Dry Ethyl Acetate Research Articles

Комплексные исследования содержания биологически активных веществ в продуктах деструкции кородревесных отходов, образующихся при длительном хранении

The study of the content of biologically active substances in the samples of the bark-wood waste destruction products (BWW) was continued. BWW were taken at a depth of 1 to 27 meters of the bark dump of OJSC Syktyvkar LDK, located in the Forestry microdistrict of Syktyvkar. The hexane-soluble substances content is in ranges from 0.78 to 1.89% of the dry mass of BWW. The minimum content was found in the first (0.24%) and last samples (0.21%) at the minimum and maximum depth, the maximum – in samples at a depth of 3 to 9 m (1.66–1.89%). The variation of the hexane extract (HE) content in BWW’s dry mass depending on the depth of occurrence is not clear. The HE content in the dry ethyl acetate extract is mainly within 50%. The minimum content was found in the first sample at a depth of up to 1.5 m (34.9%), the maximum in the last sample at a depth of 27.0 m, where it reaches 66% of the dry weight of the ethyl acetate extract. The analysis of the obtained hexane extracts by thin-layer chromatography showed that the HE contains substances with a mobility coefficient of 0.61, which coincide with dihydroquercetin and some phenolic acids previously detected in ethyl acetate extracts. Six phenolic compounds were detected by high-performance liquid chromatography in hexane extracts. Protocatechic acid, vanillic acid, trans-p-coumaric acid and its cis isomer were identified by chromatographic and spectral characteristics.

Isolasi Bakteri Rhizosfer Tanaman Nilam (Pogostemon cablin Benth.) yang Berpotensi sebagai Penghasil Senyawa Antibakteri terhadap Bakteri Penyebab Infeksi Saluran Pencernaan

Telah dilakukan penelitian isolasi bakteri rhizosfer pada Tanaman nilam (Pogostemon cablin Benth.). Penelitian ini bertujuan untuk memperoleh isolat bakteri rhizosfer tanaman nilam yang berpotensi sebagai penghasil senyawa antibakteri terhadap bakteri penyebab infeksii saluran pencernaan. Tahap pertama, dilakukan isolasi bakteri yang berasal dari rhizosfer tanaman nilam. Uji skrining antibakteri dengan metode tanding, diperoleh isolat IBRN-3 dan IBRN-5 menghambat pertumbuhan semua bakteri uji. Isolat IBRN-3 dan IBRN-5 difermentasi. Hasil fermentasi diesktraksi dengan pelarut etil asetat menghasilkan ekstrak etil asetat fermentat kering. Dilakukan identifikasi Kromatografi Lapis Tipis terhadap ekstrak etil asetat IBRN-3 dan IBRN-5 menggunakan eluen kloroform:metanol (8:1) dan diilanjutkan dengan uji KLT-Bioautografi. Diperoleh hasil bercak pada IBRN-3 dengan nilai Rf 0.93 menghambat bakteri E. coli, S. aureus , nilai Rf 0.82 menghambat B. subtillis, S. dysenteriae, nilai Rf 0.64 menghambat S. aureus dan S. thypii, nilai Rf 0.89, 0.36, 0.24 menghambat S. dysenteriae, nilai Rf 0.84 dan 0.74 menghambat S. aureus. Sedangkan untuk IBRN-5, diperoleh bercak dengan nilai Rf 0.91 menghambat B. subtillis, E. coli S. thypii, nilai Rf 0.95 menghambat S. aureus, S. dysenteriae , nilai Rf 0.84 menghambat B. subtillis, S. thypii, nilai Rf 0.83 menghambat S. dysenteriae, dan nilai Rf 0,74 menghambat S. thypii.

Evaluation of the insecticidal potential of leaf extracts of Anadenanthera colubrina var. cebil (Griseb) Altschul against Tetranychus urticae Koch and Sitophilus zeamais Mots

The deterioration and degradation of crops by insects causes economic losses of several billion dollars and affects food security. Sitophilus zeamais and Tetranychus urticae are two economically important species of agricultural crops around the world. The high toxicity of synthetic insecticides and the development of insect resistance to currently used chemicals stimulate the investigation of plant-derived insecticides as new alternatives for pest control. The insecticidal properties of secondary metabolites have been recognized, and have been confirmed scientifically in the last decades. The extract in cyclohexane (Ch) and ethyl acetate (Ea) of the leaves of Anadenanthera colubrina var. cebil collected in the dry and rainy seasons were evaluated for the survival and nutritional physiology of S. zeamais (maize weevil) and for the acaricidal effect front T. urticae (two-spotted spider). All extracts induced mortality of S. zeamais; however, only cyclohexane dry season (Chd) and ethyl acetate in the rainy season (Ear) caused significant mortality (p <0.05), more than 50%, promoting physiological damage to insects in all concentrations tested. In the mortality tests with the spider mite, extracts Chd and Ear showed an LC50 of 52.75 and 156.42 mg.mL-1. Still, in the same test, it can be observed that oviposition was also susceptible to extracts. Therefore, the extracts of A. colubrina are a source of compounds capable of interfering with and impairing the metabolism of the two studied pests.

Synthesis and chemical modification of maleic anhydride copolymers with 2-amino ethyl benzoate groups

Maleic anhydride (MAN) copolymers with methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate monomers at 1:3 mole ratios were synthesized by free radical polymerization in the presence of azobis(isobutyronitrile) as initiator and dry ethyl acetate as solvent. Copolymer compositions were obtained using related proton nuclear magnetic resonance (1HNMR) spectra, and the polydispersity of the copolymers was determined by gel permeation chromatography. Then, a solution of 2-amino ethyl benzoate salt as a nucleophilic reagent reacted through the ring opening of anhydride groups in copolymers resulting to modified copolymers Iab to Vab. All the prepared polymers were characterized by Fourier transform infrared and1H NMR spectroscopic techniques. The glass transition temperature (Tg) of all copolymers before and after modification was determined by dynamic mechanical thermal analysis (DMTA). It was shown that chemical modification of MAN copolymers with 2-amino ethyl benzoate substituents as side chains decreased the free volume of the polymers, and therefore, the rigidity and Tg are increased.

Phytochemical Screening and Nematicidal Activity of Cinnamon and Ginger Extracts Against Root-knot Nematode (Meloidogyne incognita) Infecting Tomato

The purpose of this work was to assess the nematicidal and antioxidantactivities of different extracting solvents from cinnamon (Cinnamomum zeylanicum)and ginger (Zingiber officinale) against Meloidogyne incognita infecting tomato.Three solvents namely n-hexane, ethyl acetate and methanol were used.Phytochemical analysis of such extracts revealed the presence of morecomponents in ethyl acetate and methanolic extracts than n-hexane extract of eithercinnamon or ginger. The highest amount of total phenolics and flavonoids weredetected in ethyl acetate extract of both ginger and cinnamon reaching 105.6; 93.6mg gallic acid /g and 54.2; 45.1 mg quercetin/ g dry weight, respectively.Additionally, ethyl acetate and methanolic extracts of ginger exhibited the highestantioxidant activity (DPPH free radicals) reaching 90.0 and 89.1%, respectively. Theefficacy of cinnamon and ginger using three solvents at two concentrations (50 and10ul) on juveniles mortality of Meloidogyne incognita was studied in vitro. Ethylacetate extracts gave better results than did methanol or hexane extracts. Gingerextracts gave promising results after 72hr of exposure compared to cinnamon ones.Hence, among ginger extracts the maximum mortality in nematode juveniles wasachieved with ethyl acetate (68.0 %) followed by methanol (42.0%) and hexaneextracts (30%) @ the concentration of 50μl after 72 hours of exposure. Ginger ethylacetate (300 ppm) proved to be the best for enhancing total plant fresh weight withpercentage of increase over control amounted to 196.0 %. Population densities,root galling and number of egg masses were significantly suppressed with suchtested extracts. Leaves of tomato were assayed for NPK, total cholorophyll,proteins, and phenols. Activities of polyphenol oxidase (PPO), peroxide oxidase(PO) were also evaluated in roots of tomato infected with M. incognita. PO activitywas much greater in ginger ethyl acetate at lower concentration (100 ppm).Conversely, PPO activity was increased in cinnamon ethyl acetate (100 ppm).Thepresent study revealed high potential antioxidants and nematicidal properties inboth cinnamon and ginger. The biological activities of these plants might beattributed to the various kind of secondary metabolites.

An approach to effective green extraction of triterpenoids from outer birch bark using ethyl acetate with extractant recycle

The outer birch bark of Betula pendula Roth. was extracted using dry ethyl acetate, wet ethyl acetate (∼3.5% H2O) by the classical reflux boiling. The yields of the extracts, the content of triterpenoids and polar impurities were compared with the results of the extractions employing aqueous ethanol (5% H2O). A higher content of betulin and a lower content of polar impurities were found for ethyl acetate extractions compared with the ethanol-based experiments. Alkaline washing of betulin concentrates was proposed as an alternative cost-effective method for purifying extracts of polar impurities. The uptake of residual miscella on the depleted birch bark was assessed to be up to 200–300% relative to the bark charge. An efficient recovery of the residual ethyl acetate by hydrodistillation from the extracted bark was demonstrated. An assessment of stepwise energy consumption for the extraction, concentration of extract, solvent recovery established that the extractions using ethyl acetate are significantly energy-saving, compared with ethanol usage. Batch extraction of birch bark employing ethyl acetate (96.5%) with hydrodistillation of residual solvent from raw materials can be used for a small-scale process to obtain betulin concentrates. According to the scheme proposed, complete recycling of the organic and aqueous phases is carried out and extractant losses are practically excluded. Considering large-scale processes, the continuous extraction scheme with solvent separate recovery from waste materials in the special equipment is feasible with dry solvent application. Extracting birch bark with “green” extractant ethyl acetate is beneficial, since it provides extracts containing less polar impurities and significantly reduces energy consumption and extractant losses comparing with use of polar extractants.

Vacuum Effect on the Lactide Yield

The vacuum effect on the yield and purity of lactide obtained by catalytic lactic acid oligomer depolymerization was investigated. As raw material for the lactic acid oligomer synthesis the L-lactic acid aqueous solution was used. It was shown that the highest yield of raw-lactide takes place via distillation under a vacuum. The raw-lactide in all fractions was purified by recrystallization from dry ethyl acetate. The highest yield of raw-lactide is observed at a vacuum of 10 ... 15 mbar. The distillation process of raw-lactide is complicated with chemical reactions. Control of the reaction, raw materials and products was performed using DTA, gel permeation chromatography, infrared spectroscopy and high performance liquid chromatography.

Synthesis and chemical modification of maleic anhydride copolymers with phthalimide groups

Maleic anhydride (MAN) copolymers with methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate monomers at 1:1 mole ratios were synthesized by free radical polymerization in the presence of α,α′-azobis(isobutyronitrile) as initiator and dry ethyl acetate as solvent. Copolymer compositions were obtained using related proton nuclear magnetic resonance (1HNMR) spectra, and the polydispersity of the copolymers was determined by gel permeation chromatography. Then, a solution of phthalimide salt as a nucleophilic reagent reacted through the ring opening of anhydride groups in copolymers resulting to modified copolymers IPht to VPht. All the prepared polymers were characterized by Fourier transform infrared and 1H NMR spectroscopic techniques. The glass transition temperature (Tg) of all copolymers before and after modification was determined by dynamic mechanical thermal analysis (DMTA). It was shown that chemical modification of MAN copolymers with phthalimide substituents as side chains decreased the free volume of the polymers, and therefore, the rigidity and Tg are increased. Solubility of the copolymer products was tested in some organic solvents.

Unique bioactive polyphenolic profile of guava (Psidium guajava) budding leaf tea is related to plant biochemistry of budding leaves in early dawn

Guava leaf tea (GLT), exhibiting a diversity of medicinal bioactivities, has become a popularly consumed daily beverage. To improve the product quality, a new process was recommended to the Ser-Tou Farmers' Association (SFA), who began field production in 2005. The new process comprised simplified steps: one bud-two leaves were plucked at 3:00-6:00 am, in the early dawn period, followed by withering at ambient temperature (25-28 °C), rolling at 50 °C for 50-70 min, with or without fermentation, then drying at 45-50 °C for 70-90 min, and finally sorted. The product manufactured by this new process (named herein GLTSF) exhibited higher contents (in mg g(-1), based on dry ethyl acetate fraction/methanolic extract) of polyphenolics (417.9 ± 12.3) and flavonoids (452.5 ± 32.3) containing a compositional profile much simpler than previously found: total quercetins (190.3 ± 9.1), total myricetin (3.3 ± 0.9), total catechins (36.4 ± 5.3), gallic acid (8.8 ± 0.6), ellagic acid (39.1 ± 6.4) and tannins (2.5 ± 9.1). We have successfully developed a new process for manufacturing GLTSF with a unique polyphenolic profile. Such characteristic compositional distribution can be ascribed to the right harvesting hour in the early dawn and appropriate treatment process at low temperature, avoiding direct sunlight.

Antimicrobial activity and bioautographic study of antistaphylococcal components from Caesalpinia pyramidalis Tull.

The antimicrobial activity of dry methanol and ethyl acetate extracts for the leaves, bark of the stem, peel of the root, flower, fruit and seed of Caesalpinia pyramidalis Tull. (catingueira) was performed against seventeen isolates of Staphylococcus aureus MRSA multiresistant strains, which included two isolates of S. aureus MSSA and two ATCC strains. The antimicrobial activity was tested by the agar diffusion method and the Minimum Inhibitory Concentration (MIC) was determined. The dry methanol extract of the root showed good antimicrobial activity with a MIC of less than 0.5 mg.mL-1. The dry ethyl acetate extracts exhibited lower antimicrobial activity, which might be explained by solubility problems and less diffusion in the agar medium. Results of the bioautographies also confirmed inhibition halos corresponding to the active substances present in the leaves, as well as in the flower of C. pyramidalis. The phytochemical study of the leaves, bark of the stem, peel of the root, flower and fruit of extracts from C. pyramidalis confirmed the presence of a number of known antimicrobial agents including ursolic acid, quercetin, catechin, ellagic acid, sitosterol, flavonoids, proanthocyanidins and gallic acid.

Synthesis of Dibenzo[b,e][1,4]Diazepine Derivatives

The reaction of ( Z)-2-amino- N‘-arylbenzamidines with both 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 2,3,5,6-tetrachloro-1,4-benzoquinone have been studied. The reactions were carried at room temperature overnight in dry ethyl acetate and proceed via a charge transfer complexe to give dibenzo[ b,e][1,4]diazepine derivatives in 35–44% yield. Benzodiazepine derivatives have anti-inflammatory, antiviral, antimicrobial, antileukaemic, antiplatelet, anticonvulsant, antianxiety, antidepressive and antitumour activities. The products were fully characterised according to their spectral analyses.

Heterocyclization of N-propenyl-substituted phenothiazines and phenoxazines using electrophiles in an anhydrous medium

10-Propenylphenothiazine reacts with a catalytic amount of BF3·Et2O in dry ethyl acetate via intramolecular heterocyclization of an intermediate dimeric cation to give mainly 1-ethyl-2-methyl-3-(phenothiazin-10-yl)-2,3-dihydro-1H-pyrido[3,2,1-k,l]phenothiazine and a minor product through fission of phenothiazine which is 1-ethyl-2-methyl-1H-pyrido[3,2,1-k,l]phenothiazine. Under similar conditions 10-propenylphenoxazine gave an oligomer (degree of polymerization 4.4) and the minor product 1-ethyl-2-methyl-1H-pyrido[3,2,1-k,l]phenoxazine likely formed similarly to the phenothiazine analog from the corresponding product of intramolecular heterocyclization (the latter not being observed in the reaction mixture).

Correlation and prediction of partition coefficient between the gas phase and water, and the solvents dry methyl acetate, dry and wet ethyl acetate, and dry and wet butyl acetate

Experimental partition coefficient data have been compiled from the published literature for the water/methyl acetate, water/ethyl acetate and water/butyl acetate partition systems, log P data, and for the gas/methyl acetate, gas/ethyl acetate and gas/butyl acetate partition systems, log K data. Application of the Abraham solvation parameter model to the sets of partition coefficients leads to equations that correlate the log P data and log K data to 0.18 log units for the three dry alkyl acetate solvents. Slightly larger deviations were noted for solute partition into both wet ethyl acetate and wet butyl acetate. The derived correlations were validated using training set and test set analyses.

Synthesis of Novel Calix[4]arenes Having Benzothiazolylacetamidoalkoxy Pendants and Their Potential Application as Ag+-selective Electrodes

Calix[4]arenes, a class of macrocyclic compounds, are superb supramolecular building block for fabricating ion and molecular receptors. Appropriately functionalized calix[4]arenes have been used as carriers in ion selective membranes. Predominantly, calixarenes containing ester, ether, carboxylic acid and carbamate have been reported for using as ion-selective electrode (ISE) for alkali metal ions. Only few calixarene derivatives reported by Reinhoudt and Kim have been employed as ISE for heavy metal ions such as Cu, Hg and Cd. Kimura and coworkers reported calix[4]arene derivatives incorporating substituents such as allyl, benzyl and propargyl groups being used as soft neutral carrier for silver ion sensors. Mercaptobenzothiazoleappended calix[4]arene was used as Ag-ISE which showed the selectivity towards Ag with good discrimination against Hg. We are interested in the development of new Ag receptors for use as ionophores in Ag-selective electrodes. Herein, we report syntheses of compounds 9 and 10 bearing two benzothiazolylacetamidobutoxy groups at the narrow rim of p-tert-butylcalix[4]arene and compounds 11 and 12 consisting of benzothiazolylacetamidoethoxy groups on the narrow rim of calix[4]arene. The preliminary studies using the synthesized compounds for Ag-selective electrodes towards metal ions were carried out to see the effect of substituent groups on sensitivity and selectivity of the ionophore. Benzothiazolylacetamidoalkoxy calix[4]arenes, 9-12, have been prepared in two steps as shown in Scheme 1. The first step involved the conversion of amine groups in calix[4]arene derivatives 1-4 into corresponding cyanoacetamido groups. Using modified Salol procedure, the conversion of compound 1 to compound 5 (50%) was achieved by heating 1 with ethyl cyanoacetate. However, compounds 2-4 could not react with ethyl cyanoacetate to produce compounds 6-8. Therefore, succinimide cyanoacetate was employed instead. The cyanoacetate ester containing the succinimide group was prepared from reaction of cyanoacetic acid with Nhydroxysuccinimide in the presence of dicyclohexylcarbodiimide in dry ethyl acetate. The amines 2-4 were reacted with succinimide cyanoacetate in dry CH2Cl2 to give cyanoacetamido compounds 6-8 in 19%, 34% and 40% yields, respectively. The cyanoacetamido compounds 5-8 were then heated with 2-aminothiophenol to give the final products 912 in 59%, 64%, 64% and 20% yields, respectively. All of the compounds showed characteristic peaks of ptert-butylcalix[4]arene (or calix[4]arene) building blocks and were in cone conformations which were substantiated by two doublets of the Ar-CH2-Ar protons (J = 13-14 Hz) around 3-4 ppm in H NMR spectra. The benzothiazolylacetamido groups showed two doublets and two triplets of the benzene proton of the benzothiazolyl group, one singlet for the proton in the alpha position of the carbonyl group and

STM Study of DNA Films Synthesized on Si(111) Surfaces

The various surface types involved in the synthesis of DNA upon alcohol-terminated monolayers at Si(111) surfaces were probed using scanning tunneling microscopy (STM). Images of the initial hydrogen-terminated layer showed the typical step and terrace features which are retained after alkylation with 4,4‘-dimethoxytrityl-1-undecenol. The method of deprotection for oligonucleotides synthesized at these monolayer films was shown to have a dramatic effect on the surface. After treatment with methylamine, rinsing with water caused considerable etching of the surface; however, this was avoided by the use of a dry ethyl acetate and ether wash. There is little indication of DNA for surfaces covered with single stranded material as judged by STM imaging or tunneling spectroscopy experiments. However, after hybridization with the complementary strand, DNA−Si(111) substrates gave stable images that do not typically show the step and terrace features of the underlying alkyl monolayer. Instead wormlike features are ...

Polymorphism and Crystallization Behavior of Abbott-79175, a Second-Generation 5-Lipoxygenase Inhibitor

The crystal polymorphism of Abbott-79175, a potent second-generation 5-lipoxygenase inhibitor, has been studied. Crystallization from an ethyl acetate/heptane system in which moisture content was not controlled and from an ethanol/water system produced a crystal form I, which by differential scanning calorimetry, thermogravimetric analysis, and Karl Fischer analysis was likely a hemihydrate. This hemihydrate form of the compound was demonstrated to reversibly dehydrate/hydrate with the use of low heat and vacuum followed by exposure to water vapor (100% relative humidity). The dehydrated version of I was designated IA. However, it was shown that a relative humidity approaching 100% was required for the water to re-enter the crystal structure. X-ray powder diffraction and solid state 13C NMR data on polycrystalline samples crystallized from seven single organic solvents suggested two nonsolvated forms of the compound, II and III. The heptane addition rate to a dry ethyl acetate solution of the drug was shown to greatly affect the crystal habit, the crystallite size, and specific surface area upon its precipitation. Solution calorimetry of forms I, IA, and II showed that I had the most endothermic heat of solution, with IA and II having lower values. Initial dissolution rates of compressed disks of these forms in water showed rates of IA>II ≈ I. Considering all data, including evidence of conversion of II to I in aqueous suspension, it is suggested that the relative thermodynamic stability (at least when water was present) in decreasing order is I>II>IA, although I and II are similar energetically. The lower terminal dissolution rate for form IA was due to, in part, conversion to the less soluble Form I.

Biocatalysis in organic solvent systems using thermostable enzymes: esterase-catalysed transesterification of Z-L-tyrosine p-nitrophenyl ester

The esterase-catalysed transesterification of N- carbobenzoxy- l-tyrosine p-nitrophenol ester (Z-Tyrp-NPE) with methanol was studied with water: methanol cosolvent and with dry ethyl acetate as solvent. The crude esterase employed was fully thermostable in both solvents at 44°C. At 88°C esterase activity decreased by 90% in water: methanol (10% v/v) and 30% in dry ethyl acetate after 4 h. The initial rate of transesterification was the same order of magnitude, i.e. 1.7 and 0.95 μmol h −1 unit −1 esterase in the two solvents, respectively. However, Z-TyrpNPE solubility was about 50-fold greater in ethyl acetate compared to the water: methanol cosolvent system, accounting for a 50-fold greater quantity of product formed per experiment in ethyl acetate.

Interaction of the four stereoisomers of soman (pinacolyl methylphosphonofluoridate) with acetylcholinesterase and neuropathy target esterase of hen brain

Dilute solutions in cold dry ethyl acetate of 98–100% pure specimens of each of the four stereoisomers of soman were tested against enzymes in hen brain homogenate at 37° and pH 8.O. Rate constants for progressive inhibition of acetylcholinesterase were 10 7–10 8/mole/min for both P(−) isomers and less than 10 5 for both P(+) isomers. All isomers inhibited neuropathy target esterase non-progressively to some degree. Rate constants for progressive inhibition of neuropathy target esterase were 2.7–3.8 × 10 5/mole/min for C(−) P(+) and 2–6 × 10 4 for the others. Forced reactivation by KF was 90% initially and aging was slow in each case. Spontaneous reactivation of inhibited neuropathy target esterase was substantial during 18 hr for both P(−) isomers but not for P(+). By comparison of rate constants for the two enzymes we predict that pure P(+) isomers may cause delayed neuropathy in hens dosed at about unprotected ld 50: prophylaxis and therapy against acute cholinergic effects would have to raise ld 50 1000-fold before birds could tolerate potentially neuropathic doses of P(−) isomers.

Bistrifluoromethylaryl derivatives for drug analysis by gas chromatography electron capture negative ion chemical ionization mass spectrometry. Application to the measurement of (N-dicyclopropylmethyl)amino-2-oxazoline in plasma.

A gas chromatographic mass spectrometric assay for (N-dicyclopropylmethyl) amino-2-oxazoline in plasma with a detection limit of 0.1 ng ml-1 was required. Various fluoroaryl derivatives of this compound (code name S3341) were synthesized and their positive ion chemical ionization and electron capture negative ion chemical ionization mass spectra recorded. While fluorobenzyl derivatives of S3341 could be made by heating with the requisite benzyl bromide and diisopropylethylamine in acetonitrile, initial efforts to synthesize corresponding fluorobenzoyl derivatives using a benzoyl chloride in dry ethyl acetate at 60 degrees C were unsuccessful. Mass spectral data indicated that only a fragment of the oxazoline ring was retained in the reaction product and that an N-(2-chloroethyl)benzamide was formed. However, when diisopropylethylamine was included in the reaction mixture, a benzoyl derivative of the complete molecule was obtained. The mechanisms of these reactions are discussed. The negative ion mass spectrum of the 3,5-bistrifluoromethylbenzoyl derivative of S3341 has a base peak at m/z 420 (the molecular ion) and, when this ion is specifically monitored, an amount of derivative equivalent to 1 pg of S3341 can be detected. This allowed the development of an assay for S3341 in plasma with a precision of 9% (SD) at 0.2 ng ml-1 and a lower limit for quantitative determination of 0.1 ng ml-1.

Direct derivatization of sulphate esters for analysis by gas chromatography mass spectrometry

Gas chromatography mass spectrometry has been used to study the reaction between a range of aromatic, alicyclic and aliphatic sulphate esters and three perfluoroacylating reagents, viz. trifluoroacetic, pentafluoropropionic and heptafluorobutyric anhydride. Aromatic sulphates were found to react readily, when treated with a 1:1 mixture of a perfluoroacid anhydride and dry ethyl acetate, to form the perfluoroester derivative of the parent phenol in quantitative yield. Non-aromatic sulphates, on the other hand, gave a variety of products. A mechanism is proposed for the one-step derivatization of aromatic sulphates and the potential of the procedure for the analysis of sulphate conjugates by mass spectrometry is discussed.