Pyrrolidones as solvents

The three component condensations of aldehydes, amines and elemental sulfur using 1-methyl-2-pyrrolidone as solvent employing microwave flash heating 100-180 °C for 2-20 min give the corresponding primary, secondary and tertiary thioamides (Scheme 6).23... 

The heteroatoms S, O, and N can be introduced as substituents of the cluster under acidic conditions (see Scheme 2.2-19). For S and O, the reaction of the hydrochlorides of thiopyrrolidone or pyrrolidone, with the non-protonated form of the pyrrolidone as solvent, is the method used by most workers. The amino group can be introduced with hydroxylamine O-sulfonic acid. 

Special solvent. Newman - recommends N-methyl-2-pyrrolidone as solvent for the reaction of an aryl halide with cuprous cyanide to produce the corresponding nitrile. Dimethylformamide (b.p. 153°) has been suggested as a better solvent than originally used pyridine (b.p. 115°), but l-methyl-2-pyrrolidone has an even higher boiling point and seems still more satisfactory. An example is the synthesis of... 

Wan et al. [37] have studied the UV-vis absorption spectra of chemically synthesized POT in NMP (IV methyl pyrrolidone) as solvent from 250 to 850 nm and the spectra are given in Figure 13.12. Two absorption... 

For the addition of ethylene, EtOAc as solvent was particularly advantageous and gave 418 in 60% yield (Scheme 6.86). The monosubstituted ethylenes 1-hexene, vinylcyclohexane, allyltrimethylsilane, allyl alcohol, ethyl vinyl ether, vinyl acetate and N-vinyl-2-pyrrolidone furnished [2 + 2]-cycloadducts of the type 419 in yields of 54—100%. Mixtures of [2 + 2]-cycloadducts of the types 419 and 420 were formed with vinylcyclopropane, styrene and derivatives substituted at the phenyl group, acrylonitrile, methyl acrylate and phenyl vinyl thioether (yields of 56-76%), in which the diastereomers 419 predominated up to a ratio of 2.5 1 except in the case of the styrenes, where this ratio was 1 1. The Hammett p value for the addition of the styrenes to 417 turned out to be -0.54, suggesting that there is little charge separation in the transition state [155]. In the case of 6, the p value was determined as +0.79 (see Section 6.3.1) and indicates a slight polarization in the opposite direction. This astounding variety of substrates for 417 is contrasted by only a few monosubstituted ethylenes whose addition products with 417 could not be observed or were formed in only small amounts phenyl vinyl ether, vinyl bromide, (perfluorobutyl)-ethylene, phenyl vinyl sulfoxide and sulfone, methyl vinyl ketone and the vinylpyri-dines. 

However, morpholine-4-carboxylic acid 2-hydroxy-1-methyl-ethyl ester is formed by the reaction of PC and the substrate morpholine in an undesired side reaction. By use of 1.4-dioxane or the pyrrolidones as mediator s3 about 30 to 45% of the morphoUne is consumed by this side reaction. The by-product is contained in the PC phase and can not be extracted to the non-polar product phase. The selectivity to the desired amines is lowered, because of the consiunption of the morphoUne. Thus, PC has to be substituted by another polar solvent (e.g. water, methanol or ethylene glycol) in future experiments. The lactates react with the morphoUne, too resulting in the corresponding amide. Overall, the hydroaminomethylation in the TMS systems PC/dodecane/lactate results in a conversion of 1-octene of about 80%, but in selectivities to the amines of only 50 to 60%. 

Parrish (1977) reviewed the research and development of lactose ester-type surfactants carried out by Scholnick and his colleagues (Scholnick et al. 1974, 1975 Scholnick and Linfield 1977). Their initial attempts to form lactose esters followed the same transesterification procedures that had been used with sucrose (a fatty acid methyl ester in N,N-dimethylformamide with potassium carbonate as the catalyst). Their successful approach was the reaction of lactose in N-methyl-2-pyrrolidone as the solvent with fatty acid chlorides, resulting in yields of 88 to 95% for esters of lauric, myristic, palmitic, stearic, oleic, and tallow fatty acids. The principal product was the monoester, which is important for detergent use, since diesters and higher esters of lactose are not water soluble. 

Addition of DMAD to l-methyl-2-pyrrolidine dimethylacetal (69) in dioxane108 gave no 70, but the indoline 75, the isomeric pyrrolidones 71 and 72, and the pyrroline 76 were obtained using benzene as solvent the 1 1 adduct (73) was the major product. With DMAD, compound 73 gave 75, presumably via 74. 

Hexachlorobenzene gave 1,3,5-trifluorotrichlorobenzene when DMF or DMSO2 [41] was used as solvent, although the use of W-methyl-2-pyrrolidone (NMP) [42, 43] gave some tetrafluorodichlorobenzene that could not be fluorinated further in this mixture (Figure 9.17). 

Pyrrolidones such as 2-pyrrolidone and N-methylpyrrolidone see Section 17) are mainly used as solvents in veterinary injections. They have also been suggested for use in human pharmaceutical formulations as solvents in parenteral, oral, and topical applications. In topical applications, pyrrolidones appear to be effective penetration enhancers. Pyrrolidones have also been investigated for their application in controlled-release depot formulations. ... 

By this method, 1-bromonaphthalene affords 1-naphthonitrile in 94% yield after refluxing for 4 hrs. with pyridine as solvent the reaction mixture is heated in an oil bath at 215-225° for 15 hrs., and the yield is 82-90%. Efficient procedures for liberating the nitrile from the cuprous halide complex involve pouring the brown reaction mixture into an aqueous solution of ferric chloride (oxidizes Cu+ to Cu ", which forms no complex), ethylenediamine (forms complexes with Cu+ and Cu " ), or sodium cyanide (forms soluble sodium cuprocyanide). The higher-boiling N-methyl-2-pyrrolidone (b.p, 202°) is also satisfactory, but is more expensive. 

For preparation of an intermediate required for the synthesis of 5,5-dimethyl-pyrrolidone, Moffett used absolute ethanol as solvent and the W-5 catalyst. 

Aldehydes are converted into 1,1-difluoroethylenes by heating with triphenylphosphine and sodium chlorodifluoroacetate in glyme or diglyme. Under the same conditions, ketones do not react. However, Fuqua et ul. found that, if 1-methyl-2-pyrrolidone is used as solvent and tributylphosphine is used as base, satisfactory yields are obtained in reactions of ketones. 

Because of the solubility of copper cyanide in l-methyl-2-pyrrolidone the latter has been recommended447 as solvent for the reaction with alkyl halides. 

Reduction of ArCHO. N-Methyl-2-pyrrolidone is used as solvent. When an ArCN is treated similarly, a pyrrolo[2,3-d]pyrimidine is formed. 

Bradley et al. decomposed the complex Ni(COD)2, at room temperature and in the presence of poly(vinyl)pyrrolidone (PVP) as stabilizer, simply using dichloro-methane as solvent [173]. When they changed the ratio Ni/PVP, they observed a small variation in particle size from 2-3 nm. 

The details are described as follows exemplified for LSCF perovskite hollow fibers. To start with, a calculated quantity of PESf and pyrrolidone (PVP) additive is dissolved in A-methyl-2-pyrrolidone (NMP) solvent to form a polymer solution. A given amount of LSCF powder dried in advance is then added gradually under stirring. The stirring is usually carried out continuously for at least 48 h for complete dispersion of the powder in the polymer solution. 

The S5Tithesis of polyesterketones based on aromatic ether acids is possible in the environment of trifluoromethanesulfonic acid [249, 287], The data ofnuclear magnetic resonance have revealed [249] that such poly-esterketone comprise only the -substituted benzene rings. When using the N-cyclohexyl-2-pyrrolidone as a solvent when synthesizing polyphen-ylenesterketones and polyphenylenethioesterketones the speed of polycondensation and the molecular mass of polymers [288] increase. 

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