bluuebunny/crossref_metadata_2025 huggingface dataset:
Basis for body weight exponent (0.75) as a scaling factor in energy metabolism and risk assessment
Authors: Sidhu Kirpal S.
Published: October 2006

The basis that led to the adoption of the exponent (0.75) as a scaling factor for the relationship between body weight and energy metabolism is presented. In the risk assessment formulation, it may be appropriate to use the 0.75 power of body weight as a scaling factor for carcinogenicity data obtained from animal studies.
One‐year toxicity of orally administered acrolein to the beagle dog
Authors: Parent Richard A. , Caravello Halina C. , Balmer Marilyn F. , Shellenberger Thomas E. , Long James E.
Published: October 2006

Forty‐eight dogs were separated into four groups of six males and six females. Acrolein (0.1% aqueous) was administered in gelatin capsules to three of these groups at dosing levels of 0.1, 0.5 and 1.5 mg kg−1 day−1 based on results of a range‐finding study. After 4 weeks, the high dose was increased to 2 mg kg−1 day−1. The fourth group received deionized water in the same number of gelatin capsules as the high‐dose group. Dosing was 7 days per week for 53 weeks. Blood and biochemical measurements were made pretest and at 3‐month intervals thereafter. At termination, all dogs were subjected to full necropsy and histological exmamination.

The major test effect noted was frequent vomiting after dosing. This was observed to be dose‐dependent and the frequency decreased with time, indicating an adaptive effect. One mid‐dose female died during the test and was diagnosed as having died of severe bronchial pneumonia, probably a result of vomitus aspiration. Serum albumin, calcium and total protein values were depressed in high‐dose animals throughout the study. Some variability in red blood cell parameters and coagulation times were noted but the significance of these effects was not obvious.
Effect of single gallium arsenide exposure on some biochemical variables in porphyrin metabolism in rats
Authors: Flora S. J. S. , Gupta S. Das
Published: October 2006

Gallium arsenide (GaAs) inhibited, dose dependently, δ‐aminolevulinic acid dehydratase (ALAD) activity in blood (as observed on days 1, 7 and 15), liver and brain (on day 15) after a single oral treatment. Levels of blood zinc protoporphyrin (ZPP) and urinary Δ‐aminolevulinic acid (ALA) excretion were elevated on day 7 and day 15 following exposure to 2000 mg kg−1 GaAs. A dose‐dependent increase in blood As contents was observed while blood Ga was detectable only at higher doses.
Retention of inhaled perfluoroisobutene in the rat
Authors: Maidment M. P. , Upshall D. G.
Published: October 2006

Perfluoroisobutene (PFIB) is produced by the pyrolysis, and as a by‐product during the manufacture, of polytetrafluoroethylene. When inhaled it produces a fulminating and sometimes fatal pulmonary oedema similar to that of phosgene after a latent period of 6–8 h. As part of a study to determine the retained dose and the factors that control the amount retained, this study has investigated the retention in rats of inhaled PFIB at concentrations of 10, 50 and 250 μg l−1 in a flow‐through system combining head‐only exposure and plethysmography. Uptake of PFIB was measured by gas chromatography during elevated and reduced inspired volume and respiratory rate induced by exposure to increased CO2and injection of pentobarbitone, respectively. The percentage of PFIB retained in the upper airways and lungs was found to be 27.5, 28.1 and 23.7% of the amount inspired at the three concentrations tested. The rate of uptake (nmol min−1 kg−1) of PFIB was a power law of the amount inhaled, an nb‐fold increase in minute volume producing an n‐fold increase in uptake, where b varied between 0.4 and 0.85. Thus, doubling the inhaled dose produces a 1.3–1.8‐fold increase in uptake with a corresponding decrease in percentage retained. The relative contribution of respiratory rate and tidal volume upon PFIB retention could not be defined.
Chick embryo exposure to carbamates alters neurochemical parameters and behavior
Authors: Farage‐Elawar M. , Blaker W. D.
Published: October 2006

Recent evidence has shown that exposure to pesticides can lead to long‐term neurophysiological and functional deficits. We have demonstrated previously that locomotion in chicks exposed to some organophosphates and carbamates could be altered persistently without concomitant central or peripheral esterase inhibition. Furthermore, histopathology of the ataxic chickens showed no lesions in either the central or peripheral systems. In this study, we examined whether locomotion alterations seen in chicks exposed in ovo to carbaryl and aldicarb are accompanied by perturbations in particular central neurotransmitter systems. Carbaryl and aldicarb were injected in ovo on day 15 of incubation at 6, 16 and 65 mg kg−1 egg weight and at 0.2, 0.4 and 3.5 mg kg−1 egg weight, respectively. Neurotransmitter levels (assayed by high performance liquid chromatography with electrochemical detection) and locomotion were measured at various times (1–43 days) after dosing. At the lower doses of both carbaryl and aldicarb, a trend towards prolonged decreases in cerebral dopamine and homovanillic acid was seen. The high dose of carbaryl significantly reduced dopamine and the high dose of both compounds significantly decreased homovanillic acid and 5‐hydroxyindoleacetic acid. Persistent locomotion alterations were observed only at the higher doses of both carbaryl and aldicarb when the specific neurotransmitters measured returned to normal levels.
Cell proliferation in the respiratory tract of the rat after acute inhalation of formaldehyde or acrolein
Authors: Roemer E. , Anton H. J. , Kindt R.
Published: October 2006

Male Sprague Dawley rats were exposed by inhalation for 6 h per day on one or three successive days to 0, 2, 6 or 20 ppm formaldehyde or 0, 0.2 or 0.6 ppm acrolein. Nasal and tracheal epithelial and free lung cells were then analyzed for proliferative responses. The proliferative response was expressed as the proportion of DNA synthesizing cells determined by the 5‐bromodeoxyuridine (BrdU) labelíng technique.

Single exposure to both irritants increased the DNA synthesizing (proliferating) cells by a factor of 3. After three exposures the increase was distinctly lower. All sites analyzed showed approximately the same concentration/response pattern. Significant changes in cell proliferation could be detected at 2 ppm formaldehyde and 0.2 ppm acrolein.
Oral toxicity in weanling and adult rats and in vitro Genotoxicity of the Veterinary Anthelmintic Rafoxanide
Authors: Poul J. M. , Verlinde V. , Abjean J. P. , Laurentie M.
Published: October 2006

The oral toxicity of the veterinary anthelmintic Rafoxanide was evaluated in newborn rats exposed in utero and during lactation. In another group, 3 months of oral treatment started after weaning. Rafoxanide administration to dams (10 mg kg−1) decreased the number of pups per litter, induced high mortality (42%) and delayed the growth of offsprings before weaning. Histopathological examination of the central nervous system revealed vacuolation of the white matter. Vacuolation was particularly severe in the cerebellum of the 14–21‐day‐old rats. Rafoxanide induced, in some pups (35%), the formation of cataracts. These toxic effects seemed to be reversible and were no longer detectable after a further 3‐month administration of Rafoxanide (10 mg kg−1) to rats born of treated dams. In adult rats treated orally for 3 months with 1, 5 or 25 mg kg−1 Rafoxanide, biochemical and haematological tests did not reveal dose‐related effects. Rafoxanide had no mutagenic activity in the Ames and CHO/HGPRT tests.
Assessment of ocular toxicity in dogs during 6 months' exposure to a potent organophosphate
Authors: Atkinson John E. , Bolte Henry F. , Rubin Lionel F. , Sonawane Meena
Published: October 2006

Exposure to anticholinesterase pesticides has been associated with the development of ocular toxicity in humans and animals, ranging from blurred vision to degeneration of the optic nerve. Based on the concern for human safety, the US Environmental Protection Agency has recently required additional studies for this class of compounds, focusing on biochemical, functional and histopathological evaluation of the ocular system. This study was designed to determine the effects on the eye of ethyl parathion, a highly toxic organophosphate, when administered orally to 30 beagle dogs (five of each sex per group) at doses of 2.4, 7.9 or 794 μg kg−1 day−1 for 6 months. Control animals received corn oil. Routine ophthalmoscopic and slit lamp examinations, refraction and intraocular pressure determinations and electroretinograms were performed as functional assessments at various intervals over the study. Plasma and erythrocyte cholinesterase were determined at weeks 1, 6, 14, 20 and 26, while brain, retinal and ocular muscle cholinesterase were measured at week 26 only. Histopathological examination of the retina, optic nerve, ocular muscle and ciliary body was conducted at termination.

Plasma and erythrocyte cholinesterase was markedly depressed at 7.9 and 794 μg kg−1 day−1 as early as week 1. Retinal cholinesterase was decreased (37–55%) from control values in the 794 μg kg−1 day−1 group only. Ocular muscle cholinesterase was comparable in treated and control groups at termination. No functional impairment of the eye was noted over the 6‐month study. Based on refractive indices, intraocular pressure and evaluation of electroretinograms, it was concluded that administration of ethyl parathion at doses up to 794 γg kg−1 day−1 for 6 months does not produce functional or histopathological changes indicative of ocular toxicity. Cholinesterase inhibition, observed early in the study, does not appear to be related to the development of ocular toxicity.
Induction of cytochrome P‐450 isozymes by hexachlorobenzene in rats and aromatic hydrocarbon (Ah)—Responsive mice
Authors: Linko Patricia , Yeowell Heather N. , Gasiewicz Thomas A. , Goldstein Joyce A.
Published: October 2006

Hexachlorobenzene (HCB) differs markedly from other chlorinated benzenes (CBs) as an inducer of cytochrome P‐450 (P‐450) isozymes as determined by radioimmunoassay and immunoblotting. At > 99% pure, HCB induced both the phenobarbital‐inducible forms, cytochromes P‐450b + e (70X), and the 3‐methylcholanthrene‐inducible forms, cytochromes P‐450c (58X) and P‐450d (8X), in rat liver microsomes. The concentration of P‐450d was considerably greater than that of P‐450c in HCB‐induced rat liver. In contrast to HCB, all lower chlorinated benzenes tested were PB‐type inducers. Hexachlorobenzene increased the amounts of translatable messenger RNAs (mRNAs) for P‐450b, P‐450c, and P‐450d in rat liver polysomes, suggesting that it increases the synthesis of these proteins. Evidence that HCB interacted with the putative Ah receptor for 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) was equivocal. Western blots of liver microsomes from Ahresponsive C57BL/6J (B6) and nonresponsive DBA/2J (D2) mice demonstrated that HCB produced a large increase in P3‐450 and a very small increase in P1‐450 in the responsive strain. The increase in P1‐450 was not observed after HCB administration to nonresponsive mice, but a small increase in P3‐450 was noted. These findings suggested that HCB may act through the Ah receptor. However, HCB was at best a very weak competitor for specific binding of [3H]‐TCDD to the putative receptor in rat or mouse hepatic cytosol in vitro, producing decreases in binding of [3H]‐TCDD only at very high concentrations (10−6 to 10−5 M).
Hepatic fatty acid conjugation of 2‐chloroethanol and 2‐bromoethanol in rats
Authors: Kaphalia Bhupendra S. , Ansari G. A. S.
Published: October 2006

To study the formation of fatty acid conjugates of 2‐chloroethanol (2‐CE) and 2‐bromoethanol (2‐BE), rats were administered (by gavage) 50 mg/kg of 2‐CE and 2‐BE in mineral oil and sacrificed on fifth day of the treatment. Hepatic microsomal lipids were extracted, and the fatty acid esters were separated by preparative thin‐layer chromotography. The ester fraction was further purified by reverse‐phase, high‐performance liquid chromatography and analyzed by ammonia chemical ionization mass spectrometry. Pseudomolecular ions (M + N+H4, base peak) at m/z 336/338, 362/364, and 364/366 in a ratio of 3:1 and 380/382 and 408/410 in a ratio of 1:1 confirmed the in vivo formation of 2‐chloroethyl palmitate, 2‐chloroethyl oleate, 2‐chloroethyl stearate, 2‐bromoethyl palmitate, and 2‐bromoethyl stearate, respectively. These results demonstrate the formation of fatty acid conjugates of 2‐CE and 2‐BE in vivo. These fatty acid conjugates may be retained in the body for a longer time and cause toxic manifestations.
Hemoglobin degradation lipid peroxidation, and inhibition of na+/k+‐atpase in rat erythrocytes exposed to acrylonitrile
Authors: Farooqui Mohammed Y. H. , Mumtaz Mohammad M. , Ghanayem Burhan I. , Ahmed Ahmed E.
Published: October 2006

The effect of acrylonitrile (VCN) on erythrocyte lipid metabolism was investigated in vitro in metabolically active red cells from male Sprague‐Dawley rats containing three types of hemoglobins: oxyhemoglobin, methemoglobin, and carbon monoxyhemoglobin. VCN at the concentration of 10 mM rapidly depleted erythrocyte glutathione (GSH) (75% of control) and induced lipid peroxidation (274% of control). Degradation of oxy‐ and methemoglobin was directly proportional to the extent of lipid peroxidation (r = 0.89). Addition of glucose to the incubation medium decreased hemoglobin degradation while it slightly increased VCN‐induced lipid peroxidation. The highest amount of lipid peroxidation occurred in erythrocytes containing carbon monoxyhemoglobin and glucose. In the isolated red cell membranes incubated with 10 mM VCN, the lipid peroxidation was 400% of controls. VCN (25 mM) noncompetitively inhibited erythrocyte membrane Na+/K+‐ATPase activity and the degree of inhibition was inversely proportional to the reaction temperature (r = −0.88). These findings indicate that the VCN induced hemoglobin degradation and lipid peroxidation are two extremes of a spectrum of oxidative damage in red cells leading to a change in physical state of membrane structure causing inhibition of adenosine triphosphatase (ATPase) activity.
Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara
Authors: Sharma Om P. , Dawra Rajinder K. , Pattabhi Vasantha
Published: October 2006

Lantadene A (22 β‐angeloyloxy‐3‐oxoolean‐12‐en‐28‐oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod‐shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x‐ray diffraction of form I showed sharp peaks whereas form II did not contain distinct peaks. From single‐crystal three‐dimensional x‐ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was nontoxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity.
Isolation and characterization of mitochondrial acyl‐coa: Glycine n‐acyltransferases from kidney
Authors: Kelley Michael , Vessey Donald A.
Published: October 2006

When bovine kidney mitochondria were assayed in the presence of Triton X‐100, they were found to contain glycine N‐acyltransferase activity toward the CoA‐adducts of benzoate, butyrate, isovalerate, naphthylacetate, phenylacetate, and salicylate. Heptanoyl‐CoA activity was masked by high acyl‐CoA hydrolase activity. All activities found in detergent‐lysed mitochondria, and also that toward heptanoyl‐CoA, could be released in soluble form by repeated cycles of freeze‐thawing. Activity in the particle‐free lysate decreased in the order: phenylacetyl‐CoA >benzoyl‐CoA >salicylyl‐CoA >butyryl‐CoA >naphthylacetyl‐CoA >heptanoyl‐CoA >isovaleryl‐CoA. This is quite different from liver, where the activity toward the arylacetic acids is much lower and the other activities are higher. This reflects a major difference in the relative expression of the aralkyl and arylacetyl transferases between liver and kidney. The phenylacetyl‐CoA and naphthylacetyl‐CoA activity purified with a single protein which is termed the arylacetyl transferase. This enzyme was similar to the hepatic arylacetyl transferase in terms of its sensitivity to sulfhydryl reagents, response to cations, and molecular weight (33,500). Activity toward benzoyl‐CoA also purified as a single form which was similar to the hepatic form in its molecular weight (34,000), response to cations, and kinetic properties. Conditions leading to the inhibition of this kidney form and also the hepatic form by p‐mercuribenzoate are described.
The contribution of electrophilic and radicalic intermediates to phospholipid adducts formed by halomethanes in vivo
Authors: De Curtis Valentina , Gemma Simonetta , Sbraccia Maria , Testai Emanuela , Vittozzi Luciano
Published: October 2006

The different production of phosgene and free‐radicals from CHCl3 and CCl4 was determined in vitro and in vivo, by measuring the regioselective binding of the two intermediates to phospholipid (PL) molecules. Results clearly indicated that this assay can be successfully used to selectively detect electrophilic and radicalic metabolites produced in vivo and selectively quantitate their adducts. The in vivo biotransformation of CCl4, similarly to the in vitro situation, resulted in the formation of radicals only, the contribution of phosgene to the structural damage of PL being negligible. These findings allowed us to rule out the hypothesis of substantial formation of radicalic intermediates from CHCl3 in phenobarbital (PB)‐pretreated Sprague—Dawley (SD) rats, derived from in vitro data. While the role of reduced glutathione (GSH) in preventing COCl2‐derived damages seems to be less important in vivo than in vitro, it is not possible to rule out the action of radical scavenging systems in decreasing the level of adducts with fatty acyl chains (FC) of PL measured in vivo.
Sythesis of deuterium and tritium labeled psoralens
Authors: Isaacs Stephen T. , Rapoport Henry , Hearst John E.
Published: October 2006

Deuterium and tritium labeled 4,5′,8‐trimethylpsoralen (), psoralen (), and angelicin (), have been prepared by D2O and T2O exchange with specific activities of 228‐253 mCi/mmol. Tritium labeled 4,5′,8‐trimethylpsoralen () with a specific activity of 17.6 Ci/mmol was prepared by catalytic reduction with tritium gas followed by dehydrogenation. Tritiated 4′‐hydroxymethyl‐4,5′,8‐trimethylpsoralen () with a specific activity of 12.0 Ci/mmol was obtained by reduction of the corresponding aldehyde with sodium borotritide and elaborated to 4′‐aminomethyl‐4,5′,8‐trimethylpsoralen () (12.0 Ci/mmol) by conversion of to the chloromethyl derivative followed by the Gabriel synthesis. Tritium labeled 8‐methoxypsoralen () was prepared by demethylation of unlabeled to the phenol followed by methylation with tritiated methyl iodide.
3‐[125I] Iodo‐4‐hydroxyphenobarbitone for use in radioimmunoassay
Authors: Mason P A , Law B
Published: October 2006

A method is described for the preparation of a barbiturate derivative, 3‐iodo‐4‐hydroxyphenobarbitone, labelled with [125I]iodine. The structure of the compound was confirmed by synthesis and purification of the [127]iodine derivative followed by mass spectral studies. The [125I]iodine labelled barbiturate has proved to be chemically stable and has been shown to bind to a barbiturate antiserum. It should, therefore, prove to be very useful for the development of a radioimmunoassay for barbiturates.
Economical syntheses of 3H‐2H and 14C‐labeled ethyl acetates
Authors: Alvarez Francisco J. , Kovach Ildiko M. , Schowen Richard L.
Published: October 2006

Tritium and 14C‐labeled isomers of ethyl acetate are excellent substrates for competitive dual‐labeled radioactive isotopic measurements of β‐deuterium and β‐tritium isotope effects. Methods are given for preparation of the ethyl esters of acetic acid‐2‐3H, acetic acid‐2‐14C, and acetic acid‐2,2‐2H2‐2‐3H, and of the acetic acid ester of ethanol‐l‐14C from the least costly labeled precursors in high purity (yield 70‐80%) on the mmole scale.
Synthesis of tritium‐abeled fosfomycin
Authors: Mertel Holly E. , Meriwether Henry T.
Published: October 2006

Tritium gas was used as a labeling agent for the preparation of [1,2−3H]fosfomycin. Introduction of tritium into a precursor, the synthesis including resolution of the intermediate racemic 1,2‐epoxypropylphosphonic acid, and preparation of both amine and calcium salts of the labeled antibiotic are described.
Synthesis of dimethyl 5, 5, 6, 6 (2H4)‐2‐oxoheptylphosphonate, a deuterium labelled prostaglandin intermediate
Authors: Meese Claus O. , Borstel Bernd
Published: October 2006

The synthesis of the specifically labelled versatile prostaglandin intermediate 1b is described which involves the preparation of 2,2,3,3 (2H4)butyliodide 6b via homogenous catalytic deuteration of the acetylene 4. Examples for the preparation of prostaglandins and extensive spectroscopic data are included.
Synthesis of radioactively methyl‐labelled (l)‐carnitine
Authors: Ingalls Stephen T. , Hoppel Charles L. , Turkaly Julia S.
Published: October 2006

Commercial (l)‐carnitine chloride was N‐demethylated by the action of sodium benzenemercaptide in warm N,N‐dimethylformamide. The product 4‐(N,N‐dimethylammonio)‐3‐hydroxybutanoic acid chloride salt was isolated in good yield by ion exchange chromatography. Methylation of the product by 14C ‐iodomethane in dry methanol produced biologically active 4‐N‐ Me‐14C ‐(l)‐carnitine chloride of high specific activity in excellent yield.
Synthesis of 14C‐labeled 10,11‐epoxyfarnesyl diazoacetate, a potential photoaffinity labeling reagent for insect juvenile hormone binding proteins
Authors: Krafft Grant A. , Reich Marvin F. , Katzenellenbogen John A.
Published: October 2006

The synthesis of [14C]‐10,11‐Epoxy‐(2E,6E)‐farnesyl diazoacetate in one vessel, starting from [14C]‐glyoxylic acid, is described. This compound is useful as a potential photoaffinity labeling agent for juvenile hormone binding sites.
Synthesis of (2R,S)‐ [2‐2H] and [2,3‐2H] tryptophan
Authors: Santaniello Enzo , Ravasi Manuela , Astori Franca
Published: October 2006

α‐Deuterated tryptophan was prepared either by exchange of the α‐hydrogen of tryptophan or by hydrolysis and decarboxylation of ethyl 2‐formamido‐2‐carbethoxy‐3‐indole propionate, followed by treatment with CH3COO2H. α,β‐Dideuterated tryptophan was in turn synthetized from ethyl‐α‐acetamido‐indole‐3‐acrylate, by catalytic deuteration (2H2/Pd‐C) and alkaline hydrolysis (NaO2H/2H2O).
Synthesis and purification of methyl‐13C fluoride
Authors: Cohen Isaac , Shulman Jan , Popowicz Anthony , Ishida Takanobu
Published: October 2006

A 20 mmole quantity of methyl‐13C fluoride at a 13C‐enrichment level of 90% was prepared by a two‐step synthesis starting with methanol‐13C. The overall yield was 60% of methanol used. A series of gas‐chromatographic treatments using Ascarite, silica gel, and Chromosorb‐102 columns yielded a highly purified methyl fluoride in which the major impurities were less than 10 parts per million of carbon dioxide and 10 parts per million of methyl chloride.
A general procedure for the preparation of α, β labeled amino acids
Authors: Lemaster David M. , Richards Frederic M.
Published: October 2006

The α and β hydrogen exchange reactions catalyzed by pyridoxal have been applied to ten of the common amino acids to prepare α, β deuterated derivatives. The exchange and isolation procedure allows for numerous different samples to be processed in parallel. The deuteration at the α position range from 96 to 99% while the β deuteration levels range from 93 to 97% except for lysine (91%) which exchanges more slowly presumably due to interference of the ϵ‐amino group. The standard procedure produces approximately a gram of deuterated product for all samples except tyrosine (0.15 g) with yields from 70 to 85% using only 15 milliliters of 2H2O. The procedure has been scaled up directly to 100 millimoles for the case of alanine with virtually identical deuteration and product yield.
Synthesis of deuterated vitamin B6 compounds
Authors: Coburn S. P. , Lin C. C. , Schaltenbrand W. E. , Mahuren J. D.
Published: October 2006

3‐Hydroxy‐4‐(hydroxymethyl)‐5‐(hydroxymethyl‐d2)‐2‐methylpyridine(pyridoxine‐d2) was prepared by reduction of α4‐3‐0‐isopropylidene‐5‐pyridoxic acid with lithium aluminum deuteride. Deuterium was inserted in the 2‐methyl group using base catalyzed exchange between deuterium oxide and N‐benzyl pyridoxine. Pyridoxine‐d2 was converted to pyridoxal, pyridoxamine, pyridoxic acid, pyridoxine phosphate, pyridoxal phosphate, and pyridoxamine phosphate. After acetylation the nonphosphorylated forms could be analyzed by gas chromatography‐chemical ionization mass spectroscopy.
Preparation of all‐trans‐retinal‐11‐3H and all‐trans‐retinyl‐11‐3H acetate
Authors: Kaegi Hans H. , Bupp James E. , Degraw Joseph I.
Published: October 2006

trans‐Ionylideneacetaldehyde‐1‐3H (3) was obtained by reduction of unlabeled aldehyde 1 with lithium borotritide, followed by reoxidation of the tritio alcohol 2. Condensation of aldehyde 3 with diethyl 3‐cyano‐2‐methylprop‐2‐enylphosphonate (7) afforded retinonitrile‐11‐3H (8) which was smoothly reduced to trans‐retinal‐11‐3H (9) with diisobutylaluminum hydride. Reduction of retinal (9) with lithium borohyride followed by acetylation gave retinyl‐11‐3H‐acetate in excellent yield.
Synthesis of 14C‐labelled fluphenazine esters
Authors: Zólyomi G. , Tóth I. , Toldy L.
Published: October 2006

Fluphenazine labelled with 14C at the 3‐propyl position was prepared. Starting from K14CN, 3‐chloropropyl p‐toluenesulfonate (7) was synthesized via 3‐chloropropionic acid (4) intermediate and coupled with 2‐trifluoromethylphenothiazine. The phenothiazine derivative (8) obtained was converted into 1a, from which various long acting esters (1b, 1c, 1d) of labelled fluphenazine were prepared for comparative pharmacokinetic studies.
Regioselective deuteriation kinetics of 2‐, 4‐, and 6‐methyl groups in D2O solutions of pyrylium and N‐methylpyridinium perchlorates possessing also 3‐methyl or 3‐phenyl groups
Authors: Balaban Alexandru T. , Uncuta Cornelia , Chiraleu Filip
Published: October 2006

By 1H‐NMR it was found that 2, 3, 4, 6‐tetramethylpyrylium perchlorate (I) in D2O undergoes isotopic exchange at the 2, 4, and 6‐methyl groups with relative rates 5 : 40 : 1, respectively (assignments of α‐methyl NMR signals were substantiated by unambiguous synthesis). If the 3‐methyl group is replaced by a 3‐phenyl group, the relative rates for the pyrylium salt III are 2.5 : 49 : 1, respectively (in D2O + CD3OD). On the other hand, the relative rates for the 2, 4, and 6‐methyls in 1,2,4,6‐tetramethyl‐3‐phenylpyridinium perchlorate are 12 : 1 : 4, respectively (in D2O + CD3OD + NaOD). These rate differences allow the preparation of selectively deuteriated pyrylium or pyridinium salts, and of other aromatic or heterocyclic compounds starting from pyrylium salts with selectively deuteriated side‐chains.
An improved synthesis of catechol‐U‐14C
Authors: Heys J. R. , Chew E. H. , Saugier J. H.
Published: October 2006

The high yield, four‐step synthesis of catechol‐U‐14C from benzene‐U‐14C is described. Intermediates in the preparation include phenol‐U‐14C and o‐methoxyphenol‐U‐14C [guaiacol‐(phenyl‐U‐14C)].
A comparative study of radioiodination of simple aromatic compounds via N‐halosuccinimides and chloramine‐t in TFAA
Authors: Youfeng He , Coenen H. H. , Petzold G. , Stöcklin G.
Published: October 2006

A comparative study of radioiodination of simple aromatic compounds using N‐chlorosuccinimide (NCS), N‐bromosuccinimide (NBS), N‐chlorotetrafluoro‐succinimide (NCTFS) and Chloramine‐T (CAT) has been carried out in trifluoroacetic anhydride (TFAA) as an aprotic solvent. Optimization of the iodination procedure has been performed using anisole as the model substrate. A fast and simple “one‐pot” synthesis via NCTFS, NCS or CAT leads to iodoanisoles with a radiochemical yield of about 70 %. For comparison, toluene and benzene have also been radioiodinated.
Methodes De Synthese Du P‐Chlorophenylacetonitrile (Noyau 14 C‐U)
Authors: Noel J. P. , Pichat L.
Published: October 2006

Three reactions schemes were explored for the preparation of pure isomer free [ring U‐14C] parachlorophenylacetonitrile (pCPN). The first route through the cyanomethylation of [U‐14C] p‐dichlorobenzene with acetonitrile in presence of sodium amide in liquid ammonia gave actually a mixture of meta and para chlorophenylacetonitrile in contradiction with a literature report (5). The second route involved the preparation on a microscale of [U‐14C] p‐chlorophenylmagnesium chloride in T.H.F, and its hydroxymethylation to [ring U‐14C] p‐chlorobenzyl alcohol with formaldehyde. This route gave low yields of isomer free pCPN. The third reaction scheme supplied pCPN in 9 steps from [U‐14C] aniline. [ring U‐14C] acetanilide 11 was brominated and after deacetylation isomer free p‐bromoaniline 13 was obtained. 13 was diazotized and transformed into [U‐14C] p‐chloro bromobenzene: 14 which gave the corresponding Grignard 15 with Mg in ether. Carbonation of 15 gave [ring U‐14C] p‐chlorobenzoic acid which was reduced (LAH) into the corresponding alcohol which by reaction with bromotrimethylsilane gave [ring U‐14C] p‐chlorobenzyl bromide 9. Condensation of 9 with KCN in presence of crown ether 18 c 6 gave [ring U‐14C] p‐chlorophenylacetonitrile which was purified by medium pressure column liquid chromatography. The overall yield from [U‐14C] aniline was 26%. The radiochemical purity was better than 99.5% ‐ specific activity : 46 mCi/mmole.
The deuteration of the histones of physarum polycephalum as a step towards the preparation of selectively deuterated nucleosome core particles
Authors: Carpenter B. G. , Sewell F. M.
Published: October 2006

Physarum polycephalum can be grown in shake flask culture where all of the peptone component of the feed stock has been replaced by a deuterated algal hydrolysate. These conditions give approximately 35% overall deuterium incorporation into the basic nuclear proteins. This level of incorporation, together with the maintenance of a reasonable maximum growth, show P. polycephalum to be a convenient system for the preparation of nucleosome core particles with selectively deuterated histones. Selectively deuterated core particles offer considerable advantages over uniformly protonated ones when structural studies using neutron scattering are carried out.

A combination of proton and deuterium magnetic resonance spectroscopy shows that under the conditions so far studied the deuterium incorporation is not uniformly distributed throughout the amino acid residues of the proteins. A 60% deuteration of the terminal apolar methyl groups is accompanied by only 28% deuteration of the hydrogen atoms bound to the α‐carbon.

Our observation that α‐carbon hydrogens are exchanged in vitro reactions with 2H3O+, albeit at elevated temperature, could well indicate these hydrogens are exchanged in vivo with the solvent water of the growth medium. Suggestions are made as to other possible variations in feed stock components which could lead to a higher overall levelof deuterium incorporation.

Deuteration ‐ Physarum polycephalum ‐ neutron scattering ‐ histones ‐ nucleosome core particles.
Preparation of multitritiated arenes
Authors: Cacace Fulvio , Speranza Maurizio , Wolf Alfred P. , Ehrenkaufer Richard
Published: October 2006

The decay technique, currently applied to the study of ionic processes in gaseous and liquid systems, requires multitritiated precursors to generate labeled daughter ions. The preparation of three such precursors, namely C63HxH6−x, C63HxH5−xCH3, and C6H5C3H3−x is described. The ring–labeled precursors were obtained from the cyclization of C23H2, and respectively of a C23H2/propyne mixture, carried out at 25°C over a K2CrO4–promoted silica–alumina catalyst. The side–chain tritiated toluene was prepared by allowing 3H2O and benzotrichloride to react over a Zn mirror at 200°C. Details of the procedures employed for the radiometric and the isotopic analysis of the multilabeled products are reported.
Preparation of 2‐[125I] iodohistamine‐labelled Δ8‐tetrahydrocannabinol‐11‐oic acid for use in cannabinoid radioimmunoassay
Authors: Law B , Mason P A , Moffat A C , King L J
Published: October 2006

A simple method is described for the preparation of 2‐[125I]iodohistamine‐labelled Δ8‐tetrahydrocannabinol‐11‐oic acid with high specific activity for use in radioimmunoassay. This compound is produced in high yield and shows excellent radiochemical stability when stored at 4°C. The radiolabelled cannabinoid has been shown to bind avidly to four different broadly specific cannabinoid antisera. It is the only [125I] labelled cannabinoid suitable for use in radioimmunoassay with such antisera.
A procedure for the radioiodination of a ganglioside derivative
Authors: Klemm Nancy , Su Song‐Nan , Harnacker Barbara , Jeng Ingming
Published: October 2006

A procedure for the preparation of a radioiodinated derivative of ganglioside GM1 has been devised. Carbon 6 of the terminal galactosyl residue of GM1 was converted to an aldehyde by galactose oxidase. The adduct formed by this oxidation product of GM1 with tyramine was reduced with sodium cyanoborohydride. The tyramine moiety covalently attached to GM1 was then labelled by the conventional iodine chloride procedure. The technique described herein is simple and economical for the preparation of a highly radioactive GM1 derivative.
Preparation of 4‐iodo‐2‐methyl‐1‐butene‐1,1‐d2
Authors: Wolff Steven , Agosta William C.
Published: October 2006

A nine‐step preparation of 4‐iodo‐2‐methyl‐1‐butene‐1,1‐d2 (9) from 2‐methylbutyrolactone (1) is described.
Synthèese De Molécules Amphiphiles Marquées Aux Isotopes Stables 13C et 15N
Authors: Bouloussa O. , Dizabo P.
Published: October 2006

Partant de Ba13CO3, K13CN ou de phtalimide, nous décrivons la synthèse et la purification d'acides gras, d'amines grasses et de N acyl amino acides marqués spécifiquement au 13C ainsi que d'amines grasses marquées à l'azote 15. L'identification et la pureté de ces composés ont été effectuées par SM et RMN 13C.
Synthèses D'indoles Et d'Indolizines Marqués Spécifiquement par 13C dans le Cycle Pentagonal
Authors: Lautie M. F. , Corval M.
Published: October 2006

The syntheses of 2‐13C and 3‐13C indoles and indolizines and 1‐13C indolizine are described. They are obtained from 1‐13C bromoacetaldehyde on (2‐pyridyl) ethylacetate for 2‐13C indolizine, and through cyclisations of suitably labelled intermediates:o‐formotoluidide for 2‐13C indole, o,β‐dinitrostyrene for 3‐13C indole, and 3‐(2‐pyridyl)‐1 propanol for 3‐13C and for 1‐13C indolizines. Every position is more than 90% 13C‐ labelled.
Synthese von [2′‐14C] 8‐Methoxypsoralen
Authors: Zipp H. , Zimmer A. , Koss F. W.
Published: October 2006

Die Synthese von 14C‐Ring‐markiertem 8‐Methoxypsoralen (MELADININE) wird beschrieben. Auf die säulenchromatographische Reinigung der einzelnen Produkte sowie auf die radiodünnschichtchromatographische Reinheit und Identitätskontrolle besonders des Endproduktes wird eingegangen. Ausgehend von (2‐14C)‐Chloressigsäure und Pyrogallol werden 860 mg (4 mMol) (2′‐14C)‐8‐Methoxypsoralen mit einer spezifischen Radioaktivität von 1,3 mCi/mMol, [6,0 μCi/mg; 2,2 × 105 Bq/mg] in einer 8‐Stufen‐Synthese hergestellt. Die Ausbeute, präparativ und radiochemisch, beträgt 16 % d. Th.
Synthesis of n‐octyltrichlorosilane labeled with 13C in the terminal position
Authors: Gangoda M. E. , Gilpin R. K.
Published: October 2006

This report describes the synthesis of carbon‐13 labeled n‐octyltrichloro silane from 13C‐barium carbonate. The product is labeled at the 8‐position of the alkyl chain.
Preparation of methyl [1‐14C]docosa‐7,10,13,16‐tetraenoate
Authors: Neergaard Jon R. , Coniglio John G. , Smith Howard E.
Published: October 2006

Methyl [1‐14C]docosa‐7,10,13,16‐tetraenoate was prepared from [1‐14C]arachidonic acid by two successive Arndt‐Eistert syntheses which also can be used for the step‐wise homologation of other labeled fatty acids. After purification by gas chromatography the specific activity was 6.16 mCi/mmol, and the radiochemical purity was 97%.
Synthesen von [191Os]‐Osmocen‐Derivaten und Vergleich ihrer Organ‐Verteilung mit Ruthenocen‐Derivaten bei Mäusen
Authors: Schachschneider Gert , Wenzel Martin
Published: October 2006

By the exchange of the central atom of ferrocenes with 191OsCl4 in the presence of HCl labelled osmocenes were gained with radiochemical yields up to 45 %. The organ‐distribution of the labelled osmocenes were compared with that of the homologous ruthenocenes and that of the OsCl4 and RuCl3.
The synthesis of 4‐d2, 5‐d2 and 4,5‐d4‐2‐dicyclopropylmethylamino‐Δ2‐oxazolines
Authors: Ehrhardt J. D.
Published: October 2006

The synthesis of deuterated ethanolamines and deuterated 2‐dicyclopropylmethylamine‐Δ2‐oxazolines is described.
A convenient and highly regio‐specific deuteriation of the pterocarpanoid phytoalexin maackiain
Authors: Stoessl Albert , Stothers J. B.
Published: October 2006

A procedure is described which allows specific deuteriation at the 4‐position of maackiain (3‐hydroxy‐8,9‐methylenedioxypterocarpan) to the extent of about 30%.
Synthesis of 14C‐ and 3H‐labelled β ‐casomorphin‐5
Authors: Hartrodt B. , Toth G. , Neubert K. , Sirokmán F. , Baláspiri L. , Schulz H.
Published: October 2006

β‐casomorphin‐5, tyrosyl‐prolyl‐phenylalanyl‐prolyl‐glicine, labelled with 14C and 3H in the N‐terminal tyrosine residue, was synthesized by stepwise elongation, using [Dit]1‐β‐casomorphin‐5 as precursor for catalytic tritiation. The specific radioactivities of the two peptides were 1.6 mCi/mmol [59.2 MBq/mmol] and 44.1 Ci/mmol [1.63 /Bq/mmol], respectively. Both were biologically fully active as compared with a synthetic reference material.
A facile synthesis of [1‐13C]benzonitrile by bromination‐dehydrobromination of [1‐13C]1‐cyanocyclohexene
Authors: Yuan Sun‐Shine , Ajami Alfred M.
Published: October 2006

[1‐13C]1‐Cyanocyclohexene can be bisbrominated by N‐bromosuccinimide and then aromatized by triethylamine to give [1‐13C] benzonitrile in 90% yield. This allylic bisbromination‐dehydrobromination reaction is generally applicable to the transformation of other 1‐substituted cyclohexenes into benzenoid derivatives.
Synthesis of 14C‐labelled bis‐azo biphenyl dyes
Authors: Milam D. Franklin , Lynn Robert K.
Published: October 2006

Two 14C‐labelled bis‐azo biphenyl dyes have been prepared from uniformly ring‐labelled 14C‐benzidine and 14C‐3, 3′‐dimethylbenzidine. The amines were tetra‐azotized with sodium nitrite and HCL. Direct Blue 6 was then prepared from tetra‐azo benzidine by allowing it to react with two equivalents of H acid (8‐amino‐1‐naphthol‐3,6‐disulfonic acid mono sodium salt) under basic conditions. Acid Red 114 was prepared from tetra‐azo 3,3′‐dimethylbenzidine by sequential reaction with one equivalent of G acid (2‐naphthol‐6,8‐disulfonic acid dipotassium salt) followed by one equivalent of phenol. This product was then esterified with p‐toluenesulfonyl chloride to give acid Red 114.
Synthesis of p125I ‐amphetamine
Authors: Duterte D. , Morier E. , le Poncin‐Lafitte M. , Rapin J. R. , Rips R.
Published: October 2006

p‐iodo‐amphetamine was synthesized by the Sandmeyer reaction from iodine and p‐NH2‐amphetamine, in which the amino aliphatic group was protected by an easily hydrolysable group: t‐butyloxycarbonyl. Iodine was obtained by oxidation of Na 125I with periodate in an acidic medium. The yield was 50% with a specific activity of 25 mCi/mmol.
Solution synthesis of 14C‐labeled thymopoietin32–36 using catalytic transfer hydrogenation as the final deprotection step
Authors: Tjoeng Foe‐Siong , Heavner George A.
Published: October 2006

A 14C‐labeled pentapeptide, [14C]Arg‐Lys‐Asp‐Val‐Tyr (6), corresponding to the active fragment 32–36 of thymopoietin II has been synthesized by a solution method with a 44 percent radiochemical yield. 14C‐labeled Z‐Arg(HCl)‐OH was coupled to the protected tetrapeptide Lys(Z)‐Asp(OBzl)‐Val‐Tyr(Bzl)‐OBzl using dicyclohexylcarbodiimide and 1‐hydroxybenzotriazole to give the protected pentapeptide 5 with a specific activity of 340 mCi/mmol. Catalytic transfer hydrogenation was used to remove the protecting groups and the free peptide was purified by gel filtration and high performance liquid chromatography.
The synthesis of polyunsaturated glyceryl alkyl ethers tritiated at C‐2
Authors: Halperin Gideon
Published: October 2006

The synthesis of polyunsaturated trialkyl glyceryl ether tritiated at C‐2 of the glycerol carbon chain having identical 1,3‐alkyl groups is described.
A novel method for the preparation of adenosine 3′5′ cyclic phosphate labelled with 14C or 3H
Authors: Pandey V. N. , Nair C. K. K. , Pradhan D. S.
Published: October 2006

High yields of cyclic AMP (cAMP) and cyclic GMP (cGMP) could be obtained by near quantitative conversions of adenine and guanine by aerobically‐grown nonproliferating cells of Corynebacterium murisepticum. The procedure is especially suited for the preparation of 14C or 3H labelled cAMP and cGMP from respective purine base precursors.
Syntheses Nouvelles DE LA Mevalonolactone Marquee Au 14C, 13C, 3H ‐ (RS) Mevalonolactone (14C‐3′) et (RS) Mevalonolactone (3H‐3′)
Authors: Rousseau Bernard , Beaucourt Jean‐Pierre , Pichat Louis
Published: October 2006

Two procedures are described for the two step synthesis of [3′‐14C] mevalonolactone and [3H‐methyl] mevalonolactone from radioactive methyl magnesium iodide. The first route involves the addition of radiolabeled methyl magnesium iodide with 1(2,4,10 trioxa adamantyl) 4‐trityloxy 2‐butanone : 6 followed by hydrolysis with acid. The overall yield from methyl iodide was 37 % : specific activity 49 mCi/mMol. [3‐13H] mevalonic acid was prepared by the same technique at a specific activity of : 3,8 Ci/mMol. The second route relies on the addition of radiolabeled methylmagnesium iodide upon 1,1‐dimethoxy 5‐(2‐tetrahydropyranyloxy)‐3‐pentanone : 12 followed by the oxidative hydrolysis of the reaction product with bromine‐water‐hydrochloric acid. The overall yield was 40 % from methyl iodide : specific activity : 1 mCi/mMol. The multi step synthesis of synthons : 6 and 12 are fully described.
Syntheses of chirally labelled [4‐13C]‐β‐hydroxyvaline and [4,4,4‐2H3]‐β‐hydroxyvaline
Authors: Aberhart D. John
Published: October 2006

(E)‐[4‐13C]‐3‐Methylcrotonic acid was converted to [4‐13C]‐3‐methyl‐2,3‐epoxybutyric acid, which was treated with ammonia to yield a mixture of [4‐13C]‐β‐hydroxyvaline and [4‐13C]‐β‐amino‐α‐hydroxyisovaleric acid, from which the β‐hydroxyvaline of known chirality at C‐3 relative to C‐2 was isolated. Similarly, (E)‐[4,4,4‐2H3]‐3‐methylcrotonic acid was converted via the epoxide, into a mixture of [4,4,4‐2H3]‐β‐hydroxyvaline and [4,4,42H3]‐β‐amino‐α‐hydroxyisovaleric acid, from which the β‐hydroxyvaline was isolated.
Reaction of 14CO2 with grignard reagents to form either carboxylic acids or ketones. A novel convenient route to [2‐14C] glycerol and [1‐14C] Glycolic acid
Authors: Wirz B. , Küng W.
Published: October 2006

The reaction of CO2 with GRIGNARD reagents carrying an ether grouping in a sterically suitable position can be directed to afford predominantly either the carboxylic acid or the symmetrical ketone. Thus, the magnesiumorganic compounds prepared from chloromethyl‐methyl ether, benzyl‐chloromethyl ether and 2‐methoxy‐bromobenzene, upon treatment with CO2 under appropriate conditions give the corresponding ketones in excellent yield. An attempt is made to rationalize this finding from a mechanistic viewpoint. The easily accessible 1,3‐bis(benzyloxy)‐acetone represents a convenient intermediate for an efficient and simple synthesis of glycerol.
Synthese DE LA pentamethylmelamine (tetraméthyle 14C), un nouvel agent antitumoral
Authors: Do‐Cao‐Thang  , Nguyen‐Hoang‐Nam  , Hoellinger H. , Pichat L.
Published: October 2006

(tetramethyl‐ 14C)Pentamethylmelamine 6, a new antitumor agent, was prepared by a three‐step synthesis starting with (14C)CH3I. Toluene‐p‐sulphonamide was condensed with (14C)CH3I to give labelled NN‐dimethyltoluene‐p‐sulphonamide. 14C‐labelled dimethylamine was released from the dimethylamide by the action of 48% HBr and NaOH, then reacted with 2,4‐dichloro‐6‐methylamino‐1,3,5‐triazine to afford 6. After purification by silicagel column chromatography 6 was obtained in a 8.5% yield from (14C)CH3I and a radiochemical purity of 99%, specific activity : 78.5 mCi/mmole.
Radiosynthesis of high specific activity tritium‐labeled precocene II
Authors: Bowers William S. , Franke Lothar , Soderlund David M.
Published: October 2006

The insect antijuvenile hormone precocene II (6,7‐dimethoxy‐2,2‐dimethylchromene) was radiosynthesized, incorporating tritium specifically in the gem‐dimethyl group at high specific activity. 7‐Hydroxycoumarin was methylated (CH3I/KOH) and then oxidized at 6‐position (K2S2O8/NaOH). The resulting 6‐hydroxy‐7‐methoxycoumarin was methylated (CH3I/KOH) and reacted with excess C3H3MgI to give precocene II‐[2‐methyl‐3H] at a specific activity of 32 Ci/mmol. This synthetic scheme offers access to radiolabeled preparations of a wide variety of mono‐ and dialkoxy‐substituted analogues of precocene II.
The synthesis of [4,6‐2H] salicylates
Authors: Hall C. Richard , Ley Ronald V.
Published: October 2006

[4,6‐2H] Salicylic acid, salicyluric acid and methyl salicylate are prepared by hydrogenolysis of 3,5‐dichlorophenol followed by carboxylation with sodium ethyl carbonate.
Synthesis of 2,4′,5‐trichloro [14C]biphenyl mercapturic acids
Authors: Bergman Ake , Bakke Jerome E. , Feil Vernon J.
Published: October 2006

The synthesis of 3‐ and 4‐S‐(N‐acetyl)cysteinyl‐2,4′,5‐trichloro[14C]biphenyl is described. 4‐Chloro[14C]aniline was used as starting material. The products were obtained after an aryl coupling of the amine with 2,5‐dichloronitrobenzene, a reduction of the nitrogroup and finally coupling of the diazotized trichlorobiphenyl amine with cuprous N‐acetylcysteine mercaptide.
Synthesis of model oligosaccharides of biological significance. 3. Synthesis of carbon‐13 labelled trimannosides
Authors: Winnik F. M. , Carver J. P. , Krepinsky J. J.
Published: October 2006

Two isomeric trimannosides labelled with carbon‐13 at one specific anomeric position have been synthesized. Methyl 2‐O‐allyl‐4,6‐O‐benzylidene‐α‐D‐mannopyranoside was reacted with tetra‐O‐acetyl‐D‐mannopyranosyl‐1‐13C bromide. The disaccharide obtained was glycosylated with tetra‐O‐acetyl‐D‐mannopyranosyl bromide after hydrolysis of the benzylidene group. This sequence led to methyl 3‐O‐α‐D‐mannopyranosyl‐α‐D‐mannopyranoside after deblocking of all hydroxyl groups. When the 13C‐labelled and unlabelled glycosyl bromides were added to the methyl mannoside in the reversed order, methyl 3‐O‐α‐D‐mannopyranosyl‐6‐O‐α‐D‐mannopyranosyl‐1‐13C‐α.D‐mannopyranoside was obtained.
Synthesis of 1‐13C and 3‐13C isotopic isomers of aspartic and glutamic acids
Authors: Fotadar Upinder , Cowburn David
Published: October 2006

Convenient routes to 1‐C and 3‐C labeled glutamic and aspartic acids and to their precursors are described.
Synthesis of 35S‐ and 14C‐labeled famotidine, a new potent histamine H2 receptor antagonist
Authors: Tamazawa Kazuharu , Arima Hideki
Published: October 2006

Famotidine, 3‐[[[2‐[(diaminomethylene)amino]‐4‐thiazolyl]methyl]thio]‐ N2‐sulfamoylpropionamidine, a new potent histamine H2 receptor antagonist, was labeled with 35S and 14C for metabolic studies at specific activities of 45.7 μCi/mg (VIb) and 47.6 μCi/mg (VIc) respectively.
Triethyl [1‐14C]phosphonoacetate from [14C]carbon dioxide
Authors: Crevoisier Michel , Guilford William J. , Coates Robert M.
Published: October 2006

Lithiation of diethyl methylphosphonate (1) with n‐butyllithium followed by carbonation with [14C]carbon dioxide and esterification with diazoethane afforded high specific activity triethyl [1‐14C]phosphonoacetate (4) in 62% yield.