bluuebunny/crossref_metadata_2025 huggingface dataset:
Peptidic hormone interactions at the molecular level‐preparation of highly labelled 3H oxytocin
Authors: Morgat J. L. , Hung Lam Thanh , Cardinaud R. , Fromageot P. , Bockaert J. , Imbert M. , Morel F.
Published: October 2006

The tritium labelling of oxytocin has been attained by a two step procedure. First, di‐iodo oxytocin is prepared. After a survey of various iodination reagents, ICI has been selected as it reacts much more rapidly with the tyrosyl ring than with the disulfide bridge, which under mild conditions remains unaffected. The di‐iodo derivative, nevertheless, has lost most or all of its biological activity. Catalytic substitution of the peptide bound iodine by tritium results in labelling the hormone and in restoration of the biological activity. The 3H oxytocin obtained retains 90 % of its hydrosmotic activity and about 65 % of its avian depressor activity. Its specific radioactivity reaches 36 Ci/mMole, a value allowing further studies of the hormone at a molecular level.
Preparation of some mercuri‐derivatives of fluorescein labelled with isotopes 197Hg or 203Hg. I. Study of preparation methods
Authors: Ratuský J. , Kronrád L. , Málek P. , Vavrejn B. , Kolc J.
Published: October 2006

A method for preparation of mercuri‐derivatives of fluorescein labelled by 197Hg or 203Hg from mercuric acetate and fluorescein has been described. Individual products formed in the reaction mixture were isolated with both paper chromatography and chromatography on alumina column. Their identification was carried out by determining the amount of mercury contained in individual chromatographic fractions. Polarographic observation of the overall mercurization reaction has shown that proceeds rather fast. Similar situation is also valid for exchange reaction between mercuricacetate‐203Hg and individual derivatives of fluorescein.
Preparation of some mercuri‐derivatives of fluorescein labelled with isotopes 197Hg or 203Hg. II. Study of conditions for optimum yield of individual fractions
Authors: Kronrád L. , Ratuský J. , Málek P. , Vavrejn B. , Kolc J.
Published: October 2006

The work is a continuation of the preceding study of possibilities for preparation of labelled derivatives of fluorescein. The conditions under which it is possible to get maximum possible yield of individual products from reaction mixture of mercuric acetate‐203Hg and fluorescein has been studied in detail. It has been found that the yield of derivatives with different mercury content depends to a great extent on the molar ratio of both reaction components. In the first, rapid step of mercurization approximately the same amount of all products is formed regardless of the molar ratio of reaction components. By heating the equilibrium is shifted in favour of the product corresponding to the given molar composition of reaction mixture. The detailed procedures for preparation of difluoresceinyl mercury‐203Hg and hydroxymercurifluorescein‐203Hg have been given.
Preparation of some mercuri‐derivatives of fluorescein labelled with isotopes 197Hg and 203Hg. III. Recoil‐labelling of derivatives
Authors: Kronrád L. , Ratuský J. , Málek P. , Vavrejn B. , Kolc J.
Published: October 2006

The possibility of preparation of mercuriderivatives of fluorescein labelled with 197 Hg by irradiation of the respective compounds in a nuclear reactor has been studied. For all investigated compounds, specific activity high enough could be obtained without any significant radiation decomposition. In cases, when the target molecule contained more than one target atom‐bis (hydroxymercurifluoresceinyl) mercury and bis (hydroxymercurifluorescein)‐higher enrichment factor for some products could be obtained. The recommended procedure for preparation of difluoresceinylmercury‐197 Hg by this method has been given.
Syntheses of 1‐O‐methyl‐14C‐DL‐myo‐inositol (methyl‐14C‐bornesitol) and 5‐O‐methyl‐14C‐myo‐inositol (methyl‐14C‐sequoyitol)
Authors: Shah R. H. , Loewus F.
Published: October 2006

1‐O‐ and 5‐O‐Methyl‐14C‐myo‐inositols (methyf‐14C‐bornesitol and ‐sequoyitol) were synthesized by methylation of appropriately blocked myo‐inositol derivatives with methyl = 14C iodide and potassium hydroxide. The benzyl blocking groups of 1‐O‐methyl‐14C‐3,4,5, 6‐tetra‐O‐benzyl‐DL‐myo‐inositol and 1,2,3,4, 6‐penta‐O‐benzyl‐5‐0‐methyl‐14C‐myo‐inositol were cleaved by hydrogenolysis catalyzed by palladium on carbon‐palladium chloride (5 : 1) to obtain the 1‐O‐ and 5‐O‐methyl‐14C‐myo‐inositols respectively.
Synthesis of L‐glutamine‐S‐14C, L‐glutamic acid‐5‐14C, and L‐ornithine‐5‐14C
Authors: Havránek Miloš , Kopecká‐Schadtová Hana , Vereš Karel
Published: October 2006

On alkylation of K14CN with the methyl ester of L‐α‐benzyl‐oxycarbonylamino‐γ‐bromobutyric acid, the methyl ester of L‐α‐benzyloxycarbonylamino‐γ‐cyano‐14C‐butyric acid (II) was obtained The latter was submitted to mild alkaline hydrolysis to yield the free nitrilo acid III which on treatment with hydrogen bromide solution in acetic acid gave L‐glutamine‐5‐14C in one reaction step. L‐Ornithine‐5‐14C was prepared by catalytic hydrogenation of the nitrilo ester II, and L‐glutamic‐5‐14C acid was obtained on acid hydrolysis of the same compound (II). The activated ester (2, 4, 5‐trichlorophenyl ester) of acid III may serve as a suitable intermediate for the preparation of glutamine or ornithine peptides. All prepared substances were optically active L‐forms.
Four syntheses incorporating carbon‐14 or tritium into trans‐1‐methyl‐1,4,5,6‐tetrahydro‐2‐[2‐(2‐thienyl)vinyl]pyrimidine (pyrantel, banminth®)
Authors: Figdor S. K. , Schach Wittenau M. Von , Faulkner J. K. , Monro A. M.
Published: October 2006

Labelled pyrantel, an anthelmintic agent, was required for metabolism studies in several animal species. Four labelled syntheses are described incorporating carbon‐14 or tritium into selected sites of the pyrantel molecule. The ultimate location of the marker in each synthesis was chosen in order to yield information about the metabolic breakdown patterns of pyrantel.
Synthesis of cholesterol‐20‐14C
Authors: Porto Ana M. , Gros Eduardo G.
Published: October 2006

Cholesterol‐20‐14C was synthesized in four steps from pregnenolone‐20‐14C. The labelled intermediates were proven to be cholest‐5‐ene‐3β, 20α‐diol acetate‐3, cholesta‐5, 20 (22)‐diene‐3β‐ol acetate, and cholesterol acetate by 1H‐n.m.r. spectroscopical analysis. Cholesterol‐20‐14C was obtained with a radiochemical purity exceeding 99%.
The synthesis and purification of 4‐[14C]‐ and 7α[3H]‐androsta‐4,16‐dien‐3‐one
Authors: Wilkinson M. , Coombs M. M. , Gower D. B.
Published: October 2006

The synthesis of radioactive androsta‐4,16‐dien‐3‐one from both 4‐[14C]‐ and 7α‐[3 H]‐testosterone has been achieved using modifications of a method due to Henbest. Contrarily to this earlier report, yields of purified androstadienone were approximately 6%. Other compounds, which may be ring D isomers, have been separated by column chromatography on silicic acid impregnated with silver nitrate. Labelled 17‐epitestosterone acetate is also formed in this reaction, and may be readily isolated.
Preparation of ring labelled adamantane derivatives II. 2‐adamantanone‐2−14C, adamantane‐2−14C and 1‐methyladamantane‐2 or 4−14C
Authors: Liggero Samuel H. , Majerski Zdenko , von R. Schleyer Paul , Wolf A. P. , Redvanly C. S. , Wynberg Hans , Boerma J. A. , Strating J.
Published: October 2006

A high‐yield, relatively simple synthetic route leading to incorporation of 14C into the secondary position of the adamantane nucleus is described. The synthesis was achieved by the sequence shown in Figure 2. The key steps involved the introduction of a 14C label by diazomethane‐14C ring expansion of adamantanone to give 4‐homoadamantanone‐4−14C (I). Benzylic acid rearrangement of the corresponding homoadamantane diketone (II) gave hydroxy acid (III) which was converted by a novel reaction (SOCl2/benzene) to 2‐adamantanone‐2−14C (IV). The overall yield of labelled 2‐adamantanone was 66%. Wolff‐Kishner reduction of (IV) gave adamantane‐2−14C (V). This was converted to the l‐methyl derivative (VII) by treatment of the corresponding bromide (VI) with methylmagnesium bromide.
Synthesis of 6‐n‐propyl‐2‐thiouracil‐6−14C
Authors: Thornhill D. P. , Sitar D. S.
Published: October 2006

6‐n‐Propyl‐2‐thiouracil‐6−14C was prepared from sodium butyrate‐1−14C, with a radiochemical yield of 34%. Butyryl chloride‐1−14C was prepared from butyric acid‐1−14C and condensed with sodio ethylacetoacetate to yield ethyl β‐oxohexanoate‐β−14C. The β‐keto ester was condensed with thiourea in sodium ethoxide to yield the 2 substituted thiouracil.
Tritiation of organic compounds by electrolytic reduction I. Uracil‐5‐t from 5‐bromouracil
Authors: Bratu Cristina
Published: October 2006

Uracil was tritiated to uracil‐5‐t by electrolytic reduction of 5‐bromouracil in tritiated water. No secondary chemical or radio‐chemical reactions took place.
The synthesis of 14C‐uniformly ring labeled 3,3′,5,5′‐tetra‐tert‐butyldiphenoquinone
Authors: Heeg J. F. , Born G. S. , White H. C.
Published: October 2006

14C‐uniformly ring labeled 3,3′,5,5′‐tetra‐tert‐butyldiphenoquinone was synthesized from 2,6‐di‐tert‐butylphenol. Chemical purity was established by mixed melting point, thin‐layer and gas‐liquid chromatography. Radiochemical purity was determined using auto‐radiography in conjunction with thin‐layer chromatography and liquid scintillation techniques. Structure was confirmed by elemental analysis, ultraviolet‐visible and infrared spectroscopy and nuclear magnetic resonance.
Markierte verbindungen IX (1) mechanismus der reaktion von hexachlorpropen zu trichlororthoacrylsäureestern, 14C‐markierte chlor‐C3‐verbindungen
Authors: Boberg Friedrich , Khalaf Hosni , Kirchhoff Klaus
Published: October 2006

The SN2′‐mechanism is proved for the reaction of hexachloro‐propene to trichloroorthoacrylic acid methylester. Moreover 14C‐labelled chloro‐C2‐ and chloro‐C3‐compounds given in reaction schemes 1–3 are synthesized.
Small‐scale degradation of carbon‐14 labelled carboxylic acids. I. Modification of the hunsdiecker reaction
Authors: Susan A. B. , Nystrom R. F.
Published: October 2006

A modified Hunsdiecker reaction is described for the degradation of the silver salts of acetic acid‐1−14C, acetic acid‐2−14C, propionic acid‐1−14C, propionic acid‐3−14C, n‐butyric acid‐1−14C and n‐butyric acid‐2−14C to carbon dioxide, silver bromide and an organic bromide containing one less carbon atom than the acid, on a 0.5 to 10 millimole scale. This reaction is performed by allowing the silver salt of a carbon‐14 labelled acid to react with bromine vapor in a sealed tube. Then the separation, purification and determination of the amount of each degradation product is accomplished by use of high vacuum techniques. Finally, the products which are obtained in a radiochemically pure form are analyzed for radioactivity by liquid scintillation counting.
Synthesis of 15α, 15β, 21, 21, 21−3H5‐pregn‐5‐en‐3β‐ol‐20‐one
Authors: Ranzi B. M. , Ronchetti F. , Russo G.
Published: October 2006

The readily accessible pregna‐5,16‐dien‐3 β‐ol‐20‐one (1) was transformed into 3β‐acetoxy‐pregna‐5,17‐dien‐20‐isopropoxy‐16‐one (9). This compound was labelled by base‐catalyzed isotopic exchange and then reconverted into labelled pregna‐5,16‐dien‐3β‐ol‐20‐one (13). Hydrogenation of this last one furnished the title compound (14). The labelling extent in the 15α,15β and 21 positions was determined by combined chemical and microbiological methods.
Zur tritiummarkierung von purinpolyribonucleotiden
Authors: Lauschke Udo , Lodemann Edgar , Wacker Adolf
Published: October 2006

Purine polyribonucleotides were labeled with tritium in the 8‐position of the purine ring by heating in tritiated water. An increase in the time of reaction raises the specific activity of the products thus obtained. However under these conditions the degree of fragmentation of the polynucleotides also rises.
Synthesis of homovanillic acid‐2−14C, homoprotocatechuic acid‐2−14C, 3′, 4′‐dihydroxymandelic acid‐2−14C and 1‐(4 hydroxy‐3‐methoxyphenyl)‐ethylene glycol‐1−14C
Authors: Liebman A. A. , Malarek D. H. , Dorsky A. M. , Kaegi H. H.
Published: October 2006

Specifically labelled phenylacetic acid and mandelic acid derivatives, metabolites of L‐Dopa, have been synthesized via the intermediary labelled benzyl alcohols, which were prepared by reduction of the methyl esters of the appropriate benzoic acids. The benzyl alcohols have been converted to the corresponding phenylacetonitriles via the intermediate chlorides and to the cyanohydrins via the intermediate aldehydes in yields significantly higher than previously reported. Overall radiochemical yields of the title compounds were in the order of 25% from 14CO2 and specific activities ranged from 4–10 mC/mmole. The collated procedures have general applicability.
Labelled compounds of potential biological interest II, ‐ application of the yavorsky method for tritiation
Authors: Telc Andrija , Brunfelter Björn , Gosztonyi Tamas
Published: October 2006

The application of the Yavorsky method for tritiation of a number of aminoacetanilides, 2‐amino‐1‐phenylpropane derivatives and some other compounds is described and briefly discussed.
New possibilities of enzymic synthesis of radioactive nucleotides. IV. Application of in vivo tryptophan‐stabilized enzyme system from regenerating rat liver for the synthesis of radioactive thymidine 5′ ‐ phosphates in vitro
Authors: Filip Jiri , Hybs Karel , Nejedly Zdenek , Greger Januaz , Vesely Jiri , Cihak Alois
Published: October 2006

The enzymatic extract ptepared from 48h. regenerating rat liver stabilized with dietary L‐tryptophan possesses the enhanced thymidine and thymidylate kinase activity. The optimal conditions for the phosphorylation of thymidine in vitro were found and the possibility for the preparativer uses was considered. The amount of newly formed thymidine 5′‐monophosphate and 5′ ‐triphosphate depends on the level of adenosine 5′ ‐triphosphate in the reaction mixture, on the temperature of incubation and on the concentration of Mg2+ ‐ions.
Synthesis of 14C‐labelled thyrotropin releasing hormone [pyroglutamylhistidyl‐14C(U)‐prolineamide]
Authors: Flouret George , Alter Arthur , Gendrich Ronald
Published: October 2006

A simplified synthesis of pyroglutamylhistidyl‐prolineamide (TRH) was developed for the purpose of making labelled TRH. Pentachlorophenyl pyroglutamate was reacted with histidine to make pyroglutamylhistidine, and the dipeptide was coupled in situ with prolineamide by means of dicyclohexylcarbodiimide to yield the desired hormone. Both the dipeptide and the hormone were purified by chromatography on silica gel. This method of synthesis was conveniently adapted to synthesize TRH‐14C starting with histidine‐14C (U). Purification of labelled TRH was accomplished by preparative TLC.
Radiochemical syntheses. Part III (1) ‐ the synthesis of tritiated α‐ecdysone and 25‐ deoxy‐α‐ecdysone of high specific activity(2)
Authors: Hafferl W. , Wren D. L. , Marshall J. P. , Calzada M. C. , Siddall J. B.
Published: October 2006

23, 24‐3 H‐α‐ecdysone and 23, 24‐25‐3 H‐25‐deoxy‐α‐ecdysone were prepared by catalytic hydrogenation of 2ß, 3α, 14α, 22R, 25‐pentahydroxy‐5β‐cholest‐7‐en‐23‐yn‐6‐one with tritium gas and palladium on charcoal in ethanol. Radioactivity and purity measurements of the stored highly labelled compounds are described.
Synthesis of 3H‐ and 14C‐labelled 0‐(3‐morpholinoethoxy)‐diphenylether hydrochloride
Authors: Horie Tohru , Fujita Takeshi
Published: October 2006

The methods for preparation of 14C or 3H labelled compound of 0‐(β‐morpholinoethoxy)‐diphenylether hydrochloride (MPE‐HCI) have been investigated. (1)Starting from guaijacol and 14 C‐bromobenzene (U), the synthesis of MPE‐phenyl‐ 14C (U)‐HCI has been accomplished by a heterogeneous palladium‐catalyzed exchange reaction in a yield of 60%.
Synthesis of organic compounds labelled with hydrogen isotopes. I ‐ exchange of halogen atoms in halohydrins for hydrogen isotopes to prepare alcohols labelled with deuterium or tritium
Authors: Egyed J. , Neszmélyi A. , Beke I. , Baitz E.
Published: October 2006

A method has been developed for the preparation of alcohols labelled with hydrogen isotopes, from halohydrins. The synthesis has been performed via Grignard reagents in one step, in the course of which the halogen substituent has exchanged for magnesium which then exchanges for the hydrogen isotope required
Use of L‐ [14C]glycerotetrulose for the enzymatic preparation of 14C‐ labelled intermediates of the pentose phosphate pathway
Authors: Clark M. G. , Blackmore P. F. , Williams J. F.
Published: October 2006

L‐/14C/glycerotetrulose (L‐/14C/erythrulose) was prepared by a two step process. Step one involved the formation of L‐/14C/glycerotetrulose 1‐phosphate by condensation of specifically 14C‐labelled 1, 3‐dihydroxydimethyl ketone 1‐phosphate (dihydroxyacetone phosphate) with formaldehyde as catalysed by crystalline rabbit muscle aldolase. Step two involved the enzymatic dephosphroylation of L‐/14C/erythrulose 1‐phosphate. Based on the criteria of the constancy of the specific activity of L‐erythrulose and its derivatives, namely L‐erythrulose phenylosazone and L‐erythrulose o‐nitrophenylhydrazone, the compound was concluded to be pure.

Using /1‐14C/‐ and /2‐14C/ dihydroxyacetone phosphate, L‐/1‐14C/‐ and L‐/2‐14C/ erythrulose were prepared and used for the enzymatic preparation of D‐/1‐14C/‐ and /2‐14C/xylulose 5‐phosphate, D‐/1‐14C/‐ and /2‐14C/ fructose 6‐phosphate, D‐/1‐14C/‐ and /2‐14C/ altroheptulose 7‐phosphate, D‐1‐14C/‐ and /2‐14C/ mannoheptulose 7‐phosphate and D‐/1‐14C/‐ and /2‐14C/ glycero D‐ido octulose 8‐phosphate. The authenticity of each of the prepared 14C‐labelled sugar phosphates was verified by chromatographic and specific degradative procedures.
Synthesis of 3H‐ and 14C‐labelled doisynolic and marrianolic acids, and stability of tritium label
Authors: Kundu Nakuleswar , Osawa Yoshio
Published: October 2006

3H‐ and 14C‐Labelled doisynolic acid was prepared from 6,7‐3H‐, 2,4,6,7‐3H‐ and 4‐14C‐labelled oestradiol and oestrone by a regulated alkali fusion. Labelled marrianolic acid was similarly prepared from labelled oestriol. Unstability of regiospecific tritium labels in alkali was observed by use of double labelled compounds.
Ethyl esters of Ω‐carboxamidoaliphatic acids‐14CONH2
Authors: Tolman V. , Cabak J. , Benes J.
Published: October 2006

Ethyl esters of 2‐cyanoacetic, 3‐cyanopropionic and 4‐cyanobutyric acids ‐ 14CN were prepared by reaction of the appropriate halogenated esters with potassium cyanide‐14C. Conversion of these cyanoesters into iminoether hydrochlorides and subsequent thermal decomposition gave ethyl esters of malonamic, succinamic and glutaramic acids ‐14CONH2.
Chemical studies on tobacco smoke XXIII. Synthesis of carbon‐14 labelled myosmine, nornicotine and N′‐nitrosonornicotine
Authors: Hu M. W. , Bondinell W. E. , Hoffmann D.
Published: October 2006

dl‐Nornicotine‐2′‐14C was synthesized in four steps. Nicotinic acid (carboxyl‐14C) was first esterified with diazomethane to yield methyl nicotinate (carboxyl‐14C). The ester was condensed with 3‐lithio‐N‐trimethylsilyl‐2‐pyrrolidone to give 3‐nicotinoyl‐N‐trimethyslsilyl‐2‐pyrrolidone (ketone carbonyl‐14C), which was hydrolyzed and decarboxylated in concentrated hydrochloric acid to give myosmine‐2′‐14C.

Reduction of myosmine‐2′14C gave nornicotine‐2′‐14C. Reaction of nornicotine‐2′‐14C in hydrochloric acid with sodium nitrite gave N′‐nitrosonornicotine‐2′‐14C. Purification of labelled myosmine, nornicotine, and N′‐nitrosonornicotine was accomplished by preparative thin layer chromatography.
Carboxyl group ‐CO2 exchange in the thermal decomposition of aliphatic dicarboxylic acid salts
Authors: Szabolcs A. , Szammer J.
Published: October 2006

The exchange reaction of carboxyl groups with carbon dioxide has been studied in thermal decomposition of aliphatic dicarboxylic acid disodium salts. It has been found that exchange takes place under given experimental conditions. In some cases the process results in considerable exchange even in lower conversion ranges therefore it is of significance in the field of isotopes techniques.
Synthesis of 3‐methyl‐4‐phenyl‐3‐butenamide‐1‐14C and N,N‐dideutero‐3‐methyl‐4‐phenyl‐3‐butenamide
Authors: Valcavi U.
Published: October 2006

The syntheses of 3‐methyl‐4‐phenyl‐3‐butenamide, an hypolipemic compound, labelled 1‐14C (VIII) and N,N‐dideutero (XI) are described. The 2‐methyl‐3‐phenyl‐2‐propenyl chloride (VI), reacting with cuprous cyanide‐14C, gave the 3‐methyl‐4‐phenyl‐3‐butenonitrile‐1‐14C (VII) which, treated with hydrochloric acid‐water, gave the 3‐methyl‐4‐phenyl‐3‐ butenamide‐1‐14C (VIII). The 3‐methyl‐4‐phenyl‐3‐butenonitrile (X), treated with hydrochloric acid‐D2O, gave the N,N‐dideutero‐3‐methyl‐4‐phenyl‐3‐butenamide (XI).
Synthesis of 2,6‐dimethoxy [U‐14C] phenol
Authors: Miller J. J. , Olavesen A. H. , Curtis C. G.
Published: October 2006

The preparation of 2, 6‐dimethoxy [U‐14C]phenol was carried out in five steps from [U‐14C]phenol. [U‐14C]Phenol was converted to 2‐[U‐14C]phenoxy‐5‐nitrobenzophenone which was sequentially hydroxylated with hydrogen peroxide‐acetic acid to give the di‐ortho hydroxylated phenolic intermediate, 2‐(2′',6″‐dihydroxy [U‐14C]phenoxy)‐5‐nitrobenzophenone. Methylation of this intermediate and subsequent scission of the aryl ether link with piperidine gave the required di‐ortho substituted phenol. An alternative sequence was investigated for the conversion of 2‐(2″‐hydroxy‐phenoxy)‐5‐nitrobenzophenone to 2‐(2″,6″‐dimethoxyphenoxy)‐5‐nitrobenzophenone but it gave a poorer overall yield with an unstable intermediate. Characterization data are included.
Site‐specific labeling of indole derivatives; 3‐(dimethylaminomethyl) indole‐2‐2H (1)
Authors: Bosin T. R. , Rogers R. B.
Published: October 2006

A procedure for the site‐specific labeling of indole derivatives has been developed. The procedure utilizes the blocking and activating properties of the p‐toluenesulfonyl group which allows for the facile metalation at the 2‐position of indole with n ‐butyllithium and incorporation of deuterium upon reaction with 2H2O. Removal of the p‐toluenesulfonyl group is achieved by treatment with sodium in liquid ammonia and occurs with retention of the label.
Micro‐scale preparation of 4‐thiouracil labelled with 14C or 14C + 35S
Authors: Seda J. , Votruba L. I. , Tykva R.
Published: October 2006

A selective and quantitative method was developed for a microscale preparation of 4‐thiouracil‐2‐14C by the direct thiation of uracil‐2‐14C. From pyridine, dioxane, and tetralin as the thiation solvents, the best yield was obtained in dioxane (96.6% of 4‐thiouracil‐2‐14C). The simultaneous labelling with 14C + 35S was obtained by isotope exchange with elemental sulfur‐35S on refluxing in dimethylformamide. The present procedure may be used as a general method for the preparation of 14C or 14C + 35S labelled bases of nucleic acids of both the pyrimidine and purine type as well as the corresponding nucleosides and nucleotides.
Synthesis of papaverine and quinopavine specifically labeled with 14C
Authors: Ithakissios S. D. , Tsatsas G. , Nikokavouras J. , Tsolis A.
Published: October 2006

1‐(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

Diazepam‐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

The 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

The 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

In 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

1,4‐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

The 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

Existing 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

[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

Urea 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

For 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

Multicurie 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

Cyaclopentadienyl 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

Geraniol‐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

1′,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

A 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

Catalytic 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

The 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

A 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

In 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

This 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

Hunt'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

Educators 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

I'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

The 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

The 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.