Anilines deuteriated

Thiophenyl acetates (366 R = Me) and propionates (366 R = Et) react with electrogenerated polysulflde ions S3 in DMF to yield thiocarboxylate ions, thiolate ions, and phenyl tetrasulfanide (367), the last deriving from the reaction of thiolate ions with sulfur (Scheme 48). Smdies of the aminolysis by a set of substimted anilines of Y-aryl dithio-2-thiophenates (368 X = S) and dithio-2-furoates (368 X = O) in acetonitrile have shown that the rate-determining step in these reactions is the departure of the thiophenolate ion from the zwitterionic tetrahedral intermediate T= = (Scheme 49). Experiments with deuteriated anilines yielded k i/IcQ values of 1.7-1.9,... 

Recently, Capon and Wu49 have reported the generation of secondary enamines from their TV-trimethylsilyl derivatives through hydrolysis. In DMSO-d6 (99% v/v)-D20 (1% v/v) solution, enamine 40 is converted to the TV-deuteriated enamine 41 quantitatively in 5-10 min at room temperature. The solution obtained is stable for several hours, but over a period of 2-3 days 41 is oxidized to acetone and iV-deuterio-TV-phenylforma-mide. On adding 15% (v/v) D20/DC1 (0.1 M) to the solution, enamine 41 is completely hydrolyzed to 2-[2//]isobutyraldehyde and aniline without detection of any intermediates. Enamine 42 is formed by the acid-catalyzed hydrolysis of 40 (Scheme 3). Similar results are obtained with other iV-aryl enamines. 

Bock and coworkers104 have determined proton spin-lattice relaxation times for N,N-dideuterioaniline in perdeuteriobenzene and perdeuterioaniline solutions as a function of the concentration and temperature at 260-360 K. The activation energies of the intra- and inter-molecular relaxation rates were of similar magnitude, namely 4.5 and 4.4 kcalmol-1. At 293 K, the rotational correlation time of the aniline molecule in infinitely dilute perdeuteriobenzene solution was approximately half that of the partially deuteriated aniline molecule, namely 3.0 x 10-12 and 6.3 x ICC12 s 1, respectively. In infinitely dilute perdeuterioaniline the rotational correlation time of (V,iV-dideuterioaniline was 19 x ICC12 s. ... 

The spectral data of monodeuteriated anilines (complete deuteriation to ND2, and partial deuteriation to NHD, is a popular tool in focusing on these absorption problems and in order to avoid confusion with other overtone bands57 - 59) and the differences in spectral data of corresponding pairs of ortho- and para-substituted anilines enable evaluation of the effect of the ortho substitution on the spectroscopic properties60. In the case of 2-trifluoromethylaniline (9), there are indications of the presence of an intramolecular hydrogen bond61-63. 

The 13C resonances of atoms bearing a partially deuteriated amino group in aniline and in its derivatives 27-29, and in o-nitroaniline derivative71, appear as a multiplet. 

VI. KINETIC ISOTOPE EFFECTS INVOLVING DEUTERIATED ANILINES... 

Furthermore, the magnitude of kn/kD is shown to reflect the tightness or distance dxY in Scheme 22. The kH/kD values measured in MeCN with deuteriated anilines are presented in Table 3 for secondary alkyl arenesulfonates52. For these reactions, the size... 

TABLE 10. Kinetic isotope effects with deuteriated aniline nucleophiles... 

A number of other examples of useful applications of KIEs involving deuteriated aniline nucleophiles are reported15e g. Elucidation of the TS structures is facilitated by means of nucleophile KIEs in conjunction with the sign and magnitude of the cross-interaction constants. 

A conversion of N-deuteriated aniline hydrochloride into ring-deuteriated anilines can also be regarded as a rearrangement13. According to kinetic study, this process follows an intramolecular electrophilic mechanism and should be considered as a transfer of a migrant from the amino group to the aromatic ring. 

The kinetics and mechanism of the aminolysis of phenyl-substituted phenyl phosphonyl chlorides (136) with anilines (135) were investigated in MeCN at 55.0 °C. Very sensitive variation of /Oy(5/Oy2>0) with the change of substituent on the nucleophile Sax) led to a large negative cross-interaction constant, pxY = Spy)/ Sox) = —1.31. The secondary kinetic isotope effects observed with deuteriated aniline nucleophiles were of the inverse type (/th/ d = 0.61-0.87), and small A// (1.6-9.7kcalmor ) and large negative A5 (—43 to —65 e.u.) values were... 

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