bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of papaverine and quinopavine specifically labeled with 14C
Authors: Ithakissios S. D. , Tsatsas G. , Nikokavouras J. , Tsolis A. 
Published: October 2006

Abstract1‐(3,4‐Dirmethoxybenzyl)‐6, 7‐dimethoxyisoquinoline (papaverine) labeled with 14C in either the benzyl or 4‐carbon position and 1‐(3,4‐dimethoxyphenyl) 6,7‐dimethoxyisoquinoline (quinopavine) labeled with 14C at the 1,4 or 4‐methoxyphenyl position were synthesized. The 3,4‐dimethoxybenzoic acid‐carboxyl‐14C.(I) was, employed as the precursor in the synthesis of, all the above compounds except the 4‐methoxyphenyl labeled where 3‐methoxy‐4‐14C‐methoxybenzoic acid was employed (XII). The reduction of 3,4‐dimethoxybenzoylchloride 14C (VII) led to the formation of 3,4‐dimethoxybenzaldehyde‐carbonyl 14‐C (VIII) from which 2‐(3,4‐dimethoxyphenyl)‐2‐methoxyethylamine‐2‐14C (XI) was obtained through reduction of the corresponding 14C‐labeled substituted nitrostyrene (IX). 3,4‐Dimethoxybenzoic acid‐carboxyl‐14C (I) was employed in the synthesis of (3,4‐dimethoxyphenyl)‐acetonitrile‐2‐14C (IV) from which a) 2‐(3,4‐dimethoxyphenyl)‐ethylamine‐2‐14C (VI) was obtained on reduction and b) (3,4‐dimethoxyphenyl)‐acetic acid‐2‐14C (V) on alkaline hydrolysis. On heating together at 200°C the corresponding acids and amines in the absence as well as in the presence of decaline (solvent), or by a Schotten‐Bawmann reaction, the corresponding amines were obtained and them cyclized in the presence of phosphorus oxychloride. The 3, 4‐dihydro‐products were dehydrogenated in the presence of palladium‐pumice which acted as a catalyst. The cyclization of N‐(3,4‐dimethoxyphenyl‐2‐methoxyethyl‐2‐14C) 3,4‐dimethoxyphenyl‐acetamide (XVI) gave straightway the corresponding 14C) 3,4‐dimethoxyphenyl‐acetamide (XVI) gave straightway the corresponding 14C‐marked papaverine.
Synthesis of carbon‐14 labeled 1,4‐benzodiazepnies. II.(1) diazepam‐14C, demethyldiazepam‐14C, and ketazolam‐14C
Authors: Hsi Richard S. P. 
Published: October 2006

AbstractDiazepam‐14C and demethyldiazepam‐14C are synthesized from glycine‐1‐14C. Addition of diketene to diazepam‐14C leads to ketazolam‐14C. The reaction conditions for the formation of ketazolam from diazepam is studied using high‐pressure liquid chromatography in conjunction with radioactivity determinations.
The preparation and purification of ethyl 6‐ethyl‐4‐hydroxy [3‐14C] cinnol‐3‐YL carboxylate (ICI 75,186)
Authors: Longworth S. W. , Bigg D. C. H. , White D. F. , Burns J. 
Published: October 2006

AbstractThe preparation of ethyl 6‐ethyl‐4‐hydroxy[3‐14C] cinnol‐3‐ul carboxylate (ICI 75,186) from diethyl[2‐14C]malonate in five stages is described, together with the purification procedures involved. The overall radiochemical yield, at a specific activity of 3.3 μCi/mg, was 10%.
The tritium incorporation into the solvents under conditions of catalytic hydrogenation
Authors: Hanus J. , Cerny B. , Benes J. 
Published: October 2006

AbstractThe incorporation of tritium gas into dioxan, tetrahydrofuran, ethyl acetate, dimethylformamide, dimethylacetamide, dimethylsulfoxide and acetic acid anhydride was studied in the presence of heterogeneous catalysts PdO (Adams), PtO2 (Adams), Pd/BaSO4 (10%). For the solvents and catalysts investigated the following dependencies were observed:

Wllzbach reaction of the solvents takes only a negligible part in the total incorporation into the solvents.
The traces of exchanging impurities in solvents caused much higher incorporation.
In the case of non exchanging solvents, practically all the radioactivity incorporated is bound on tritium water.
A new approach to specific labelling of organic compounds with tritium: Catalysed exchange in solution with tritium gas
Authors: Evans E. Anthony , Sheppard Hilary C. , Turner John C. , Warrell David C. 
Published: October 2006

AbstractIn a new approach to the specific labelling of organic compounds with tritium use is made of isotope exchange with tritium of certain specific hydrogen atoms in organic molecules when stirred with tritium gas in solution at room temperature in the presence of a metal hydrogen transfer catalyst. Specifically labelled tritiated compounds of high specific activity and radio‐chemical purity are obtained.The method can be used for labelling a wide variety of organic compounds including purines, purine nucleosides and nucleotides, aromatic amines and amino acids, carbohydrates and steroids. Numerous examples are cited and possible mechanisms discussed.
Synthesis of carbon‐14labelled antimicrobial agents, I, synthesis of 1,4‐dihydro‐1‐methoxy‐6,7‐methylenedioxy‐4‐oxo‐quinoline‐3‐carboxylic‐3‐14C acid (AB‐206‐3‐14C)
Authors: Yoshitake A. , Makari Y. , Endo M. 
Published: October 2006

Abstract1,4‐Dihydro‐1‐methoxy‐6,7‐methylenedioxy‐4‐oxoquinoline‐3‐carboxylic acid (I) (AB‐206), a new synthetic antimicrobial agent, was labelled with carbon‐14 at C‐3 position of the quinolinone ring for metabolic studies. The synthesis was achieved according to the reaction schemes shown in Fig. 1 and 4; which involved a newly devised key‐reaction, the condensation of diethyl malonate‐2‐14C with ethyl orthoformate and 3,4‐methylene‐dioxyaniline in the presence of anhydrous zinc chloride as a catalyst to ethyl α‐carbethoxy‐β‐(3,4‐methylenedioxyanilino) acrylate‐2‐14C (III). The overall radiochemical yield of AB‐206‐3‐14C (I) was 9.6% from methanol‐14C.
Synthesis of [14C]‐fenfluramine and [14C]‐S780
Authors: Hawkins D. R. , Midgley I. 
Published: October 2006

AbstractThe syntheses of 1‐m‐trifluoromethylphenyl‐2‐N‐ethylaminopropane (I; Ponderax®) and 1‐m‐trifluoromethylphenyl‐2‐N‐β‐benzoyloxyethylaminopropane (II; S780) labelled with carbon‐14 at the benzylic position have been accomplished in seven stages starting from Ba14CO3. The overall radiochemical yield was 9% and both products were obtained with a radiochemical purity in excess of 98%.
The synthesis of 14C‐methylene diiodide and 14C‐propane‐1,3‐dibromide
Authors: Jones A. R. 
Published: October 2006

AbstractExisting methods have been adapted for the small scale synthesis of the title compounds in high yield. Modification of the iodoform reaction enables 1,3‐14C‐acetone (I) to be converted in over 95% yield to 14C‐iodoform (II) which is reduced by sodium aresenite to 14C‐methylene diiodide (III). Lithium aluminium hydride reduction of 14C‐diethyl malonate (IV) to 14C‐propane‐1, 3‐diol (V), followed by acetylation and displacement with hydrobromic acid, produces 14C‐propane‐1,3‐dibromide (VII) in 87% overall yield. The use of u‐. 2‐ or 1,3‐14C–diethyl malonate enables propane ‐1,3‐dibromide to be synthesised in any desired labelling pattern. Compounds III V and VII are useful difunctional 1‐ and 3‐carbon intermediates for further radioactive syntheses.
The synthesis of trideuterated diethylstilbestrol ([1,1,1‐D3] E‐3,4‐di‐(4‐hydroxyphenyl)‐hex‐3‐ene)
Authors: Marshall Penelope J. , Engel Lewis L. 
Published: October 2006

Abstract[1,1,1‐D3] E‐3,4‐Di‐(4‐hydroxyphenyl)‐hex‐3‐ene has been synthesized from 1,2‐di‐(4‐methoxyphenyl)‐butan‐1‐one. Reaction of this ketone with [2,2,2‐D3] ethyl magnesium iodide yields [1,1,1‐D3]3,4‐di‐(4‐methoxyphenyl)‐hexan‐3‐ol, which on dehydration with potassium hydrogen sulfate and demethylation with methyl magnesium iodide yields isotopically pure trideuterated diethyl‐stilbestrol. Isotopically pure [2,2‐D2] 3,4‐di‐(4‐dydroxyphenyl)‐hex‐3‐ene cannot be prepared by this route from [1,1‐D2] ethyl magnesium iodide.
Syntheses with stable isotopes: Urea‐13C, urea‐12C, and urea‐13C‐15N2
Authors: Whaley Thomas W. , Ott Donald G. 
Published: October 2006

AbstractUrea has been prepared from the reaction of carbon monoxide and ammonia in the presence of sulfur. The reaction has been applied to the synthesis of urea‐13C, urea‐12C, and urea‐13C‐15N2.
Dispositif Automatique de Transfert de Gaz (Tritium, Deuterium, Hydrogene)
Authors: Morgat J. L. , Desmares J. , Cornu M. 
Published: October 2006

AbstractFor a very long time numerous devices have been proposed to compress the tritium gas stocked under reduced pressure. The Toepler pump is nevertheless the most utilized apparatus for this purpose, despite many disadvantages. To avoid the troubles of a conventional vacuum line. an automatic gas transfert machine has been built.
Synthesis, purification, storage and isotopic analysis of CT4 on the multicurie scale
Authors: Cacaoe Fulvio , Schüller Manfred 
Published: October 2006

AbstractMulticurie amounts of CT 4 were prepared from T 2 via a twosteps synthesis with an overall yield of ca. 75%. After purification, the radio gas chromatographic analysis of the product revealed only a 0.5% T2 (or HT) impurity. The isotopic analysis, carried out independently by mass spectrometry and by high‐resolution gas chromatography, showed that, immediately after preparation, tritiated methane aontained over 97.8 mol% CT4, with only traces of particular tritiated methanes. However self radiolysis, in particular fast intermolecular H/T scrambling, caused severe storage problems. Even after dilution with a thousand‐fold exaess of CH4, radiation‐induced isotopic exahanges led to serious contamination of CT4 by partially tritiated methanes. A dramatic improvement was obtained, without further dilution of CT4, by addition of 1 ‐ 2 mol% NH3, which completely suppressed radiolytic H/T scrambling. A preparative gas chromatographic technique was developed, which allows isolation of CT4 in a state of high radiochemical and isotopic purity.
Synthesis of cyclopentadienyl‐X‐13C thallium
Authors: Larsen Samuel D. , Vergumini Phillip J. , Whaley Thomas W. 
Published: October 2006

AbstractCyaclopentadienyl thallium has been prepared with one carbon position labeled at a concentration greater than 90 atom % carbon‐13. A new method for incorporating a carbon‐13 label into cyclopentadiene is reported which relies on the reaction of the di‐Grignard reagent of 1,4‐dibromobutane with isopropyl formate13C. The product of this reaction, cyclopentanol‐1‐13C, is converted to cyclopentadienyl‐X‐13C thallium.
Synthesis of geraniol‐9‐14C. methods for obtaining labeled geraniols free of citronellol
Authors: Rajan Sundar J. , Wemple James 
Published: October 2006

AbstractGeraniol‐9‐14C has been prepared starting with methyl lithium‐14C. Methods have been developed for obtaining radiolabeled geraniol free of citronellol and other by‐products.
The synthesis of deuterium, carbon‐14, and carrier‐free tritium labeled cannabinoids
Authors: Pitt C. G. , Hobbs D. T. , Schran H. , Twine C. E. , Williams D. L. 
Published: October 2006

Abstract1′,2′‐Dehydroolivetol and its monomethyl ether, 5′‐bromoolivetol, and olivetol‐5,‐2H3, have been synthesized. Acid catalyzed condensation of the latter three compounds with p‐mentha‐2,8‐dien‐1‐ol gave 1′,2′‐dehydro‐Δ8‐THC methyl ether, 5′‐bromo‐Δ8‐THC, and Δ9‐THC‐5′‐2H3, respectively. 5′‐Bromo‐Δ8‐THC served as a precursor of 4′,5′‐dehydro‐Δ8‐ and Δ8‐THC, 4′‐ and 5′‐hydroxy‐Δ8‐THC, 5′‐dimethylamino‐Δ8‐THC and 5′‐carboxy‐Δ8‐THC. Reduction of 4′,5′‐dehydro‐Δ8‐ and Δ9‐THC in the presence of homogeneous catalysts afforded tritium labeled Δ8‐THC (50 Ci/mmole) and Δ9‐THC (58 Ci/mmole), respectively. Syntheses of Δ9‐THC‐11‐2H3, Δ9‐THC‐11‐14C cannabinol‐5,‐2H3′ and other labeled cannabinoids are described.
Synthesis of betamethasone‐l,2‐3h2 17‐benzoate
Authors: Kobari T. , Watanabe S. , Ikegami S. 
Published: October 2006

AbstractA new convenient method for the preparation of the title compound is described. The method consists of selective tritiation of betamethasone 17‐benzoate (9α‐fluoro‐11β,17,21‐trihydroxy‐16β‐methyl‐1,4‐pregnadiene‐3,20‐dione 17‐benzoate) (1) with the use of tris(triphenylphosphine)rhodium chloride as catalyst, followed by dehydrogenation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ).A favorable overall radiochemical yield is obtained.
Systematic comparison of catalytic mechanisms of hydrolysis and transfer reactions classified in the EzCatDB database
Authors: Nagano Nozomi , Noguchi Tamotsu , Akiyama Yutaka 
Published: October 2006

AbstractCatalytic mechanisms of 270 enzymes from 131 superfamilies, mainly hydrolases and transferases, were analyzed based on their enzyme structures. A method of systematic comparison and classification of the catalytic reactions was developed. Hydrolysis and transfer reactions closely resemble one another, displaying common mechanisms, single displacement, and double displacement. These displacement mechanisms might be further subclassified according to the type of catalytic factors and nucleophilic substitution involved. Several types of catalytic factors exist: nucleophile, acid, base, stabilizer, modulator, cofactors. Nucleophilic substitution might be categorized as SN1/SN2 (or dissociative/associative) reactions. The classification indicates that some mechanisms favor particular types of catalytic factors. In hydrolyses of amide bonds and phosphoric ester bonds, mechanisms with single displacement tend to use inorganic cofactors such as zinc and magnesium ions as important catalysts, whereas those with double displacement frequently do not use such cofactors. In contrast, hydrolyses of O‐glycoside bond rarely use such cofactors, with one exception. The trypsin‐like hydrolytic reaction, which is catalyzed by the classic catalytic triad comprising serine/histidine/aspartate, can be considered as a “super‐reaction” because it is observed in at least three nonhomologous enzymes, whereas most reactions are singlets without any nonhomologous enzymes. By dividing complex reactions into several reactions, correlations between active site structures and catalytic functions can be suggested. This classification method is applicable to other reactions such as elimination and isomerization. Furthermore, it will facilitate annotation of enzyme functions from 3D patterns of enzyme active sites. The classification is available at http://mbs.cbrc.jp/EzCatDB/RLCP/index.html. Proteins 2007. ©2006 Wiley‐Liss, Inc.
Effects of Structure on 1‐Octanol/Water Partitioning Behavior of Aliphatic Amines and Ammonium Ions
Authors: Takayama Chiyozo , Akamatsu Miki , Fujita Toshio 
Published: October 2006

AbstractThe partition coefficients of 45 neutral aliphatic amines and the ion‐pair formation‐partition equilibrium constants with picrate of 66 aliphatic ammonium ions, determined using a 1‐octanol/water system, were analyzed by means of free‐energy‐related substituent constants and the multiple regression technique. The hydrophobic, electronic, steric, and hydrogen bonding effects of N‐substituents governing the partitioning behaviors were quantitatively separated by means of an equation: log K = a∑π + ρI∑σI ∑δiE (Ri) + bnH + c, where K is the equilibrium constant, and ρI, δi, b, and c are susceptibility constants and the intercept. ∑π and ∑σI, are, respectively, the sum of the hydrophobic π values and the inductive electronic σI values of three or four N‐substituents. E (Ri) is a modified steric constant derived from the Dubois E′s value considering the branching effect of N‐substituents, Rj, in which i = 1 ∼ 3 for amines and i = 1 ∼ 4 for ammonium ions. Ri is classified according to the relative magnitude of E values so that E (R1) ≤ E (R2) ≤ E (R3) ≤ E (R4). nH is the number of NH hydrogens of the (conjugate) ammonium ion. It was shown that the definitely intermolecular type of steric effect in the ion‐pairing is nicely elucidated with the E constant of component N‐substituents.
PCB and Related Compound Binding to the Ah Receptor(s) Theoretical Model Based on Molecular Parameters and Molecular Mechanics
Authors: McKinney J. D. , Darden T. , Lyerly Mark A. , Pedersen L. G. 
Published: October 2006

AbstractA model previously developed for describing PCB binding to cytosol receptors is tested with binding data from a set of PCBs [Bandiera et al., Biochem. Pharmacol. 32: 3803–3813 (1983)] which exhibit a broad range of intermolecular forces. The binding of molecules which would be expected to be dominated by dispersive interactions is correlated well with binding constants determined by polarizability and stacking distance parameters. The binding data for molecules which have substituents capable of exerting other electronic effects on binding correlate less well as expected. The stacking model was shown to be consistent with the minimum separation distances found by molecular mechanics. This simple model based on molecular parameters is a more universally applicable model for Ah receptor‐aromatic hydrocarbon binding since it can explain the exceptions found for the previous rectangular (3 × 10Å) box model.
Becoming a scientist: The role of undergraduate research in students' cognitive, personal, and professional development
Authors: Hunter Anne‐Barrie , Laursen Sandra L. , Seymour Elaine 
Published: October 2006

AbstractIn this ethnographic study of summer undergraduate research (UR) experiences at four liberal arts colleges, where faculty and students work collaboratively on a project of mutual interest in an apprenticeship of authentic science research work, analysis of the accounts of faculty and student participants yields comparative insights into the structural elements of this form of UR program and its benefits for students. Comparison of the perspectives of faculty and their students revealed considerable agreement on the nature, range, and extent of students' UR gains. Specific student gains relating to the process of “becoming a scientist” were described and illustrated by both groups. Faculty framed these gains as part of professional socialization into the sciences. In contrast, students emphasized their personal and intellectual development, with little awareness of their socialization into professional practice. Viewing study findings through the lens of social constructivist learning theories demonstrates that the characteristics of these UR programs, how faculty practice UR in these colleges, and students' outcomes—including cognitive and personal growth and the development of a professional identity—strongly exemplify many facets of these theories, particularly, student‐centered and situated learning as part of cognitive apprenticeship in a community of practice. © 2006 Wiley Periodicals, Inc. Sci Ed 91:36–74, 2007
An experiment in “bi‐curricular teaching” with ninth grade science and english students
Authors: Knapp John 
Published: October 2006

AbstractThis paper is an informal discussion of an experiment in combining some of the teaching objectives of ninth grade science and English in the form of a “Voluntary Science‐English Term Paper Project”. The purpose here is to present a practical illustration of a method of achieving certain short term goals common to both high school science and English. The project, carried out in a rural high school in central Virginia, proved to be an economical way of achieving certain goals within a traditionally‐oriented curriculum.
Free‐choice experiences: How do they help children learn?
Authors: Linn Marcia C. 
Published: October 2006

AbstractHunt's theory of intrinsic motivation and the open education movement suggests that student choice is an important variable in instruction. Piagetian theory emphasizes the importance of interactive experiences and exposure to materials as opposed to direct instruction. In this study, interactive free choice learning experiences are compared to and combined with the lecture‐demonstration approach. The goal of both forms of instruction was to teach children to criticize and control experiments. The lecture‐demonstration approach without opportunities for free choice was superior to free choice alone or free choice combined with the lecture‐demonstration approach in teaching students to criticize experiments. Lecture‐demonstration followed by free choice was superior to free choice followed by lecture‐demonstration, and to free choice combined with lecture‐demonstration in teaching students to design controlled experiments. Results suggest that the ability to criticize experiments is a necessary condition for acquiring the ability to design controlled experiments. Contrary to some of Piaget's statements and to recent research (Kuhn & Angelev, 1976), this study suggests that instruction combined with exposure to materials is more effective than exposure alone in fostering an ability to criticize and control experiments. Results suggest that free choice is an effective instructional tool only after students have some familiarity with the goals of instruction. That is, students who are able to criticize experiments can learn to design controlled experiments from a free‐choice program.
Using graphic organizers to increase achievement in middle school life science
Authors: Hawk Parmalee P. 
Published: October 2006

AbstractEducators are constantly searching for teaching procedures that will produce greater cognitive learning and at the same time make learning more appealing. Also, faced with economic problems, educators are looking for techniques that are both inexpensive and effective. The teaching strategy, Graphic Organizers, explained and used in the study reported here, presents information in an organized and structured manner with no expenditures other than paper, pencil, and instructor time. Graphic organizers require minimal training time with teachers, little investment in materials, no investment in equipment, and no change in the existing physical plant. Research conducted (Hawk, 1982; Hawk, McLeod and Jeane, 1981) using graphic organizers has shown them to be significantly beneficial to student achievement.
Elementary science as a little added frill: A report of two case studies
Authors: Schoeneberger Mary , Russell Thomas 
Published: October 2006

AbstractI'm quite certain that you could go for a year without teaching science and there would be no comment. Parents sec science as a little added frill, maybe. I don't think they see it being as important, for instance, as math is–that you know how to add, subtract or that you are able to read.
Students' Preconceptions about the Epistemology of Science
Authors: Ryan Alan G. , Aikenhead Glen S. 
Published: October 2006

AbstractThe North American confusion of science with technology can cloud epistemic views. This should be kept in mind as one reads the following analysis of students' views on the epistemology of science. Chances are great that when students talk about science, they are probably talking about technology, specifically medical and environmental technological investigations.
The relationship of pupil control to preservice elementary science teacher self–efficacy and outcome expectancy
Authors: Enochs Larry G. , Scharmann Lawrence C. , Riggs Iris M. 
Published: October 2006

AbstractThe investigators' intentions in this study were to examine preservice elementary teachers' sense of self‐efficacy with regard to science teaching and to define the construct of self‐efficacy with greater clarity. Additionally, the construct of pupil control was examined. To gather information toward these purposes, we investigated the following questions: Do prospective elementary teachers' efficacy beliefs relate to their beliefs concerning classroom management or control?; and How is a measure of self‐efficacy related to prospective teachers' self‐reported choice concerning the teaching of science, amount of time spent in performing “hands‐on” science, and/or perceived effectiveness as future elementary science teachers? Self‐efficacy was measured as two distinct constructs, personal self‐efficacy and outcome expectancy. Significant correlations were found between personal science teaching self‐efficacy and (1) the number of college science courses taken; (2) the number of years of high school science taken; (3) respondent's choice of science instructional delivery; and (4) respondent's perceived effectiveness in teaching science. When the outcome expectancy subscale is considered, however, only one significant correlation is indicated; perceived effectiveness in teaching science was significantly correlated with outcome expectancy. Personal science teaching self‐efficacy was significantly correlated with pupil control ideology while outcome expectancy was not. © 1995 John Wiley & Sons, Inc.