1
644
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 9, September, 2001
Romanov et al.
poured into ice (∼100 g), washed with cold water (3½15 mL),
solution of N-diphenylmethylpiperazine (6 mmol) in diethyl
ether (2 mL) was added to a solution of compound 9
dried with MgSO , and distilled to give imidoyl bromide 5.
4
Dehydrohalogenation of imidoyl bromide 5 in the presence
of triethylamine. N-(α-Hydrohexafluoroisopropyl)trifluoro-
acetimidoyl fluoride (6). Triethylamine (6 mmol) was added
with stirring at 10 °C to a mixture of 5 (6 mmol) and norbornene
(3 mmol) in ether (5 mL). The reaction mixture was kept at
∼20 °C for 3 days with periodical stirring, and then water
(3 mL) and CH Cl (3 mL) were added. The organic layer
2
2
was separated, dried with Na SO , and distilled to give com-
2
4
(
12 mmol) in dry diethyl ether (15 mL). The reaction mixture
pound 11.
was stirred for ∼4 h and kept at ∼20 °C for 10 h. The precipitate
of triethylamine hydrobromide was filtered off and washed with
dry ether (5 mL). Distillation of the filtrate gave imidoyl
fluoride 6 as a mixture with diethyl ether (1 : 1), b.p. 3840 °C.
Reaction of imidoyl chloride 1c with CsF. A. Imidoyl
chloride 1c (0.06 mol) was added with stirring at 20 °C over
1-Perfluoroethyl-5-[4-(2-phenylpropan-2-yl)phenyl]-
2,4,4,6-tetrakis(trifluoromethyl)-1,4-dihydropyrimidine (12). A
solution of 4-(2-phenylpropan-2-yl)phenol (3 mmol) and tri-
ethylamine (3 mmol) in diethyl ether (2 mL) was added to a
solution of compound 9 (3 mmol) in ether (2 mL). The
reaction mixture was kept at ∼20 °C for 3 days with periodical
1
0 min to a suspension of dry CsF (0.17 mol) in sulfolane
stirring, and then water (2 mL) and CH Cl (2 mL) were
2 2
(
10 mL); the reaction proceeded exothermically (∼35 °C).
added. The organic layer was separated, dried with Na SO ,
2 4
and distilled to give ether 12.
Fractionation gave imidoyl fluoride 6 and 5-fluoro-1-perfluoro-
ethyl-2,4,4,6-tetrakis(trifluoromethyl)-1,4-dihydropyrimidine 9.
B. Imidoyl chloride 1c (0.05 mol) was added at 35 °C over
References
3
0 min to a suspension of CsF (0.27 mol) in sulfolane (10 mL).
The reaction mixture was heated to boiling and kept with
stirring for 3 h. Fractionation gave dihydropyrimidine 9.
1. I. L. Knunyants and A. F. Gontar, in Soviet Scientific
Reviews, Chemistry Reviews; Harwood Acad. Pub. London,
1983, 5.
2. C. Waksdman, Chemistry of Organic Fluorine Compounds II:
A Critical Review, Eds. M. Hudlicky and A. E. Pavlath,
1995, p. 450.
3. A. V. Fokin, A. F. Kolomiets, and N. V. Vasil´ev, Usp.
Khim., 1984, 53, 398 [Russ. Chem. Rev., 1984, 53 (Engl.
Transl.].
4. S. N. Osipov, A. F. Kolomiets, and A. V. Fokin, Usp.
Khim., 1992, 61, 1463 [Russ. Chem. Rev., 1992, 61 (Engl.
Transl.].
MS (EI, 70 eV), m/z (I (%)): 490 [M]+ (4), 471 [M F]
+
rel
(
[
(
21), 421 [M CF ]+ (12), 333 [M CF3 CF3]+ (5), 245
3
+
+
M CF2 C N] (80), 226 (5), 195 (10), 69 [CF3]
2
100), 28 (12).
N-(Perfluoroisopropenyl)trifluoroacetimidoyl chloride (7).
A mixture of imidoyl chloride 1c (12 mmol), BF NEt
3
3
(
18 mmol), and dry dioxane (3 mL) was heated in a sealed tube
at 110120 °C for 50 min. Double fractionation gave com-
pound 7, which may contain 510 % of the starting imidoyl
chloride 1c since they have close physicochemical properties
and are difficult to separate by distillation. The properties of
compound 7 are given for a high-purity sample (98%) obtained
in one of the experiments.
5. K. Tanaka, H. Daikaku, and K. Mitsuhashi, Chem. Lett.,
1983, 9, 1463.
N-Methyltrifluoroacetimidoyl fluoride (8). Imidoyl chlo-
ride 1a (0.128 mol) was added with stirring at 40 °C over
6. W. P. Norris and H. B. Jonassen, J. Org. Chem., 1962,
27, 1449.
7. D. V. Romanov, V. S. Kulish, V. F. Cherstkov, and N. V.
Vasil´ev, Izv. Akad. Nauk, Ser. Khim., 1998, 2560 [Russ.
Chem. Bull., 1998, 47 (Engl. Transl.].
8. E. Kupce and R. Freeman, J. Magn. Reson. (A), 1995,
115, 273.
9. E. J. Bourne, S. H. Henry, C. T. M. Tatlow, and J. C.
Tatlow, J. Chem. Soc., 1952, 4015.
5
0 min to a suspension of CsF (0.256 mol) in dry sulfolane
15 mL) with trapping of volatile products at 78 °C. Fraction-
ation gave imidoyl fluoride 8.
-Perfluoroethyl-2,4,4,6-tetrakis(trifluoromethyl)-1,4-
dihydropyrimidin-5-ol (10). Water (11 mmol) and dioxane
2 mL) were added to compound 9 (1.8 mmol). The reaction
(
1
(
mixture was kept at ∼20 °C for 14 days and, after the addition
of Freon 113 (5 mL), washed with water (5½2 mL). The
aqueous phase was extracted with Freon (3½1.5 mL). The
combined organic phase and Freon extracts were dried with
10. A. Gordon and R. Ford, The Chemist´s Companion.
A Handbook of Practical Data, Techniques and References,
Wiley, New York, 1972.
Na SO for 24 h. Fractionation gave compound 10.
2
5
4
-[4-(Diphenylmethyl)piperazin-1-yl]-1-perfluoroethyl-
Received February 20, 2001;
in revised form April 17, 2001
2
,4,4,6-tetrakis(trifluoromethyl)-1,4-dihydropyrimidine (11). A