A non-anhydrous, minimally basic protocol for the simplification of nucleophilic 18F-fluorination chemistry

Abstract Fluorine-18 radiolabeling typically includes several conserved steps including elution of the [18F]fluoride from an anion exchange cartridge with a basic solution of K2CO3 or KHCO3 and Kryptofix 2.2.2. in mixture of acetonitrile and water followed by rigorous azeotropic drying to remove the water. In this work we describe an alternative “non-anhydrous, minimally basic” (“NAMB”) technique that simplifies the process and avoids the basic conditions that can sometimes limit the scope and efficiency of [18F]fluoride incorporation chemistry. In this approach, [18F]F− is eluted from small (10–12 mg) anion-exchange cartridges with solutions of tetraethylammonium bicarbonate, perchlorate or tosylate in polar aprotic solvents containing 10–50% water. After dilution with additional aprotic solvent, these solutions are used directly in nucleophilic aromatic and aliphatic 18F-fluorination reactions, obviating the need for azeotropic drying. Perchlorate and tosylate are minimally basic anions that are nevertheless suitable for removal of [18F]F- from the anion-exchange cartridge. As proof-of-principle, “NAMB” chemistry was utilized for the synthesis of the dopamine D2/D3 antagonist [18F]fallypride.

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The comparative study of linear solvatation energy relationship for the reactivity of pyridine carboxylic acids with diazodiphenylmethane in protic and aprotic solvents

Journal of the Serbian Chemical Society ◽

10.2298/jsc120713078d ◽

2012 ◽

Vol 77 (10) ◽

pp. 1311-1338 ◽

Cited By ~ 4

Author(s):

Sasa Drmanic ◽

Jasmina Nikolic ◽

Aleksandar Marinkovic ◽

Bratislav Jovanovic

Keyword(s):

Solvent Effects ◽

Kinetic Data ◽

Aprotic Solvent ◽

Isonicotinic Acid ◽

Linear Regression Analysis ◽

Multiple Linear Regression Analysis ◽

Reaction Rates ◽

Aprotic Solvents ◽

Pyridine Carboxylic ◽

The Comparative Study

Protic and aprotic solvent effects on the reactivity of picolinic, nicotinic and isonicotinic acid, as well as of some substituted nicotinic acids with diazodiphenylmethane (DDM) were investigated. In order to explain the kinetic results through solvent effects, the second-order rate constants for the reaction of the examined acids with DDM were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of the multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of the contributions of the initial and the transition state. The signs of the equation coefficients support the already known reaction mechanism. The solvatation models for all the investigated acids are suggested and related to their specific structure.

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Acid-Base Equilibria of Substituted Pyridine N-Oxides in N,N-Dimethylformamide and Dimethyl Sulfoxide

Australian Journal of Chemistry ◽

10.1071/ch9930185 ◽

1993 ◽

Vol 46 (2) ◽

pp. 185 ◽

Cited By ~ 34

Author(s):

L Chmurzynski ◽

Z Warnke

Keyword(s):

Dimethyl Sulfoxide ◽

Linear Relationship ◽

Aprotic Solvent ◽

Heterocyclic Amines ◽

Aprotic Solvents ◽

Acid Base ◽

Acidity Constants ◽

Pka Values ◽

Weak Tendency

Acidity constants have been determined potentiometrically for a variety of conjugate acids of substituted pyridine N-oxides in N,N- dimethylformamide ( dmf ) and dimethyl sulfoxide ( dmso ). The pKa values in these solvents varied in the same direction and correlated with the pKa values of these species in water and in the protophobic aprotic solvent acetonitrile. Further, a linear relationship has been established between the pKa values in the two protophilic aprotic solvents under study. The most basic substituted pyridine N-oxides exhibited a weak tendency towards cationic homoconjugation in dmf , whereas in the more basic dmso the homoconjugation equilibrium was not established for any of the heterocyclic N-oxides. The phenomenon of cationic homoconjugation was also not observed with pyridine as a representative of heterocyclic amines, both in dmf and dmso. This finding complies with the results obtained in other polar aprotic solvents.

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SIMULATIONS ON NICKEL TARGET PREPARATION AND SEPARATION OF Ni(II)-

GANENDRA Majalah IPTEK Nuklir ◽

10.17146/gnd.2011.14.1.26 ◽

2011 ◽

Vol 14 (1) ◽

Author(s):

Sunarhadijoso Soenarjo ◽

Wira Rahman ◽

Sriyono Sriyono ◽

Triyanto Triyanto

Keyword(s):

Anion Exchange ◽

Acidic Solution ◽

Nickel Chloride ◽

Exchange Chromatography ◽

Acid Mixture ◽

Spectrometric Analysis ◽

Basic Solution ◽

Anion Exchange Column ◽

Target Holder ◽

Target Preparation

SIMULATIONS ON NICKEL TARGET PREPARATION AND SEPARATION.OF Ni(II)-Cu(II) MATRIX FORPRODUCTION OF RADIOISOTOPE64Cu64Ni (p,n) 64 and retained on the column while the nickel was kept in the form of Ni2+ 2+ 2+ and CuCl while the nickel was totally in the form of Ni2+ while the nickel was found as both Ni2+ and NiCl while the nickel was mostly in the form of Ni2+. The retained CuCl was then changed back into Cu2+ Keywords 64 Cu, Anion exchange chromatography.: Nickel target preparation, Radioisotope Cu-64, Separation of Ni(II)-Cu(II) matrix, Nuclear reaction of 64Ni(p,n) cation form andeluted out the column by using HCl 0.05 M. The 42– 4 2–.The best condition of separation was in HCl 8 M in which the radioactive copper was mostly in the form of CuCl 42– 42– . In the condition ofHCl 9 M, the radioactive copper was mostly in the form of CuCl 42– cation. It was found that the electroplating result from the acidic solution was more satisfied than that from the basic solution. By conditioning the matrix solution at HCl 6 M, the radioactivecopper was found in the forms of Cucation and eluted off from the column. The retained radioactive copper was then eluted out the column in the condition of dilute HCl changingback the copper anion complex into Cu42– Cu. The nickel target preparation was performed by means of electroplating method using acidic solution of nickel chloride - boric acid mixture and basic solution of nickel sulphate – nickel chloridemixture on a silver- surfaced-target holder. The simulated solution of Ni(II) – Cu(II) matrix was considered as thesolution of post-proton-irradiated nickel target containing both irradiated nickel and radioactive copper, but in thepresented work the proton irradiation of nickel target was omitted, while the radioactive copper was originallyobtained from neutron irradiation of CuO target. The separation of radioactive copper from the nickel target matrixwas based on anion exchange column chromatography in which the radiocopper was conditioned to form anioncomplex CuClg-spectrometric analysis showed a single strong peak at 511 keVwhich is in accord to g-annihilation peak coming from positron decay of Cu-64, and a very weak peak at 1346 keVwhich is in accord to g-ray of Cu-64.. The simulations on Nickel target preparation and separation of Ni(II)- Cu(II) matrix has been carried out as a preliminary study for production of medical radioisotope Cu-64 based onnuclear reaction of

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ANION-EXCHANGE SEPARATION OF NEPTUNIUM FROM URANIUM AND THORIUM IN BASIC SOLUTION.

10.2172/4069794 ◽

1970 ◽

Author(s):

A. P. Masino ◽

K. A. Orlandini ◽

S. Fried ◽

D. Cohen

Keyword(s):

Anion Exchange ◽

Basic Solution ◽

Anion Exchange Separation

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Tropolone-triethylamine equilibria in various solvents

Australian Journal of Chemistry ◽

10.1071/ch9800491 ◽

1980 ◽

Vol 33 (3) ◽

pp. 491 ◽

Cited By ~ 3

Author(s):

B Poh ◽

H Siow

Keyword(s):

Nuclear Magnetic Resonance ◽

Dielectric Constant ◽

Aprotic Solvent ◽

Ion Pair ◽

Pair Formation ◽

Spectroscopic Methods ◽

Aprotic Solvents ◽

Ion Pair Formation ◽

No Formation ◽

Hydrogen Bonded

Infrared and nuclear magnetic resonance spectroscopic methods were used to study the tropolonetriethylamine equilibria. In aprotic solvents tropolone transfers its proton to triethylamine to form an ion pair which is in equilibrium with the intramolecularly hydrogen-bonded tropolone. The extent of ion pair formation increases with the dielectric constant of the aprotic solvent. Unlike the case of the p- nitrophenol-triethylamine system, there is no formation of a hydrogen bonded complex between tropolone and triethylamine. In the case of the tropolone-dibutylamine system in aprotic solvents, only ion pair formation is observed.

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Dihydrolevoglucosenone (Cyrene) as a bio-based alternative for dipolar aprotic solvents

Chemical Communications ◽

10.1039/c4cc04133j ◽

2014 ◽

Vol 50 (68) ◽

pp. 9650-9652 ◽

Cited By ~ 160

Author(s):

James Sherwood ◽

Mario De bruyn ◽

Andri Constantinou ◽

Laurianne Moity ◽

C. Rob McElroy ◽

...

Keyword(s):

Aprotic Solvent ◽

Aprotic Solvents ◽

Dipolar Aprotic Solvent ◽

Dipolar Aprotic Solvents

Dihydrolevoglucosenone (Cyrene) is a bio-based molecule, derived in two simple steps from cellulose, which demonstrates significant promise as a dipolar aprotic solvent.

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Basicité de solvants dipolaries aprotoniques

Canadian Journal of Chemistry ◽

10.1139/v76-301 ◽

1976 ◽

Vol 54 (13) ◽

pp. 2101-2109 ◽

Cited By ~ 10

Author(s):

Robert Domain ◽

Marcel Rinfret ◽

Robert L. Benoit

Keyword(s):

Gas Phase ◽

Aprotic Solvent ◽

Aprotic Solvents ◽

Fluorosulfonic Acid ◽

Calorimetric Data ◽

Proton Affinities ◽

Enthalpy Changes ◽

Solvent Basicity ◽

Enthalpy Of Protonation ◽

Dipolar Aprotic Solvents

The basicities of five dipolar aprotic solvents, sulfolane, propylene carbonate, acetonitrile, dimethylformamide, dimethyl sulfoxide, and of water have been characterized by using as parameter the solvation enthalpy of the gaseous proton. The corresponding values of ΔH(g → s)(H+) are deduced from experimental calorimetric data on the reaction HCl(g) → H+(s) + Cl−(s) and the known enthalpy changes for H+(g) → H+(aq) and Cl−(aq) → Cl−(s). The transfer enthalpies of Cl− from water to solvent are estimated on the basis of an extrathermodynamic assumption. The values obtained for ΔH(g → s)(H+) are (kcal mol−1): TMS(−252.6), AN(−256.6), PC(−259.5), H2O(−270.0), DMF(−276.7), DMSO(−276.1). These values are compared to other parameters currently used to define the basicity of these solvents whether as molecules or as media. Thus, proton affinities are such that in the gas phase, acetonitrile is more basic than water by 17 kcal mol−1, while in the liquid phase our results indicate that acetonitrile is less basic than water by 13 kcal mol−1. This variation of 30 kcal mol−1 is attributed to differences in the nature of the solvated proton H+(s) in both solvents: several indications suggest that H+(s) is present as H+(AN)2 in AN, an aprotic solvent, while it is stabilized as H+(H2O)n in water, a protic solvent because of the formation of hydrogen bonds of a cooperative nature. Solvent basicity orders as defined with respect to ΔH(g → s)(H+) and ΔH(g → s)(HA) are shown to differ and the consequences as to the solvent effect on the dissociation of acids HA are considered. Further, there is a nearly linear relationship for the five dipolar aprotic solvents between the values of ΔH(g → s)(H+) and the enthalpy of protonation in fluorosulfonic acid.

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Diformylxylose as a New Polar Aprotic Solvent Produced from Renewable Biomass

Green Chemistry ◽

10.1039/d1gc00641j ◽

2021 ◽

Author(s):

ANASTASIA KOMAROVA ◽

Graham R Dick ◽

Jeremy Luterbacher

Keyword(s):

Aprotic Solvent ◽

Aprotic Solvents ◽

Renewable Biomass ◽

Polar Aprotic Solvent

Demand for sustainable polar aprotic solvents is increasing due to their unique solubilizing properties and the toxicity of conventional analogs, which are facing pressure from extensive safety legislation. Polar aprotic...

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