bluuebunny/crossref_metadata_2025 huggingface dataset:
Nef Alleles from Human Immunodeficiency Virus Type 1-InfectedLong-Term-Nonprogressor Hemophiliacs with or without Late Disease Progression Are Defective in Enhancing Virus Replication and CD4 Down-Regulation
Authors: Crotti Andrea , Neri Francesca , Corti Davide , Ghezzi Silvia , Heltai Silvia , Baur Andreas , Poli Guido , Santagostino Elena , Vicenzi Elisa
Published: October 2006

Infection
with human immunodeficiency virus (HIV)-encoding defective
nef
variants may contribute to a relatively benign course of disease in a
minority of long-term nonprogressors (LTNP). We have examined the
functions of
nef
alleles from six individuals belonging to the
same cohort of hemophiliacs infected with HIV-1 prior to 1985 and
classified as LTNP in 1995. Three out of six individuals have
progressed to HIV disease (late progressors [LP]), whereas the three
remainders have maintained their LTNP status at least up to 2003. The
nef
alleles were obtained from both plasma virus and
peripheral blood mononuclear cells of all six individuals in 1995 and
1998. The proportion of sequences containing mutations not yielding Nef
expression significantly diminished in 1998 versus that in 1995.
Several previously defined functional regions of intact
nef
alleles were highly conserved. However, the major variant obtained in
1998 from plasma RNA of five out of six individuals significantly
reduced HIV infectivity/replication and impaired Nef-mediated CD4 but
not major histocompatibility complex class I antigen down-modulation
from the cell surface. Thus, functional alterations of the
nef
gene are present in both LP and LTNP, suggesting that Nef defectiveness
in vitro is not necessarily associated with the long-term maintenance
of LTNP status. Of interest is the fact that isolates from three out of
three LP showed a dual CCR5/CXCR4 coreceptor use (R5X4), in contrast to
those from LTNP, which were exclusively R5. Thus, in vivo evolution of
gp120 Env to CXCR4 use appears to be associated with HIV disease
progression in individuals infected with
nef
-defective
viruses.
Insulin-like growth factor-I receptors in atherosclerotic plaques of symptomatic and asymptomatic patients with carotid stenosis: effect of IL-12 and IFN-γ
Authors: Jia Guanghong , Cheng Gang , Soundararajan Krish , Agrawal Devendra K.
Published: October 2006

The balance between apoptosis and survival of vascular smooth muscle cells (VSMCs) in the fibrous cap appears to best correlate with plaque instability or stability and is controlled by growth factors and cytokines. We recently reported the inhibition of insulin-like growth factor (IGF)-I-induced proliferation and increase in apoptosis of VSMCs by atheroma-associated cytokines. Here we assessed the expression of IGF-I receptor (IGF-IR) in atherosclerotic plaques and in plaque VSMCs of asymptomatic and symptomatic patients with carotid stenosis and examined the effect of IGF-I, IL-12, and IFN-γ on the expression of IGF-IR and IGF-binding protein (IGFBP)-3 in plaque VSMCs. We observed significantly lower density of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic nuclei and increased positive immunoreactivity to IGF-IR and mRNA transcripts of endogenous IGF-I and IGF-IR in asymptomatic than in symptomatic plaque VSMCs. Positive correlation was found between apoptosis and IGF-IR expression in asymptomatic ( r2= 0.942) and symptomatic ( r2= 0.908) plaque VSMCs. The specific binding of125I-labeled IGF-I was 3.7-fold higher in plaque VSMCs of asymptomatic patients than in symptomatic patients. IGF-I increased both IGF-IR mRNA transcripts and expression of IGFBP-3 in VSMCs of asymptomatic plaques. IL-12 and IFN-γ decreased IGF-IR mRNA transcripts and further increased the expression of IGFBP-3 in asymptomatic VSMCs but had no effect in symptomatic VSMCs. These data suggest that the decreased expression of IGF-IR mRNA and increased expression of IGFBP-3 in carotid plaques of symptomatic patients could be due to atheroma-associated cytokines and this could result in plaque instability.
The College drive to regionalise continues
Authors: Towell Elaine
Published: October 2006

In the past, the College's role has focused on setting and monitoring standards for basic surgical training and, through the specialist advisory committees, higher surgical training. These standards are now made explicit through the intercollegiate surgical curriculum. Since 2000, the College has focused on the management and delivery of training at the coalface. A recent regionalisation initiative, 'schools of surgery', will allow deaneries, Trusts and the College to engage in a constructive dialogue about surgical education and related challenges, such as balancing service and education needs.
Sensitive Detection of KIT D816V in Patients with Mastocytosis
Authors: Tan Angela , Westerman David , McArthur Grant A , Lynch Kevin , Waring Paul , Dobrovic Alexander
Published: October 2006

Background: The 2447 A>T pathogenic variation at codon 816 of exon 17 (D816V) in the KIT gene, occurring in systemic mastocytosis (SM), leads to constitutive activation of tyrosine kinase activity and confers resistance to the tyrosine kinase inhibitor imatinib mesylate. Thus detection of this variation in SM patients is important for determining treatment strategy, but because the population of malignant cells carrying this variation is often small relative to the normal cell population, standard molecular detection methods can be unsuccessful.

Methods: We developed 2 methods for detection of KIT D816V in SM patients. The first uses enriched sequencing of mutant alleles (ESMA) after BsmAI restriction enzyme digestion, and the second uses an allele-specific competitive blocker PCR (ACB-PCR) assay. We used these methods to assess 26 patients undergoing evaluation for SM, 13 of whom had SM meeting WHO classification criteria (before variation testing), and we compared the results with those obtained by direct sequencing.

Results: The sensitivities of the ESMA and the ACB-PCR assays were 1% and 0.1%, respectively. According to the ACB-PCR assay results, 65% (17/26) of patients were positive for D816V. Of the 17 positive cases, only 23.5% (4/17) were detected by direct sequencing. ESMA detected 2 additional exon 17 pathogenic variations, D816Y and D816N, but detected only 12 (70.5%) of the 17 D816V-positive cases. Overall, 100% (15/15) of the WHO-classified SM cases were codon 816 pathogenic variation positive.

Conclusion: These findings demonstrate that the ACB-PCR assay combined with ESMA is a rapid and highly sensitive approach for detection of KIT D816V in SM patients.
Hat Sertürner reines Morphin isoliert? Zur papierchromatographischen Reinheitsprüfung von Alkaloiden
Authors: Häussermann H. , Schecker H.‐J.
Published: October 2006

Im „Sertürner‐Jahr”︁ 1955 gab unser verehrter Lehrer, Prof. v. Bruchhausen, uns die Anregung: „In Ihrer Apotheke hat doch früher Sertürner gearbeitet. Prüfen Sie doch mal nach, ob er wirklich reines Morphin isoliert hat.”︁ Diesem Gedanken sind wir gefolgt. Die erste Nacharbeit erfolgte durch Robiquet, der einst einen ähnlichen Auftrag von seinem Lehrer Gay‐Lussac erhielt (1) (2). Die Anregung führte allgemein zu Arbeiten über die papierchromatographische Reinheitsprüfung von Alkaloiden, die noch nicht abgeschlossen sind. Über die Ergebnisse bei der Bearbeitung der speziellen Sertürner‐Morphin‐Frage soll hier berichtet werden.
Über die Chlormethylierung des o‐ und Novo‐vanillins und die Gewinnung von 4‐Hydroxy‐5‐alkoxy‐isophthalaldehyden
Authors: Profft E. , Kŕause W.
Published: October 2006

Die Chlormethylierung des o‐ und Novo‐Vanillins wurde durchgeführt. Nach Sommelet konnten daraus die entsprechenden 4‐Hydroxy‐5‐alkoxyisophthalaldehyde erhalten werden. Eine einfache Methode zur Darstellung dieser wurde erarbeitet und eine Reihe von Chlormethylverbindungen synthetisiert.
Potentialverlauf bei der Quecksilberacetat‐Dehydrierung von tertiären Aminen mit und ohne ÄDTA. 3. Mitt.: Darstellung von Hydroxylactamen durch Quecksilber(II)‐ÄDTA‐Dehydrierung
Authors: Möhrle H. , Rohrer H. , Altenschmidt W.
Published: October 2006

Die vergleichenden Messungen des Potentials bei der Dehydrierung von Spartein und Nicotin mit Quecksilber(II)‐acetat und Quecksilber(II)‐ÄDTA liefern folgende Ergebnisse:

1. Die Dehydrierung mit Quecksilber(II)‐acetat erfolgt stets bei höherem Potential als mit Quecksilber(II)‐ÄDTA, was auch durch theoretische Berechnungen bestätigt wird.

2 Bei der Umsetzung der Amine mit Quecksilber(II)‐ÄDTA entstehen ebenso wie bei der Reaktion mit Quecksilber(II)‐acetat primär Quecksilber(I)‐Ione, die von ÄDTA zu Quecksilber(II)‐Ionen und Quecksilber disproportioniert werden.
Die Acylierung primärer Alkohole mit Dialkyl‐aminoäthanol‐Esterbasen
Authors: Eckert Th.
Published: October 2006

Dialkyl‐aminoäthanol‐Esterbasen können zur Acylierung primärer Alkohole verwendet werden. Da hier tertiäres Amin und umzusetzende Estergruppe covalent miteinander verbunden sind, kommt es bei Verwendung der Esterbasen als basische Katalysatoren der eigenen Alkoholyse zu einer katalytischen Kettenreaktion. In wasserfreien und wäßrigen Medien werden eine Reihe von neuen Estern, insbesondere Ester der Hydroxyalkyl‐xanthine, synthetisiert.
Beiträge zur Darstellung und Analytik alkylsubstituierter Pyridincarbonsäuren. 2. Mitt.: Die Darstellung methyl‐ und äthylsubstituierter Pyridincarbonsäuren
Authors: Reppel L. , Eilhauer H. D. , Kretschmer P.
Published: October 2006

Zur analytischen Prüfung werden Methyl‐ und Äthyl‐pyridinmonocarbonsäuren durch direkte Sulfonierung von Pyridinbasen und durch Aufbau des Pyridinringes dargestellt: 2‐, 4‐, 5‐, 6‐Methyl‐nicotinsäure, 2‐, 4‐, 5‐, 6‐Äthylnicotinsäure und 5‐Äthyl‐picolinsäure.
Umsetzungsgeschwindigkeiten bei der Quecksilberacetat‐Dehydrierung von Spartein und Nicotin mit und ohne Zusatz von ÄDTA. 4. Mitt.: Darstellung von Hydroxylactamen durch Quecksilber(II)‐ÄDTA‐Dehydrierung
Authors: Möhrle H. , Rohrer H. , Altenschmidt W.
Published: October 2006

Potentialverlauf und Reaktionsgeschwindigkeit im Temperaturbereich 30 bis 85° bei der Dehydrierung von Spartein und Nicotin mit Quecksilber(II)‐acetat bzw. Quecksilber(II)‐ÄDTA ergeben folgende Befunde:

A) Das vom System Platin‐Kalomel‐Elektrode angezeigte Potential des Reaktionsgemisches ist bei der Dehydrierung mit Quecksilber(II)‐acetat höher als bei der Umsetzung mit Quecksilber(II)‐ÄDTA

B) Die Dehydrierung der organischen Substanzen verläuft mit Quecksilber‐(II)‐acetat langsamer als mit Quecksilber(II)‐ÄDTA

C) Bei der Umsetzung der organischen Verbindung mit Quecksilber(II)‐ÄDTA entstehen ebenso wie bei der Reaktion mit Quecksilber(II)‐acetat primär Quecksilber(I)‐ionen.
Zum Mechanismus der Reduktion Schiffscher Basen mit aktiviertem Aluminium. 3. Mitt. über Cytostatica
Authors: Schönenberger H. , Thies H. , Rappl A.
Published: October 2006

Bei der Reduktion Schiffscher Basen mit aktiviertem Aluminium lassen sich die Ausbeuten an monomeren und dimeren Reduktionsprodukten durch Zugabe unterschiedlicher Alkoholmengen beliebig variieren. Kleine Alkoholmengen begünstigen die Bildung der dimeren, große hingegen die der monomeren Reduktionsprodukte.
Über die Herstellung neuer lokalanästhetisch wirksamer Verbindungen
Authors: Schönenberger H. , Vogel H. , Bamann E.
Published: October 2006

Es werden Verfahren zur Herstellung von „doppelt ringoffenem Cocain und Norcocain”︁ beschrieben. Geeignet sind zwei Verfahren, die von Acetessigester bzw. Crotonester und Aminoalkoholen ausgehen und zu den Zwischenprodukten β‐Hydroxyalkylaminobuttersäureestern führen. Durch Benzoylierung werden aus diesen die lokalanästhetisch wirksamen Verbindungen N‐Methyl‐N‐(3‐n‐butanol‐1‐benzoesäureester)‐β‐aminobuttersäuremethylester und N‐(3‐n‐Butanol‐1‐benzoesäureester)‐β‐aminobuttersäuremethylester hergestellt.
Über die Papaverrubine A und E. 4. Mitt.: Rotfärbungsalkaloide der Gattung Papaver
Authors: Pfeifer S. , Banerjee S. K.
Published: October 2006

Es werden Isolierung und Eigenschaften der Papaverrubine A und E aus Papaver rhoeas L. beschrieben. Im Hinblick auf das allgemeine chemische Verhalten und auf Grund von Untersuchungen zur Rotfärbungsreaktion muß eine große strukturelle Ähnlichkeit dieser Stoffe mit dem aus Opium isolierten Porphyroxin bestehen.
Acyl‐tetrahydro‐homophthalsäureanhydride. 3. Mitt. über Acylderivate methylenaktiver Dicarbonylverbindungen
Authors: Schnekenburger J.
Published: October 2006

5,6,7,8‐Tetrahydro‐homophthalsäureanhydrid läßt sich in Gegenwart von N,N‐Dimethylanilin durch Carbonsäurechloride zu Enolestern von 4‐Acyl‐5,6,7,8‐tetrahydrohomophthalsäureanhydriden, in Gegenwart von Pyridin durch Chloride aliphatischer Carbonsäuren zu 4‐Acyl‐5,6,7,8‐tetrahydro‐homophthalsäureanhydriden acylieren. Die Umsetzung mit Chloriden aromatischer Carbonsäuren führt in Gegenwart von Pyridin zu neutralen stickstoff‐haltigen Verbindungen. 4‐Aroyl‐5,6,7,8‐tetrahydro‐homophthalsäureanhydride lassen sich durch pyridinkatalysierte Partialhydrolyse ihrer Enolester darstellen.
Spektroskopische Untersuchungen über die Struktur der Acylderivate von methylenaktiven Dicarbonsäureanhydriden. 5. Mitt. über Acylderivate methylenaktiver Dicarbonylverbindungen
Authors: Schnekenburger J.
Published: October 2006

Die Struktur einer Reihe von 4‐Acyl‐homophthalsäureanhydriden (1) sowie deren Enolestern (2) und Enoläthern (3) wurde mit Hilfe von UV‐ und IR‐Spektren untersucht. Die Substanzen (1) liegen im festen Zustand als 4‐Acyl‐3‐hydroxy‐isocumarine, in Lösung als α‐substituierte 4‐Hydroxymethylenhomophthalsäureanhydride vor. Die Substanzen (2) besitzen die Struktur von α‐substit. 4‐Acyloxymethylen‐homophthalsäureanhydriden mit cis‐Stellung von Enolester‐ und Carbonylgruppe. Von den beiden cis‐trans‐isomeren Enolbenzoaten des 4‐Benzoyl‐homophthalsäureanhydrids enthält das hauptsächlich gebildete gelbe Isomer die cis‐, das daneben in geringer Menge anfallende farblose Isomer die trans‐Stilbengruppierung. Die Substanzen (3) können sowohl als Derivate der kristallinen Form als auch der in Lösung überwiegenden Form erhalten werden.
Über die Autoxydation und fermentative Oxydation des Hämatoxylins
Authors: Frömming K.‐H. , Heinrichs U.
Published: October 2006

Bei der fermentativen und nichtfermentativen Oxydation von Hämatoxylin (I) entsteht als erstes isolierbares Oxydationsprodukt Hämatein (II). Als primäres Oxydationsprodukt bildet sich bei der fermentativen Oxydation jedoch das o‐Chinon VI oder VII, das sich in einem nichtfermentativen Prozeß in das stabilere, energieärmere II umwandelt; II stellt nicht das Endprodukte der Oxydation dar.
Die basischen Inhaltsstoffe des Aronstabes (Arum maculatum L.)
Authors: Stahl Egon , Kaltenbach U.
Published: October 2006

Aus frischen Blättern von Arum maculatum L. wurde eine wasserdampfflüchtige Basenfraktion gewonnen. Sie enthielt neben Nikotin (0,7 mg/kg Frischdroge) Spuren eines weiteren Alkaloids und größere Mengen von Äthyl‐, Isobutyl‐ und Isoamylamin. Nichtflüchtige Alkaloide waren in der Droge nicht nachweisbar, wohl aber nichtflüchtige prim. Amine in Spuren.
Zur Stereochemie der katalytischen Hydrierung von Dihydroxybenzolen
Authors: Zymalkowski F. , Strippel G.
Published: October 2006

Zweiwertige Phenole und Cyclohexandione werden mit Rh/Al2O3 und Rh/Pt unter Normalbedingungen glatt zu Cyclohexandiolen hydriert. Diese fallen als cis/trans‐Isomerenpaare an, deren gaschromatographische Analyse beschrieben wird. Der sterische Verlauf der Hydrierungen läßt sich durch Änderung des Wasserstoffdruckes variieren. Die Ergebnisse werden diskutiert.
Der Einfluß von Lösungsmitteln auf den Verlauf der Reduktion Schiffscher Basen mit aktiviertem Aluminium
Authors: Schönenberger H. , Thies H. , Rappl A.
Published: October 2006

Bei der Umsetzung von Benzylidenalkylaminen mit aktiviertem Aluminium in Äthanol entstehen Gemische aus Benzylalkylaminen und N,N′‐Dialkyl‐α,α′‐diphenyläthylendiaminen in einem Verhältnis, das durch das Mengen‐verhältnis Benzylidenalkylamin: Äthanol bestimmt wird. Die Verdünnung des Reaktionsansatzes mit indifferenten Lösungsmitteln (Toluol, Ligroin) führt zu keiner Veränderung der Ausbeute, ein Zusatz von basischen Verbindungen (Dioxan, Triäthylamin) fördert die Bildung des N,N′‐Dialkyl‐α,α′‐diphenyläthylendiamins. Es wird angenommen, daß konkurrierende Adsorptions‐ und Desorptionsgleichgewichte von Basen‐ und Äthanolmolekeln an der Aluminiumoberfläche für diese Vorgänge ausschlaggebend sind.
Zur Kenntnis der Vitalischen Farbreaktion. 1. Mitt.: Über β‐Eliminierungen mit Carbanion‐Zwischenstufen
Authors: Schwenker G.
Published: October 2006

In der Vitalischen Farbreaktion entsteht beim Eindampfen von Atropin (I) mit HNO3 neben nichtnitrierten Verbindungen der 4‐Nitroatropin‐salpetersäureester (V). Außerdem wird stets auch 4‐Nitroapoatropin (VI) gefunden, das wahrscheinlich sekundär aus V durch β‐Eliminierung von HNO3 entsteht. Sowohl V als auch VI geben mit Basen die charakteristische blauviolette Farbe.

Es wird nachgewiesen, daß es sich bei der farbigen Verbindung um ein mesomeriestabilisiertes Anion handelt, das in einem β‐Eliminierungs‐Additionsgleichgewicht die Rolle einer Zwischenstufe spielt. Die verwendete Base dient dabei als Nucleophil, außer HO− können auch andere Anionbasen genügender Nucleophilie, wie CN− oder C3H7S− Verwendung finden. Die Additionsprodukte der konjugierten Säuren der letzteren an VI wurden isoliert.

Die bis zur Erreichung eines Gleichgewichts ablaufende β‐Eliminierung folgt dem E 1 cB‐Mechanismus, dessen Nachweis bisher nur in Ausnahmefällen und der extrem kurzen Lebensdauer der Anionen wegen nur indirekt gelang. Die unter den Bedingungen der Farbreaktion in hoher Konzentration vorliegenden Anionen haben dagegen eine beträchtliche Lebensdauer und sind wegen ihrer im sichtbaren Spektralbereich liegenden Lichtabsorption bequem nachzuweisen und quantitativ zu verfolgen.
Zur Chemie und Pharmakologie der Alkaloide Damascenin und Arecolin 1. Mitt.: Beiträge zur Synthese von Damascenin und Damasceninhomologen
Authors: Mutschler E.
Published: October 2006

Ausgehend von der 3‐Methoxybenzoesäure wurde eine verbesserte Damasceninsynthese gefunden: 3‐Methoxy‐benzoesäure wird mit Methanol und HCl‐Gas verestert, der Ester bei Temperaturen von etwa —10° in Acetanhydrid mit konzentrierter Salpetersäure nitriert und nach katalytischer Reduktion mit Raney‐Nickel mit Methyljodid methyliert. In Anlehnung an die Damasceninsynthese von Kaufmann und Rothlin wurde der 3‐Äthoxy‐2‐äthylamino‐benzoesäuremethylester hergestellt.
Amtsenthebung und Emigration Klassischer Phiologen
Authors: Ludwig Walther
Published: October 2006

A short description of the situation of Classical Studies in Germany in 1932/33 is followed by a survey on the Classical scholars who emigrated from Germany in the Thirties. 13 Classicists are discussed in more detail (E. Norden, F. Jacoby, P. Maas, P. Friedländer, E. Fraenkel, H. Fränkel, W. Jaeger, E. Kapp, R. Pfeiffer, G. Rohde, K. v. Fritz, R. Walzer, F. Solmsen). They emigrated into Switzerland, Turkey, and especially to England and the U.S.A. The impact they had on the Classical Studies of these countries, and the impact these countries had on their life and scholarship is being considered.
Die Emigration der Kulturwissenschaftlichen Bibliothek Warburg und die Anfänge des Universitätsfaches Kunstgeschichte in Großbritannien
Authors: Wuttke Dieter
Published: October 2006

Aby M. Warburg (1866‐ 1929) the famous art historian, critic and great promoter of cultural history collected a unique research library which became a semiofficial part of the newly founded University of Hamburg called „Kulturwissenschaftliche Bibliothek Warburg”︁ in 1920. At the end of 1933 this library and its staff left Germany in order to prevent the Nazis from destroying this Jewish foundation. Great Britain gave home to it and at the end of 1944 London University incorporated the library now named The Warburg Institute. The Warburg Institute efficiently helped to promote art history as an academic discipline in Great Britain though its actual aims are of interdisciplinary nature and go far beyond art history as it has been the case since the days of Warburg.
Verzeitlichungs‐ und Historisierungstendenzen in der frühen Geologie und Paläontologie
Authors: Langer Wolfhart
Published: October 2006

Steno described in 1669 geological sections which were interpreted as the result of a series of earlier events. Steno used actuogeological methods. This was the first step towards temporalizing nature. Steno was succeeded by a lot of other researchers from different European countries. It is amazing to see, that “actualism” was widespread during the 18th century. The next step was the discovery that fossils are extinct beings (Ray, Hooke and others). Using methods of comparing anatomy W. Hunter (forerunner of Cuvier) could prove in 1769 that the Mastodon is an extinct vertebrate. The work of Soulavie in France (1780) is stressed. He held in his hand the key for solving the problem of index‐fossils. About 1800 the importance of fossils for stratigraphy and describing a history of the earth was recognized. Theories and hypotheses were needed to explain the fossil documents (strange shells in older strata and higher developed mammals in younger strata). All these theories couldn't propose a feasible mechanism for the change of beings during the history of the earth. But it could be said, that all fossils proove a history of life and the earth i. e. a progressive development in one sense, a development which is not reversible.
Stand und Perspektiven einer Geschichte der Pflanzenbauwissenschaft
Authors: Böhm Wolfgang
Published: October 2006

Die Einsicht, daß das Studium jeder Wissenschaft ohne Kenntnisse deren Geschichte nur ein unvollständiges Studium sein kann, hat in den letzten Jahren deutlich zugenommen. Unter den Agrardisziplinen dokumentiert jetzt auch die Pflanzenbauwissenschaft dieses neue Denken. Zum ersten Male seit dem Ende des Ersten Weltkrieges liegen in Deutschland wieder pflanzenbauliche Hochschullehrbücher vor, in denen der Geschichte der eigenen Fachdisziplin ein kurzes Kapitel gewidmet ist1.
Sarton, Science, and the End of History
Authors: Meinel Christoph
Published: October 2006

Ausgehend von der Frage George Sartons nach der Bedeutung von Auschwitz und Hiroshima für die Geschichte der Wissenschaften soll hier der Versuch unternommen werden, die Geschichte der Naturwissenschaften und der Technik einmal von ihrem möglichen und mit naturwissenschaftlich‐technischer Perfektion herbeiführbaren Ende her zu bedenken: dem atomaren, biologischen und chemischen Holokaust, der, in Perversion, dann den vollständigsten Triumph über die Natur bedeutete, den Wissenschaft und Technik erringen könnten. Muß daher die Geschichtsschreibung der Naturwissenschaften, wenn sie glaubwürdig und aufrichtig bleiben will, nicht um historiographische Ansätze und Urteile bemüht sein, die sich, wenn denn das Ende politisch und technisch schon jetzt erreichbar ist, auch angesichts solcher Perspektive verantworten lassen?.
Theophrast über Pflanzenkrankheiten. Ein Beitrag zur Geschichte der Phytopathologie in der Antike
Authors: Wöhrle Georg
Published: October 2006

Already before Theophrastus there was a botanical literature which also dealt with the diseases of plants, but we have only indirectly access to it — mainly by way of Theophrastus. The botanical excursus of the Hippocratic series of writings De genitura, De natura pueri, De morbis IV, which attributes the health of plants to a balance of warmth and cold and a correct quantity of specific humidity, forms an exception. This excursus hints at what is more fully developed in Theophrastus discussion of the diseases of plants: The diseases of plants are understood in close analogy to those of animals or human beings. In both cases, a basic distinction is made between inner, dietetic diseases and outer, traumatic ones. According to Theophrastus, especially humidity and an innate warmth are life‐sustaining factors. A disturbance of the natural humidity/warmth‐household must be counteracted by respective measures. As far as the terminology of plant diseases is concerned, Theophrastus relies on already existing concepts. Classical literature after Theophrastus has made no substantial contributions to phytopathology.
Der Begriff der Naturgeschichte nach J. F. Blumenbach anhand seiner Korrespondenz mit Jean‐André DeLuc. Ein Beitrag zur Wissenschaftsgeschichte bei der Entdeckung der Geschichtlichkeit ihres Gegenstandes
Authors: Dougherty F. W. P.
Published: October 2006

Article withdrawn at the request of the author's representative.
Das Problem der “entscheidenden Experimente”
Authors: Kaiser Walter
Published: October 2006

In this historical essay an attempt is made to discuss the problem of decisive experiments both from the point of view of History of Science and of Philosophy of Science. The first part deals with Francis Bacon's idea of instantiae crucis and with the use of the term experimentum crucis mainly in optics. With respect to the experimental confirmation of Maxwell's electrodynamics the Duhem‐Quine Thesis is discussed. Duhem had argued that not a single hypothesis but only a complete theory is examined by experiment. So a single experiment neither can prove nor can disprove a single hypothesis. With regard to Bucherer's and Neumann's data concerning the velocity‐dependence of the electron's mass the question of the certainty of conclusions arising from experimental tests is treated. In the last parts the really historical problem of the decisive experiments is considered, namely the gap between the context of design of an experiment and the context of evaluation of an experiment in retrospect. The examples here are the Michelson‐Morley experiment, the Franck‐Hertz experiment, and the Compton‐Effect. In the conclusion parity violation is discussed. Perhaps due to the possibility of a single alternative in theory and an unambiguous result of the experiment this test really was crucial. In general, however, the experimentum crucis will prove to be a very seldom event.
Amateurs and the Rise of Astrophysics 1840–1910
Authors: Hufbauer Karl
Published: October 2006

This essay examines the role of amateurs in founding the astronomical subdiscipline of astrophysics. During 1840–1870, they initiated many of the observing programs that came to comprise the new specialty. And during 1870–1910, they participated both in the ongoing research of the field and the campaign to provide it with an institutional base. These general trends are illustrated by examples from the lives of ten prominent amateur solar physicists.
Synthesis of N‐phenyl‐2‐[1,4,5,8‐14C]naphthylamine, N‐phenyl‐2‐[8‐13C] naphthylamine, and N‐[U‐14C]phenyl‐2‐naphthylamine
Authors: Walker G H , Hathway D E
Published: October 2006

N‐Phenyl‐2‐naphthylamine has been synthesized (1) with 14C in positions 1, 4, 5 and 8, (2) with 13C in position 8 (small amounts of [1‐13C] naphthalene and 2‐[8‐13C]naphthylamine are formed as by‐products), and (3) with the N‐phenyl nucleus uniformly labelled with 14C.
Isotopic exchange in heterocyclic quaternary salts. II. (1) Hydrogen‐deuterium exchange ln active c‐methyl groups
Authors: Bologa Margareta , Barabás A. , Dénes Viorica I. , Chiraleu F.
Published: October 2006

The non‐catalysed H‐D exchange in heterocyclic quaternary ammonium salts (1–3) was studied by1H‐nmr. Exchange occurs only at the C‐CH3group, at a rate decreasing in the order X = C(CH3)2, Se, CH=CH, S, NCH3. In substituted benzothiazolium salts the exchange rates decrease in the series Y = NO2, Cl, H, OCH3. Chemical shifts (δ) of C‐CH3and N‐CH3groups decrease in the same sequence. Both exchange rate constants and chemical shifts can be related ta Hammett σp‐ values of the Y substituents. The mechanism p of the exchange reaction is briefly discussed.
The synthesis of dimethoxymethyl phenobarbital labeled with 14C
Authors: Wang Theodore S. T.
Published: October 2006

Dimethoxymethyl phenobarbital (DMMP), labeled with 14C on the ring and side chains was prepared for drug metabolism studies. The synthesis of DMMP‐ethyl‐1–14C (4a) in four steps provided a 43% yield from ethyl‐1–14C iodide. The yields of DMMP‐2–14C (4b) and DMMP‐dimethylene‐14C (4c) were 87.5% and 30% respectively.
Synthesis of high specific activity tritium‐labelled dotriacontane
Authors: Houseman T. H. , Binns S. H. , Phillips K.
Published: October 2006

The tobacco smoke particulate phase marker dotriacontane was labelled with tritium at positions 15, 16, 17 and 18 by the catalytic reduction of dotriaconta‐15, 17‐diyne. This was obtained by oxidatively coupling hexadec‐1‐yne, in turn prepared by reaction of monosodium acetylide with myristyl bromide.
Synthesis of 14C‐labelled 4‐chloro‐3‐sulfamoyl‐N‐(3aα,4α,5,6,7α,7aα‐hexahydro‐4,7‐methano‐isoindolin‐2‐yl)‐benzamide
Authors: Nakamura Takaharu , Hamano Sachiyuki , Horie Tohru
Published: October 2006

14C‐Labelled compound of antihypertensive 4‐chloro‐3‐sulfamoyl‐N‐(3aα, 4α, 5, 6, 7α, 7aα ‐hexahydro‐4, 7‐methano‐isoindolin‐2‐yl) ‐benzamide (IV) was synthesized for biotransformation studies in three steps with p‐chlorobenzoic acid‐carbonyl‐14C (I) as the labelled starting material.
Synthesis of [14C]labelled pyrano[3,4‐b]‐and thiopyrano[3,4‐b]indoles, and indeno[2,1‐c]pyran derivatives
Authors: Ferdinandi E. S. , Hicks D. R. , Verbestel W. , Raman P.
Published: October 2006

The synthesis of four structurally similar [14C]labelled compounds having a novel heterocylic ring system is described. Three compounds with a tetrahydropyrano (or thiopyrano) indole nucleus were prepared from suitably substituted [14C]tryptophols and were labelled in the pyrano or thiopyrano ring. The preparation of the [14C]tryptophol intermediates from the appropriate gramine is described. The synthesis of the fourth compound, a tetrahydroindenopyran derivative labelled in the indene nucleus, involved a novel preparation of [14C]indene.
Preparation Du Dihydro Lanosterol (3H)‐24,25 (Note De Laboratoire)
Authors: Nicolas A. , Bascoul J. , de Paulet A. Crastes , Pichat L.
Published: October 2006

24,25‐3H dihydro lanosterol is obtained by catalytic reduction of lanosterol with tritium at atmospheric pressure. Its specific activity is 23 Ci/mMole. Natural lanosterol impurities do not disturb the synthesis.
L‐carboranylalanine substituted TMV, a highly boron labeled virus as a model for slow neutron therapy of tumors
Authors: Escher E. , Leukart O. , Kriwaczek V. M.
Published: October 2006

The use of the newly synthesized 10‐boron atoms containing amino acid L‐o‐carboranylalanine (Car) as a useful tool in slow neutron therapy of tumors is proposed and its attempted application with a Car‐substituted Tobacco mosaic virus (TMV) is described and discussed. Also the synthesis of 10B‐enriched decaborane as a precursor of Car is described.
17,18‐tritium labeled prostaglandins
Authors: Hsi Richard S. P.
Published: October 2006

The triple bond in 3α,5α‐dihydroxy‐2β‐(3α‐hydroxy‐trans‐1‐octen‐5‐ynyl)‐lα‐cyclopentylacetic acid γ‐lactone bis‐2‐tetrahydropyranyl ether (I) was reduced with tritium gas in the presence of tris‐(triphenylphosphine) ‐rhodium chloride to give 3α,5α‐dihydroxy‐2β‐(3α‐hydroxy‐5,5,6,6‐tetratritio‐trans‐l‐octenyl)‐lα‐cyclopentylacetic acid γ‐lactone (II). The diol‐lactone II was converted in five steps via modified Corey synthesis to prostaglandin E2‐17,18‐3H4 (VI). Reduction of VI gave prostaglandin E1‐17,18‐3H4 (VII) and its 13,14‐dihydro (VIII) and 13,14‐dihydro‐15‐dehydro (IX) derivatives. The prostaglandin E's were dehydrated to afford the corresponding tritium labeled prostaglandins A2 (X) and A1 (XI).
Synthese von 1,1′‐hexamethylen‐bis‐[5‐(4‐chlor[2(N)‐3H]‐phenyl)‐biguanid]‐digluconat (3H‐chlorhexidin‐digluconat)
Authors: Drahowzal Franz A. , Wiesinger Franz
Published: October 2006

3H‐Chlorohexidine dihydrochloride is obtained from the reaction of 1,6‐hexamethylendiamin dihydrochloride with 4‐chloro [2(n)‐3H] phenyl dicyandiamide. The later has resulted from condensation of 4‐chloro[2(n)‐3H] anilin with dicyandiamide. By hydrogenation of 4‐chloro‐2‐jodoanilin with gaseous tritium the 4‐chloro[2(n)‐3H] anilin is formed.
Synthesis of 6‐(Nα‐acetyl‐lysyl)‐11‐norleucine‐substance P‐(6–11)‐hexapeptide labelled with tritium on the phenylalanine residue in position 7
Authors: Bienert M. , Niedrich H. , Teplán I. , Medzihradszky K.
Published: October 2006

Nα‐Ac‐Lys‐(Phe‐4‐3H)‐Phe‐Gly‐Leu‐Nle‐NH2, a modified Substance P fragment with full activity on smooth muscle has been prepared by catalytic tritiation of the corresponding precursor peptide containing p‐chlorophenylalanine in position 7. The precursor peptide has been synthesized by stepwise couplings from the C‐terminal end, using t‐butyloxycarbonyl‐amino acid 2,4,5‐trichlorophenyl esters. The specific radioactivity of the tritiated product obtained was 23 Ci/mmole.
A convenient synthesis of creatine‐15N from glycine‐15N via sarcosine‐15N
Authors: Greenaway W. , Whatley F. R.
Published: October 2006

The preparation of creatine‐15N monohydrate from glycine‐15N with the isolation of sarcosine‐15N as an intermediate is described. Glycine‐15N (97.3 atom% 15N) is converted to benzenesulphonyl glycine‐15N, which is methylated to give benzenesulphonyl sarcosine‐15N. The latter is hydrolysed to sarcosine‐15N, which is isolated by ion exchange chromatography. Sarcosine‐15N is converted to creatine‐15N monohydrate by reaction with cyanamide in aqueous solution in the presence of sodium chloride and catalytic amounts of ammonium hydroxide‐14N. The creatine‐15N monohydrate precipitated from the above reaction mix is recrystallized from boiling water. The yield of sarcosine‐15N from glycine‐15N is 78% of theory and that of recrystallized creatine‐15N monohydrate from glycine‐15N is 59% of theory.
Synthesis of 14C‐labeled 2,4,2,′5′‐tetrachlorobiphenyl
Authors: Moriya Takashi
Published: October 2006

A synthetic procedure for 2,4,2,′5′‐tetrachlorobiphenyl‐1,2,3,4,5,6‐14C6 is presented. 2,4‐Dichloroaniline‐14C6 was prepared in 46.7% yield from benzene‐14C6 via m‐dinitrobenzene‐14C6, m‐dichlorobenzene‐14C6 and 2,4‐dichloronitrobenzene‐14C6. 2,4‐Dichloroaniline‐14C6 was coupled with p‐dichlorobenzene to produce 14C‐labeled tetrachlorobiphenyl. The yield was 21% based on 2,4‐dichloroaniline‐14C6.
Unnatural nucleosides and nucleotides. III. Preparation of 2‐14C and 4‐14C labelled 5‐alkyluracils and 5‐alkyl‐2′‐deoxyuridines
Authors: Szabolcs A. , Kruppa G. , Sági J. , Ötvös L.
Published: October 2006

2‐14C Labelled 5‐alkyluracils were prepared by condensation of the diethylacetals of α‐formyl‐carbonic acid esters with 14C‐thiourea. Compounds labelled at 4‐C were synthesized by condensation of the labelled carboxylic acid derivatives with thiourea.

β‐Anomers of 5‐alkyl‐2′‐deoxyuridines were obtained in a fairly good radiochemical yield. Alkyl substituents ranged from methyl to tetradecyl, isopropyl and tertbutyl.
Synthesis of 123I‐labelled 4‐iodo‐2, 5‐dimethoxyphenylisopropylamine
Authors: Braun Gisela , Shulgin Alexander T. , Sargent Thornton
Published: October 2006

A rapid and convenient synthesis of the psychotomimetic agent 4‐iodo‐2, 5‐dimethoxyphenylisopropylamine is described, incorporating the radioisotope 123I (T1/2 13 hr). With the amine function of 2, 5‐dimethoxyphenylisopropylamine blocked as the phthalimide, it was found that the aromatic 4‐position could be directly iodinated with iodine monochloride. The phthalic acid moiety was rapidly removed with hydrazine in butanol to provide the title compound, as the hydrochloride salt, in an overall yield of 10% and in a reaction time of less than one half‐life.
Synthesis of deuterium labelled 2,2‐dimethoxypropanes
Authors: Creer Michael H. , Herold David A. , Elwood Thomas A. , Futrell Jean H.
Published: October 2006

A method of preparing two 2,2‐dimethoxypropanes‐d6 is described.
Synthesis of 14C labelled drotaverinum hydrochloride
Authors: Koltai E. , Bánfi D. , Engler J. , Volford J. , Mészáros Z.
Published: October 2006

Drotaverinum hydrochloride was labelled with 14C isotope in position 1 of the isoquinoline ring. A rapid synthesis with high radiochemical yield was elaborated.
Synthesis of α‐acetoxy‐n‐nitroso‐4[3H]‐pyrrolidine
Authors: Saavedra Jose E. , Hecker Lanny I. , Farrelly James G.
Published: October 2006

Tritium labeled α‐acetoxy‐N‐nitroso‐4[3H]‐pyrrolidine 3, an important model compound used in the study of the metabolism of nitrosopyrrolidine, has been prepared from commercially available 4[3H]‐l‐proline. The synthesis involves two steps; first the nitrosation of the aminoacid to N‐nitroso‐4[3H]‐l‐proline 2, followed by the oxidative decarboxylation with lead tetraacetate in dicloromethane with 1.2 equivalents of pyridine to α‐acetoxy‐N‐nitroso‐4[3H]‐pyrrolidine in 23% overall yield. The compound was further purified by HPLC.
Synthesis, chromatography and tissue distribution of methyl‐11c‐morphine and methyl‐11C‐heroin
Authors: Kloster G. , Machulla H.‐J. , Röder E.
Published: October 2006

11C‐Morphine was prepared by methylation of normorphine with 11CH3I. Acetylation of this compound yields heroin. The radiochemical yield is 9% for morphine and 4% for heroin at a specific activity of 1.63 mCi/μmole. Synthesis time including purification by hplc is 18 min for 11C‐morphine and 36 min for 11C‐heroin, respectively. The tissue distribution of both these compounds was determined in rats at different times after an i.v. injection. The main accumulation of activity is in the small intestine, followed by kidney and liver. Little activity was detected in the brain.
The synthesis of [14C] ‐labelled haloperidol and [d4]‐and [d8] haloperidol
Authors: Fellows I. , Harrow T. A. , Honeyman R.
Published: October 2006

The synthesis Of[14C] haloperidol for use in metabolism studies, and the synthesis Of[d4]‐and[d8] haloperidol for use in bioavailability studies, is described.
Synthesis of osseous specific 32P‐labeled disodium ethane‐1‐hydroxy‐1,1‐diphosphonate
Authors: McCreary Lionel D. , Tofe Andrew J. , Francis Marion D.
Published: October 2006

High specifie activity 32P‐Iabeled disodium ethane‐1‐hydroxy‐1,1‐diphosphonate has been prepared for specific use as a radiotherapeutic ameliorative treatment of osseous tumors by reacting 32P‐labeled phosphorus trichloride, acetic acid and water. This compound has been purified by crystallization of the disodium salt from a water‐ethanol solution. Product identity and purity were established by reverse isotope dilution analysis. Spectrochemical quantitation, thin layer chromatography, radionuclide beta energy and half‐life determinations are presented as essential procedures for establishing chemical and radiochemical purity when human distribution studies are planned.
Tritium and deuterium exchange‐labeling of aromatic and organometallic compounds in heptafluorobutyric acid
Authors: Hanzlik Robert P. , Wiley Robert A. , Gillesse Timothy J.
Published: October 2006

The use of heptafluorobutyric acid (HFBA) as a solvent/reagent for tritiation (or deuteration) or aromatic organic and organometallic compounds is described. Typically the substrate (0.1–1 mmole) and tritium oxide (5–25 μl, 5 Ci/g) are dissolved in 0.3–1 ml HFBA and heated at 130–145° for 4–7 days. Aromatic compounds bearing electron‐donating substituents are tritiated much more readily than those bearing electron withdrawing substituents. Substrate decomposition was minimal, and good to excellent yields of relatively pure tritiated materials are obtained simply by cooling, neutralization, and extraction. Detailed studies of deuterium exchange in HFBA‐d under analogous conditions are also reported.
Synthesis of some unsymmetrically deuterated cyclohexanols
Authors: Stibbe W. , Schrumpf G.
Published: October 2006

The preparations of [1,2,2,3,3,6,6‐D7]Cyclohexanol, and of two isotopameric [1,2,2,3,4,5,5,6,6‐D9]Cyclohexanols are described. The isotopic purity of the deuterium labeled cyclohexanols is better than 90 %.
Determination of tritium or deuterium in the methyl group of labeled organic compounds
Authors: Valentekovic D. , Hirwe N. S. , Nystrom R. F.
Published: October 2006

The determination of the isotopic content of C‐methyl groups in selected tritium and deuterium labeled compounds by modification of the Kuhn‐Roth method is presented. Oxidation of the deuterated or tritiated compound using a solution of sodium dichromate and sulfuric acid at 50–85°C allows isotopic assay of the C‐methyl group as acetic acid.
An efficient and convenient synthesis of 5‐(3,3‐dimethyl‐14C‐1‐triazeno)‐imidazole‐4‐carboxamide
Authors: Farquhar D. , Benvenuto J. A. , Loo Ti Li
Published: October 2006

Reaction of dimethylamine‐14C with a four‐fold molar excess of 5‐doazoimidazole‐4‐carboxamide in methanol followed by column chromatography of the product on basic alumina afforded 5‐(3,3‐dimethyl‐14C‐1‐triazeno)imidazole‐4‐carboxamide in 70–75% yield and greater than 99.9% radiochemical purity. The preparation is suitable for chemical and biological mechanistic studies.
An improved method of preparation of potassium cyanide‐14C
Authors: Perry Clark W. , Burger Walter , Delaney Charles M.
Published: October 2006

A safe procedure for the conversion of barium carbonate‐14C to potassium cyanide‐14C on a 6–7 mmol scale in 90–98% yield was developed. Barium carbonate 14C was heated with excess potassium azide in a matrix of sand without added potassium metal, allowing safe, rapid and convenient recovery of the cyanide.
Syntheses de Phenyl‐2 Oxetannes marques au Deuterium et AU13C
Authors: Schaal C. , Ricard M.
Published: October 2006

Five mono, di, tri and pentadeuterated 2‐ phenyloxetanes were prepared either by tosylation and cyclisation of the corresponding 2‐phenyl propanediol (mono, di, tri, pentadeuterated) or from the benzoyl ethylacetate by exchange under acid conditions. The 2‐phenyloxetane 13C was synthesized from benzaldehyde 13C.
The synthesis of deuterium labelled analogues of a novel antidiarrhoeal agent, 2‐[ 3,3‐diphenyl‐3‐(2‐methyl‐1,3,4‐oxadiazol‐5‐yl) propyl] ‐2‐azabicyclo[2,2,2] octane
Authors: Buckley P. H. , Dickens J. P. , Harrow T. A. , Honeyman R.
Published: October 2006

The synthesis of three deuterated analogues[d4, d6 and d9] of the novel antidiarrhoeal agent 2‐[3,3‐diphenyl‐3‐2‐methyl‐1,3,4‐oxadiazol‐5‐yl) propyl]‐2‐azabicyclo[2,2,2]octane is described. The compounds prepared were of high isotopic purity and were used in metabolism and bioavailability studies.
The preparation of Nτ‐ [3H]methylhistamlne dihydrochloride and Nτ‐methyl[α,β,2,4,5‐14c5]histamlne dihydrochloride
Authors: Knight R. I. , Morecombe D. J. , Saunders D. , Smith I. R.
Published: October 2006

In order to study some aspects of the central metabolism of histamine we have prepared Nτ‐ [3H]methylhistamine dihydrochloride from [3H]methyl iodide by chemical synthesis and Nτ‐methy[α,β,2,4,5‐14C5]histamine dihydrochloride from [α,β,2,4,5‐14C5]histamine dihydrochloride by an enzymatic method.
Syntheses with stable isotopes: DL‐valine‐13C3
Authors: Whaley T. W. , Kerr V. N. , Lyle T. A. , Daub G. H. , Olsont E. S.
Published: October 2006

The synthesis of DL‐2‐amino‐3‐methyl‐13C‐butanoic‐3,4‐13C3 acid (DL‐valine‐13C3) is described. Acetonitrile‐2‐13C was converted to 2‐methyl‐13C‐2‐thiazoline, which was dialkylated with methyl‐13C iodide to give 2‐(isopropyl‐13C3)‐2‐thiazoline. Subsequent reduction and hydrolysis of the isopropylthiazoline afforded 2‐methyl‐13C‐propanal‐2,3‐13C2, which was isolated as the bisulfite addition product. A modified Strecker synthesis with the bisulfite compound gave DL‐valine‐13C3 in good overall yield.
Marquage par le 14C du Chlorhydrate de Diphenyl Acetate de NN Diethyl Amino‐2 Ethyle ou Adiphenine
Authors: Madelmont Jean‐Claude , Michelot Josette
Published: October 2006

L 'adiphénine a été marquéé en deux positions par 14C ‐ sur la partie éthanol amine par l'intermédiaire d'éthanolamine 14C ‐ sur le groupe carboxyle à l'aide de dioxyde de carbone 14C.
Tritium labelling of morpholine on gamma‐irradiated silica gel
Authors: Crossley P. C. , Hannan S. F. , Odell A. L.
Published: October 2006

The use of gamma‐irradiated silica gel to promote exchange between tritium gas and carbon‐bound hydrogen has been previously described.(1,2,3) The suitability of this method for labelling molecules containing labile as well as carbon‐bound hydrogen has not hitherto been reported.

The labelling of morpholine to facilitate its use as a weak base indicator as part of a study of intracellular pH(4) afforded an opportunity to test the suitability of gamma‐irradiated silica gel as a labelling reagent.
Synthesis of (1‐14C)valine
Authors: Meesschaert B. , Adriaens P. , Eyssen H.
Published: October 2006

The method for the synthesis of DL‐(1‐14C)valine (reaction of ethyl N‐(1‐phthalimido)‐isobutyl‐1‐carbamate with K14CN in ethyl alcohol, followed by acidic hydrolysis of the labelled nitrile) reported by Egyed et al. (Acta Chim. Hung. 38: 123, 1963) was studied. The yield of valine could be increased to 75‐80 % by using dry isopropyl alcohol and extending the hydrolysis with hydrochloric acid‐acetic acid to 36 hours. This is better than or comparable to the yields obtained with the Strecker or Bucherer methods. Since the replacement of the phthalimido ring with cyanide proved to be of the SN1 type, a stereospecific synthesis of L‐ or D‐(1‐14C)valine was not possible.
Synthesis of 21‐[82Br]‐21‐deoxyuridine
Authors: Lee Y. W. , Knaus E. E. , Wiebe L. I.
Published: October 2006

Reaction of 2,21‐anhydrouridine (2) with [82Br]‐ammonium bromide in the presence of one equivalent p‐toluenesulfonic acid afforded 21‐[82Br]‐21‐deoxyuridine (3) in 73.4% chemical yield with a specific activity of 0.58 mCi mM−1. Alternatively, direct activation of 21‐bromo‐21‐deoxyuridine at a thermal neutron flux of 1 × 1012n cm−2s−1 gave 21‐[82Br]‐21‐deoxyuridine, with a specific activity of 0.6‐0.7 mCi mM−1 for a 3 hr irradiation. 21‐[82Br]‐21‐deoxyuridine was rapidly purified by high pressure liquid chromatography with an elution time of 18 minutes, or by preparative thin layer chromatography.
Preparation of carbon‐14 labelled mecarbam (O,O‐DI‐[1‐14c]‐ethyl s‐[N‐ethoxycarbonyl‐N‐methylcarbamoylmethyl] phosphorothiolothionate)
Authors: Hudson H. R. , Pianka M. , Powroznik L. , Lynch V. P.
Published: October 2006

O,O‐Vi‐ [1‐14C]‐ethyl S‐ [N‐ethoxycarbonyl‐N‐methylcarbamoylmethyl] phosphorothiolothionate has been prepared with a specific activity of 1.97 mCi mmol−1. The procedure involved the interaction of [1‐14C]‐ethanol with phosphorus pentasulphide in benzene, followed by conversion of the so‐formed diethyl dithiophosphoric acid to its potassium salt and reaction of this with ethyl N‐chloroacetyl‐N‐methylcarbamate in acetone. G.l.c. analysis of the final product in benzene solution showed the purity to be not less than 97 %.
A convenient method for the specific tritium labelling of beta‐adrenoceptor antagonists
Authors: Arfwidsson Anders , Hallhagen Göran , Hoffmann Kurt‐Jürgen
Published: October 2006

The specific tritium labelling of beta‐adrenoceptor antagonists of the general structure ArOCH2CH(OH)CH2NHR is described. The tritium label is introduced in the 2‐position in the aminohydroxypropoxy side‐chain starting from ArOCH, an intermediate in the synthesis of the unlabelled compound. The key step is a reduction of the corresponding bromoketone ArOCH2COCH2Br using readily available sodium borohydride‐3H as the labelling reagent. The 2‐position has proven stable enough to be suitable for most biochemical applications, e.g. metabolic studies. Five examples are given, including alprenolol‐3H and metoprolol‐3H.
Synthesis of 5′, 5′‐Dideuterated nucleoside and nucleotide anabolites of 6‐Mercaptopurine
Authors: Jardine Ian , Weidner Mark M.
Published: October 2006

6‐Mercaptopurine riboside, 6‐methylmercaptopurine riboside, 6‐mercaptopurine riboside‐5′‐phosphate and 6‐methylmercaptopurine riboside‐5′‐phosphate were synthesized with 2 deuteriums in the ribose moiety at the 5′‐position so as to act as internal standards for the quantitation of these anabolites of 6‐mercaptopurine from biological media by gas chromatography‐selected ion monitoring mass spectrometry with chemical ionization.