bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of the Bischler–Napieralski exocyclic and endocyclic dehydration products in the radiosynthesis of (R)‐(‐)‐[6a‐14C]apomorphine
Authors: Kitson Sean L. 
Published: July 2007

AbstractThis paper will outline the mechanism of the Bischler–Napieralski cyclodehydration for the radiosynthesis of (R)‐(‐)‐[6a‐14C]apomorphine 1. The carbon‐14 radiosynthesis of (R)‐(‐)‐[6a‐14C]apomorphine was first reported by Kitson and Knagg in May 2006. The Bischler–Napieralski cyclodehydration of 3,4‐dimethoxy‐2‐nitrophenyl‐N‐phenethyl[carboxyl‐14C]acetamide 5 was initiated using a mixture of P2O5/POCl3 in refluxing toluene. This generated the endocyclic dehydration product 1‐(3,4‐dimethoxy‐2‐nitrobenzyl)dihydro[1‐14C]isoquinoline 4. The Bischler–Napieralski endocyclic dehydration by‐product was identified from 1H NMR and MS to be 3‐(6,7‐dimethoxyanthranil)‐dihydro[1‐14C]isoquinoline 7. The action of POCl3 in acetonitrile on 3,4‐dimethoxy‐2‐nitrophenyl‐N‐phenethyl[carboxyl‐14C]acetamide 5 gave exclusively the exocyclic dehydration product 1‐(3,4‐dimethoxy‐2‐nitrobenzal)‐1,2,3,4‐tetrahydro[1‐14C]isoquinoline 8. Copyright © 2007 John Wiley & Sons, Ltd.
Cu(I)Br‐mediated preparation of 14C‐labeled 3‐pyridineacetate derivatives and synthesis of a novel 14C‐labeled PDE‐IV inhibitor
Authors: Ho Jonathan Z. , Braun Matthew P. 
Published: July 2007

AbstractAn efficient protocol for the synthesis of 14C‐labeled 3‐pyridineacetate (1) and its N‐oxide ([14C]2) is described. Oxidation of this pyridine ([14C]1) to its N‐oxide ([14C]2) proceeded in high yield using H2O2 with MeReO3 as a catalyst. The reaction employs readily available diethyl [2‐14C]malonate. This method has proven to be general in preparation of other pyridineacetate derivatives and their N‐oxides which have been typically difficult to prepare by other means. Our development of the Cu(I)Br‐coupling methodology as well as application to the synthesis of a 14C‐labeled phosphodiesterase‐IV (PDE‐IV) inhibitor, [14C]3, are also reported. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of aryl [35S]sulfones: Friedel–Crafts sulfonylation of aryl ethers with high specific activity [35S]methanesulfonyl chloride
Authors: Wallace Michael A. , Raab Conrad , Dean Dennis , Melillo David 
Published: July 2007

AbstractLewis acid‐assisted sulfonylation of anisole with [35S]methanesulfonyl chloride afforded high specific activity aryl [35S]sulfones. Demethylation and treatment with triflic anhydride gave the versatile [35S]triflate 1 in good overall yields. The [35S]sulfone triflate could be further functionalized by catalyzed aminations, Stille couplings, and cyanation. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of isotopically labelled amino acids
Authors: Rees David O. , Bushby Nick , Harding John R. , Song Chuanjun , Willis Christine L. 
Published: July 2007

AbstractAn efficient approach to the enantioselective synthesis of a series of amino acids from either bromoacetyl bromide or glycine is described using a [2,3]‐sigmatropic rearrangement to establish the stereogenic centre at C‐2 under mild conditions. Protected allylglycine 5 is a valuable building block to several amino acids e.g. hydrolytic cleavage of the auxiliary in 5 followed by deprotection gave L‐allylglycine in 92% yield whilst oxidative cleavage of the terminal alkene followed by deprotection gave L‐aspartic acid in 67% yield over the 2 steps. Furthermore alkene 5 may be converted to hydroxy ester 8 which is an intermediate for the synthesis of various amino acids including L‐lysine and L‐proline. Since the enantiomer of sultam 1 is commercially available, the analogous D‐amino acids may be synthesised. This chemistry is readily adapted for the incorporation of isotopic labels for example for the synthesis of [1,2‐13C2,15N]‐L‐homoserine 14. Copyright © 2007 John Wiley & Sons, Ltd.
Improved analysis of tritiated samples via a 3H‐NMR cryo‐probe
Authors: Alexakis Efstathios , Bloxsidge James P. , Jones John R. , Lockley William J. S. 
Published: July 2007

AbstractTritium (3H) NMR spectra of a number of compounds prepared via metal‐catalyzed H/T reduction/exchange of unsaturated hydrocarbons are presented. These show the considerable benefits that emerge from using a tritium cryo‐probe. Copyright © 2007 John Wiley & Sons, Ltd.
Radiolabelled compounds production programme in India
Authors: Jayachandran Narath , Unny V. K. P. , Sivaprasad N. 
Published: July 2007

AbstractThe paper highlights our experience of more than four decades of research gained and expertise attained in the production of various radiolabelled compounds. An active programme for the production of various classes of compounds labelled with radioisotopes like 14C, 3H, 35S, 32P, 33P and 125I by well‐standardized procedures is going on in the country. Recent trends show an increasing demand for the custom‐synthesis of various labelled compounds, especially those labelled with 14C. Copyright © 2007 John Wiley & Sons, Ltd.
Scrambling versus specific processes in gaseous organic ions during mass spectrometric fragmentation: elucidation of mechanistic origins by isotope labelling – an overview
Authors: Kuck Dietmar 
Published: July 2007

AbstractThe use of isotope labelling for the elucidation of mass spectrometric fragmentation mechanisms is demonstrated in various cases of different nature. The intermediacy of ion/neutral (I/N) complexes during fragmentation, being both analytically and fundamentally relevant, is discussed and studies on the regiospecific and irreversible intracomplex hydride transfer reactions within ‘designed’ deuterium‐labelled I/N complexes are reported. By contrast, several types of scrambling processes, being due to reversible isomerization reactions prior to mass spectrometric fragmentation, are presented, exemplifying complete and incomplete, progressive and composite scrambling in gaseous organic ions. Copyright © 2007 John Wiley & Sons, Ltd.
Chiral superbases: the proton affinities of 1‐ and 2‐aza[6]helicene in the gas phase
Authors: Roithová Jana , Schröder Detlef , Míšek Jiří , Stará Irena G. , Starý Ivo 
Published: July 2007

AbstractThe proton affinities (PAs) of 1‐ and 2‐azahelicene were determined using various mass spectrometric techniques and complementary results from density functional theory. With PAs of about 1000 kJ mol−1, the helical backbone of both compounds offer promising perspectives for future research on enantioselective reactions of these helical nitrogen bases. Copyright © 2007 John Wiley & Sons, Ltd.
Nordihydroguaiaretic acid induces astroglial death via glutathione depletion
Authors: Im Joo‐Young , Han Pyung‐Lim 
Published: July 2007

AbstractNordihydroguaiaretic acid (NDGA) is known to cause cell death in certain cell types that is independent of its activity as a lipoxygenase inhibitor; however, the underlying mechanisms are not fully understood. In the present study, we examined the cellular responses of cultured primary astroglia to NDGA treatment. Continuous treatment of primary astroglia with 30 μM NDGA caused >85% cell death within 24 hr. Cotreatment with the lipoxygenase products 5‐HETE, 12‐HETE, and 15‐HETE did not override the cytotoxic effects of NDGA. In assays employing the mitochondrial membrane potential‐sensitive dye JC‐1, NDGA was found to induce a rapid and almost complete loss of mitochondrial membrane potential. However, the mitochondrial permeability transition pore inhibitors cyclosporin A and bongkrekic acid did not block NDGA‐induced astroglial death. We found that treatment with N‐acetyl cysteine (NAC), glutathione (GSH), and GSH ethyl ester (GSH‐EE) did inhibit NDGA‐induced astroglial death. Consistently, NDGA‐induced astroglial death proceeded in parallel with intracellular GSH depletion. Pretreatment with GSH‐EE and NAC did not block NDGA‐induced mitochondrial membrane potential loss, and there was no evidence that reactive oxygen species (ROS) production was involved in NDGA‐induced astroglial death. Together, these results suggest that NDGA‐induced astroglial death occurs via a mechanism that involves GSH depletion independent of lipoxygenase activity inhibition and ROS stress. © 2007 Wiley‐Liss, Inc.
Phosphorylation‐dependent dimerization and subcellular localization of islet‐brain 1/c‐Jun N‐terminal kinase‐interacting protein 1
Authors: Borsello T. , Centeno C. , Riederer I.M. , Haefliger J.‐A. , Riederer B.M. 
Published: July 2007

AbstractIslet‐brain 1 [IB1; also termed c‐Jun N‐terminal kinase (JNK)‐interacting protein 1 (JIP‐1] is involved in the apoptotic signaling cascade of JNK and functions as a scaffold protein. It organizes several MAP kinases and the microtubule‐transport motor protein kinesin and relates to other signal‐transducing molecules such as the amyloid precursor protein. Here we have identified IB1/JIP‐1 using different antibodies that reacted with either a monomeric or a dimeric form of IB1/JIP‐1. By immunoelectron microscopy, differences in the subcellular localization were observed. The monomeric form was found in the cytoplasmic compartment and is associated with the cytoskeleton and with membranes, whereas the dimeric form was found in addition in nuclei. After treatment of mouse brain homogenates with alkaline phosphatase, the dimeric form disappeared and the monomeric form decreased its molecular weight, suggesting that an IB1/JIP‐1 dimerization is phosphorylation dependent and that IB1 exists in several phospho‐ forms. N‐methyl‐D‐aspartate receptor activation induced a dephosphorylation of IB1/JIP‐1 in primary cultures of cortical neurons and reduced homodimerization. In conclusion, these data suggest that IB1/JIP‐1 monomers and dimers may differ in compartmental localization and thus function as a scaffold protein of the JNK signaling cascade in the cytoplasm or as a transcription factor in nuclei. © 2007 Wiley‐Liss, Inc.
Metabotropic glutamate receptors: Phosphorylation and receptor signaling
Authors: Kim Chul Hoon , Lee Jinu , Lee Jae‐Youn , Roche Katherine W. 
Published: July 2007

AbstractMetabotropic glutamate receptors (mGluRs) play important roles in neurotransmission, neuronal development, synaptic plasticity, and neurological disorders. Recent studies have revealed a sophisticated interplay between mGluRs and protein kinases: activation of mGluRs regulates the activity of a number of kinases, and direct phosphorylation of mGluRs affects receptor signaling, trafficking, and desensitization. Here we review the emerging literature on mGluR phosphorylation, signaling, and synaptic function. © 2007 Wiley‐Liss, Inc.
ECONOS in the epoch of CARS renaissance
Authors: Zheltikov A. M. , Radi P. P. 
Published: July 2007

AbstractThe fifth European Conference on Nonlinear Optical Spectroscopy (ECONOS), continuing a long‐standing tradition of European CARS Workshops (ECWs), was held in Smolenice, Slovakia, in April 2006. This special issue includes 15 contributions from ECONOS authors, giving a flavor of the most interesting topics covered by ECONOS'2006. Copyright © 2007 John Wiley & Sons, Ltd.
Collisionally induced dephasing and rotational energy transfer in the CO2 Fermi dyad ‘red’ Q‐branch 1285 cm−1
Authors: Arakcheev V. G. , Kireev V. V. , Morozov V. B. , Olenin A. N. , Tunkin V. G. , Valeev A. A. , Yakovlev D. V. 
Published: July 2007

AbstractThe present paper is focused on the development of an adequate description of collisionally induced dephasing and rotational energy transfer (RET) in the CO2 Fermi dyad ν1/2ν2. We have made comparative analysis of two approaches to RET simulation for the 2ν2 Q‐branch 1285 cm−1 based on spectral exchange (SE) and rotational relaxation (RR) ideas. A special fitting procedure based on the minimization of an approximation error has been developed for fitting theoretical impulse responses to the experimental ones measured by picosecond time‐domain coherent anti‐Stokes Raman spectroscopy (CARS). A series of experiments on frequency‐domain CARS were carried out in order to improve measurements of the dephasing time T2 and to extend the simulation to the whole gas density range using a uniform set of fitting parameters. Special attention was paid to a detailed analysis of the rotational structure manifestation in the impulse response beating structure. In the case of the ‘red’ Q‐branch, the RR model proved to be more appropriate in comparison with the SE model. It is shown that the rotational structure contribution to the time‐domain signal decay and the cumulative spectral width remains essential and comparable with the collisional dephasing contribution up to the highest gas densities. Copyright © 2007 John Wiley & Sons, Ltd.
Identification of Lepidium meyenii (Walp.) based on spectra and chromatographic characteristics of its principal functional ingredients
Authors: Jin Wenwen , Zhang Yongzhong , Mei Song , Xiong Yue , Yang Qin , Yu Longjiang 
Published: July 2007

AbstractLepidium meyenii Walp. (maca), a perennial herbaceous plant with narrow distribution in the Andean region, was cultivated by local residents as early as 1600 BC. It has high nutritional value and multiple medicinal effects. The plant source of maca is now scarce because maca products are becoming increasingly popular in the world as dietary supplements. This means that studies on the identification of maca materials are now urgent. In present work, natural plants with similar appearance or medicinal effects, including maca, radish (Raphanus sativus L.), oriental ginseng (Panax ginseng C. A. Mey.), American ginseng (Panax quinquefolium L.) were investigated. Their alkaloid extracts of the hypogeal parts were analysed by FTIR and TLC. The essential oils (steam distillates) were analysed by GC/MS. Through comparison of the characteristics of their spectra and chromatograms, it was found that the functional ingredient extracts of maca have unique FTIR, TLC and GC/MS behaviours. The secondary amide group (CH2NHCOCH2) and the phenyl structure in FTIR, the multiple spots at different RF values colourised by modified Dragendorff's reagent, and the characteristic peaks produced by the major essential oil components (e.g. phenylacetonitrile, benzaldehyde, 3‐methoxyphenylacetonitrile) in GC/MS are distinct. These behaviours can be applied to the identification of maca or maca products in the market. Copyright © 2007 Society of Chemical Industry
Sucrose biosensor as an alternative tool for sugarcane field samples
Authors: Kennedy John F , Pimentel Maria do Carmo B , Melo Eduardo HM , Lima‐Filho José L 
Published: July 2007

AbstractThe goal of this preliminary study was to produce an alternative tool for measuring the amount of sucrose in samples without pre‐treatment and use it in the sugarcane field or mobile units. The technology developed makes payment for the sugarcane much more reliable to the producer and also can improve the quality control of the final product. A flow injection analysis system for measuring sucrose using invertase (E.C. 3.2.1.26), and glucose oxidase (E.C.1.1.3.4) (GOD) was developed. The biosensor was made using invertase and GOD incorporated into active graphite paste mixed with tetracyanoquinodimethane as mediator. The system was able to measure sucrose from 50 up to 200 mmol L−1 with a response time of 5 min using 400 µL of sample in 100 mmol L−1 phosphate buffer pH 6.5. This sucrose biosensor showed a sensitivity of 174 ± 8.7 nA mg−1 of sucrose, being a robust system to measure high concentrations of sucrose in sugarcane crops and industrial and fermentation processes, without dilution or pre‐treatment of the samples. Interference from organic acids, mainly ascorbic acid (+350 mV versus Ag/AgCl), was reduced in this system using the potential of 100 mV vs. Ag/AgCl. The active electrode was stable during 2 months at 4 °C. Copyright © 2007 Society of Chemical Industry
Proximal composition and in vitro digestibility of starch in lima bean (Phaseolus lunatus) varieties
Authors: Bello‐Pérez Luis A , Sáyago‐Ayerdi Sonia G , Chávez‐Murillo Carolina E , Agama‐Acevedo Edith , Tovar Juscelino 
Published: July 2007

AbstractBACKGROUND: Beans are rich and inexpensive sources of proteins and carbohydrates around the world, but particularly in developing countries. However, many legume varieties are still underutilized. In this study, physical characteristics of the seeds of three Phaseolus lunatus cultivars were characterized. Also, the chemical composition and starch digestibility in the cooked beans were assessed.RESULTS: ‘Comba floja’ variety exhibited the highest thousand‐kernel weight whereas the lowest was found in ‘comba violenta’. This agrees with seed dimensions: ‘comba floja’ had the Longest seeds (16.36 mm) and ‘comba violenta’ the shortest ones (13.98 mm). All samples exhibited high protein content, but levels in ‘comba blanca’ variety (216 g kg−1) were lower than the in other two cultivars. Total starch (370–380 g kg−1) and potentially available starch content (330–340 g kg−1) were similar in the three varieties. Resistant starch level in the cooked seeds ranged between 38 and 45 g kg−1. Low enzymatic hydrolysis indices (HI) were recorded (30.2–35%), indicating a low digestion rate for Phaseolus lunatus starch. HI‐based predicted glycemic indices ranged between 34% and 39%, which suggests a ‘slow carbohydrate’ feature for this legume.CONCLUSION: Phaseolus lunatus beans appear to be a good source of protein and slow‐release carbohydrates with potential benefits for human health. Copyright © 2007 Society of Chemical Industry
Chemical composition and in vitro starch digestibility of pigmented corn tortilla
Authors: Hernández‐Uribe Juan Pablo , Agama‐Acevedo Edith , Islas‐Hernández José Juan , Tovar Juscelino , Bello‐Pérez Luis A 
Published: July 2007

AbstractBACKGROUND: Tortillas were prepared from two (blue and regular white) maize varieties and compared with regard to chemical composition and in vitro starch digestibility, i.e., available starch (AS), total (RS) and retrograde (RRS) resistant starch contents, amylolysis rate and predicted glycemic index (pGI). The impact of cold storage (4 °C) on digestibility was also investigated.RESULTS: Despite its higher protein and lipid contents, pigmented tortilla exhibited lower AS content than the white product. AS in both types of tortilla decreased during the first 2 days of storage, and remained stable thereafter. Blue tortilla had lower RS content (21 g kg−1 dry matter basis) than the white tortilla (30 g kg−1 dry matter basis). RS values were slightly higher in 2 day‐stored tortillas than in their fresh counterparts. Although the RRS content in recently made white tortillas was greater than in the colored preparation, stored blue tortillas exhibited double RRS values compared with freshly baked samples. α‐Amylolysis of blue tortilla was slower than in the white sample. Consequently, blue tortilla exhibited a lower pGI value. pGI for the white tortilla decreased upon cold storage, a change that was not be observed for the colored preparation.CONCLUSION: Starch digestibility characteristics of blue tortilla make it suitable for people with special nutritional or metabolic requirements. Copyright © 2007 Society of Chemical Industry
Effect of formulated zimmu (Allium cepa L. × Allium sativum L.) extract in the management of grain mold of sorghum
Authors: Karthikeyan Muthusamy , Sandosskumar Rajendran , Radhajeyalakshmi Raju , Mathiyazhagan Subramanian , Khabbaz Salah Eddin , Ganesamurthy Kulandaivelu , Selvi Balasubramanian , Velazhahan Rethinasamy 
Published: July 2007

AbstractBACKGROUND: The in vitro antifungal activity of zimmu (Allium cepa L. × Allium sativum L.) extract against Aspergillus flavus Link., Fusarium moniliforme Sheld, Curvularia lunata (Wakker) Boedijn and Alternaria alternata (Fr.) Keissler, the fungi associated with grain mold of sorghum, was evaluated. An emulsifiable concentrate (EC) formulation of zimmu extract was prepared and its efficacy in controlling grain mold was tested under field conditions.RESULTS: The leaf extract of zimmu exhibited strong antifungal activity against A. flavus, F. moniliforme, C. lunata and A. alternata and caused in vitro fungal growth inhibition of 73.3%, 71.1%, 70.0% and 74.4%, respectively. Foliar application of zimmu formulation 50 EC at 3 mLL−1 (v/v) concentration 60, 75 and 90 days after sowing significantly reduced the incidence of grain mold and increased the grain weight and grain hardness. A significant reduction in the aflatoxin B1 content in sorghum grains was observed when sorghum plants were sprayed with zimmu formulation 50 EC at 0.3% concentration. Western blot analysis revealed that a thaumatin‐like protein (TLP) a molecular mass of 23 kDa that cross‐reacted with zeamatin antiserum was expressed at higher levels in sorghum grains after treatment with zimmu formulations.CONCLUSION: The leaf extract of zimmu exhibited antifungal activity against sorghum grain mold fungi. The formulated zimmu extract was significantly effective in reducing the grain mold incidence in sorghum under field conditions. This formulated zimmu extract offers a novel alternative for eco‐friendly management of grain mold of sorghum. Copyright © 2007 Society of Chemical Industry
Covalent interactions between proteins and oxidation products of caffeoylquinic acid (chlorogenic acid)
Authors: Prigent Stéphanie VE , Voragen Alfons GJ , Visser Antonie JWG , van Koningsveld Gerrit A , Gruppen Harry 
Published: July 2007

AbstractBACKGROUND: The interactions between phenolic compounds and proteins can modify protein properties important in the food industry. To understand the effects of these interactions, the covalent interactions between caffeoylquinic acid (chlorogenic acid, CQA) oxidised by polyphenol oxidase (PPO) at acidic pH 6 (pH 6) and α‐lactalbumin, lysozyme and bovine serum albumin (BSA) were compared with non‐enzymatically induced covalent interactions at alkaline pH (pH 9). The effects of these modifications on protein properties were examined.RESULTS: Both ways of modification seemed to result in protein modification mainly via dimeric rather than monomeric CQA quinones. These modifications led to a decrease in the number of free primary amino groups of the proteins. Modification with CQA alone induced a low degree of protein dimerisation, which also occurred through the action of PPO alone. Modification drastically reduced the solubility of lysozyme over a broad pH range, whereas that of α‐lactalbumin was strongly reduced only at pH values close to its pI. The solubility of BSA was much less affected than that of the other proteins and only at acidic pH.CONCLUSION: These results indicate some similarities between modifications at pH 6 and 9 and that both modifications clearly change the functional properties of globular proteins. Copyright © 2007 Society of Chemical Industry