Amides hexafluorophosphate

The solvents themselves are adsorbed on the electrode surface, as is shown by the capacitance-potential graphs illustrated in Fig. 9 (Payne, 1967, 1970) potassium hexafluorophosphate, the electrolyte in each of the solvents, is thought to be adsorbed only very weakly. The solvents show somewhat differing curves and the peaks have been interpreted both in terms of competition between the solvent and anions for sites at the surface and also in terms of solvent reorientation. Ethers are adsorbed from the amide solvents most strongly at the potentials around the peaks and this has been postulated to be due to an increase in freedom for the solvent to rotate at these potentials (Dutkiewicz and Parsons, 1966). 

The initial route to taranabant relied on a late stage amide bond coupling between racemic amine rac-2 and pyridine acid 3 mediated by (benzotriazol-l-yloxy)tripyr-rolidinophosphonium hexafluorophosphate (Py-Bop), followed by chiral HPLC separation of the product to afford a single enantiomer (Scheme 9.1). 

In 2002, Leadbeater and Torenius reported the base-catalyzed Michael addition of methyl acrylate to imidazole using ionic liquid-doped toluene as a reaction medium (Scheme 6.133 a) [190], A 75% product yield was obtained after 5 min of microwave irradiation at 200 °C employing equimolar amounts of Michael acceptor/donor and triethylamine base. As for the Diels-Alder reaction studied by the same group (see Scheme 6.91), l-(2-propyl)-3-methylimidazolium hexafluorophosphate (pmimPF6) was the ionic liquid utilized (see Table 4.3). Related microwave-promoted Michael additions studied by Jennings and coworkers involving indoles as heterocyclic amines are shown in Schemes 6.133 b [230] and 6.133 c [268], Here, either lithium bis(trimethylsilyl)amide (LiHMDS) or potassium tert-butoxide (KOtBu) was em-... 

The microwave-assisted thionation of amides has been studied by Ley and coworkers using a polymer-supported thionating reagent [115]. This polymer-supported amino thiophosphate serves as a convenient substitute for its homogeneous analogue in the microwave-induced rapid conversion of amides to thioamides. Under microwave conditions, the reaction is complete within 15 min, as opposed to 30 h by conventional reflux in toluene (Scheme 7.95). The reaction has been studied for a range of secondary and tertiary amides and GC-MS monitoring showed that it proceeded almost quantitatively. More importantly, this work was the first incidence of the use of the ionic liquid l-ethyl-3-methylimidazolium hexafluorophosphate... 

The synthesis of a dipeptide dihydrothiazole by way of an imidate is shown in Scheme 13.[521 The Boc-protected amino acid 37 (in this case Val) was converted into the primary amide 38 by the mixed anhydride coupling with ammonia. The amide was then directly converted into the imidate 39 using triethyloxonium hexafluorophosphate which was subsequently condensed with H-Cys-OEt to provide the dihydrothiazole 40. 

Although fluorine is known to be a rather poor leaving group in substitution reactions, some examples have been reported for the replacement of fluorine by N-nucleophiles. Here, substitution can proceed with amines,1 -3 amides,4 amidines,5-6 hydrazines3-7 or azides.8-9 Nitriles in the presence of nitrosyl hexafluorophosphate replace fluorine in alkyl fluorides, in a Ritter-like reaction, to form tV-alkylnitrilium species, which are hydrolyzed to amides.10... 

Here we give an example of this method. The resin-bound 229 was treated with 0-bcnzotriazolyl-/V,/V,/V, /V -tetramethyluronium hexafluorophosphate (HBTU) in anhydrous dichloromethane, and intramolecular amide bond formation occurred to afford resin-bound nitrobenzothiazepine 230 (Equation 19) <1999TL4939>. 

Abbreviations BAL, backbone amide linker BSA, bis(trimethylsilyl)acetamide DBU, 1,8-diazabicyclo[5.4.0]undec-7-ene DCE, dichloroethane DCM, dichloromethane DIC, 2-diisopropylcarbodiimide DIEA, diisopropylethyl amine DMAP, A,A-dimethylaminopyr-idine DMF, dimethylformamide DMSO, dimethyl sulfoxide EDC, l-(3-dimethylaminopro-pyl)-3-ethylcarbodiimide hydrochloride HBTU, [0-(7-azabenzotriazol-l-yl)-l, 1,3,3-tetramethyluronium hexafluorophosphate MCPBA, m-chloroperoxybenzoic acid NMP, N-methylpyrrolidinone NMM, A-methylmorpholine PfP, pentafluorophenol RT, room temperature TFA, trifluoroacetic acid THF, tetrahydrofuran. 

However, when considering the choice of ionic liquid it is worth noting that a number of the anions that are utilized in ionic liquids have already been investigated as dopants for conducting polymers using a conventional molecular solvent/electrolyte system. For example, the relative merits of the trifluoromethane-sulfonate [OTfp [37], hexafluorophosphate [PF6]- [38. 39], sulfonated aromatics [40, 41] and, particularly, bis(trifluoromethanesulfonyl)amide [NTf)] [37, 42-45] anions have been well studied and it may be pertinent to consider this research when selecting an ionic liquid for investigation. 

The hexafluorophosphate adducts tend to decompose but the complexes with the corresponding amides are stable even after dehydration [20]. 

Boc-D-7-hydroxy-l,2,3,4-tetrahydroisoquinoline-3-carboxylic acid was dissolved in THF containing benzotriazol-l-yl-oxy-tris-(dimethylamino)phosphonium hexafluorophosphate and triethylamine and heated with the Step 1 product until amidation was completed. Thereafter, the coupled product was isolated. 

Peptide coupling reagent bromotris(pyrrolidino)phosphonium hexafluorophosphate (PyBrOP) was used in synthesis of 10-membered succinyl bis(amide) 27 in 57% yield (Equation 3) <2002TL2593>. Similarly, 1,6-diazacyclo-decane substituted on only one nitrogen atom was prepared by reaction of A -trityl-protected linear triamine with succinyl anhydride. The amides were further reduced to amines using LAH <2002TL2593>. 

Amides. Amides can be prepared by reaction of alkyl halides with nitriles in the presence of nitrostjnium hexafluorophosphate at —15 to 25°. 

Abbreviations used Dde, N-[l-(4,4-dimethyl-2,6-dioxocyclohexadiene)]-ethyl DIEA, diisopropylethylamine DMF, N,N-dimethylformamide EDC, l-Ethyl-3-(3 -dimethylaminopropyl)carbodiimide hydrochloride HOBt, 1-hydroxybenzotriazole NHS, N-hydroxysuccinimide NMP, l-methyl-2-pyrroIidinone PAL, Peptide Amide Linker [5-(4-(9-fluorenylmethyloxycarbonyl) aminomethyl-3,5-dimethoxyphenoxy) valeric acid] PyBOP, Benzotriazole-l-yl-oxy-trispyrrolidino-phosphonium hexafluorophosphate TFA, trifluoroacetic acid. 

DyCl3, Dyprosium chloride, 22 39 DyFi8N8oj, 2C,2H72, Dyprosium(III), hex-akis(diphenyIphosphinic amide)-, tris(hexafluorophosphate), 23 180 DyN30,3C8Hi8, Dyprosium(III), trini-... 

FisNiOjPnYbCnHr , Ytterbium(III), hex-akis(diphenylphosphinic amide)-, tiis(hexafluorophosphate), 23 180 FeBF2,02CiiHi3, Iron(lH-), dicarbonyI(ii -cyclopentadienyI)(V-2-methyI-l-pro-phenyl)-, tetrafluoroborate(l-),... 

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