DIMETHYL AMMONIUM TRIFLUOROACETATE

Bis(bis-hexyl-amino)-methylene] dimethyl-ammonium trifluoroacetate... 

REGIOSELECTIVE MANNICH CONDENSATION WITH DIMETHYL(METHYLENE)AMMONIUM TRIFLUOROACETATE 1-DIMETHYLAMINO-4-METHYL-3-PENTANONE... 

The less highly substituted Mannich bases can also be prepared directly from ketones and dimethyl(methylene)ammonium trifluoroacetate by the procedure reported here, which takes advantage of the isomerization of Mannich bases in trifluoroacetic acid. (In acetic acid the Mannich bases undergo elimination of dimethylamine to give a-methylene ketones.) This method is rapid and affords products having an isomeric purity of at least 90% without difficult separations. The 49-57% yield of l-(di-methylamino)-4-methyl-3-pentanone obtained with this procedure compares favorably with the overall yields of amino ketones prepared by the indirect routes mentioned previously. 

Butanone, 4-(dimethylamino)-3,3-dimethyl- (8, 9) (53921-82-7) Dimethyl(methylene)ammonium trifluoroacetate Ammonium, di-methylmethylene-, salt with trifluoroacetic acid (1 1) (8) ... 

Cationics of the structure alkylamidopropyl-A/-(2,3-dihydroxy)-A/A/-dimethyl-ammonium chloride have been analysed on a column (150 x4 mm i.d.) of micro-Bondapak CN with water/acetonitrile/THF (57 42 1 by volume) containing 0.1% trifluoroacetic acid as mobile phase and differential refractive index detection [32]. Quantification was by external standard and the method was applied to cosmetic products. 

A procedure in which the iminium salt shown, A, N-dimethyl(methylene) ammonium trifluoroacetate, is isolated and added separately to an enolate ion allows Mannich bases to be prepared by routes other than those involving acidic media. This procedure is exemplified by entry 4. N,iV-Dimethyl(methylene) ammonium iodide is commercially available as Eschenmoser s salt and is sufficiently electrophilic so as to react directly with enol silyl ethers in neutral media. Ketone enolates have been converted to Mannich bases with Eschen-moser s salt (entry 5). 

Aqueous salt solutions such as saturated 2inc chloride [7646-85-7] or calcium thiocyanate [2092-16-2] can dissolve limited amounts of cellulose (87). Two non-aqueous salt solutions are ammonium thiocyanate [1762-95-4]— uoamonia. and lithium chloride /744Z-4/A/—dimethyl acetamide [127-19-5]. Solutions up to about 15% can be made with these solvents. Trifluoroacetic acid [76-05-17—methylene chloride [75-09-2] and /V-methy1morpho1ine N-oxide [7529-22-8]—(92—94) are two other solvent systems that have been studied (95). 

Scheme 2.12 shows some representative Mannich reactions. Entries 1 and 2 show the preparation of typical Mannich bases from a ketone, formaldehyde, and a dialkylamine following the classical procedure. Alternatively, formaldehyde equivalents may be used, such as l>is-(di methyl ami no)methane in Entry 3. On treatment with trifluoroacetic acid, this aminal generates the iminium trifluoroacetate as a reactive electrophile. lV,A-(Dimethyl)methylene ammonium iodide is commercially available and is known as Eschenmoser s salt.192 This compound is sufficiently electrophilic to react directly with silyl enol ethers in neutral solution.183 The reagent can be added to a solution of an enolate or enolate precursor, which permits the reaction to be carried out under nonacidic conditions. Entries 4 and 5 illustrate the preparation of Mannich bases using Eschenmoser s salt in reactions with preformed enolates. 

A major advantage is the potential to lock (and protect) written information in the photobistable material. A number of chemical gated systems involving mutual regulation of the photochromic event and, for instance, fluorescence, ion binding, or electrochemical properties have been reported.1501 Scheme 19 illustrates a chiral gated response system based on donor-acceptor substituted alkene 17.[511 The photochemical isomerization process of both the M-ds and the P-trans form was effectively blocked by the addition of trifluoroacetic acid. Protonation of the dimethyl-amine donor unit of M-rfs-17a and P-trons-17b resulted in an ineffective acceptor-acceptor (nitro and ammonium) substituted thioxanthene lower half. Since the stereoselective photoisomerization of 17 relies on the presence of both a donor and acceptor unit, photochemical switching could be restored by deprotonation by the addition of triethylamine. 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

Scheme 1 Reduction of Methionine Sulfoxide with Ammonium lodide/Dimethyl Sulfide in Trifluoroacetic...

Transient siloxanolate anionic catalysts prepared by reacting four moles of D-4 with one of tetramethyl ammonium hydroxide at 80 C are effective for equilibrating "neutral" systems such as the epoxy ( ), "basic" dimethyl-amino (64) or aminopropyl (59,67) end-blockers and D-4. With "acidic" functionality on the end-blocker, we have successfully utilized trifluoroacetic acid for the equilibrations. Further details of the oligomer synthesis and their utilization in segmented copol)nners will be described in future publications. 

OXIDATION, REAGENTS Acetyl nitrate. Bis(tri-n-butyltin)oxide. Bromine-Hexameth-ylphosphoric triamide. f-Butyl perbenzoate. Ceric ammonium nitrate. N-chlorosuc-cinimide-Dimethyl sulfide. Chromic add. Chromic anhydride. Chromic anhydride-Acetic anhydride. Chromic anhydride-Hexamethylphosphoric triamide. 2,3-Dichloro-5,6-dicyano-l,4-benzoquinone. Dimethyl sulfoxide. Dimethyl sulfoxide-Trifluoro-acetic anhydride. Diphenylseleninlc anhydride. Iodine tris(trifluoroacetate). Lead tetraacetate. N-Methylmorpholine -N-oxide. p-NitrobenzenesulfonyI peroxide. Oxygen, singlet. Palladlumfll) chloride. Peroxybcnzimidic acid. Phenylseleninyl chloride. N-Phenyl-l,2,4-triazoline-3,5-dione. Potassium chromate. Potassium superoxide. Pyri-dinium chlorodiromate. Salcomine. Silver carbonate-Celite. Sodium hypochlorite. Sulfuryl chloridc-Silica gel. Thallium(III) acetate. ThaUium(III) nitrate. Triphenyl phosphite ozonide. Trltyl tetrafluoroborate. Uranium hexafluoride. 

A -oxide/water (NMMO/H2O) lithium chloride/dimethyl acetamide (LiCl/ DMAc) trifluoroacetic acid/methylene chloride (TFA/CH2CI2) calcium thiocyanate/water (Ca(SCN)2/H20) ammonia/ammonium thiocyanate (NH3/ NH4SCN) zinc chloride/water (ZnCl2/H20) and sodium hydroxide/water (Na0H/H20). Two newly reported solvents are also of interest one based on an ionic liquid, namely, l-butyl-3-methylimidazolium chloride [1] and a polar fluid/salt solvent, ethylene diamine/KSCN, discussed in Section 12.4. 

DOTMA, l,2-dioleyl-3-iV,iV,iV-trimethylaminopropane chloride DC-Chol, 3-j8-[A-(A, A -dimethyl-ethane)carbamoyl]cholesterol DMDHP, ( )-N,N-[bis(2-hydroxyethyl)]-iV-[2,3-bis(tetradecanoyloxy)propyl]ammonium chloride DMRIE, l,2-dimyristyloxypropyl-3-dimethyl-hydroxyethyl ammonium bromide DOTAP, l,2-dioleoyloxy-3-(trimethylamino)propane DHDEAB, A,A-di-n-hexadecyl-iVA -dihydroxyethylammonium bromide HDEAB, N-n-hexadecyl-iVA -dihydroxyethylammonium bromide MOOHAC, A-methyl-A- -octadecyl-iV-oleyl-iV-hydroxyethylammonium chloride DOMHAC, N-methyl-AA-di-n-octadecyl-iV-hydroxyethylammonium chloride DOHEMAB, A,A-di[0-hexadecanoyl]hydroxyethyl-A-hydroxyethyl-A-methylammonium bromide DOSPA, 2,3-dioleoyloxy-A-[2-(sperminecarboxamido)ethyl]-A,A-dimethyl-l-propanaminium trifluoroacetate DDAB, dioctadecyldimethylam-monimn bromide DOPE, l,2-dioleoyl-propyl-3-phosphatidylethanolamine. 

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