Dimethylformamide, solvent

Many acyclic enamines form thioamides when they are allowed to react with elemental sulfur at room temperature in dimethylformamide solvent 138). They also produce cyclic 1,3-dithiole by-products, which become main products at higher temperatures 135). For example, the reaction of l-(N-morpholino)-l-phenylethene (106) and sulfur in dimethylformamide solvent yields 1,3-dithiole 107. 

Cross-hnked polyacrylamides are a group of hydrophihc solid supports introduced primarily for preparation of biopolymers (Fig. 4). Unhke PS resins, polyacrylamides have excellent swelling capacity in both protic (water, alcohols) and aprotic (dichloromethane, dimethylformamide) solvents [88]. These beads are stable towards bases, acids, and weak reducing and oxidizing agents [89]. Predictably, conditions under which amide bonds are cleaved (i.e., sodium in liquid ammonia) [90] lead to rapid decomposition of the polymer. 

The salt is an ambient nucleophile and can undergo either N or 0 alkylation. Chung and Tieckelmann (17) have shown that unsubstituted pyridone sodium salts in acetonitrile or dimethylformamide solvent form primarily the N-alkylated product. Using 3-substituted... 

However, the iodo-substituent, which might be expected to show similar behavior, is well behaved. The behavior of the substituents MeSO, SCF3, and CF3SO would be instructive in this connection, but no data exists for these substituents in any of the sets. The substituents NHCOMe and OCgHs, which involve competing conjugative interaction mechanisms, as well as coplanarity problems, are only moderately well behaved in the sets. Calculated values of vary from —.74 to -.86 for the former and -.74 to -.92 for the latter. There is, however, a considerable presumption in the case of the NHCOMe substituent that this behavior is solvent related. The value —.74 (reaction 6) is obtained in water solvent at 25°, and the value —.86 (reaction 23) is obtained in dimethylformamide solvent at 17°. The 0/j(ba) values calculated for the NHCOMe substituent show similar trends with solvent, as shown in Table XVI. 

As, for the most part, the corresponding ester derivatives are a more important synthetic target, recent literature has demonstrated methods to prepare the esters directly. Examples include the use of nickel carbonyl in a methanol/dimethylformamide solvent system(37) the direct conversion of benzyl alcohol to methylphenyl-acetate using cobalt carbonyl(38) and a reaction system which utilizes an ammonium salt bound to an organic polymer(39). 

All types of nitro compds react easily with bases, forming diverse types of products (Ref 36) In the case of TNT, 2,4,6-trinitrobenzyI anion (I) is formed initially and rapidly. It is a highly reactive species thought to be intermediate in the many reactions of TNT conducted under basic conditions discussed above (Refs 32 61). The anion is formed without side reactions by the action of 1,1 f,3,3f-tetramethylguanidine in dimethylformamide solvent (Ref 106). Based on... 

The cyclisation of (22) to the /J-lactam system, which is a thermodynamically unfavourable reaction, is promoted by using sodium hydride as the base in a dichloromethane-dimethylformamide solvent system at high dilution. 

Dimethylformamide, Solvents, UCB Chemicals - Methylamines Derivatives, www.chemicals.ucb-group.com, 2003. 

Cellulose can also blend with natural or synthetic polymers to produce adhesives. The recent development of new cellulose solvents(iO), such as lithium chloride/dimethyacetamide solvent, dinitrogen tetroxide/dimethylformamide solvent, dimethyl sulfoxide/paraformaldehyde solvent, have provided the potential to produce uniform cellulose polyblends. 

Pyridinium dichromate (PDC) The problem caused by the acidic nature of PCC is largely removed by using the neutral reagent PDC . For example, geraniol (7.5) was oxidized to geranial (7.6) in 92% yield by PDC in DMF (dimethylformamide) solvent. 

Platinum catalysis of hydroformyiation has seen remarkable progress in the last twenty years. The metal has extremely low or nonexistent activity. A phosphine complex, [Ph3P)3PtH] PF6, is a low activity catalyst at 150°C and 10 MPa of H2/CO. A phosphine platinum(II) iodide, (Ph3P)2M2. is somewhat better, giving 89% conversion of olefin to aldehydes at 180°C and 25 MPa pressure in 1 hr in dimethylformamide solvent. 

The 60 MHz proton nmr shift, AB, for the N - CH2 protons in tris(N,N-diethyldithiocarbamato)iron(III) was determined in a number of solvents and in some solvent mixtures over a wide temperature range. (The diamagnetic contribution to the nmr shift was obtained by measuring the nmr shift of the N - CH protons in the diamagnetic cobalt analogue). In this paper six different solvents were used acetone, benzene, carbon disulfide, chloroform, dimethyl-formamide and pyridine. Also three chloroform-dimethylformamide solvent mixtures were used 0.75, 0.49 and 0.24 mole fraction of chloroform. 

Estimated from Cook, D., and Parker, A. J. "Halide Exchange at a Saturated Carbon Atom in Dimethylformamide Solvent. Comparison of Experimental Rates and Arrhenius Parameters with Values Calculated by Ingold." /. Chem. 

---