized by the reaction of 3-phenacryloyl chloride with α-hydroxyalkyl phosphonate. All new compounds were characterized by elemental analysis, IR, and 1H NMR spectroscopy as well as by mass spectrometry. The results of preliminary bioassay indicate that some of the target compounds have excellent inhibitory activities on Triticum aestivum (wheat) and Brassica napus L. (rape).
TL;DR: In this paper, 3,4-dihydropyrimidin-2-(1H)-ones and their sulfur derivatives were efficiently synthesized by a one-pot cyclocondensation reaction of aromatic and aliphatic aldehydes, β-dicarbonyl compounds and urea (or thiourea) in the presence of sulfuric acid immobilized on activated charcoal (133% w/w).
Abstract: Various 3,4-dihydropyrimidin-2-(1H)-ones (DHPMs) and their sulfur derivatives were efficiently synthesized by a one-pot cyclocondensation reaction of aromatic and aliphatic aldehydes, β-dicarbonyl compounds and urea (or thiourea) in the presence of sulfuric acid immobilized on activated charcoal (133% w/w). The reactions were carried out in refluxing n-hexane-acetonitrile (2.5:0.5 mL) within 5–150 min to give 3,4-dihydropyrimidinones (or thiones) in high to excellent yields (81–97%).
TL;DR: The Schiff bases derived from the condensation of 2-aminobenzothiazole derivatives and their silicon(IV) complexes with the general formula R2Si(L)Cl (R = Et, Bu, Ph, L = 2-(2-hydroxy-3-methoxy) benzylideneaminobenzo-thiazole) have been synthesized.
Abstract: The Schiff bases derived from the condensation of 2-aminobenzothiazole derivatives and 2-hydroxy-3-methoxybenzaldehyde and their silicon(IV) complexes with the general formula R2Si(L)Cl (R = Et, Bu, Ph, L = 2-(2-hydroxy-3-methoxy) benzylideneaminobenzo-thiazole) have been synthesized. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including IR and NMR (1H, 13C, and 29Si) spectroscopy. The analytical data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) and fungi (Aspergillus niger and Candida albicans). The complexes were found to be more potent as compared to the ligands. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Relat...
TL;DR: In this paper, a wide range of Phthalimidoacyl isothiocyanates was used in addition-cyclization reactions to obtain derivatives of quinazoline, benzoxazole, benzimidazole and oxatriazepine.
Abstract: Phthalimidoacyl isothiocyanates 1a,b participated in a wide range of addition–cyclization reactions. Simultaneous or subsequent cyclization of the obtained adducts gave derivatives of quinazoline, benzoxazole, benzimidazole, 1,2,4-triazole, and oxatriazepine. The structures of all the products were confirmed by microanalytical and spectroscopic data.
TL;DR: In this article, the reaction of nucleophilic phosphacumulene ylides with visnaginone and khellinone afforded the corresponding phosphanylidene and furochromene derivatives.
Abstract: The reaction of nucleophilic phosphacumulene ylides with visnaginone and khellinone afforded the corresponding phosphanylidene and furochromene derivatives. Moreover, pyranochromenes were obtained from the reaction of chromene carbaldehydes with phosphacumulenes. On the other hand, the phosphanylidene-cyclobutylidenes and their dimers were produced from the reaction of furochromene carbaldehydes with the same phosphonium reagents.
TL;DR: Hexacoordinated organosilicon complexes of type R3Si(L) have been synthesized and characterized by elemental analysis, molar conductance, and spectroscopic studies as discussed by the authors.
Abstract: Hexacoordinated organosilicon complexes of type R3Si(L) (R = ethyl, butyl, phenyl; HL = ligand, obtained by the condensation of 4-aminoantipyrine with 2-hydroxyacetophenone, 2-hydroxybenzophenone, 2-hydroxybenzaldehyde, and 2-hydroxynapthaldehyde) have been synthesized and characterized by elemental analysis, molar conductance, and spectroscopic studies (IR, 1H, 13C, and 29Si NMR). The spectroscopic studies indicated that the ligands acted as tridentate coordinating through azomethine nitrogen, carbonyl oxygen, and oxygen of hydroxyl after deprotonation to the central silicon atom. The ligands and their organosilicon complexes have been evaluated for antimicrobial activities against fungi (Aspergillus niger and Candida albicans), and against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), and Gram-negative bacteria (Escherichia coli). The aim of the present work is to synthesize novel eco-friendly fungicides and bactericides and to study the effect of the biological activity of...
TL;DR: Diorganotin(IV) complexes of an extended system derived from the condensation of pyridoxal hydrochloride with 2-amino phenol (H2L1), 2amino-4-methyl phenol, 2-amide-4 chloro phenol and 2-amber-4nitro phenol have been synthesized by the reaction of dichlorodiorgan-IV in a 1:1 molar ratio with these ligands as mentioned in this paper.
Abstract: Diorganotin(IV) complexes of an extended system derived from the condensation of pyridoxal hydrochloride with 2-amino phenol (H2L1), 2-amino-4-methyl phenol (H2L2), 2-amino-4-chloro phenol (H2L3), 2-amino-4-nitro phenol (H2L4), 1-amino-2-naphthol hydrochloride (H2L5) have been synthesized by the reaction of dichlorodiorganotin(IV) in a 1:1 molar ratio with these ligands. Spectral studies (IR, 1H, 13C, 119Sn NMR) along with physical data evidenced the formation of penta-coordinated species with the ligands acting as tridentate (ONO) with oxygen occupying the axial positions, and nitrogen at one of the equatorial positions. The ligands and their organotin complexes have been evaluated for antimicrobial activity against phytopathogenic fungi Candida albicans and Aspergillus niger at 25 ± 1 °C and bacteria Bacillus subtilis, Escherichia coli, and Staphylococcus aureus at 37 ± 1 °C. The activities of the ligands have been enhanced on complexation and the results indicate that they exhibit significant ...
TL;DR: In this article, it was shown that 1-alkoxy-1,2-dihydrophosphinine oxides with alkyl halides can be obtained in boiling acetone in the presence of K2CO3.
Abstract: 1-alkoxy-1,2-dihydrophosphinine oxides 4 may be prepared by the reaction of 1-hydroxy-1,2-dihydrophosphinine 1-oxide 3 with alkyl halides. The best results were obtained in boiling acetone in the presence of K2CO3. The outcome of the alkylation of 3-hydroxy-6,6-dichloro-3-phosphabicyclo[3.1.0]hexane 3-oxide 5 was dependent on temperature. Butylation at 56 °C in acetone using K2CO3 afforded mainly the expected phosphinate 6, but an increase in the temperature led to opening of the cyclopropane ring, resulting in the formation of 1-butoxy-1,2-dihydrophosphinine oxide 4a as the major product.
TL;DR: In this paper, a green, straightforward, and novel method for the oxidation of thiols to the corresponding disulfides was reported using hydrogen peroxide catalyzed by tetrabutylammonium iodide (TBAI) without solvents at room temperature.
Abstract: A green, straightforward, and novel method for the oxidation of thiols to the corresponding disulfides is reported using hydrogen peroxide catalyzed by tetrabutylammonium iodide (TBAI) without solvents at room temperature. The corresponding disulfides were obtained with excellent yields and short reaction times.
TL;DR: In this paper, the 1H NMR variable temperature spectra for 3c were studied and the results were reported, showing that these stabilized phosphorus ylides exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond.
Abstract: The reaction between dialkyl acetylene dicarboxylate and 2-aryl-1,3-dioxane-4,6-dione derivatives in the presence of triphenylphosphine in ethyl acetate led to stable phosphorus ylides in good yields. These stabilized phosphorus ylides exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond. The 1H NMR variable temperature spectra for 3c are studied and the results are reported.
TL;DR: In this paper, a series of new piperazine phosphoramide derivatives of 4-hydroxycoumarin were synthesized through a facile phosphorylating reaction.
Abstract: A series of new piperazine phosphoramide derivatives of 4-hydroxycoumarin were synthesized through a facile phosphorylating reaction starting from 4-hydroxycoumarin and various phosphorylating agents. The title compounds were characterized by IR, NMR, electrospray ionization-mass spectrometry, and high-resolution mass spectrometry, and their spectroscopic data were further analyzed to feature the related spectroscopic characteristics of the compounds of this class.