T. Abe et al. / Journal of Fluorine Chemistry 99 (1999) 51±57
55
helium in all cases. Infrared spectra were measured on a
Shimadzu FTIR-8000PC spectrometer using a 6 cm gas cell
with KBr windows. 19F NMR spectra were measured on a
Varian Unity Inova 300 spectrometer (282.238 MHz for 19F
Methyl F-[(4-methylpiperazinyl)acetate] (nc) had b.p. of
138±1418C, d420 1.6972, n2D0 1.3221. IR (capillary ®lm):
2968 (w), ꢀ(C=O) 1794 (ms), 1445 (m), 1416 (m), 1330±
1370 (vs), 1260±1320 (vs), 1130±1245 (vs), 1071 (s), 953
(s), 897 (ms), 858 (m), 843 (m), 748 (ms), 729 (ms), 677 (w).
19F NMR (CDCl3): ꢁ 52.7 (quintet, 3F, JF±F14.1 Hz,
CF3), ꢁ 86.1 (quintet, 2F, JF±F11.3 Hz, NCF2±), ꢁ 90.6
(t, 4F, JF±F12.1 Hz, (±CF2)2NCF2±), ꢁ 92.4 (q, 4F, JF±
1
and 299.95 MHz for H, respectively). Chemical shifts for
19F and 1H NMR spectra were reported respective to CFCl3
and TMS, respectively. Positive shifts were down®eld from
the reference. Mass spectra were measured on a Shimadzu
GC/MS-QP5000 instrument ®tted with a capillary column
(Neutra Bond-1, 30 m long, 0.25 mm ID, 1.5 mm thick) at
70 eV.
12.1 Hz, CF3N(CF2±)2). 1H NMR: ꢁ 4.00 (s, 3H, OCH3).
F
MS: 387 [M±F] (0.4), 347 [M±CO2CH3] (3.0), 259
C4F8CO2CH3 (2.2), 164 C2F4N (6.6), 145 NC2F4OCH3
(2.9), 119 C2F5 (4.4), 114 C2F4N (17.1), 109 CF2CO2CH3
3.1. Fluorination of 1,4-bis(2-hydroxyethyl)piperazine (1)
(15.9), 100 C2F4 (9.3), 69 CF3 (28.6), 59 CO2CH3 (100),
50 CF2 (2.7).
Sample 1 (38.2 g, 0.219 mol) was charged into a cell
containing 450 ml electrically puri®ed HF, and the solution
was subjected to ¯uorination with an anodic current density
of 2.9 A/dm2, a cell voltage of 6.7±7.8 V, and a cell tem-
perature of 7±88C over a period of 637 min (225 A h). At the
®nal stage of the ¯uorination, the voltage reached 7.9 V.
The ef¯uent gases from the cell were passed over NaF
pellets and then condensed in a trap cooled to 788C. The
gaseous products which did not condense in the 788C trap
were then bubbled through a ¯uoropolymer bottle contain-
ing water and a gas washing bottle containing an aqueous
solution of a mixture of K2CO3, KOH and KI. All products
except new ones were identi®ed by comparison of their
infrared spectra and GLC retention times with those of
authentic samples. New compounds were separated from
the other products by use of semi-preparative GLC, and their
structures were determined on the basis of their IR, 19F
NMR and Mass spectra.
The products (12.1 g) condensed in the 788C trap
consisted of F-N,N-dimethylacetyl¯uoride (17) (1.5 g), F-
(N,N-diethyl)methylamine (3.3 g), F-N,N-diethylaminoace-
tyl¯uoride (18) (2.9 g), F-1,4-dimethylpiperazine (19)
(2.4 g), F-(4-methylpiperazinyl)acetyl ¯uoride (10)
(0.9 g) and unidenti®ed (1.3 g). Cell drainings (11.0 g)
consisted of 18 (1.0 g), 19 (1.0 g), 10 (3.4 g), F-[1,4-bis(-
¯uorocarbonylmethyl)piperazine] (11) (3.4 g), and uniden-
ti®ed (1.3 g). The yield of 10 and 11 was 5.6 mol% and
3.7%, respectively, based on the sample.
1,4-Bis(methoxycarbonyldi¯uoromethyl)octa¯uoropi-
perazine (nc) had b.p. of 160±1628C, d420 1.6972, nD20 1.3514.
IR (capillary ®lm): 2968 (w), ꢀ(C=O) 1794 (vs), 1445 (m),
1410 (m), 1352 (vs), 1220±1330 (vs), 1110±1210 (vs), 1059
(s), 955 (s), 843 (ms), 793 (ms), 750 (s), 668 (w). 19F NMR
(CDCl3): ꢁ 86.1 (m, 4F, NCF2±), ꢁ 90.6 (m, 8F, ±
N(CF2)2±). 1H NMR: ꢁ 4.00 (s, 6H, OCH3). MS: 427
[M±F] (0.6), 387 [M±CO2CH3] (5.2), 238 C4F10 (3.3),
174 C3F6N (5.8), 164 C3F6N (4.0), 145 NC2F4OCH3
(1.3), 119 C2F5 (1.8), 114 C2F4N (14.3), 109 CF2CO2CH3
(28.3), 100 C2F4 (19.6), 81 CF2OCH3 ; C2F3 (25.6), 69
CF3 (9.3), 59 CO2CH3 (100), 65 CF2NH (13.8), 59
CO2CH3 (100), 50 CF2 (2.2).
Compounds 10 were derivatized into an amide of p-
methoxyaniline for further characterization: 7.30 g
(0.06 mol) of p-methoxyaniline dissolved in 30 ml of
methylenechloride and 20.1 g (0.2 mol) of triethylamine
was placed in a 100 ml polytetra¯uoroethylene beaker,
and a portion (4.50 g) of product collected at 788C trap
was added dropwise while shaking. After the reaction, the
mixture was left standing in a draft overnight. The residue
was dissolved in a mixture of hexane and acetonitrile (1:1)
and analyzed by TLC. The crude product was puri®ed by
column chromatography (hexane/acetonitrile as eluent) to
give F-[(4-methylpiperazinyl)acetyl]-p-methoxyanilide
(0.47 g, 21% yield) as white crystals.
F-[(4-methylpiperazinyl)acetyl]-p-methoxyanilide (nc):
m.p. 106±1078C. IR (KBr disk): 1709 ꢀ(C=O). 19F NMR
(CDCl3): ꢁ 52.7 (quintet, 3F, JF±F14.1 Hz, CF3N±), ꢁ
86.1 (quintet, 2F, JF±F11.3 Hz, NCF2±), ꢁ 90.6 (t, 4F,
JF±F12.1 Hz, (±CF2)2NCF2±), ꢁ 92.4 (qualtet, 4F, JF±
Further analysis of 10 and 11 was conducted for their
methyl esters. Methyl esters of 10 and 11 were prepared by
mixing about 2 g of cell drainings with 1 ml of methanol.
The reaction was completed within a few minutes. The
lower layer of the reaction mixture was then separated and
subjected to semi-preparative GLC to give small quantities
of corresponding methyl esters.
12.1 Hz, (±CF2)2NCF2). 1H NMR: ꢁ 4.00 (s, 3H, OCH3).
F
MS: 497 M (27.4), 150 C8H8NO2 (11.4), 149 C8H7NO2
(100), 134 C2F5NH (13.0), 122 C7H8NO2 (39.2), 119
C2F5 (7.2), 114 C2F4N (13.8), 69 CF3 (20.1).
F-(4-methylpiperazinyl)acetyl ¯uoride (10). IR (gas):
ꢀ(C=O) 1794 (ms), 1360 (ms), 1312 (vs), 1283 (ms),
1259 (m), 1227 (vs), 1184 (m), 1150 (m), 1103 (m),
1159 (m), 961 (ms).
3.2. Fluorination of N,N-bis(2-hydroxyethyl)methylamine
(2)
F-[1,4-bis(¯uorocarbonylmethyl)piperazine] (11). IR
(gas): ꢀ(C=O) 1794 (vs), 1340 (vs), 1308 (vs), 1281 (s),
1244 (s), 1200 (vs), 1083 (m), 1048 (m), 955 (s), 823 (m).
Sample 2 (41.0 g, 0.344 mol) was ¯uorinated similarly
under the following conditions: 2.9 A/dm2, 6.1±6.3 V, 7±
88C, 675 min (251 A h). The work-up gave the following