N. Uematsu et al. / Journal of Fluorine Chemistry 127 (2006) 1595–1600
1599
through a dropping funnel, while keeping the temperature
below 30 8C over 3 h. After the completion of the addition, the
reaction mixture was stirred at 40 8C for 1 h to form the sodium
salt 10. The formation of the sodium salt 10 was confirmed by
19F NMR. To the flask was added the mixture of 85% H3PO4
(230.0 g, 2.0 mol) and water (230 mL). Then the flask
was heated at 160 8C, and the protonated compound 13 and
water were collected in the flask cooled by ice bath. The
lower layer was separated, washed three times with water, dried
over Na2SO4, and filtered to give a colorless liquid 13. The yield
of 13 was determined by 19F NMR (231.1 g, 0.77 mol, 86%
yield).
BuLi solution in n-hexane (431 mL, 0.689 mol) through a
dropping funnel at À78 8C. The reaction mixture was stirred at
À78 8C for 0.5 h and then elevated to 0 8C. To the flask was
added 15 (104.4 g, 0.3 mol) through a dropping funnel at 0 8C.
After the completion of the addition, the reaction mixture was
stirred at 0 8C for 1 h. The formation of the vinyl compound 16
was confirmed by 19F NMR. Then the reaction mixture was
quenched with water, and the solvent was removed under
reduced pressure. To the residue was added HFC43-10mee and
water. After the insoluble material was filtered off through
Celite, the organic layer was separated and the aqueous layer
was extracted twice with HFC43-10mee. The combined
organic layers were dried over Na2SO4 and concentrated
under reduced pressure. The residue was purified by reduced
distillation to give a colorless liquid 16 (57.56 g, 0.175 mol,
58% yield).
19F NMR d À147.91 (d, 1F, J = 52 Hz), À114.21 (s, 2F),
À86.99 (d, 1F, J = 134 Hz), À86.53 (s, 3F), À84.67 (d, 1F,
J = 134 Hz), 42.73 (s, 1F). 1H NMR d 6.07 (d, 1H, J = 52 Hz).
4.2. Preparation of 1-[1,1,2,2-tetrafluoro-2-(1,2,2,2-
tetrafluoroethyloxy)-ethanesulfonyl]-imidazole (15)
b.p. 61–62 8C/3 mmHg. 19F NMR d À137.81 (dd, 1F,
J = 112, 66 Hz), À123.11 (dd, 1F, J = 112, 85 Hz), À115.70 (s,
2F), À115.51 (dd, 1F, J = 85, 66 Hz), À84.47 (s, 2F). 1H NMR
d 7.23 (s, 1H), 7.48 (s, 1H), 8.16 (s, 1H). GC–MS (CI) m/z 329
(MH)+.
To a 1 L round-bottom flask equipped with a mechanical
stirring and a dropping funnel was added a dispersion of
60 wt.% NaH in a mineral oil (25 g, 0.625 mol), and washed
with n-hexane to obtain a NaH powder. Then dry 1,2-
dimethoxyethane (300 mL) was added to the flask, and cooled
to 0 8C. To the flask was added a solution of imidazole (38.5 g,
0.566 mol) in dry 1,2-dimethoxyethane (200 mL) through a
dropping funnel at 0 8C. After the completion of the addition,
the reaction mixture was stirred at room temperature for 1 h.
The reaction mixture was cooled to 0 8C followed by addition
of 13 (170 g, 0.566 mol) through a dropping funnel. After the
completion of the addition, the flask was elevated to room
temperature with stirring for 12 h. The formation of the
imidazole derivative 15 was confirmed by 19F NMR.
The reaction mixture was quenched with water (20 mL),
and the solvent was removed under reduced pressure. To the
residue was added HFC43-10mee and water. The organic layer
was separated and the aqueous layer was extracted twice
with HFC43-10mee. The combined HFC43-10mee layers
were washed twice with a diluted aqueous NaOH solution
and dried over Na2SO4. The solvent was removed under
reduced pressure and the residue was purified by reduced
distillation to give a colorless liquid 15 (139.8 g, 0.402 mol,
71% yield).
4.4. Preparation of 1-[1,1,2,2-tetrafluoro-2-
(trifluoroethenyloxy)-ethanesulfonyl]-imidazole (16) using
SHMDS
To a 200 mL round-bottom flask equipped with a magnetic
stirring and a dropping funnel were added 15 (6.6 g,
0.019 mol) and dry THF (20 mL, no stabilization) under a
N2 atmosphere. To the flask was added 1 M SHMDS solution
in THF (40 mL, 0.04 mol) through a dropping funnel at 0 8C.
After the completion of the addition, the reaction mixture was
stirred at 0 8C for 1 h. The formation of the vinyl compound 16
was confirmed by 19F NMR. Then the reaction mixture was
quenched with water, and HFC43-10mee was added. The
organic layer was separated and the aqueous layer was
extracted twice with HFC43-10mee. The combined organic
layers were dried over Na2SO4 and concentrated under
reduced pressure. The residue was purified by reduced
distillation to give a colorless liquid 16 (1.8 g, 0.0055 mol,
29% yield).
b.p. 65–66 8C/3 mmHg. 19F NMR d À147.94 (d, 1F,
J = 52 Hz), À115.70 (s, 2F), À85.75 (s, 3F), À84.77 (d, 1F,
4.5. Preparation of 1,1,2,2-tetrafluoro-2-
(trifluoroethenyloxy)-ethanesulfonyl fluoride (8)
1
J = 154 Hz), À83.17 (d, 1F, J = 154 Hz). H NMR d 6.57 (d,
1H, J = 52 Hz), 7.15 (s, 1H), 7.38 (s, 1H), 8.03 (s, 1H). GC–MS
(CI) m/z 349 (MH)+.
The mixture of 16 (7.87 g, 0.024 mol) and 46 wt.% HF
aqueous solution (9 mL) was heated with stirring at 60 8C for
0.5 h to separate into two layers. The lower layer was separated
and washed with water to obtain a colorless liquid 8. The yield
of 8 was determined by 19F NMR (4.79 g, 0.017 mol, 71%
yield).
4.3. Preparation of 1-[1,1,2,2-tetrafluoro-2-
(trifluoroethenyloxy)-ethanesulfonyl]-imidazole (16) using
LHMDS
To a 2 L round-bottom flask equipped with a mechanical
stirring and a dropping funnel were added hexamethyldisila-
zane (111 g, 0.689 mol) and dry THF (500 mL, no stabiliza-
tion) under a N2 atmosphere. To the flask was added 1.6 M n-
19F NMR d À138.70 (dd, 1F, J = 113, 68 Hz), À123.76 (dd,
1F, J = 113, 85 Hz), À116.38 (dd, 1F, J = 85, 68 Hz), À114.23
(s, 2F), À86.06 (s, 2F), 42.82 (s, 1F). GC–MS (EI) m/z 280
(M)+.