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H.-J. Cristau et al. / Journal of Organometallic Chemistry 592 (1999) 29–33
1
4. Experimental
remaining solution. 5% yield. H-NMR (D2O): l=3.2
(t, JHD=1.6, 6H; CH2D), 3.2 (s, 3H, CH3); 13C-NMR
2
1
1
All reactions were run under dry nitrogen in flame-
dried glassware unless otherwise noted. Ether was
freshly distilled from sodium–benzophenone. H-NMR
(D2O): l=57.6 (tt, JCN=4, JCD=22.1, 3C; CH2D),
57.9 (t, JCN=4, 1C; CH3); MS (FAB/NBA): 77 [M+].
1
1
and 13C-NMR spectra, recorded at room temperature
on a Bruker AC200 spectrometer, were referenced to
TMS (l in ppm, J in Herz). The splitting pattern
abbreviations are as follows: s, singlet; d, doublet; t,
triplet; q, quartet; INVGATE sequence (D1=5 s) was
used for 13C NMR. Mass spectra (MS) were obtained
on a Jeol JMS-DX 300 instrument (positive FAB) using
m-nitrobenzyl alcohol as matrix.
4.2. Trimethylammonium methylide (2) and
monodeuteromethyltrimethylammonium chloride (9)
To 2 g (13 mmol) of dried tetramethylammonium
bromide 1 in 50 ml dry ether are dropped 11 ml (13
mmol) of n-BuLi in hexane (1.44 M). After 2 days at
20°C, the mixture gave a negative Gilman test [5]; 1.2
ml of 37% DCl–D2O is added to give a quantitative
1
2
yield of 9. H-NMR (D2O): l=3.2 (t, JHD=1.6, 2H;
CH2D), 3.2 (s, 9H; CH3); 13C-NMR (D2O): l=57.6 (tt,
1JCN=4, 1JCD=22.1, 1C; CH2D), 57.9 (t, 1JCN=4,
3C; CH3); MS (FAB/NBA): 75 [M+].
4.1. Tris(monodeuteromethyl)methylammonium
bromide (6)
4.1.1. Methanol-d1-OD (7)
A mixture of paraformaldehyde (1.68 g, 19 mmol) in
15 ml dry m-xylene and sodium borohydride-d4 (0.59 g,
14 mmol) in 5 ml D2O, was stirred for 15 min at 20°C.
From the mixture were distilled 2.5 ml of a liquid
(Eb760=65°C) containing CH2DOD–m-xylene–CH3-
OD, respectively, in a 38:4:1 molar ratio: CH2DOD 7:
1H-NMR: l=3.2 (t, 2JHD=1.6) [4]; 13C-NMR: l=
4.3. Dimethylammonium dimethylide (4) and
bis(monodeuteromethyl)dimethylammonium chloride (10)
To 2 g (13 mmol) of dried 1 in 50 ml dry ether are
dropped 22 ml (26 mmol) of n-BuLi in hexane (1.44
M). After stirring for 7 days at 20°C, the Gilman test
became negative. The heterogeneous white mixture is
quenched with 2.4 ml (26 mmol) of 37% DCl–D2O.
1
49.9 (t, JCD=21.6).
2
1H-NMR (D2O): l=3.2 (t, JHD=1.6, 4H; CH2D), 3.2
4.1.2. Tris(monodeuteromethyl)methylammonium
bromide (6)
(s, 6H; CH3); 13C-NMR (D2O): l=57.6 (tt, JCN=4,
1
1
1JCD=22.1, 2C; CH2D), 57.9 (t, JCN=4, 2C; CH3);
This mixture, containing 88% of methanol-d1-OD, is
added to the dibromotriphenylphosphorane (31P-NMR
(CDCl3) l=40), prepared at 10°C from dry
triphenylphosphine (11.8 g, 45 mmol) and bromine
(2.32 ml, 45 mmol) in DMF (200 ml). The evolved
monodeuteromethylbromide 8 is bubbled, at −50°C,
into DMF simultaneously to a counter-current of
gaseous anhydrous trimethylamine. After 2 h, the fil-
trated solid (0.45 g) is a mixture of methyldeutero-
methylammonium bromides [MeNHn(CH2D)3−n]+X−
(n=0–3). Addition of an aqueous solution of potas-
sium hydroxide transforms most of the salts (n"0) into
volatile amines. The expected salt 6 is isolated from the
MS (FAB/NBA): 76 [M+].
4.4. Bis(2,2-diphenyl-2-hydroxyethyl)-dimethyl-
ammonium bromide (5)
To the heterogeneous white mixture of 4, 4.74 g (26
mmol) benzophenone are added (slightly exothermic).
After a further 2 days at 20°C, the addition of 3 ml of
47% aqueous HBr (26 mmol), gives a suspension. The
yellow solid is dissolved in chloroform and precipitated
into 200 ml of ether. After filtration, the combined
Scheme 5. Deuteration of the tetramethylammonium monoylide 2 and diylide 4.