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We report a 4-t-butylbenzyl derivatization for the analysis of carboxylic acids by GC–MS (EI). Carboxylic acids were analyzed as a 4-t-butylbenzyl ester after the derivatization with 4-t-butylbenzyl bromide. On the mass spectra of 4-t-butylbenzyl ester, [M-15]+ ions were observed with high intensity. These ions were tertiary benzyl cations generated by the elimination of a methyl radical from molecular ions. After optimization of the 4-t-butylbenzyl derivatization conditions using microwave reactor, we established a method for the determination of the carboxylic acids in water samples. The method showed good sensitivity and good reproducibility, and was successfully applied to the analysis of rain water samples.

In the analysis of short-chain carboxylic acids such as formic acid and acetic acid in aqueous solution using extractive alkylation gas chromatography, tetrahexylammonium bromide (THAB) as a phase-transfer catalyst (PTC) causes a high intensity and broad peaks in the gas chromatogram, and interfere with the detection of carboxylic acid derivatives. By an easy treatment of the extractive alkylation solution with perchloric acid and n-hexane, it is possible to remove more than 95% of THAB, and to provide good gas chromatogram with a little admixture of carboxylic acid derivatives. The desensitization was 16% at the maximum, the contamination of the glass insert in gas chromatograph and liquid phase in column by THAB was minimized, and trouble in continuous measurement could be avoided.

The catalytic synthesis of γ-butyrolactams was established via [3 + 2]-cycloaddition of cyclopropanes with isocyanates. An organotin iodide ate complex, MgBr(+)[Bu2SnBrI2](-), was employed as an effective catalyst. Simple cyclopropanes that lack aryl or vinyl substituents were useful precursors. Even acyl cyclopropanes were applicable. The hybrid characteristics of a tin complex, acidic MgBr(+) with nucleophilic tin iodide, was responsible for the catalytic reaction.

Donor-acceptor cyclopropanes are useful building blocks for catalytic cycloaddition reactions with a range of electrophiles to give various cyclic products. In contrast, relatively few methods are available for the synthesis of homoallylic alcohols through coupling of vinylcyclopropanes (VCPs) with aldehydes, even with transition-metal catalysts. Here, we report that the hydrostannation of vinylcyclopropanes (VCPs) was effectively promoted by dibutyliodotin hydride (Bu2 SnIH). The resultant allylic tin compounds reacted easily with aldehydes. Furthermore, the use of Bu2 SnIH was effectively catalytic in the presence of hydrosilane as a hydride source, which established a coupling reaction of VCPs with aldehydes for the synthesis of homoallylic alcohols without the use of transition-metal catalysts. In contrast to conventional catalytic reactions of VCPs, the presented method allowed the use of several VCPs in addition to conventional donor-acceptor cyclopropanes.

In this study, the Bu2SnIH-catalyzed direct coupling of 1,3-dienes with aldehydes was developed. This reaction could be suitable for coupling without the use of transition-metal catalysts. Many types of aldehydes were applied to this reaction. The addition of MeOH promoted the catalytic cycle.

The reductive aldol reaction of enones has been established catalyzed by Br 2 InOMe (cat.)–MePhSiH 2 system where Br 2 InH acted as an active catalytic species. Addition of 1.0 equivalent of MeOH was essential for catalytic turnover. The system, Br 2 InOMe(cat.)–MePhSiH 2 –MeOH, provided highly chemo- and diastereoselective reductive aldol reaction of enones with functionalized substrates such as α-bromo carbonyls, α-keto esters and α-alkoxy ketones.

2-Methyleneaziridines proved to be good substrates for the cycloaddition with isocyanates, for which a tin iodide system, Bu2SnI2–LiI, was employed as an effective catalyst. Products were derived from N-attack of the ring-opened metalloenamine intermediate.

A tin-catalyzed reaction of α-hydroxy ketones with 1,1-dicyanoalkenes produced 2-amino-4,5-dihydrofuran-3-nitriles. In the catalytic reaction, tin enolates were generated from α-hydroxy ketones as active catalytic species. The highly basic ability of the Sn-O bonds played an important role in the reactions. This tin-catalyzed reaction was highly atom-economical and required no other metal reagents.

A tin-catalyzed reaction of α-hydroxy ketones with 1,1-dicyanoalkenes produced 2-amino-4,5-dihydrofuran-3-nitriles. In the catalytic reaction, tin enolates were generated from α-hydroxy ketones as active catalytic species. The highly basic ability of the Sn-O bonds played an important role in the reactions. This tin-catalyzed reaction was highly atom-economical and required no other metal reagents.

The synthesis of γ-butyrolactams via [3 + 2]-cycloaddition of cyclopropanes with isocyanates is described.

Synthesis of 4-hydroxy-2-oxazolidinone derivatives was accomplished from the reaction of α-hydroxy ketones with isocyanates in the presence of a catalytic amount of a tin alkoxide. The reactions proceeded under mild conditions and are highly atom economical.

Allylhafnium compounds were generated by transmetalation between allyl-SnBu3 and HfCl4 in EtCN. A highly α-selective addition reaction of prenyltributyltin to imines was observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Hydrostannation of vinylcyclopropanes (VCPs) followed by reaction with aldehydes gives access to homoallylic alcohols without the use of transition-metal catalysts.

Various branched isomers of 4-nonylphenol (NP) and, in addition, the other 4-alkylphenols (APs) were synthesized and their estrogenic activities were assessed using the yeast two-hybrid system. We investigated the relationships between the structure of the nonyl group of NP isomers and their estrogenic activities based on the following five factors: the length of the main alkyl chain, the degree of branching on the α-carbon, the degree of bulkiness, the position of the branch, and the cyclic structure in the nonyl group. An appropriate length of the main alkyl chain was essential for the estrogenic activity. A small effect of the branching on the α-carbon was observed. The importance of the bulkiness and position of the branch in the nonyl group was suggested from the results of the synthesized NP isomers possessing the high estrogenic activities. The bulkiness on the β-carbon was the most important factor for the high estrogenic activity. The investigation of the cyclic structure also indicated the significance of the bulkiness around the β-carbon. The bulkiness on the γ-carbon was also suggested to be an important factor. The metabolic effect of the synthesized APs on the estrogenic activity was also examined using a liver S9. The estrogenic activities of the selected APs were either reduced or lost. In addition, GC-MS analyses of the commercial NP and synthesized NP isomers revealed that the nine synthesized NP isomers were included in the commercial NP.

A reliable method combining solid-phase extraction, derivatization and gas chromatography-chemical ionization mass spectrometry (GC-CI-MS) was developed for the measurement, in river and sewage effluent water, of four select model compounds of dicarboxylic metabolites (dm-CA 5–8 P1EC) and other dicarboxylic metabolites (CA 5–8 P1ECs) of nonylphenol polyethoxylates. These selected isomers were referred as dm-CA 5–8 P1ECs because they have an α,α-dimethyl configuration (expressed as “dm”), five to eight C atoms and a carboxyl group in the alkyl chain, and an ethoxy acetic acid group. The derivatization of terminal carboxyl groups was successful with (trimethylsilyl)diazomethane. The best extraction conditions were obtained using an Oasis HLB cartridge as a sorbent bed and 4 ml of MTBE/methanol (9:1, v/v) elution mixture. The method detection limits of 0.03–0.07 μg/l for dm-CA 5–8 P1ECs were attained in 500 ml pure water. The recovery was then evaluated for pure water, river and sewage effluent water samples. The high recoveries of typically >89% for each isomer indicated the high performance of the method. Although dm-CA 5–8 P1ECs were not detected in the collected water samples, 21 isomers of CA 5–8 P1ECs were identified by CI-MS and the tentative structures of six out of them were elucidated, mainly limited to the branch at α-C atom, by studying the EI-mass spectra. The relative concentrations of individual CA 5–8 P1EC metabolites were calculated based on dm-CA 5–8 P1ECs. The results showed that the main degradation on the nonyl chain occurred via the elimination of two carbon-units and the concentrations in Japan were much lower than those in Taiwan and Italy.

河川水中のノニルフェノールポリエトキシレートおよびその分解生成物 (エチレンオキシド鎖1～18のノニルフェノールエトキレート, ノニルフェノール, ノニルフェノキシ酢酸およびノニルフェノキシエトキシ酢酸) の簡便な一斉分析法として, ミセル動電クロマトグラフィー (MEKC) の評価を行った.Oasis HLBカートリッジ (N-ビニルピロリドン-ジビニルベンゼン共重合体) に試料水1000mlを通して104倍濃縮し, デオキシコール酸ナトリウムをミセル形成剤とするMEKCにより分析した.河川水に添加した試料成分の回収率は82%以上, 相対標準偏差は3.0～15%と良好であった.まだ検討すべき課題もあるが, 本法が上記物質の簡便な一斉分析法として有望なことが示された.

This paper describes the liquid-phase microextraction (LPME) of tributyltin (TBT) and triphenyltin coupled with gas chromatography–tandem mass spectrometry. The 4-fluorophenylation and ethylation reactions were used for the derivatization of the organotins. For the two derivatizations, the LPME parameters such as organic solvent, stirring rate, temperature, extraction time and the other additional conditions were examined. Using pure water, the calibration curves, method detection limits (MDLs) and reproducibilities (RSDs) of the two derivatizations were compared under the respective optimized procedures. The 4-fluorophenyl derivatization, which showed a lower MDL (0.36 ng/l) and better reproducibility (RSD = 11% at 10 ng/l) for TBT, was applied to the analysis of seawater. The TBT was detected in the range from 1.1 to 2.0 ng/l in the seawater samples collected in Osaka Bay.

Derivatization of tributyltin for tandem mass spectrometry is described. Tributyltin (TBT) and triphenyltin (TPT) were derivatized with sodium tetrakis(4-fluorophenyl)borate. After optimization of their MS/MS conditions, derivatization conditions were examined. Under the optimum conditions using in-situ derivatization, the calibration curves for the TBT and TPT were linear in the ranges of 0.4 - 200 and 1.2 - 200 pg of Sn, respectively. The detection limits for TBT and TPT were 0.07 and 0.43 pg of Sn, respectively. In the case of TBT, the detection limit with 4-fluorophenylation was improved about five times compared with that with pentylation (0.35 pg). This improvement is ascribed to the bond-dissociation energy of Sn-aryl being stronger than that of Sn-alkyl. Namely, the selective fragmentation of 4-fluorophenyl TBT resulted in high sensitivity. The relative recoveries of TBT and TPT from seawater were 99 and 109%, respectively. The method was successfully applied to the seawater samples.

An efficient method for the simultaneous determination of the degradation products of nonylphenol polyethoxylates (NPnEOs, n = number of ethoxy units), i.e., nonylphenol (NP), NPnEOs (n=1–3), nonylphenoxy carboxylic acids (NPnECs, n=1–2, number of ethoxy units plus an acetate) and their halogenated derivatives (XNP, XNP1EO and XNP1EC; X=Br or Cl), in water samples were developed. After trimethylsilylation with N,O-bis(trimethysilyl)acetamide, all the analytes were determined by gas chromatography–tandem mass spectrometry (GC–MS–MS) with electron ionization (EI). The ion peaks of [M−85]+ of the derivatives were selected as precursor ions and their product ions showing the highest intensities were used for the quantitative analysis. The instrumental detection limits were in the range from 2.1 to 11 pg. The recoveries of the analytes from the water samples were optimized by using solid-phase extraction (SPE). The deuterated reagents of octylphenol, octylphenol monoethoxylate and octylphenoxyacetic acid were used as the surrogates. The method detection limits (500 ml water sample) using C18 SPE were from 2.5 to 18 ng/l. The recoveries from spiked pure water and the environmental water samples were greater than 78%. The method was successfully applied to environmental samples. Remarkably, the concentrations of the halogenated compounds (ClNP, ClNP1EO and BrNP1EO) were detected at the hundreds of ng/l levels in the Neya river.

A simple and sensitive method for the determination of alkylphenols in water samples has been developed using gas chromatography-mass spectrometry. Alkylphenols were determined after the extractive derivatization with pentafluoropyridine. The derivatization of alkylphenols efficiently proceeded to give the corresponding 4-tetrafluoropyridyl derivatives under the biphasic reaction system. The derivatization conditions including the phase-transfer catalyst, the amount of pentafluoropyridine, the reaction time, the concentration of NaOH and organic solvent were optimized. On the mass spectra of these derivatives, intense specific ion peaks were observed: m/z 256 for 4-n-alkylphenols and m/z 284 for 4-tert.-alkylphenols. Calibration curves were linear in the range of 20-1000 ng/l (200-10,000 ng/l for nonylphenol), and the detection limits varied between 6.93 and 15.7 ng/l (85.2 ng/l for nonylphenol). The average recoveries of the alkylphenols in a fortified river water sample (100 ng/l except for nonylphenol: 1000 ng/l) ranged from 91.1 to 112%. The relative standard deviations were found to be between 5.6 and 16%. This method was successfully applied to the determination of alkylphenols in river water.

The determination of organotin compounds in water using gas chromatography-tandem mass spectrometry (GC-MS-MS) is described. Several organotin derivatives were synthesized by the reaction of organotin chlorides with Grignard reagents such as methyl-, propyl- and pentylmagnesium halides. After the optimization of the GC-MS-MS conditions, several derivatizations with the Grignard reagents were compared by evaluating the molar responses and volatilities of the derivatives and derivatization yields. As a result, the derivatizing reagent of choice is pentylmagnesium bromide. Calibration curves for the mono-, di- and tributyltins and mono-, di- and triphenyltins with pentylmagnesium bromide were linear in the range of 0.5-100 pg of Sn. The instrumental detection limits of six organotins ranged from 0.20 to 0.35 pg of Sn. The recovery tests from water samples (500 ml) were performed by using sodium diethyldithiocarbamate (DDTC) as a complexing reagent. Except for monophenyltin, the absolute recoveries of organotins from pure water at 200 ng of Sn/l were satisfactory. The recoveries calibrated by surrogate compounds (perdeuterated organotin chlorides) ranged from 71 to 109%. The method detection limits ranged from 0.26 to 0.84 pg of Sn (500-ml sample). This method was applied to the recovery of organotins from river water and seawater. The calibrated recoveries were between 90 and 122%.

非イオン界面活性剤ノニルフェノールポリエトキシレート (NPnEOs) の代謝産物ノニルフェノール (NP) , ノニルフェノールモノエトキシレート (NP1EO) , ノニルフェノールジエトキシレート (NP2EO) , ノニルフェノールトリエトキシレート (NP3EO) , ノニルフェノキシ酢酸 (NP1EC) , ノニルフェノキシエトキシ酢酸 (NP2EC) , そして臭素化ノニルフェノールモノエトキシレート (BrNP1EO) (これらを全て併せてNPE-cと称す) の内分泌攪乱性を酵母Two-hybrid法により評価した.試験したNPE-cのうち, 有意なエストロゲン様活性が認められたのはNPのみであり, 17βエストラジオール (E2) 相対活性にして2.1×10-4相当の活性を示した.肝代謝を模したS9mix処理により, E2およびNPのエストロゲン様活性はそれぞれ元の300分の1 (E2) および17.5分の1 (NP) に低下することが確認されたが, 一方, 処理を行わない場合には活性が認められなかったNP1EOについてもE2相対活性にして6.5×10-6相当のエストロゲン様活性が認められるようになった.NPE-cの肝代謝においては, よりエストロゲン様活性の高い物質を生成する可能性のあることが示唆された.NPE-cについてエストロゲン様活性に加え, プロゲストロゲン様活性, アンドロゲン様活性および甲状腺ホルモン様活性を測定したが, いずれも有意な活性は認められなかった.

2-Methyleneaziridines are used as substrates for the synthesis of cyclopentylidenamines via a [3 + 2] cycloaddition with dicyanoalkenes using Bu2SnI2 as an effective catalyst.

2-Methyleneaziridine are a good substrate for the catalytic synthesis of cyclopentylidenamines via a [3 + 2] cycloaddition of 1,1-dicyanoalkenes using Bu2SnI2 as an effective catalyst. A C-attack from 2-methyleneaziridine yielded the desired products.

Native and three selectively methylated β-cyclodextrin (β-CD)-bonded stationary phases without an unreacted spacer arm for liquid chromatography were prepared, where heptakis(2-O-methyl)-β-CD, heptakis(3-O-methyl)-β-CD and heptakis(2,3-di-O-methyl)-β-CD were used as the methylated β-CDs. The enantiomer separation abilities of the resulting β-CD stationary phases for 12 pairs of dansylamino acid enantiomers and six pairs of N-3,5-dinitrobenzoyl amino acid methyl esters as model solutes were investigated. The effects of pH and methanol content of the mobile phase on the retention and resolution were examined to optimize the mobile phase conditions. The optimum resolution for the dansylamino acids was achieved using a mobile phase consisting of 1.0% triethylammonium acetate buffer (pH 5.0)–methanol (v/v 4/6) on the β-CD stationary phase. Heptakis(3-O-methyl)- and heptakis(2,3-di-O-methyl)-β-CD-bonded stationary phases showed little enantiomer separation abilities for the dansylamino acids. The heptakis(2-O-methyl)-β-CD-bonded stationary phase exhibited no enantioselectivities for those solutes. For the N-3,5-dinitrobenzoyl amino acid methyl esters, the optimum resolution was achieved using a mobile phase consisting of 1.0% triethylammonium acetate buffer (pH 5.0)–methanol (v/v 9/1) on a heptakis(2-O-methyl)-β-CD stationary phase. The heptakis(2,3-di-O-methyl)-β-CD-bonded stationary phases exhibited no enantioselectivities for the N-3,5-dinitrobenzoyl amino acid methyl esters. β-CD and heptakis(3-O-methyl)-β-CD-bonded stationary phases had no enantiomer separation abilities for those solutes except for the N-3,5-dinitrobenzoyl phenylalanine methyl ester.

Native and three selectively methylated γ-cyclodextrin (γ-CD)-bonded stationary phases without an unreacted spacer arm for HPLC were prepared, where octakis(2-O-methyl)-γ-CD, octakis(3-O-methyl)-γ-CD and octakis(2,3-di-O-methyl)-γ-CD were used as the methylated γ-CDs. The enantiomer separation abilities of the resulting γ-CD stationary phases for 11 pairs of dansylamino acid enantiomers as model solutes were investigated. The effects of pH and methanol content of the mobile phase on the retention and resolution were examined to optimize the mobile phase conditions. The optimum resolution was achieved using a mobile phase consisting of 1.0% triethylammonium acetate buffer (pH 5.0)–methanol (8:2, v/v). γ-CD-bonded stationary phase and octakis(3-O-methyl)-γ-CD-bonded stationary phase exhibited good enantiomer separation ability for the dansylamino acids among the four γ-CD stationary phases examined in this study. In particular, octakis(3-O-methyl)-γ-CD-bonded stationary phase showed the better enantiomer separation than γ-CD-bonded stationary phase except for dansyl- dl -leucine and -glutamic acid. Octakis(2-O-methyl)- and octakis(2,3-di-O-methyl)-γ-CD-bonded stationary phases had no enantiomer separation abilities for those solutes. The results suggest the important role of the hydroxyl groups at the 2-positions on the rim of the γ-CD cavities in the enantiomer separation for the dansylamino acids.

This paper describes the δ-carbonylation of saturated alcohols which uses a 1,5-hydrogen-transfer reaction of alkoxyl radicals and subsequent carbonylation at the δ-carbon atoms as the key. The carbonylation reactions of five classes of saturated alcohols, namely, primary alcohols having primary δ-carbons, primary alcohols having secondary δ-carbons, primary alcohols having tertiary δ-carbons, secondary alcohols having primary δ-carbons, secondary alcohols having secondary δ-carbons, were carried out, in which lead tetraacetate (LTA) was used as a one-electron oxidant to generate the alkoxyl radicals. Carbonylation of these saturated alcohols, except for primary alcohols having tertiary δ-carbons, took place to afford δ-lactones in moderate to good yields. The mechanism of the remote carbonylation likely involves (1) alkoxyl radical generation via LTA oxidation of a saturated alcohol, (2) conversion of this alkoxyl radical to a δ-hydroxyalkyl radical by a 1,5-hydrogen-transfer reaction, (3) CO trapping of...

The separation of eleven priority (EPA) phenols and eighteen chlorophenols via micellar electrokinetic chromatography (MEKC) is described. Disodium 5,12-bis(dodecyloxymethyl)-4,7,10,13-tetraoxa-1.16-hexadecanedisulfonate (DBTHX), disodium 5,13-bis(dodecyloxymethyl)-4,7,11,14-tetraoxa-1,17-heptadecanedisulfonate (DBTHP) and disodium 5,13-bis (dodecyloxymethyl)-4,7, 11,14-tetraoxa-9,9-dimethyl-1,17-heptadecanedisulfonate (DBTDMHP) were used as the double-chain surfactants. The EPA phenols were baseline separated by MEKC with 7.5 mM DBTHP. The detection limits of the phenols for a signal-to-noise ratio of 3 were in the range 0.5×10 -2 - 3.0×10 -2 mM. The relative standard deviation (RSD) of the capacity factors and peak areas for the phenols over the range of 0.31 - 1.8 mM were 0.21 - 1.4% and 1.9 - 4.3%, respectively. The separations of eighteen chlorophenols together with phenol were also carried out by MEKC with these surfactants. These phenols except for 2,3,5- and 2,4,5-trichlorophenol could each be separated with 10 mM DBTHX.

2-Methyleneaziridines proved to be good substrates for the cycloaddition with isocyanates, for which a tin iodide system, Bu2SnI2–LiI, was employed as an effective catalyst. Products were derived from N-attack of the ring-opened metalloenamine intermediate.

Three surfactants, p-bis(2-dodecyloxymethyl-3-oxa-6-sodiosulfonatohexyloxy)benz ene (BDSB) having two sulfonate groups and two lipophilic chains, disodium 10-dodecanoyl-5,15-bis(dodecyloxymethyl)-10-aza-4,7,13,16-tetra oxa-1,19-nonadecanedisulfonate (DDBTN) having two sulfonate groups and three lipophilic chains and disodium 4,11-bis(dodecyloxymethyl)-3,6,9,12-tetraoxa-1,14-tetrade canedionate (DBTT) having two carboxylate groups and two lipophilic chains, were used in micellar electrokinetic chromatography (MEKC). Eight naphthalene derivatives were baseline separated at 10 mM BDSB or 5 mM DBTT, and five flavone derivatives at 5 mM BDSB, DDBTN or DBTT. The elution order of the naphthalene derivatives in MEKC with BDSB was identical with that with DDBTN. However, this elution order was different from that found with DBTT. In the case of the flavone derivatives, BDSB, DDBTN and DBTT produced the identical elution order. These double- and triple-chain surfactants exhibited different selectivity when compared with widely used sodium dodecyl sulfate.

Treatment of vinylcyclopropanes with CO in the presence of Bu 3 SnH and AIBN (catalytic) leads to a stannylformylated product via a cyclopropylcarbinyl radical opening to a homoallylic radical.

Various oxazole derivatives are synthesized from naturally occurring glycolide (I) and lactides (VI) by tin-catalyzed cycloaddition to isocyanates (II) or isothiocyanates (IV) under microwave irradiation.

Title compounds are synthesized by reaction of α-hydroxy ketones with aliphatic as well as aromatic isocyanates (II) in the presence of a tin alkoxide catalyst either under conventional heating or microwave irradiation.

Efficient separation of carbon monoxide from a binary mixture of carbon monoxide and hydrogen with selenium and secondary amines has been developed. The process consists of (i) selective reaction of CO with selenium and a secondary amine to form the corresponding ammonium carbamoselenoate 1 and (ii) thermolysis of 1 to form pure CO (99.9%) quantitatively. A Se–alcohol system is also usable but the results are inferior to that with a Se–amine system.

SiH2Ph2 and alcohol promoted reductive aldol reactions of the enone (I) with ketones are carried out in the presence of catalytic amounts of SnHClBu2 (SnH2Bu2/SnCl2Bu2) to give the corresponding β-hydroxy ketones in a highly chemo- and diastereoselective manner.

SiH2Ph2 and alcohol promoted reductive aldol reactions of the enone (I) with ketones are carried out in the presence of catalytic amounts of SnHClBu2 (SnH2Bu2/SnCl2Bu2) to give the corresponding β-hydroxy ketones in a highly chemo- and diastereoselective manner.

Allylation of α-dicarbonyl compounds (I), (VI) or (X) with allyl- or crotyl-tributyltin reagents followed by cyclization with isocyanates (III) provides access towards polyfunctionalized oxazolidinones, e.g. (IV), (V)/(VI) or (VIII).