Radioanalytical quality control of11C,18F and123I-labelled compounds and radiopharmaceuticals

Machulla, Hans-Juergen; Laufer, Peter; Stöcklin, G.

doi:10.1007/bf02517513

Cited by 31 publications

(14 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reaction 2 is effectively blocked at 1 atm as evidenced by the small ZC1 COPY. Of the alternatives to reaction 2, reaction 4 appears larger than (3) in that ZCz COPY > Z(C3 + Cd) COPY and further (3a) > (3') and (6) > (5). As will be shown, the reaction pathway designated by (4) is sufficiently large that pathway 3 is eliminated at higher pressures and that hydrogen abstraction (6) from the reactive cage wall overshadows collisional deexcitation (5).…”

Section: Resultsmentioning

confidence: 92%

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

To¹,

Berg²,

Grauer³

et al. 1976

J. Phys. Chem.

View full text Add to dashboard Cite

Publication costs assisted by the U.S. Energy Research and Development AdminlstratlonThe reactions of lZsI activated by radiative neutron capture with acetylene occur primarily through an addition channel forming an electronically excited reaction intermediate. Acetylene is unlike olefins in that no photochemical addition occurs under conditions simulating sample handling. In an excess of gaseous acetylene, at l atm 14.9 f 0.6% of lZsI is stabilized as organic activity to the following extent: CH3I 0.49%, CH& 0.70%; C2H31 0.40%, CzH5I 9.30%; i-C3H7I 2.71%; CH~CH~CHICHS 1.10%, CH3(CH2)3I 0.20%. The effects of rare gas additives in moderating lZ8I with gaseous CzH2 were determined in an effort to ascertain the nature of the activation process. Only the C2H51281 yield is decreased by the presence of rare gases, suggesting that both hot lZsI ions and thermal I+(lD2) and other excited ions are involved in the primary addition to acetylene. The gas to condensed phase studies showed a depletion of all C1, vinyl iodide, Cs, and C4 128I-labeled products; where the only product observed in high pressure gas and condensed phase systems was C2H51281. A reaction scheme is proposed which postulates the existence of an excited complex reaction intermediate. The properties of the proposed complex are compared qualitatively to those predicted by RRKM, "caged" complex, and caging radical theories of enhancement yields.

show abstract

Section: Resultsmentioning

confidence: 92%

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

To¹,

Berg²,

Grauer³

et al. 1976

J. Phys. Chem.

View full text Add to dashboard Cite

show abstract

“…Uracil and deoxyuridine were labeled with iodine-123 via the iodide-iodate reaction with reported specific activities up to 10 6 Ci/mmole [ 163]. Iodate and bromate were also used in conjunction with decay-generated radiohalogens (for reviews see [3,5], although it is debatable whether the reactive species in this case are formed via equation (13) [ 164,165],…”

Section: Direct Electrophilic Halogenationmentioning

confidence: 99%

“…Preparatively, radio GC is of limited value, as only relatively small molecules (such as substituted benzene derivatives) can be isolated by this technique. HPLC is of greater utility due to the variety of compounds which can be isolated, and has become a standard method for the quality control of radiohalogenated compounds [31,307],…”

Section: Mr χ**-•mentioning

confidence: 99%

No-Carrier-Added Radiohalogenation Methods with Heavy Halogens

1983

Self Cite

View full text Add to dashboard Cite

Radiolabeling methods with the heavy halogens bromine, iodine and astatine are reviewed. The methods are evaluated on the basis of their underlying chemical principles and their usefulness for the no-carrier-added labeling of biologically-useful compounds. Special emphasis is placed on the stability, specific activity, and quality control of radiohalogenation products using the shortlived, neutron-deficient nuclides 7s ' 7 'Br, '"I, and 2 "At in view of their importance as radiopharmaceuticals.

show abstract

“…column temperature 140°C, He carrier gas) as checked by reinjection of the product peaks. The isomers of astatoaniline were separated by high pressure liquid chromatography on stainless steel columns packed with Merckosorb Si-60 and a mixture of n-heptane, di-n-butylether, propionic acid, and acetic acid (510 : 200: 30: 8) as an eluent [37],…”

Section: Methodsmentioning

confidence: 99%

Replacement Reactions of EC-Produced ²¹¹At in Benzene and Halobenzenes

et al. 1979

View full text Add to dashboard Cite

EC-produced 21 'At /Hot reactions / Aromatic halogenated compounds SummaryHalogen and hydrogen replacement reactions in gaseous, liquid, and solid benzene and halobenzenes by astatine atoms produced via the 211 Rn(EC) 211 At nuclear process were investigated. The halogen replacement increases in the order C 6 H 5 F < C 6 H 5 C1 < C 6 H 5 Br < C 6 H 5 1, while the hydrogen replacement decreases in the same order. The halogen substitution yields were found to be linearly dependent on the bond strength of the halogen to be replaced in both liquid and gaseous systems. The isomer distribution of hydrogen replacement-products is nearly statistical in all the halobenzenes, independent of the phase. In liquid and solid aniline the hydrogen substitution yields were found to be in the same range. The results lead to the conclusion that the replacement reactions of EC-produced 2 " At in the systems studied are hot homo lytic processes, similar to those of hot halogens formed via (n, 7) and (n, 2n) nuclear reactions.Astatine, the heaviest member of the halogen family, was initially characterized as a halogen with rather metallic features [1,2]. Therefore, organic compounds of polyvalent astatine were synthesized and investigated first [3]. Later, however, chemical reactions of monovalent astatine with the formation of covalent C-At bonds were also successfully studied in both aliphatic [4-7] and aromatic [8-10] systems. The recently developed methods for the production and reliable chromatographic identification of organic astatine compounds [7 -12] also made it possible to investigate the chemical reactions of energetic astatine atoms formed in nuclear transformations.The first experiments of this kind were preliminary studies of the chemical consequences of the 211 Rn(EC) 211 At process in benzene [13] and some aliphatic hydrocarbons [14], as well as the preparation of astatobenzene using the recoil astatine formed in the 209 Bi(a, 2n) 211 At nuclear reaction with triphenylbismuth as a target [15]. More systematic investigations of EC-induced 211 At reactions with aromatic compounds were begun recently in these laboratories [16,17].The aim of the present work was to extend the investigations of high energy halogenation to the heaviest member of the halogen series. The study of halogen and hydrogen replacement reactions in benzene and halobenzenes should provide additional data for a better understanding of the substitution mechanisms by energetic halogen atoms [18][19][20][21][22], Among these, the reactions induced by EC-or ß + -decay processes [23][24][25][26][27] are of special interest, because the nucleogenic atoms exhibit relatively small translational energies, compared to those generated via (η, γ) or (n, 2n) nuclear reactions. They may therefore provide valuable information on the energy and charge of the reacting species. Furthermore these studies would supply new information about the reactivity of astatine towards organic substrates, a subject which has not been sufficiently explored.In the case of the EC-decay...

show abstract

Radioanalytical quality control of11C,18F and123I-labelled compounds and radiopharmaceuticals

Cited by 31 publications

References 7 publications

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

No-Carrier-Added Radiohalogenation Methods with Heavy Halogens

Replacement Reactions of EC-Produced ²¹¹At in Benzene and Halobenzenes

Contact Info

Product

Resources

About

Radioanalytical quality control of11C,18F and123I-labelled compounds and radiopharmaceuticals

Cited by 31 publications

References 7 publications

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

Gas to liquid to solid transition in halogen hot atom chemistry. 3. Evidence for an excited reaction intermediate in the (n,.gamma.)-activated reactions of iodine with acetylene

No-Carrier-Added Radiohalogenation Methods with Heavy Halogens

Replacement Reactions of EC-Produced 211At in Benzene and Halobenzenes

Contact Info

Product

Resources

About

Replacement Reactions of EC-Produced ²¹¹At in Benzene and Halobenzenes