- A Comparison of Immobilised Triphenylphosphine and 1-Hydroxybenzotriazole as Mediators of Catch-and-Release Acylation Under Flow Conditions
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Described herein is a comparative study of immobilised triphenylphosphine (PS-PPh3) and 1-hydroxybenzotriazole (PS-HOBt) to mediate amide couplings under continuous flow. Compared to Appel-type amidations (PS-PPh3), the developed ‘catch-and-release’ approach (PS-HOBt) afforded near-quantitative amide conversions. Utilising this strategy, sulfonyl chloride amenability enabled facile access to an expanded library of sulfonate and sulfonamides. Post-constructional peptide modification was also demonstrated, affording two Nβ-functionalised pentapeptides in high yields and purities. In contrast to frequently utilised coupling agents, the PS-HOBt resin could be recycled six times without a reduction in efficacy or regeneration requirements.
- Aldrich-Wright, Janice R.,Dankers, Christian,Gordon, Christopher P.,Jurisinec, Ashley,Menti-Platten, Maria,Tadros, Joseph
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supporting information
(2022/03/07)
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- Behaviour of the extractant Me-TODGA upon gamma irradiation: Quantification of degradation compounds and individual influences on complexation and extraction
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Diglycolamides (DGAs), and in particular N,N,N′,N′-tetraoctyl diglycolamide (TODGA), are well-known candidates for the co-extraction of trivalent actinides (An(iii)) and lanthanides (Ln(iii)) from highly acidic aqueous solutions of nuclear waste. A derivative of TODGA, the so-called Me-TODGA with the addition of a methyl-substituent on the central part of the TODGA molecule, has been proposed to improve its stability properties and extraction behaviour. This work describes the stability and viability of Me-TODGA by studying the properties of its degradation compounds formed upon gamma irradiation. The main degradation products have been synthesised and studied individually. Particular attention has been paid to their quantification, as well as their complexation and extraction properties, for a better understanding of the degradation pathways and the behaviour of the solvents upon gamma irradiation. The extraction behaviour of irradiated Me-TODGA solvents and their degradation compounds have been studied toward the fission products and lanthanides present in a highly active raffinate (HAR) solution. Binding properties of parent molecules (TODGA and Me-TODGA) and their main degradation compounds with Ln(iii) have also been determined in a homogeneous phase. All the results obtained on degradation compounds are compared with those of the parent molecules in order to assess the effects of these compounds on the separation process. Among the radiolytic compounds, 2-hydroxyoctylamides are the most problematic compounds not only because of their high affinity for lanthanides but also for other fission products.
- Hubscher-Bruder,Mogilireddy,Michel,Leoncini,Huskens,Verboom,Galán,Nú?ez,Cobos,Modolo,Wilden,Schmidt,Charbonnel,Guilbaud,Boubals
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p. 13700 - 13711
(2017/11/27)
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- Gamma-radiolytic stability of new methylated TODGA derivatives for minor actinide recycling
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The stability against gamma radiation of MeTODGA (methyl tetraoctyldiglycolamide) and Me2TODGA (dimethyl tetraoctyldiglycolamide), derivatives from the well-known extractant TODGA (N,N,N′,N′-tetraoctyldiglycolamide), were studied and compared. Solutions of MeTODGA and Me2TODGA in alkane diluents were subjected to 60Co γ-irradiation in the presence and absence of nitric acid and analyzed using LC-MS to determine their rates of radiolytic concentration decrease, as well as to identify radiolysis products. The results of product identification from three different laboratories are compared and found to be in good agreement. The diglycolamide (DGA) concentrations decreased exponentially with increasing absorbed dose. The MeTODGA degradation rate constants (dose constants) were uninfluenced by the presence of nitric acid, but the acid increased the rate of degradation for Me2TODGA. The degradation products formed by irradiation are also initially produced in greater amounts in acid-contacted solution, but products may also be degraded by continued radiolysis. The identified radiolysis products suggest that the weakest bonds are those in the diglycolamide center of these molecules.
- Galn, Hitos,Zarzana, Christopher A.,Wilden, Andreas,Nez, Ana,Schmidt, Holger,Egberink, Richard J. M.,Leoncini, Andrea,Cobos, Joaqun,Verboom, Willem,Modolo, Giuseppe,Groenewold, Gary S.,Mincher, Bruce J.
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p. 18049 - 18056
(2015/10/28)
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- Synthesis and FTIR spectroscopic study of some N-monosubstituted propanamides
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In the present work we investigated the conformations of some N-mono-substituted propanamides of general formula CH3CH2CONHR, wherein R is chosen from n-(C1-C9)alkyl, cyclo(C3-C6)alkyl, some branched (C3-C6)alkyl or phenyl. The amides were synthesised by the well known Schotten-Baumann reaction-acylation of the corresponding amines with propionyl chloride. On the basis of FTIR data for diluted solutions (concentrations below 10-3 mol dm-3) of N-mono-substituted propanamides in carbon tetrachloride, chloroform, dichloromethane, or a 1:1.5 mixture of benzene and carbon tetrachloride the exact position of the N-H stretching band was established. For spectroscopic data the different conformational isomers were assigned and its structures unequivocally proven. These results are in good accordance with 1H NMR and MS data.
- Antonovi?,Stojanovi?,Bo?i?,Nikoli?,Petrovi?
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p. 421 - 423
(2007/10/03)
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