1 -Methylpyrrolidin-2-one

Likewise, 2-(2-aminoethylsulfanyl)benzenesulfonamidccan be obtained from 2-fluorobenzene-sulfonamide (0.85 mol) and 2-aminoethanethiol (1.06 mol) with potassium carbonate (2.13 mol) in 1-methylpyrrolidin-2-one (530mL) (2 h at 140 C) yield 68.5%. mp 86-87 C (SFI more reactive than NH2).7... 

In contrast, dipolar aprotic solvents possess large relative permittivities (sr > 15), sizeable dipole moments p > 8.3 10 ° Cm = 2.5 D), and average C.f values of 0.3 to 0.5. These solvents do not act as hydrogen-bond donors since their C—H bonds are not sufficiently polarized. However, they are usually good EPD solvents and hence cation sol-vators due to the presence of lone electron pairs. Among the most important dipolar aprotic solvents are acetone, acetonitrile [75], benzonitrile, A,A-dimethylacetamide [76, 77], A,A-dimethylformamide [76-78], dimethylsulfone [79], dimethyl sulfoxide [80-84], hex-amethylphosphoric triamide [85], 1-methylpyrrolidin-2-one [86], nitrobenzene, nitro-methane [87], cyclic carbonates such as propylene carbonate (4-methyl-l,3-dioxol-2-one) [88], sulfolane (tetrahydrothiophene-1,1-dioxide) [89, 90, 90a], 1,1,3,3-tetramethylurea [91, 91a] and tetrasubstituted cyclic ureas such as 3,4,5,6-tetrahydro-l,3-dimethyl-pyr-imidin-2-(l//)-one (dimethyl propylene urea, DMPU) [133]. The latter is a suitable substitute for the carcinogenic hexamethylphosphoric triamide cf. Table A-14) [134]. 

Other examples of this type of reaction are Sn2 reactions between azide ion and 1-bromobutane [67], bromide ion and methyl tosylate [68], and bromide ion and iodoethane [497]. In changing the medium from non-HBD solvents (HMPT, 1-methylpyrrolidin-2-one) to methanol, the second-order rate constants decrease by a factor of 2 10 [67], 9 10 [68], and 1 10 [497], respectively. The large decrease in these rate constants in going from the less to the more polar solvent is not only governed by the difference in solvent polarity, as measured by dipole moment or relative permittivity, but also by the fact that the less polar solvents are dipolar aprotic and the more polar solvents are protic cf. Section 5.5.2). 

Bis(tetrathiafulvalenyl) derivatives 703 were prepared from the iodo-TTF precursor 702 via Ullmann coupling (copper in refluxing DMF) or by the reaction with copper(i) thiophene-2-carhoxylate (CuTC) in 1-methylpyrrolidin-2-one (Equation 91) <19988826, 2000JMC1273>. 

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