N, jV-Dimethylformamide

Vigreux column. When no more methanol distills over (ca. 24 h), the dark brown reaction mixture is reduced in volume by the distillation of 100 mL of toluene. While the flask is still hot, 300 mL of cyclohexane are added with vigorous stirring and a yellow, crystalline solid comes out of solution. At this point, the copious amount of solid makes stirring difficult. The mixture is allowed to stand overnight and the yellow solid is collected by suction filtration. The solid is washed with 2 1 cyclohexane/toluene (ca. 300 mL) and, then cyclohexane and is allowed to air dry. The solid is then dried in a vacuum dessicator (25°C, 24 h) to remove the last traces of N,N-dimethylformamide dimethylacetal (a small amount of sublimation of the product will occur). Failure to completely remove the last traces of N,JV-dimethylformamide dimethylacetal results in the gradual darkening of the product over several months time. Yield 190.3 g (86% based on 2-acetylpyridine), mp 127-128°C. 

Typical linear sweep voltammetry data for the reduction of 1,1-diphenylethylene in N, JV-dimethylformamide in the presence of methanol3... 

Heterogeneous charge transfer kinetic study of the reduction of benzonitrile (BN) in N, JV-dimethylformamide using NPSVa... 

Interestingly, all attempts to introduce an azido group at C-6 in 13 by use of sodium azide in N,JV-dimethylformamide failed. Instead of the azido derivative, the crystalline derivative 273, containing no thiocyano, isothiocyano, methylsulfonyl, or azido group (as indicated by i.r. and H-n.m.r. spectra), was obtained.23... 

H3OMC reacts with rhodium trichloride in N,JV-dimethylformamide causing decarbonylation of the solvent and incorporation of one molecule of dimethylamine in the resulting metal complex Rh(OMC)DMA [21], following a pathway already observed in the case of porphyrins [22, 23]. 

MejCO, acetone Me2SO, dimethyl sulfoxide MeOH, methanol HCONMej, N, jV-dimethylformamide AcOH, acetic acid CDC13, deuterated chloroform. 

Formylation according to the Vilsmeier-Haack method occurs also in position 3 (or 4) in good yield (Eq. 30).82,72 N,iV-Dimethylthio-formamide may advantageously replace N,jV-dimethylformamide (Eq. 31).70... 

Unsubstituted 1,3,4-selenadiazole (176) was synthesized by Kendall and Olofson by the reaction of N,JV-dimethylformamide azine (175) with hydrogen selenide in the presence of small amounts of pyridine. In addition to 176, N,iV-dimethylselenoformamide (177) was formed in equal yield. [Eq. (46)]. 

PMMA, is different in CDC13 and in CD3CN.301 Similar results were obtained for iso tactic and syndio tactic PMMAs in toluene-fi 8, nitrobenzene- and N, jV-dimethylformamide-d7 at 110°C and 60°C, and in CDC13 and nitromethane- 3 at 60°C.310... 

An alternative approach to the synthesis of benzodiazepines involves the reaction of /3-chlorovinyl carbonyl compounds with o-phenylenedi-amine. In the first example methyl /3-chlorovinyl ketone was used to obtain 5-methylbenzodiazepinium chloride.31 An extensive investigation has been made of the use of /3-chlorovinylaldehydes for the preparation of 2,3-substituted benzodiazepines.3233 The preferred conditions for reaction were in alcoholic hydrogen chloride. By this means a variety of 2-aryl-, 2,3-cycloalkeno-, and 2,3-diarylbenzodiazepines was prepared. If no acid is present an uncyclized anil results, formed by condensation of one amino group with the aldehyde. Since the /3-chlorovinylaldehydes are themselves readily obtained by reaction of a-methylene ketones with phosphoryl chloride and N, JV-dimethylformamide or jV-methylformani-lide,34 this provides an attractive route to 2,3-disubstituted benzodiazepines. 

The solvent used may be water in admixture with methanol, 2-methoxy-ethanol, or N,jV-dimethylformamide the customary oxidizing agent is K3[Fe(CN)6], but Na2Cr04, H202, or Cu(ii)Fe(m), and Ag salts are also suitable. The pH has a decisive influence on oxidative as on direct azo coupling phenols are coupled in a weakly alkaline solution, amines in a mineral acid or acetate-buffered solution. 

Lee KH, Kim ETY, La YM, Lee DR, Sung NH (2002) Influence of a mixing solvent with tetrahydrofuran and N, JV-dimethylformamide on electrospun poly(vinyl chloride) nonwoven mats. J Pol5rm Sci B Polym Phys 40 2259-2268... 

Other A/7V-dialkylformamides including commercially available TV-methylformanilide, N-formylmorpholine, /V-formylpipcridinc, A/iV-diethylformamidc and A, jV-dimethylformamide (DMF) can be employed with essentially the same procedure. With /V,/V-dimethylformamide, care has to be exercised because of the volatility of the product, which can be purified by distillation or chromatography of its hydrochloride salt. 

Hasegawa and Fletcher25,37 studied the reaction of some aldoses, mainly 2-acetamido-2-deoxyaldohexoses, with 2,2-dimethoxypro-pane-N V-dimethylformamide-p-toluenesulfonic acid at 25 and 80°. The products obtained at the two temperatures differed markedly, and, again, lack of activity at the anomeric hydroxyl group in the presence of N,N-dimethylformamide was noted. To account for this phenomenon, it was postulated that the dimethyl acetal ofA/JV-dimethyl-formamide, presumably formed in situ, reacts to afford highly labile (dimethylamino)methylene acetals which may thereby permit insertion of isopropylidene groups in abnormal positions. 

Although reaction in JV,N-dimethyIformamide greatly facilitates methylation, the method suffers from the limitation that it often gives low recoveries of methylated polysaccharides, and the effectiveness of the methylation appears to depend on the volume of N,M-dimethylformamide used. Even with monosaccharides, incomplete methylation has been reported. D. A. Rees and coworkers have given detaUs of a modified Kuhn methylation for carrageenan, and they also described the methylation of dextran and of a xylan from red seaweed in N-methyl-2-pyr-rolidinone. A micro Kuhn method suitable for oligosaccharides has been described by Perila and Bishop. ... 

Polyvinylidene fluoride PPy Polypyrrole P(VDF-TrFE) Poly(inylidene difluoride-trifluoroethylene) PANi Polyaniline PEO Poly(ethylene oxide) PU Polyurethane PBT Poly (butylene terephthalate) DMF N, iV-dimethylformamide THF Tetrahydrofuran TFA Trifluoro acetic acid FA Formic acid DCM Dichloromethane DMAc N, jV-dimethylacetamide HFIP Hexafluoro-2-propanol. 

Acrylamide impurities (dissolve the sample in a minimum amount of methanol) also separate formamide, acetamide, dimethylformamide, jV-methylacetamide, propionamide, N,N-dimethylacetamide... 

Although the use of N,N-dimethylformamide permits satisfactory chlorination or bromination of primary positions at room temperature, side reactions can occur between carbon tetrahalides, triphenylphosphine, and JV,N-dimethylformamide that can, in some cases, result in low yields of halogenated products (see also, Section II, 2c p. 230). 

An attempt to alkylate phenothiazine with propargyl bromide using sodium hydride in dimethylformamide afforded a 70% yield of N-( 1 -propynyl)pheno-thiazine instead of the expected JV-(2-propynyl)phenothiazine [7], This reaction (Eq. 33) constituted the first synthesis of an ynamine [7]. Other diaryl-... 

To generate the phosphorane, Magnone [80,81], Wang et al. [82] and John and Paust [83] used respectively sodium methoxide, triethylamine/MgCh in JV,A/-dimethylacetamide and LiOH in N,N-dimethylformamide. For the isomerization step, the two first authors emploied rose Bengal as photosensitizer and the latter Erythrosine B, to give isotretinoin, Fig. (45). 

Sn2 displacement of a methanesufonyloxy group on C-4 by thiocyanate ion under unusual conditions (in JV,N-dimethylformamide, for 72 hat room temperature) for 9, and in N,N-dimethylformamide for 16 h at 45° for 10. It is noteworthy that the Sn2 displacement in these reactions favored the... 

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