Acid In Diethyl Ether Research Articles

Unveiling the Unusual Mn(CO)3 Migration in a Manganese Cyclohexenyl Complex by DFT Computations.

Homogeneous catalysis involving a transition metal agostic interaction (TM…H…C) is an attractive strategy for C-H bond activation, in which the transition metal agostic intermediates serve as the critical component. To investigate the roles of manganese agostic intermediates in the unusual migration of the Mn(CO)3 fragment in the (exo-phenyl)(η3-cyclohexenyl)manganese tricarbonyl [(Ph)(η3-C6H8)Mn(CO)3] (complex 1) under the protonation of tetrafluoroboric acid-diethyl ether (HBF4.Et2O), a comprehensive density functional theory (DFT) theoretical study was performed. The computational results showed that formation of the [(cyclohex-3-enyl)-η6-benzene]manganese tricarbonyl complex [(C6H9)(η6-Ph)Mn(CO)3+][BF4] (complex 2) was achieved via a series of mono-agostic and di-agostic intermediates. The overall rate-limiting step for this unusual migration of the Mn(CO)3 fragment is the formation of the di-agostic (η2-phenyl)manganese complex 8 (4 → 5 → 8) with a Gibbs barrier of 15.4 kcal mol-1. The agostic intermediates with TM…H…C agostic interactions were well-characterized by geometry parameters, Atoms-In-Molecules (AIM) analyses, and the Natural Adaptive Orbitals (NAdOs). The located pathways in the current study successfully explained the experimental observations, and the findings on the TM…H…C agostic interaction provided a new aspect of the catalytic reaction with the manganese complex.

Синтез и строение гидрата бис(2,4-диметилбензолсульфоната) трифенилвисмута

The interaction of triphenylbismuth with 2,4-dimethylbenzenesulfonic acid in diethyl ether in the presence of tert-butyl hydroperoxide have synthesized triphenylbismuth bis(2,4-dimethylbenzenesulfonate) hydrate. The X-ray diffraction pattern has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (MoKα-radiation, λ = 0.71073 Å, graphite mono-chromator) of crystals 1 [C34H34O6,5S2Bi, M 819.71, monoclinic syngony, symmetry group C2/c; cell parameters: a = 34.948(16) Å, b = 9.210(5) Å, c = 21.114(9) Å, α = γ = 90.00 degrees, β = 99.97(2) degrees; V = 6693(6) Å3; the crystal size is 0.38 × 0.14 × 0.06 mm; intervals of reflection indexes are –45 ≤ h ≤ 45, –11 ≤ k ≤ 11, –27 ≤ l ≤ 27; total reflections 52257; independent reflections 7691; GOOF 1.026; R1 = 0.0325, wR2 = 0.0776; residual electron density is 0.98/–0.82 e/Å3] the bismuth atom have a distorted trigonal-bipyramidal coordination. The OBiO axial angles are 171.58(12) degrees; the sum of the CBiC angles in the equatorial plane is 360 degrees. The lengths of the Bi–O axial bonds are 2.274(3) Å and 2.284(3) Å; The range of changes in the lengths of the Bi–C equatorial bonds is 2.188(5)–2.209(4) Å. The structure of triphenylbismuth bis(2,4-dimethylbenzenesulfonate) hy-drate contains intramolecular contacts between the bismuth and oxygen atoms of the sulfonate lig-ands; the Bi···O=S distances are 3.178(10) and 3.261(10) Å, which is less than the sum of the Van der Waals radii of bismuth and oxygen (3.59 Å). A water molecule is connected by a hydrogen bond O–H···O=S 2.50 Å with the oxygen atom of the sulfonate ligands. Complete tables of atomic coordinates, bond lengths, and bond angles for the structures were deposited at the Cambridge Crystallographic Data Center (no. 1919942, deposit@ccdc.cam.ac.uk, http://www.ccdc.cam.ac.uk).

Investigation of the influence of a plasticizer based on adipic acid diethyl ether (DEAC) on the structure and properties of a zinc silicate anticorrosion coating

Investigation of the influence of a plasticizer based on adipic acid diethyl ether (DEAC) on the structure and properties of a zinc silicate anticorrosion coating

Development of Methods for the Synthesis of Malathion-D<sub>6</sub>, Chlorophos-D<sub>6</sub>, and Dichlorophos-D<sub>6</sub> for Use as Internal Standards in the Analysis of Medicinal Plant Raw Materials and Herbal Medicinal Products

Scientific relevance. Deuterated analogues of test substances, when used as internal standards, enable analysts to determine traces of residual pesticides in a medicinal plant raw material by gas or liquid chromatography coupled with mass spectrometry. This prompts the search for an undemanding method for the synthesis of deuterated reference standards, with the ultimate goal of expanding the range of reference standards produced in Russia.Aim. The study aimed to synthesise deuterated reference standards (malathion-D6, chlorophos-D6, dichlorophos-D6, and their precursors) and determine their spectral characteristics using 1Н, 2Н, 13С and 31Р nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry.Materials and methods. The study involved methanol-D4, phosphorus pentasulfide, phosphorus trichloride, maleic acid diethyl ether, triethylamine, hydroquinone, and chloral hydrate. The authors recorded 1H, 2H, 13C, and 31P NMR spectra using a QONE AS400 NMR spectrometer operating at a temperature of 298 °K and respective frequencies of 399.83, 61.38, 100.55, and 161.85 MHz. Mass spectra were obtained using an analytical system comprising an Agilent Infinity 1260 liquid chromatograph equipped with an automatic sample injector and coupled with a Thermo Scientific Orbitrap Fusion Lumos high-resolution mass-selective tandem spectrometer operating in electrospray ionisation mode.Results. The authors used existing methods for the synthesis of organophosphate pesticides as a basis and developed synthesis routes to produce the deuterated analogues malathion-D6, chlorophos-D6, and dichlorophos-D6. The synthesised compounds were identified by NMR spectroscopy and high-resolution mass spectrometry.Conclusions. The synthesised compounds are highly pure and suitable for use as internal standards in the determination of organophosphate pesticides in medicinal plant raw materials. The synthesis methods developed by the authors can be used to produce reference standards in Russia.

Potent and biostable inhibitors of the main protease of SARS-CoV-2

Potent and biostable inhibitors of the main protease (Mpro) of SARS-CoV-2 were designed and synthesized based on an active hit compound 5h (2). Our strategy was based not only on the introduction of fluorine atoms into the inhibitor molecule for an increase of binding affinity for the pocket of Mpro and cell membrane permeability but also on the replacement of the digestible amide bond by a surrogate structure to increase the biostability of the compounds. Compound 3 is highly potent and blocks SARS-CoV-2 infection invitro without a viral breakthrough. The derivatives, which contain a thioamide surrogate in the P2-P1 amide bond of these compounds (2 and 3), showed remarkably preferable pharmacokinetics in mice compared with the corresponding parent compounds. These data show that compounds 3 and its biostable derivative 4 are potential drugs for treating COVID-19 and that replacement of the digestible amide bond by its thioamide surrogate structure is an effective method.

Allobetulin

Allobetulin was synthesized at room temperature, starting from betulin by Wagner–Meerwein rearrangement in the presence of tetrafluoroboric acid diethyl ether complex. The structure of the compound obtained was confirmed by spectroscopic methods (1H, 13C NMR and IR).

Halocyclobutanol Dehydration En Route to Halocyclobutenes

AbstractA new method for the preparation of halocyclobutenes is described. The developed process involves the dehydration of halocyclobutanols by using tetrafluoroboric acid–diethyl ether complex in dichloromethane at room temperature. The process allows for high yields of halocyclobutenes to be achieved by using alcohols that do not trigger the formation of isomeric allylic halides.

Synthesis and anticorrosive activity of two new imidazo[1, 2-a]pyridine Schiff bases

In the present work, the synthesis of two new imidazo[1, 2-a]pyridine derivatives belonging to the schiff base family was performed. They are named respectively : (E)-N-(7-methyl-2-phenylimidazo[1,2-a]pyridin-3-yl)-1-(thiophen-2-yl)methanimine (IP1) and (E)-N-(7-methyl-2-phenylimidazo[1,2-a]pyridin-3-yl)-1-(5-nitrothiophen-2-yl)methanimine (IP2). The ligands were synthesized from a condensation reaction between 2-phenylimidazo[1,2-a]pyridin-3-amine and a commercial aldehyde (2-thiphencarbaldehyde for IP1 and 5-Nitro-2-thiophencarbaldehyde for IP2 in the presence of a catalytic amount of acetic acid in diethyl ether). The structures of the titrated compounds were determined using various spectroscopic techniques such as 1H NMR, 13C NMR, FT-IR and MS.However, the synthetic ligands showed very good inhibitory efficacy against corrosion of mild steel in 1 M HCl medium. This was evaluated by various electrochemical techniques such as mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The experimental results showed that the inhibitory efficiency of the synthesized ligands improves with the increase of concentration to reach the maximum value of 91% for IP1 and 96% for IP2 for a concentration of 10−3M, which translates that the surface covered by the inhibitor increases with the concentration. In addition, quantum chemical calculation based on density functional theory (DFT) confirmed the existence of good correlations between experimental and predicted spectroscopic data. Surface analysis carried out by SEM and AFM showed a smooth surface in the presence of the ligands IP1 and IP2.

Синтез и строение бис(2,5-диметилбензолсульфоната) и бис(дибромфторацетата) трис(3-фторфенил)сурьмы

The interaction of tris(3-fluorophenyl)antimony with 2,5-dimethylbenzenesulfonic or dibromofluoroacetic acid in diethyl ether in the presence of tert-butyl hydroperoxide has synthe-sized tris(3-fluorophenyl)antimony bis(2,5-dimethylbenzenesulfonate) (1) and tris(3-fluorophenyl)antimony bis(dibromofluoroacetate) (2). The X-ray diffraction pattern has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (MoKα-radiation, λ = 0.71073 Å, graphite monochromator) for crystal 1 [C34H30F2O6S2Sb, M 777.45, the triclinic syngony, the symmetry group P–1; cell parameters: a 10.634(18) Å, b 11.38(2) Å, c 14.31(3) Å, α = 90.51(8) degrees, β = 90.35(11) degrees, γ = 112.79(5) degrees; V = 1596(5) Å3; the crystal size is 0.5×0.48×0.17 mm; intervals of reflection indexes are –15 ≤ h ≤ 14, –15 ≤ k ≤ 15, –19 ≤ l ≤ 19; total reflections 30473; independent reflections 8318; Rint 0.0920; GOOF 1.894; R1 = 0.1699, wR2 = 0.4237; residual electron density 6.78/–5.48 e/Å3] and crystal 2 [C22H12O4F7SbBr2, M 754.89, the triclinic syngony, the symmetry group P–1; cell parameters: a 8.98(3) Å, b 10.41(2) Å, c 14.92(3) Å, α = 90.77(7) degrees, β = 90.73(9) degrees, γ = 113.95(10) degrees; V = 1275(5) Å3; the crystal size is 0.65 × 0.32 × 0.14 mm; intervals of reflection indexes are –13 ≤ h ≤ 13, –15 ≤ k ≤ 14, –21 ≤ l ≤ 21; total reflections 61066; independent reflections 8511; Rint 0.0863; GOOF 1.983; R1 = 0.1529, wR2 = 0.4647; residual electron density 4.41/–3.48 e/Å3] the antimony atoms have a distorted trigonal-bipyramidal coordination. The axial OSbO angles are 178.2(3) (1) and 174.0(4) (2); the sum of the CSbC angles in the equatorial plane is 360. The Sb–O and Sb–C bond lengths are 2.108(9)–2.131(12) Å and 2.090(14)– 2.21(3) Å. The structural organization of crystals 1 and 2 is controlled by intermolecular bonds O···H 2.53–2.70 Å (1) and 2.57–2.60 Å (2), F•••H 2.46–2.59 Å (1) and Br•••H 3.02 Å (2). In 2 the short contacts C··· F have been observed between the aryl ligands of neighboring molecules 3.079 and 3.085 Å. Complete tables of coordinates of atoms, bond lengths and valence angles for structures 1 and 2 are deposited at the Cambridge Structural Data Bank (no. 2055553, 2055764; depos-it@ccdc.cam.ac.uk; http: //www.ccdc.cam.ac.uk).

Synthesis and Characterization of a Novel Triangular Rh2Au Cluster Compound Inspired by the Isolobality Concept.

The synthesis of [Rh2(η5‐Cp)2(μ‐H)(μ‐PPh2)2]BF4 (2) by protonation reaction of the metal basic complex [Rh2(η5‐Cp)2(μ‐PPh2)2] (1) with tetrafluoroboric acid in diethyl ether is described. Complex salt 2 was obtained in high yield and fully characterized by spectroscopic means and X‐ray crystal diffraction. Applying the isolobal analogy between H and the fragment Au(PPh3) as a synthetic strategy on the reaction of compound 2 with equimolar amounts of [Au(CH3)(PPh3)] in refluxing acetone resulted in the formation of the expected triangular cluster compound [Rh2{μ‐Au(PPh3)}(η5‐Cp)2(μ‐PPh2)2]BF4 (3) in good yield. Metal cluster salt 3 was fully characterized by spectroscopic data and its molecular structure in the crystal was determined by X‐ray diffraction. The structural comparison of the protonated dirhodium core in the cationic complex of 2 with the Rh2Au framework in 3 is in good accordance with the isolobal relation between H+ and Au+ because they share the respective same position in these closely related molecular structures.

Состав травы короставника полевого (<i>Knautia arvensis</i>L.)

С помощью ТСХ в траве Knautia arvensis обнаружены фенолкарбоновые кислоты и флавоноиды. Методом спектрофотометрии количественно оценено содержание фенольных веществ в пересчете на хлорогеновую кислоту (от 1,05 до 2,08 %), по этому веществу предложено стандартизовать образцы травы Knautia arvensis. Методом ВЭЖХ-УФ выявлено присутствие о-кумаровой, галловой, неохлорогеновой, хлорогеновой, кофейной, изоферуловой и розмариновой кислот, а также гиперозида и кемпферола. Наибольшее содержание имеет хлорогеновая (0,29 – 0,60 %) кислота. Методом ГЖХ-МС в гексановых извлечениях найдено 92 вещества, среди которых альфа-линоленовая кислота, этиловые эфиры пальмитиновой, пальмитолеиновой, 13-метилтетрадекановой, фенилуксусной кислот, фитол, изовалеральдегид диэтилацеталь, гексагидрофарнезилацетон, диэтоксиэтан, 14-метил-8-гексадеценаль, янтарной кислоты диэтиловый эфир, дигидроцитронеллол, фенилацетальдегид и др.

Condensation of Malonic Diethyl Ester with Acrylamide

The purposeful synthesis of polyfunctional organic substances is an important task in organic chemistry, as well as for solving practical problems in technologies of fine organic chemistry and biochemistry. Here presents the results of studies on the synthesis of polyfunctional substances as possible ligand based on with malonic acid diethyl ester. The condensation of malonic acid diethyl ether with acrylamide in phase transfer catalysis conditions leads to new derivative of malonic acid-1,1-dicarbethoxy-3-carbamoilpropane. The formation of mentioned compound has been followed by the method of UV spectrometry. The complexatation of the received substance investigated in relation to iron ions also.

Бис(бромдифторацетат) три-пара-толилвисмута. Синтез и особенности строения

The interaction of tri(para-tolyl)bismuth with tert-butyl hydroperoxide and bromodifluoroacetic acid in diethyl ether have synthesized tris(para-tolyl)bismuth bis(bromodifluoroacetate). The X-ray diffraction pattern for the crystal has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (MoKα-radiation, λ = 0.71073 Å, graphite monochromator), the results are [C25H21O4F4Br2Bi, M 830.22, the triclinic syngony, the symmetry group P–1; cell parameters: a = 10.292(8), b = 11.752(9), c = 12.693(9) Å, α = 89.42(2) degrees, β = 78.04(3) degrees, γ = 78.04(3) degrees; V = 1424.8(18) Å3; the crystal size is 0.73×0.57×0.41 mm; intervals of reflection indexes are –13 ≤ h ≤ 13, –15 ≤ k ≤ 15, –16 ≤ l ≤ 16; total reflections 45443; independent reflections 7096; Rint 0.1030; GOOF 1.049; R1 = 0.0739, wR2 = 0.1834; residual electron density 2.11/–2.78 e/Å3], the bismuth atom have a distorted trigonal-bipyramidal coordination. The OBiO axial angle is 172.2(3) degrees; the sum of the CBiC angles in the equatorial plane is 360.6. The Bi–O and Bi–C bond lengths are 2.275(8), 2.295(8) Å and 2.187(10)–2.212(13) Å. The Bi•••O=С distances are 3.127(10) and 3.159(10) Å, which is less than the sum of the van der Waals radii of bismuth and oxygen (3.59 Å). There are no intermolecular contacts H∙∙∙Hal in the crystal. Complete tables of coordinates of atoms, bond lengths and valence angles for the structure are deposited at the Cambridge Structural Data Bank (no. 1923097; deposit@ccdc.cam.ac.uk; http: //www.ccdc.cam.ac.uk).

Synthesis and structure of a new tetranuclear macrocyclic antimony(v) complex

The reaction of triphenylantimony with 3,4-dihydroxybenzoic acid in diethyl ether in the presence of hydrogen peroxide afforded a tetranuclear macrocyclic complex, which was characterized by X-ray diffraction data.

Mild and Rapid Aniline/HBF4•DEE‐Catalysed Formation of Sulfinyl Imines

AbstractThe combination of anline and tetrafluoroboric acid diethyl etherate (2.5 mol% and 5 mol%, respectively) significantly accelerates the formation of sulfinyl imines in dichloromethane and isopropylacetate at room temperature compared to previous procedures. A DFT and NMR spectroscopic study shows that the anilinium tetrafluoroborate complex is solvated by sulfinamide molecules in the initial state and that the rate‐limiting step of the reaction is the addition of the sulfinamide molecule to the protonated aniline‐based imine. In addition, the catalytic system was also utilised in a one‐pot, two step reaction, where the in situ formed sulfinyl imine was arylated in a rhodium catalysed reaction with high diastereoselectivity.

Effect of homogeneous catalysts on ring opening reactions of epoxidized cooking oils

This paper shows two ways of efficiency improvement of bio-polyol synthesis to generate more environmental and economic benefits. The application of waste oil in the synthesis of plastic components allows recycling of such municipal waste and is consistent with the principles of Green and Sustainable Chemistry. The economic aspects are associated with analyzing the influence of different catalysts on the time and temperature of ring opening reactions as well as the costs of the catalysts used in this process. This work presents the impact of three types of catalysts, (sulfuric acid, acid diethyl ether complex and tetrafluoroboric acid solution in water) on the ring opening reactions of epoxidized cooking oils and the properties of the final bio-polyols.The application of sulfuric acid in this experiment required a much higher temperature than in the case of the catalysts based on tetrafluoroboric acid and a longer reaction time. The shortest reaction time was achieved using tetrafluoroboric acid diethyl ether complex but the costs of this catalyst limit its possible application. However, similar products were obtained when using a tetrafluoroboric acid solution in water and the costs of this catalyst are acceptable for industrial applications. The properties of the bio-polyols and the tendency for the occurrence of the oligomerization reaction depended on the type of the catalysts used and were confirmed by the means of Fourier transform infrared spectroscopy, gel permeation chromatography, MALDI-TOF as well as by viscosity changes. It was concluded that the type of the catalyst and its concentration have a major impact on the physical and chemical properties of the resultant bio-polyols.

4-Нитрофенилацетаты тетра- и три-(пара-толил)сурьмы. Синтез и особенности строения

The interaction of penta( para -tolyl)antimony with 4-nitrophenylacetic acid in toluene have synthesized tetra( para -tolyl)antimony 4-nitrophenylacetate ( 1 ). The reaction of tri( para -tolyl)­antimony with tert -butyl hydroperoxide and 4-nitrophenylacetic acid in diethyl ether leads to the formation of tri( para -tolyl)antimony bis (4-nitrophenylacetate) ( 1 ). The X-ray diffraction pattern has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (Mo K α -radiation, λ = 0.71073 Å, graphite monochromator) of crystals 1 [C 72 H 68 N 2 O 8 Sb 2 , M 1332.78, the triclinic syngony, the symmetry group P –1; cell parameters: a 12.08(3), b 16.46(3), c 17.79(3) Å, α = 107.61(7) degrees, β = 97.20(10) degrees, γ = 101.94(9) degrees; V = 3229(11) Å 3 ; the crystal size is 0.51×0.24×0.17 mm; intervals of reflection indexes are –10 ≤ h ≤ 10, –14 ≤ k ≤ 14, –15 ≤ l ≤ 15; total reflections 14622; independent reflections 4546; R int 0.0697; GOOF 1.072; R 1 = 0.0585, wR 2 = 0.1688; residual electron density 0.75/–0.85 e/Å 3 ] and 2 [C 37 H 33 O 8 N 2 Sb, M 755.40, the monoclinic syngony, the symmetry group P2 1 /n ; cell parameters: a 9.271(2), b 28.413(7), c 13.604(3) Å, α = 90.00 degrees, β = 105.876(2) degrees, γ = 90.00 degrees; V = 3425.5(13) Å 3 ; the crystal size is 0.95×0.58×0.34 mm; intervals of reflection indexes are –16 ≤ h ≤ 16, –50 ≤ k ≤ 50, –24 ≤ l ≤ 24; total reflections 125931; independent reflections 20517; R int 0.0450; GOOF 1.114; R 1 = 0.0511, wR 2 = 0.0993; residual electron density 0.70/–0.97 e/Å 3 ] the antimony atoms have distorted trigonal-bipyramidal coordination. The axial angles of OSbC and OSbO are 177.9 (5)°, 177.9 (5) ° ( 1 ) and 177.27(5)° ( 2 ); the sum of the angles of CSbC in the equatorial plane is 356.9°, 357.6° ( 1 ), 359.79° ( 2 ). The Sb–O and Sb–C bond lengths are 2.1443(15)–2.269(10) Å and 2.098(15)–2.170(14) Å. The structural organization of crystals 1 and 2 is controlled by intermolecular bonds O···H (2.46–2.67 Å). Complete tables of coordinates of atoms, bond lengths and valence angles for structures 1 and 2 are deposited at the Cambridge Structural Data Bank (no. 1819287, 1819295; deposit@ccdc.cam.ac.uk; http: //www.ccdc. Cam.ac.uk).

HBF4·DEE-catalyzed formation of sulfinyl imines: Synthesis and mechanistic studies

A mild acid-catalysed method is reported for the formation of sulfinyl imines from tert-butanesulfinamide and aromatic or aliphatic aldehydes using tetrafluoroboric acid diethyletherate (10 mol%) in dichloromethane. Reactions were performed at room temperature and gave the corresponding sulfinyl imines in excellent yield after 2 h. A DFT study was performed and a mechanism for the reaction is postulated.

3-Phenylphosphaprolines – Synthesis, structure and properties of heterocyclic α-phosphanyl amino acids

“Phenylphosphaprolines”, containing trivalent phosphorus within the five-membered ring of proline, were synthesized by cyclocondensation of 2-phenylphosphanyl ethylamines 1a,b with equimolar amounts of glyoxylic acid hydrate (GAH) or pyruvic acid in diethyl ether or 1,4-dioxane. Reaction monitoring revealed primary formation of acyclic intermediates that then converted more (1a) or less (1b) rapidly to the phosphanyl amino acids cis/trans-2a,b or cis/trans-4a,b. Ammonium-ethylphosphonium-bis(glycolate) impurities, e.g. 3b, were formed when an excess of GAH was applied. The conversion of 1a with phenylformic acid via the acyclic precursors 5a and 6a to the heterocyclic product cis/trans-7a was very slow, whereas heating of the mixture in 1,4-dioxane proceeded with decarboxylation to cis/trans-8a. The structures and diastereoisomer ratios of all new compounds were determined by 1H, 31P and 13C solution NMR spectra. The cis/trans-ratio of 2a depends on the synthetic route, i.e. addition of the phosphanylethyl amine 1a to GAH (acidic medium) or of GAH to 1a (basic medium). Furthermore, this ratio changed slowly during storage of the solution of 2a in CD3OD or methanol, indicating ring-opening ring-closure reactions and lower kinetic stability than for proline. XRD analyses established the structures of trans-2a and likewise of trans-4a and trans-8a, which from concentrated solutions crystallized in pure form.

Effects of Coexposure with Echinostoma caproni and Schistosoma mansoni Miracidia on Glucose and Maltose Levels in Biomphalaria glabrata as Determined by High-Performance Thin-Layer Chromatography–Densitometry

High-performance thin-layer chromatography (HPTLC)–densitometry was used to determine maltose and glucose in Biomphalaria glabrata snails subjected to either Echinostoma caproni and Schistosoma mansoni miracidia coexposure or single exposure to each of these trematode parasites. Each culture contained 800 mL of artificial spring water; snails were maintained at 25 ± 1°C and fed boiled romaine lettuce ad libitum. A sample of each population was necropsied at 2, 4, and 6 weeks post-exposure to E. caproni. The whole body of each snail was extracted with 70% ethanol for sugar analysis. Sugars were separated on 10 × 20 cm EMD Millipore Corp. HPTLC silica gel plates with a preabsorbent zone, the mobile phase was 1-butanol–glacial acetic acid–diethyl ether–deionized water (27:18:5:3), and the detection reagent was naphthol–sulfuric acid. Quantitative densitometric analysis was performed using a CAMAG TLC Scanner 3 in the absorbance–reflectance mode at 515 nm. Significant differences in maltose concentrations were shown among the four groups at 2, 4, and 6 weeks post-exposure (analysis of variance, P < 0.0125). Significant differences in glucose were found only at 2 and 4 weeks post-exposure.