MA-Dimethylformamide

Both the (RR)- and (5S)-enantiomers of hydrobenzoin (Figure I4a) have been made to react (110, 117, 118) successfully in a (2 + 2) cyclization with ethylene glycol ditosylate in the presence of bases (e.g., NaOH in dioxane or NaH in MA -dimethylformamide) to give the enantiomeric tetiaphenyl-18-crown-6 derivatives (RRRR)-73 and (SSSS)-73. The corresponding optically pure tetra-anisyl, tetra-a-naphthyl, and tetra-/3-naphthyl-18-crown-6 derivatives 74, 75, and 76, respectively, have also been prepared in similar fashion (119). It should be noted that (RRRR)- and (,SSSS)-73 have also been obtained as a result of a base-promoted (1 + 1) cyclization (120) between the chiral extended diol and... 

Aryl ethers can also represent the dominant product For example, 3,3 -bis(tri fluoromethyl)-5,5 -dinitrodiphenyl ether is obtained in 54% yield from 3,5-dini trobenzotrifluoride and potassium fluoride in MA -dimethylformamide with catalytic amounts of water at 160 °C after 24 h [110]... 

Fig. 2. The composition dependence of Ariij (mol/mol) around a methanol molecule for the (a) binary system methanol-water and for the quasi-binary system MA -dimethylformamide-methanol-water (b) jcp = 0.04 (c) jcp = 0.08 (d) jcp = 0 lb Zm = (- M + - w)) ...

Hydrazones have been employed as substrates in the synthesis of pyrazoles. Hydrazones 28 and 31, prepared from palladium-catalyzed heteroaryl halides with benzophenone hydrazone, reacted with 1,3-bifunctional substrates 29 and 32 under acidic conditions to yield pyrazoles 30 and 33, respectively <04TL5935>. Treatment of hydrazones 34 with 2,4,6-trichloro[l,3,5]triazine and MA -dimethylformamide gave iminium salts 35, which were converted to 3-aryl-4-formylpyrazoles 36 <04SL2299>. 

Corrections for the (j)2 effect can be made most readily for the mercury electrode, since the variation of with E and electrolyte concentration can be obtained from electrocapillary curves, as discussed in Section 13.2. In the absence of specific adsorption of electrolyte, (f)2 can then be calculated by assuming that the GCS model applies [from (13.3.26)]. Such corrections are less frequently attempted at solid electrodes because data about the doublelayer structure at them is often lacking. Typical results showing such corrections for the reduction of Zn(II) at a Zn(Hg) electrode in aqueous solution (58) and for the reduction of several aromatic compounds in MA -dimethylformamide solution (65) are given in Table... 

Solubility Soluble in water, MA -dimethylformamide UV-Visible (A-max) 492 nm Melting Point >360°C... 

Fig. 4, Reaction scheme for the preparation of the 2 -0-allyguanosine building block Reagents i, allyl ethyl carbonate, l,4-bis(diphenylphosphino)butane and tris (dibenzylideneacetone)dipalladium(O) in tetrahydrofuran ii, sodium azide in MA -dimethylformamide, lii, stannous chloride, thiophenol, and triethylamine in acetonitrile, iv, tetrabutylammonium fluoride in tetrahydrofuran v, adenosine deaminase in aqueous phosphate buffer pH 7.4/dimethylsulfoxide vi, A, A -dimethyl-formamide dimethyl acetal in methanol, vii, 4,4 -dimethoxytrityl chloride and triethylamine in pyridine, viii, 2-cyanoethoxy A, iV-diisopropylaminochlorophosphme and A, //-diisopropylethylamine in 1,2-dichloroethane...

Solubility Soluble in acetonitrile, dichloromethane, MA -dimethylformamide, methanol Melting Point 208... 

MA -dimethylformamide, dimethyl sulfoxide, methanol Melting Point 194-197 Absorption 482nm(MeOH)... 

Ethylenediaminetetraacetic acid (EDTA) [60-00-4] M 292.3, m 253 (dec), pK O.26 pK 0.96, pKj 2.60, pK 2.67, pK 6.16, pK 10.26. Dissolved in aqueous KOH or ammonium hydroxide, and ppted with dil HCl or HNO3, twice. Boiled twice with distd water to remove mineral acid, then recrystd from water or dimethylformamide. Dried at 110°. Also recrystd from boiling IN HCl, wash crystals with distd H2O and dried in vacuo. [Ma and Ray Biochemistry 19 751 1980.]... 

Dimethylformamide (DMF) was distilled under reduced pressure (20 ma) from calcium hydride. Diethyl phosphite may be used directly from a freshly-opened bottle or redistilled before use. 

Abbreviations arene, i/6-benzene or substituted benzene derivative bipy, 2,2 -bipyridyl Bu, Bu", Bu, iso-, n-, or rerf-butyl COD, 1,5-cyclo-octadiene Cp, /5-C5H5 DAD, dimethyl-acetylene dicarboxylate dam, 1,2-bis(diphenylarsino)methane DBA, dibenzylideneacetone DMF, A. A -dimethylformamide dpe, l,2-bis(diphenylphosphino)ethane dpen, os-l,2-bis(di-phenylphosphino)ethylene dpm, 1,2-bis(diphenylphosphino)methane ESR, electron spin resonance F6-acac, hexafluoroacetylacetone FN, fumaronitrile MA, maleic anhydride Me, methyl MLCT, metal ligand charge transfer phen, 1,10-phenanthroline Pr , Pr", iso- or n-propyl py, pyridine RT, room temperature TCNE, tetracyanoethylene tetraphos, (Ph2PCH2CH2)jP THF, tctrahydrofuran Xylyl, 2,6-Me2C6H3. 

Matsuda introduced carboxyl groups to wood meal using dicarboxylic anhydrides. Maleic (MA), succinic (SA), and phthalic anhydride (PA) were used as acid anhydrides, N,A -dimethylbenzylamine was used as a catalyst, and dimethylsulfoxide (DMSO) or dimethylformamide (DMF) was used as solvent [14]. The carboxyl groups in the esterified wood were then further reacted with epichlorohydrin to produce oligoesterified woods. A detailed description of these reactions is given in Chapter 6. 

The grafting of TAA onto poly(MA-co-ABME) is carried out either by solution polymerization using dimethyl formamide as the solvent or by suspension polymerization (better yield) using dimethylformamide as the solvent and paraffin oil as the suspending medium... 

The yield of TAA-grafted MA-ABME copolymer depends on (a) total concentration of TAA HCl and MA-ABME copolymer, (b) suspending medium (paraffin oil better than hexane), (c) solvent (dimethylformamide superior to tetrahydrofuran or acetone), and (d) ABME amount in copolymer The best resins prepared by this method using MA-ABME copolymer and TAA have a thermally regenerable capacity of about 0.7 meq/g and an acid-to-base ratio of 1.4. 

Compound (+)-27 was synthesized according to Scheme 7 by reaction of Si(OMe)4 with one mole equivalent each of (i ,) )-tartaric acid and 2-(dimethylamino)ethanol in boiling dimethylformamide and isolated in 79 % yield as a crystalline solid [10]. Its identity was established by elemental analyses, solution-state ( H, C, Si) and solid-state ( Si CP/MAS) NMR studies, and FAB-MS investigations. By analogy to (+)-25, compound (+)-27 is optically active. 

Arthur et al. reported that even in the presence of solvents in which cotton swells (HCL, dimethylformamide (DMFA) or dimethyl sulfoxide (DMSO)) about 30% of long-lived cellulose macroradicals resulting from irradiation were still unaccessible to the monomer. The same result was obtained from experiments25 involving grafting of methacrylate (MA) and methyl methacrylate (MMA) to cellulose in the presence of... 

Izutsu [37] compared the calculated EyCs) components with those found experimentally for junetions of aqueous solutions of MA-type salts with their solutions in dimethyl sulfoxide (DMSO), acetonitrile (AN), dimethylformamide (DMF), methanol (MeOH), propylene carbonate (PC), and benzonitrile (BN). Different MA salts were used, where M = Et4N, Me4N, Pr4N and Bu4N" and A = picrate, Cl , Br , I, and ClOj". The relations between the two measured and calculated components were linear, but the slope A n,eas/ caic was only equal to unity in the case of the immiscible H20-nitrobenzene junction. In the case of junctions with other solvents it was about 0.5. Even lower slopes were obtained for junctions of methanol and other organic solvents. The origin of the difference between calculated and determined (s) values is not known, but it should be kept in mind that the Lj(s) estimates are only qualitative in nature. 

Figure 27. Application of flow cell and UV spectroscopy to study the reduction of aromatic compounds in iV,iV-dimethylformamide/0.1 M BU4NBF4 a) Plot of absorbance at = 556 nm and 732 nm, of the products obtained in the reduction of anthraquinone (T) and anthracene ( ), respectively, as the galvanostatic current to the flow cell is increased and a continuous flow of 5 mL min is maintained. The substrate concentrations are both 0.1 mM and the light path is 1 cm b) and c) The absorption spectra of the product obtained from reduction of anthraquinone and anthracene, respectively, when the galvanostatic current is increased above the maximum required for generating the radical anion. The current is increased from 2.0 to 2.8 mA in steps of 0.2 mA and the development in the spectra is indicated with arrows. Isosbestic points are also indicated. For anthraquinone, the spectra of the radical anion and the dianion could be resolved whereas for anthracene the dianion is protonated and spectra of the radical anion and 9,10-dihydroanthracen-9-ide could be resolved [65].

It is well known that halomethyleneiminium salts, often prepared in situ (see Section 2.1.2.2) react with ammonium salts, primary amines, secondary amides, urea and IV-substituted ureas to afrbrd amidinium salts, from which the free amidines can be obtained by addition of bases. > 4 Some recent results are given below. Dimethylformamide chloride and other 7V,iV-disubstituted formamide chlorides were reacted with acetanilides, chloroacetanilides, 6-aminopenam derivatives, 2-aminopyrimidine, 4-aminouracil, 2-amino-4-chloropyridazine, 2-aminothiazole, 2-aminobenzothiazole and thiobenzamides to give the amidines via the amidinium salts. In the reaction of MA -disubstituted formamide chlorides with thiobenzamides the solvent seems to be decisive for the course of the reaction. In tertiary formamides the thiobenzamides are desulfurized to nitriles, whereas in CHCI3 or CCI4 amidinium salts (296 Scheme 45) are formed. From trimethylsilyl isocyanate and the fluorinated amine (297) the /V-fluorocarbonylamidine (298) is accessible. ... 

Structural studies of two complexes with dimethylformamide (DMF) and dimethylacetamide (DMA) were reported. In the former, three types of solvent molecules are embedded in the crystal lattice first, disordered isolated molecules located just above the cavities formed by the resorcinol units second, clusters of four DMF molecules located between the calixarene layers and third, single DMF molecules located inside the layers close to the alkyl chains. The challenge for solid state NMR is to recognize and locate guest molecules in the lattice. CP/MAS, dipolar dephasing and variable contact-time exper-... 

The electrode preparation, the enzyme immobilization procedure was described as follows. About two mg of acid treated MWCNTs was ultrasonicated in 1 pL of N, N dimethylformamide (DMF) until a black suspension was obtained. About 15 pi of this MWCNTs suspension was casted on the working area of SPE surface and dried in an oven at 80 °C for 30 min. About 10 pi of AChE solution (0.132 U) was dropped on the MWCNTs modified electrode surface and dried at room temperature under a current of air and used. Hydrodynamic voltammetric studies results shows that significant response was observed at MWCNT-SPE towards 2mM thiocholine, whereas the response was poor at the unmodified electrode (Fig. 2). The linear response of the MWCNT-SPE modified sensor was found to be between 5 pM - 430 pM (r2 = 0.999) with a sensitivity of 6.018 mA/M. In contrast, the response of AChE/SPE modified electrode was only 5 % and thus this result further reveals the contribution of MWCNTs in improving the sensitivity. 

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