Enzymatic synthesis of optically active ferrocenes by immobilized lipase from Candida Antarctica

Immobilized lipase (Candida Antarctica lipase, CAL) efficiently catalyzes the transesterification and amidation of the racemic ferrocenes, 1‐hydroxyethylferrocene, (±)‐ 1 , 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , with acyl esters, resulting in the formation of R products possessing high enantiomeric purity. When 1‐hydroxyethylferrocene, (±)‐ 1 , and 1‐hydroxy[3](1,1′) ferrocenophane, (±)‐ 4 , was used as substrate diisopropyl ether was a suitable solvent. In the reaction conditions investigated, the use of vinyl acetate in diisopropyl ether gave the best yield of (R)‐ 1a (49%, 99% ee) after 2 h of incubation at 30 °C. But, with the amino ferrocenes, 1‐amonoethylferrocene, (±)‐ 2 , and 1‐amono[3](1,1′) ferrocenophane, (±)‐ 5 , as substrate, diisopropyl ether was unsuitable as a solvent owing to the low solubility of the substrate in this solvent. Using tetrahydrofuran as a solvent, enzymatic amidation of 1‐amonoethylferrocene, (±)‐ 2 , gave the best yield of (R)‐ 2a (21%, 99% ee) after 120 h of incubation at 30 °C. CAL working in organic solvent is able to efficiently carry out the resolution of ferrocenyl alcohol and amine derivatives which have similar structures, such as (±)‐ 1 and (±)‐ 2 , (±)‐ 4 and (±)‐ 5 which possess central chirality. This enzyme accepted only non‐bulky primary alcohols and amines as ferrocenyl substrates. © 1999 Society of Chemical Industry     

Enzymatic kinetic resolution of [3](1,1′)ferrocenophane derivatives

Formyl- and hydroxymethyl- derivatives of [3](1,1′)ferrocenophane were enzymatically resolved with fermenting baker's yeast, immobilized lipase, and pig liver esterase.     

Two novel macrocyclic polyselenaferrocenophanes: Synthesis, crystal structures and electrochemical study

Two novel macrocyclic polyselenaferrocenophanes, 1,5,9-triselena[9]ferrocenophane (1) and 1,5,9,21,25,29-hexaselena[9.9]ferrocenophane (2), have been prepared by the reaction of 1,1’-bis(3-bromopropylseleno)ferrocene and Na₂Se. The new compounds have been characterized by a range of spectroscopic and analytical techniques, including ¹H, ¹³C NMR spectrometry and X-ray crystallography.     

Chemoenzymic synthesis of optically active 3-methyl- and 3-butylphthalides

Optically active (S)-3-methylphthalide was synthesized by the enzymic reduction of 2-iodoacetophenone using baker's yeast, followed by palladium-catalysed carbonylation under carbon monoxide. With enzymic reduction using baker's yeast, however, 2-bromo- or 2-iodovarelophenones were not reduced, even after 25 days. On the other hand, the enantioselective hydrolysis of α-alkylated 2-halobenzyl acylates using pig liver esterase, horse liver esterase or lipase from Candida rugosa resulted in the formation of (R)-α-alkylated 2-halobenzyl alcohol and (S)-acylate, and the following palladium-catalysed carbonylation of the products yielded the (R)- and (S)-3-alkylated phthalides, respectively.     

[Zn(IMI)_4](ClO_4)_2的合成与晶体结构

制备了高氯酸四咪唑合锌的单晶,用X-ray单晶面探衍射仪测定了其晶体结构。结果表明,晶体属于单斜晶系,空间群为C2/c。晶胞参数为a=1.8625(9)nm,b=0.6662(3)nmc,=1.9324(9)nm,β=115.396(5)°,晶胞体积V=2.166 0(17)nm3,计算密度Dc=1.645 g/cm3,晶胞分子数Z=4,单胞中电子数目F(000)=1 088。该化合物的分子式为[Zn(IMI)4(]ClO4)2,是由4个咪唑分子直接与二价锌离子配位、高氯酸根离子结合形成的配合物。并利用差示扫描量热法(DSC)和热重-微分热重法(TG-DTG)对该配合物的热分解进行了研究。     

Arylethyne Bromoboration–Negishi Coupling Route to E‐ or Z‐Aryl‐Substituted Trisubstituted Alkenes of ≥98% Isomeric Purity. New Horizon in the Highly Selective Synthesis of Trisubstituted Alkenes

The hitherto unprecedented palladium‐catalyzed cross‐coupling of (Z)‐β‐bromo‐β‐arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri‐tert‐butylphosphine)palladium or dichloro[N,N‐bis‐(2,6‐diisopropylphenyl)imidazol‐2‐yl](m‐chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ≥98% stereo‐ and regioselectivity, while suppressing the otherwise dominant β‐debromoboration. Together with the alkylethyne‐based protocols, the alkyne bromoboration–Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access.     

Photooxygenation of the Condensation Products of Naphthanthrone

The structure of the polycyclic aromatic hydrocarbon with the absorption maximum at 567 nm, synthesized by the condensation of naphth- anthrone (NT), was deduced to be benzo[rs]dinaphtho[2, 1, 8, 7-klmn:2, 3, 4, 5, 6-vwxyz]hexaphene (BDH) by semi-empirical molecular orbital calculation methods. The photooxygenation of BDH and benzo[op]naphtho[2, 1, 8, 7-hijk]anthra[2, 1, 9, 8-stuva]-pentacene (BNAP) due to irradiate to light with each absorption maximum was investigated by measurering the absorption spectra and applying semi-empirical molecular orbital calculation methods. BNAP is synthesized by the same reaction process together with dibenzo[de:op]dinaphtho[2, 1, 8, 7-hijk : 2′, 1′, 8′, 7′-syuv]pentacene (DDP). BNAP and BDH do not undergo photooxygenation. On the other hand, DDP undergoes photooxygenation. The empirical results were illustrated in terms of difference in heat of reaction, which were 25.5 and 30.2 kJ/mol for BDH and BNAP, respectively. Their values are considerably larger than -3.1 kJ/mol of DDP. The difference in heat of formation seems to be the reason why BDH and BNAP does not undergo photooxygenation.     

Biotransformation and DNA Adduct Formation of Trans-8,9-Dihydroxy-8,9-Dihydrodibenzo[a,l]Pyrene by Induced Rat Liver and Human CYP1A1 Microsomes

In order to explain the adduct patterns observed from the human CYP1A1-mediated binding of dibenzo[a, l]pyrene (DB[a, l]P) to DNA, we have investigated the further metabolism and DNA adduct activity of trans-DB[a, l]P-8,9-diol by induced rat liver and human CYP1A1 microsomes. trans-DB[a, l]P-8,9-diol was synthesized and metabolic studies with β-naphthoflavone-induced rat liver microsomes indicated three major metabolites: 2 diastereomers of trans,trans-8,9,11,12-tetrahydro-8,9,11,12-tetrahydroxy-DB[a, l]P and 8,9,13,14-tetrahydro-8,9,13,14-tetrahydroxy-DB[a, l]P. DB[a, l]P when activated by CYP1A1/epoxide hydrase (EH) and calf thymus DNA gave a complex pattern of DNA adducts most of which cochromatograph with syn- and anti-DB[a, l]P fjord region diol epoxide-DNA standards. Two highly polar eluting adducts were also observed, one which cochromatographs with the single major DNA adduct obtained from the CYP1A1/EH activation of trans-DB[a, l]P-8,9-diol. The relative retention time of this adduct suggests either a bis-diol epoxide adduct or a more polar diol epoxide adduct.     

Bulk anionic ring opening polymerization of silacyclopent-3-enes

Summary Poly[1,1-diphenyl-1-sila-cis-pent-3-ene](I), poly[1,1-dimethyl-1-sila-cis-pent-3-ene](II), poly[1-methyl-1-phenyl-1-sila-cis-pent-3-ene](III), poly[1-methyl-sila-cis-pent-3-ene](IV), and poly[1-phenyl-1-sila-cis-pent-3-ene](V) were prepared by bulk anionic ring opening polymerization of the corresponding 1-silacyclopent-3-enes, at room temperature by use n-butyllithium or t-butyllithium and HMPA as co-catalysts. No solvent (THF or diethyl ether) was utilized.     

Syntheses and Characterizations of Dibenzochrysenophane and Biphenylodibenzochrysenophane Directed Toward Preparation of 8-shaped Closed Circulenes

Syntheses of [2.2](3,11)dibenzo[c,l]chrysenophane, [2.2](4,4′)-biphenylo(3,11)dibenzo[c,l]chrysenophane, and [2.2](4,4′)biphenylo-(3,11)dibenzo[c,l]chrysenophadiene are described. The unusually strained structures were supported by their ¹H-NMR spectra, electronic spectra, and X-ray crystallographic analyses.     

New Rapid HPLC Method for Separation and Determination of Benzo[A]Pyrene Hydroxyderivatives

A new rapid, one-step semi-quantitative HPLC-MS method applicable for the separation and characterization of the group of total 10 BaP hydroxyderivatives (1-hydroxy benzo[a]pyrene, 2-hydroxybenzo[a]pyrene, 3-hydroxybenzo[a]pyrene, 4-hydroxybenzo [a]pyrene, 7-hydroxybenzo[a]pyrene, 8-hydroxybenzo[a]pyrene, 9-hydroxybenzo[a]py rene, 10-hydroxybenzo[a]pyrene, 12-hydroxybenzo[a]pyrene and benzo[a]pyrene-9,10-dihydrodiol) was developed, involving electrospray ionization technique (ESI) in positive mode. Its qualitative and quantitative characteristics were selected by the analysis of the model OH-BaP mixture consisted of compounds mentioned above. The model system offered the linear response in the whole concentration range used (50–1000 ng.mL^?1) as well as the resolution sufficient for semi-quantitative purposes (R_S > 0.5). Subsequently, the suitability of the developed method was tested on BaP decomposition products to be formed during photooxidation at λ = 365 nm. These analyses confirmed the applicability of the proposed method, succeeding in the identification of 5 BaP hydroxyderivatives formed upon the BaP photooxidation experiment.     

Self‐organization of amphiphilic poly[2‐(methacryloyloxy)ethyl phosphorylcholine] carrying tocopheryl moieties as terminal groups

Poly[2‐(methacryloyloxy)ethyl phosphorylcholine](PMPC) with one pendant tocopheryl moiety at the polymer terminus (PMPC‐Toco) was prepared by the radical polymerization of 2‐(methacryloyloxy)ethyl phosphorylcholine (MPC) initiated with 4,4′‐azobis[(3‐tocopheryl)‐4‐cyanopentanoate] in the presence of 2‐mercaptoethanol as a chain transfer reagent. The self‐organization of PMPC‐Toco was analyzed with fluorescence and ¹H‐NMR measurements. The critical micelle concentrations of PMPC‐Toco with [η] = 0.25, 0.13, 0.10, and 0.05 dL g^?1 were found to be 200, 100, 100, and 90 mg L^?1, respectively. The blood compatibility of PMPC‐Toco was evaluated from the Michaelis constant (K_m) for the enzymatic reaction of thrombin and a synthetic substrate, S‐2238, in the presence of PMPC‐Toco. The K_m values were 0.21, 0.23, 0.36, and 0.21 for PMPC‐Toco‐1, 2, 3, and PMPC ([η] = 0.56 dL g^?1), respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Comparison of N-Heterocyclic Aromatics Dibenzo[c,g]Carbazole and Dibenz[a,j]Acridine : Metabolism,DNA Binding and Mutation

N-Heterocyclic aromatics, such as carbazole and acridine derivatives, are environmental carcinogenic pollutants. Examples of these compounds are 7H-dibenzo[c,g]carbazole (DBC) and dibenz[a,j]acridine (DBA). The ionization potential (IP) for DBC is lower than for DBA. DBC is metabolized in lung and liver by way of phenols or directly through radical cations. DBC-induced liver and lung tumors have mutations in the 61^st codon of ras. DBA is metabolized in skin by way of a diol-epoxide of DBA. DBA-induced skin tumors have mutations in 12^th, 13^th and 61^st codons of ras. In summary, the metabolic activation of DBC proceeds through different adduction pattern pathways than does DBA and leads to different ras mutational spectra.     

Synthesis,Characterization, and Metabolism Studies of Fluspidine Enantiomers

The enantiomers of the potent σ₁ ligand fluspidine ( 1 ) were prepared by using chiral preparative HPLC. Synthesis of racemic tosylate 2 and subsequent separation of enantiomers yielded (R)‐ 2 and (S)‐ 2 in excellent enantiomeric purities. The fluspidine enantiomers (R)‐ 1 and (S)‐ 1 were synthesized from (R)‐ 2 and (S)‐ 2 by nucleophilic substitution with tetra‐n‐butylammonium fluoride, affording (R)‐ 1 with 99.6 % ee and (S)‐ 1 with 96.4 % ee. Tosylates (R)‐ 2 and (S)‐ 2 can also serve as precursors for the radiosynthesis of enantiomerically pure radiotracers [¹⁸F](R)‐ 1 and [¹⁸F](S)‐ 1 . The absolute configuration of the pure enantiomers was elucidated by comparison of their CD spectra with a calculated CD spectrum of a simplified model compound. In receptor binding studies, both enantiomers displayed very high σ₁ receptor affinity and selectivity against the σ₂ receptor. (R)‐Fluspidine ((R)‐ 1 ) is the eutomer, with a K_i value of 0.57 nM and a eudysmic ratio of 4. Incubation of (R)‐ 1 and (S)‐ 1 with rat liver microsomes led to the identification of seven and eight metabolites, respectively. Although the S‐configured enantiomer formed additional metabolite (S)‐ 1‐3 , it is metabolically more stable than (R)‐ 1 .     

联苯双(环左二烯-铁)二价阳离子作为环氧化合物聚合的有效的阳离子光聚合引发剂

Ferrocenium monocations as photoinitiators for cationic photopolymerization suffer from a limitation of low absorption and low reactivity under high-pressure Hg lamp.Here,a ferrocenium dication salt,biphenyl bis [(π-cyclopentadienyl)iron]hexafluorophosphate[bis(Cp-Fe)-biphenyl](PF6)2 was synthesized by the ligand ex-change reaction between ferrocene and biphenyl.The chemical structure was characterized with FTIR and HNMR.The separation of ferrocenium monocation cyclopentadien-iron-biphenyl hexanuorophosphate([Cp-Fe-biphenyl]PF6) and dication [bis(Cp-Fe)-biphenyl](PF6)2 was carried out by coulumn chromatography.The photoactivity of initiating photolymerization of epoxide ERl4221 was studied as a cationic photoinitiator.[Bis(Cp-Fe)-biphenyl](PF6)2 can efficiently absorb radiation above 300nm and its photoactivity is higher than that of its monocation.     

Biotransformation of l‐menthol by twelve isolates of soil‐borne plant pathogenic fungi (Rhizoctonia solani) and classification of fungi

The microbial transformation of l‐menthol ( 1 ) was investigated by using 12 isolates of soil‐borne plant pathogenic fungi, Rhizoctonia solani (AG‐1‐IA Rs24, Joichi‐2, RRG97‐1; AG‐1‐IB TR22, R147, 110.4; AG‐1‐IC F‐1, F‐4, P‐1; AG‐1‐ID RCP‐1, RCP‐3, and RCP‐7) as a biocatalyst. Rhizoctonia solani F‐1, F‐4 and P‐1 showed 89.7–99.9% yields of converted product from 1 , RCP‐1, RCP‐3, and RCP‐7 26.0–26.9% and the other isolates 0.1–12.0%. In the cases of F‐1, F‐4 and P‐1, substrate 1 was converted to (?)‐(1S,3R,4S,6S)‐6‐hydroxymenthol ( 2 ), (?)‐(1S,3R,4S)‐1‐hydroxymenthol ( 3 ) and (+)‐(1S,3R,4R,6S)‐6,8‐dihydroxymenthol ( 4 ), which was a new compound. Substrate 1 was converted to 2 and/or 3 by RRG97‐1, 110.4, RCP‐1, RCP‐3 and RCP‐7. The structures of the metabolic products were elucidated on the basis of their spectral data. In addition, metabolic pathways of the biotransformation of 1 by Rhizoctonia solani are discussed. Finally, from the main component analysis and the differences in the yields of converted product from 1 , the 12 isolates of Rhizoctonia solani were divided into three groups based on an analysis of the metabolites. Copyright © 2003 Society of Chemical Industry     

Polymerization of – Phenylmaleimide Initiated by 9-Borabicyclo[3.3.1]nonane

N-Phenylmaleimide (N-PMI) was polymerized by 9-borabicyclo[3.3.1] nonane (9-BBN) in tetrahydrofuran under argon at 0°C. The molecular weight distributions of the resulting polymers were around 1·1. The rate of poly-merization was proportional to [9-BBN]^1·18 and [N-PMI]^1·24. Hydroquinone had little effect on the rate of polymerization and on the molecular weight of the polymers obtained. Triethylamine completely inhibited the polymerization, and aniline with a relatively small pK_a value and zinc iodide effectively retarded the polymerization. The polymerization did not proceed either in polar dimethylformamide or in non-polar toluene. In polymerizations at temperatures higher than 60°C the conversions decreased. On the basis of the results, a non-radical mechanism was proposed for this polymerization. © of SCI.     

Large electrocaloric responses in [Bi1/2(Na,K)1/2]TiO3‐based ceramics with giant electro‐strains

The electrocaloric effect (ECE) is investigated through indirect measurement in two lead‐free [Bi_1/2(Na,K)_1/2]TiO₃‐based ceramics that were previously reported to display giant electro‐strains. In the Nb‐doped ceramic, denoted as BNKT‐2.5Nb, a decent temperature change of ΔT=1.85 K and an electrocaloric responsivity of ΔT/ΔE=0.37 (10^?6Km V^?1) are found around room temperature (32°C). While in the Ta‐doped ceramic, BNKT‐1.5Ta, a wide operation temperature range (T_span ~55 K) is observed near room temperature. Additional electrical measurements, as well as transmission electron microscopy experiments, are performed to identify the mechanisms of the ECE in both ceramics.     

[Co(CHZ)3](ClO4)2的快速热分解过程研究

通过TG、DSC等热分析技术可以得到物质在常规热分解过程的主要固相产物.为了进一步考察[Co(CHZ)3](ClO4)2(CoCP)的热分解行为,采用T-jump/FT-IR在线分析技术测定了CoCP的快速热分解气体产物.CoCP在1 atm下以一定的升温速率达到设定的温度进行快速热分解.利用其快速热分解过程的控制电压变化曲线,可以得知CoCP在快速热分解过程的吸热、放热变化情况;用快速扫描傅立叶变换红外,可以解析分解过程中逸出的12种红外活性气体.研究发现,在CoCP快速热分解过程所产生的12种气相产物中,以CO的浓度最高,NO和HCN为主要的含氮气相产物,含碳气相产物以CO,CO2和H2C=O为主;并给出了其主要气相产物的浓度随时间的变化曲线.     

Comparative Oncogenic Activation of 7H-Dibenzo[C,G]Carbazole and Dibenz[A,J]Acridine

7H-Dibenzo[C, G]carbazole (DBC) is a potent liver, lung and skin carcinogen while dibenz[A, J]acridine (DBA) is a moderate skin carcinogen. DBC is metabolized to phenols and DBC-DNA adducts are formed through the 2-, 3-, and 4-phenols or directly through radical cations. Mutations in ras as a result of DBC, activation are found exclusively in codon 61 in liver, lung and skin. DBA is metabolized to dihydrodiols, and phenols and DBA-DNA adducts are formed through the diol-epoxides and possibly through bis-diol-epoxides. Mutations in ras, as a result of DBA activation, are found in codons 12, 13, and 61. These results indicate that although the two compounds are structurally similar, differing by one carbon in the middle ring, there are differences in their metabolism, DNA binding, mutational spectra and target-organ carcinogenesis.