544
X. Yang et al. / Journal of Fluorine Chemistry 128 (2007) 540–544
3.3.1. 5-(3-Chloro-2,2,3,3-tetrafluoro-propyl)-4,4-
dimethyl-dihydro-furan-2-one (3a) [4]
236 (0.9, M+–CH3), 178 (8, M+–COOEt), 59 (100). HRMS
calcd. for C11H19F2NO3 252.1411, found: 252.1415.
Colorless needles, mp: 55–56 8C. 1H NMR (CDCl3) d: 1.06
(3H, s, CH3), 1.22 (3H, s, CH3), 2.25–2.51 (4H, m, 2 ꢀ CH2),
4.32 (1H, d, J = 8.9 Hz, CH). 19F NMR (CDCl3) d: ꢂ71.2 (2F,
m, ClCF2), ꢂ112.4 (2F, m, CF2CH).
3.3.6. N-Methyl-6-carbamoyl-2,2-difluoro-5,5-dimethyl
heptanedioic acid ethyl ester (5b) [4,5]
Oil. IR: nmax: 3313, 2960, 1766, 1646, 1556, 1087 cmꢂ1. 1H
NMR (CDCl3) d: 1.02 (s, 6H, 2 ꢀ CH3), 1.36 (t, J = 7 Hz, 3H,
CH3), 1.49 (m, 2H, CH2), 2.03–2.13 (m, 4H, 2 ꢀ CH2), 2.79 (d,
J = 4.8 Hz, 3H, N–CH3), 4.33 (q, J = 7 Hz, 2H, OCH2), 5.48 (s,
1H, N–H). 19F NMR (CDCl3) d: ꢂ107.1 (m, 2F, CF2).
3.3.2. 5-(2,2,3,3,4,4,5,5,6,6,7,7,7-Tridecafluoroheptyl)-4,4-
dimethyl-dihydro-furan-2-one (3b) [4]
Colorless needles, mp: 52–53 8C. 1H NMR (CDCl3) d: 1.06
(3H, s, CH3), 1.22 (3H, s, CH3), 2.25–2.51 (4H, m, 2 ꢀ CH2),
4.45 (1H, d, J = 9.2 Hz, CH). 19F NMR (CDCl3) d: ꢂ80.7 (3F,
m, CF3), ꢂ112.6 (2F, m, CF2CH2), ꢂ122.7 (2F, m, CF2),
ꢂ123.8 (2F, m, CF2), ꢂ124.2 (2F, m, CF2), ꢂ127.1 (2F, m,
CF2).
3.3.7. N-t-Butyl-6-carbamoyl-2,2-difluoro-5,5-dimethyl
heptanedioic acid ethyl ester (5c)
Oil. IR: nmax 3333, 2964, 1764, 1647, 1542, 1086 cmꢂ1. 1H
NMR (CDCl3) d: 1.02 (s, 6H, 2 ꢀ CH3), 1.34–1.37 (m, 12H,
3 ꢀ CH3 + CH3), 1.49–1.51 (m, 2H, CH2), 1.95 (s, 2H, CH2),
2.00–2.05 (m, 2H, CH2), 4.35 (q, J = 7 Hz, 2H, OCH2), 5.20–
5.30 (s, broad, 1H, N–H). 19F NMR (CDCl3) d: ꢂ106.4 (m, 2F,
CF2). EI-MS m/z (%): 308 (M+, 0.2), 292 (1), 235(M+–CO2Et,
3), 115 (100), 58 (58). HRMS calcd. for C15H27F2NO3:
307.1959, found: 307.1960.
3.3.3. 5-(3-Chloro-2,2,3,3-tetrafluoro-propyl)-3-methyl-
dihydro-furan-2-one (4a) [4,5]
1
Oil. H NMR (CDCl3) d: 1.34 (3H, d, J = 7.2 Hz, CH3),
2.17–2.42 (3H, m, CH2 + CH), 2.55–2.78 (2H, m, CH2), 4.80–
5.00 (1H, m, CH). 19F NMR (CDCl3) d: ꢂ72.5 (2F, s, ClCF2),
ꢂ113.7 (2F, m, CF2CH).
Acknowledgements
3.3.4. 2,2-Difluoro-3-(3,3-dimethyl-5-oxo-tetrahydro-
furan-2-yl)-propionic acid ethyl ester (3c) [4,5]
Oil. IR: nmax: 2968, 2939, 1781, 1469, 1092 cmꢂ1. 1H NMR
(CDCl3) d: 1.05 (s, 3H, CH3), 1.20 (s, 3H, CH3), 1.37 (t,
J = 7 Hz, 3H, CH3), 2.26–2.49 (m, 4H, CH2 + CH2), 4.31 (d,
J = 10 Hz, 1H, CH), 4.37 (q, J = 7 Hz, 2H, CH2). 19F NMR
(CDCl3) d: ꢂ109.45 to ꢂ108.91 (m, 1F), ꢂ103.00 to ꢂ102.44
(m, 1F). EI-MS m/z (%): 250 (M+, 0.9), 208 (80), 178 (M+–
The authors are indebted to the National Natural Science
Foundation of China and the Shanghai Science and Technology
Committee for the financial support.
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