Fluorinated phosphorus compounds: Part 11. The reactions of some fluorinated amines with dialkyl and bis(fluoroalkyl) phosphorochloridates

Article abstract of DOI:10.1016/j.jfluchem.2005.04.016

Dimethyl phosphorochloridate reacted with R_FCH ₂NH₂ in ether in the presence of Et₃N to afford (MeO)₂P(O)NHCH₂R_F, where R_F = CF₃ and C₂F₅, in 39 and 47% yield, respectively. Similar reactions with di-n-propyl and diisopropyl phosphorochloridates could be effected only with H₂NCH ₂CF₃ when 4-dimethylaminopyridine catalyst was added and (n-PrO)₂P(O)NHCH₂CF₃ and (i-PrO) ₂P(O)NHCH₂CF₃ were isolated in 49 and 25% yield, respectively. Treatment of POCl₃ with one molar equivalent each of H₂NCH₂CF₃ and Et₃N permitted the synthesis of Cl₂P(O)NHCH₂CF₃ in 43% yield. Bis(fluoroalkyl) phosphorochloridates (R_FO)₂P(O)Cl, where R_F = C₂F₅CH₂, C₃F ₇CH₂ and (CF₃)₂CH, reacted with 2,2,2-trifluoroethylamine and 2,2,3,3,3-pentafluoropropylamine to furnish phosphoramidates (R_FO)₂P(O)NHCH₂R, where R = CF₃ or C₂F₅, in yields of 32-67%.

Full text of DOI:10.1016/j.jfluchem.2005.04.016

Journal of Fluorine Chemistry 126 (2005) 1144–1149
www.elsevier.com/locate/fluor
Fluorinated phosphorus compounds
Part 11. The reactions of some fluorinated amines with
dialkyl and bis(fluoroalkyl) phosphorochloridates
*
Christopher M. Timperley , Matthew Waters
Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
Received 9 February 2005; received in revised form 25 April 2005; accepted 30 April 2005
Available online 1 July 2005
Abstract
Dimethyl phosphorochloridate reacted with R CH NH in ether in the presence of Et N to afford (MeO) P(O)NHCH R , where R = CF
3
F
2
2
3
2
2
F
F
and C
2
F
5
, in 39 and 47% yield, respectively. Similar reactions with di-n-propyl and diisopropyl phosphorochloridates could be effected only
NCH CF when 4-dimethylaminopyridine catalyst was added and (n-PrO) P(O)NHCH CF and (i-PrO) P(O)NHCH CF were
with H
2
2
3
2
2
3
2
2
3
isolated in 49 and 25% yield, respectively. Treatment of POCl with one molar equivalent each of H NCH CF and Et N permitted the
3
2
2
3
3
synthesis of Cl
CF
where R = CF or C F , in yields of 32–67%.
2
P(O)NHCH
2
CF
3
in 43% yield. Bis(fluoroalkyl) phosphorochloridates (R
F
O) P(O)Cl, where R
2
F
= C
2
F
5
CH
2
, C
3
F
7
CH
2
and
R,
(
3
)
2
CH, reacted with 2,2,2-trifluoroethylamine and 2,2,3,3,3-pentafluoropropylamine to furnish phosphoramidates (R
F
O)
2
P(O)NHCH
2
3
2 5
Crown Copyright # 2005 Published by Elsevier B.V. All rights reserved.
Keywords: Bis(fluoroalkyl) N-(fluoroalkyl)phosphoramidate; Dialkyl N-(fluoroalkyl)phosphoramidate; Fluorinated amine; Fluoroamine; 2,2,3,3,3-Penta-
fluoropropylamine; 2,2,2-Trifluoroethylamine
1
. Introduction
point of view of the fluoroamines, whose chemistry has
1
scarcely been explored.
Recent papers from this laboratory detail methods for
the preparation of phosphorus compounds containing
fluoroalkyl groups. This paper outlines our investigations
into the phosphorylation of fluorinated aliphatic amines to
produce dialkyl N-fluoroalkylphosphoramidates. Related
compounds A–D reported in the literature [1–6] are shown
in Fig. 1. We have previously described a simple method
for producing dialkyl N-(fluoroalkyl)phosphoramidates
which involved reaction between dialkyl phosphorochlor-
idates and fluoroamines [7] and products with trifluor-
oethyl or pentafluoropropyl amino substituents were
isolated (Scheme 1). In this study, we explore further
the scope of such chemistry. The work is novel from the
Fig. 1. Literature phosphorus compounds with N-fluoroalkylamino groups.
1
Known derivatives made in one step from 2,2,2-trifluoroethylamine
*
Corresponding author. Tel.: +44 1980 613 566; fax: +44 1980 613 834.
3 2
include its hydrochloride salt [8], diazoethane CF CHN [9] and isocyanate
E-mail address: cmtimperley@dstl.gov.uk (C.M. Timperley).
CF CH NCO [10].
3
2
0022-1139/$ – see front matter. Crown Copyright # 2005 Published by Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2005.04.016

C.M. Timperley, M. Waters / Journal of Fluorine Chemistry 126 (2005) 1144–1149
1145
Scheme 1.
2
. Results and discussion
2
.1. Dialkyl N-fluoroalkylphosphoramidates
Scheme 3.
The low basicity of fluoroalkylamines (CF CH NH , pK
b
2.2. Bis(fluoroalkyl) N-fluoroalkylphosphoramidates
3
2
2
8
.3) compared with their non-fluorinated counterparts
CH CH NH , pK 3.3) [8] should lower their reactivity
(
Bis(fluoroalkyl) phosphorochloridates are more suscep-
tible to nucleophilic attack than dialkyl phosphorochlor-
idates because the electronegative fluoroester groups render
their phosphorus atom more electron deficient [11,12]. The
greater ease of combination of 2,2,2-trifluoroethylamine
with (CF CH O) P(O)Cl compared to (CH CH O) P(O)Cl
3
2
2
b
towards electrophiles. Despite this, dimethyl phosphoro-
chloridate reacted with an equimolar mixture of 2,2,2-
trifluoroethylamine and triethylamine to give dimethyl N-
trifluoroethylphosphoramidates 1 and 2 in moderate yield
(Scheme 2). Comparable reactions with diethyl phosphoro-
chloridate gave analogous products [7].
3
2
2
3
2
2
was noted earlier [7]. Here, we show that a range of other
bis(fluoroalkyl) phosphorochloridates reacted with 2,2,2-
trifluoroethylamine to give the desired products 6–8 in yields
greater than those with the corresponding dialkyl phosphor-
ochloridates (Scheme 4). Compounds 6 and 7 were liquids,
whereas compound 8 was a low melting white solid.
The same phosphorochloridates reacted with 2,2,3,3,3-
pentafluoropropylamine to furnish homologues 9–11 in
reasonable yield (Scheme 5). All three were low melting
white solids.
The longer the ester groups of dialkyl phosphorochlor-
idates, the greater the electron density on the phosphorus
atom, making it less prone to nucleophilic attack. Branching
of the ester groups sterically hinders the phosphorus atom.
For these reasons, no reaction between di-n-propyl or
diisopropyl phosphorochloridate and 2,2,2-trifluoroethyla-
mine was observed at room temperature. Addition of the
catalyst 4-dimethylaminopyridine (DMAP) was required to
effect conversion to phosphoramidates 3 and 4 (Scheme 3).
The greater yield of n-propyl versus isopropyl product
reflects the difference in reactivity of the chloridates, di-n-
propyl phosphorochloridate reacting better than diisopropyl
phosphorochloridate, due to its less hindered nature.
An alternative route to phosphoramidates 3 and 4 was
also explored. Treatment of phosphorus oxychloride with a
molar equivalent of 2,2,2-trifluoroethylamine and triethy-
lamine gave N-(2,2,2-trifluoroethyl)phosphoramidic dichl-
oride 5 as a liquid. However, this compound failed to react
cleanly with n-propanol or isopropanol in the presence of
triethylamine, or with sodium n-propanolate or isopropa-
nolate in ether at 0 8C, which prevented access to the desired
phosphoramidates by a second route. Analytical data for the
new compounds appear in Table 1.
An interesting property of the fluorinated phosphorami-
dates is that their boiling points are higher than those of their
perprotio analogues (physical data for the latter appear in
Scheme 4.
Scheme 2.
Scheme 5.

1146
C.M. Timperley, M. Waters / Journal of Fluorine Chemistry 126 (2005) 1144–1149
base than triethylamine is usually employed to deprotonate
the NH bond and accelerate coupling [14]. In our case, the
enhanced acidity of the NH proton, due to the inductive
effect of the CF CH group, probably permitted deprotona-
3
2
tion by triethylamine.
3. Experimental
Scheme 6.
Dipropyl phosphite (n-PrO) P(O)H was obtained from
2
phosphorus trichloride and three molar equivalents of
propanol in the absence of base: our sample had bp
54 8C/0.02 mmHg [15]. Diisopropyl phosphite (i-PrO)2-
P(O)H was purchased from Aldrich Ltd. (Gillingham, UK).
Passage of an excess of chlorine gas through the phosphites
in ether at 0–5 8C, removal of solvent, and distillation gave
chloridates (n-PrO) P(O)Cl and (i-PrO) P(O)Cl with bp
ref. [13]). Most of the fluorinated phosphoramidates are
solids at room temperature, whereas their unfluorinated
counterparts are liquids. The difference is presumably due to
strong intermolecular NH. . .F bonding in the fluorinated
series.
2
2
2
.3. Bis(2,2,2-trifluoroethylamino) derivatives
48 8C/0.015 mmHg and 58 8C/0.7 mmHg, respectively, in
accordance with literature values [16]. 2,2,2-Trifluoroethyl
phosphorodichloridate [11] and bis(fluoroalkyl) phosphoro-
chloridates [17] were obtained in >98% purity using known
chemistry. Fluoroamines were purchased from Apollo
Scientific Ltd. (Stockport, UK) and other reagents, including
anhydrous solvents, from Aldrich Ltd (Gillingham, UK).
NMR spectra were obtained on a JEOL Lambda 500
Attempts to prepare phosphorodiamidic chloride 12,
phosphonodiamidates 13a–b and phosphorodiamidates
4a–b by treatment of various phosphorus dichlorides with
1
two molar equivalents of 2,2,2-trifluoroethylamine and
triethylamine gave mixtures of products (Scheme 6).
Although phosphorus oxychloride, and methyl and ethyl-
phosphonic dichloride, did furnish some of the desired
products 12 and 13a and b, respectively, as identified by
GC–MS analyses, they decomposed on attempted purifica-
tion (see Sections 3.5 and 3.6). A similar situation was
observed with the product derived from ethyl phosphorodi-
chloridate, compound 14a. Trifluoroethyl phosphorodi-
chloridate produced a 1:2 mixture of phosphorodiamidate
1
13
instrument (operating at 500 MHz for H, 125 MHz for C,
1
9
31
470 MHz for F and 202 MHz for P spectra) or a JEOL
1
Lambda 300 instrument (operating at 300 MHz for H,
1
3
19
31
75 MHz for C, 282 MHz for F and 121.5 MHz for
spectra) as solutions in CDCl , with internal reference
P
3
1
13
19
SiMe for H and C, external CFCl for F and external
3
(MeO) P (d 140 ppm) for P spectra. IR spectra were
4
3
1
3
1
4b and a similar-boiling product of molecular mass 585,
recorded as liquid films on a Nicolet SP210 instrument.
Reaction mixtures were monitored by gas chromatography–
mass spectrometry (GC–MS) using a Finnigan MAT GCQ
instrument with chemical ionisation (CI) using methane as
reagent gas. High-resolution mass spectrometry (HRMS)
data were obtained using instrumentation and conditions
described elsewhere [18].
probably structure 15, formed by condensation of the
chloridate intermediate with 14b (Scheme 7). Again,
apparent instability of the products prevented their
purification (see Section 3.7).
Non-fluorinated relatives of 15 have been made by
condensing chloridates with phosphoramidates; a stronger
Scheme 7.

C.M. Timperley, M. Waters / Journal of Fluorine Chemistry 126 (2005) 1144–1149
1147
3
.1. Dimethyl N-(fluoroalkyl)phosphoramidates
1 and 2)
1649, 1606, 1468, 1394, 1300, 1281, 1238 (P O), 1151,
À1
(
1005, 887, 829, 750, 661, 542 cm . HRMS: calculated
+
for C H F NO P 263.196 ([M À F] = 244.198), found
8
17
3
3
A solution of fluorinated amine (40 mmol) and triethy-
244.195 (error 2.9 ppm).
lamine (5.6 ml, 40 mmol) in ether (10 ml) was added
dropwise by cannula to a stirred solution of dimethyl
phosphorochloridate (5.8 g, 40 mmol) in ether (40 ml) at 0–
3.2.2. Diisopropyl N-(2,2,2-trifluoroethyl)-
phosphoramidate 4
1
5
8C. After addition, the mixture was allowed to warm to
Bp 58 8C/0.02 mmHg. Mp 34 8C. H NMR d = 4.62 (2 H,
room temperature and was left for 14 h. The precipitate of
triethylamine hydrochloride was filtered off and the filtrate
concentrated to reveal a liquid. Bulb-to-bulb distillation
under reduced pressure using a Kugelrohr apparatus, gave
the title compounds as white crystalline solids.
br m, OCH), 3.51 (3 H, br m, NHCH ), 1.32 (12 H, dd, each
1
2
3
9 Hz, CH3). C NMR d = 124.4 (tq, J = 278 and 35 Hz,
CF ), 71.3 (d, J = 6 Hz, CH), 43.4 (q, J = 34 Hz, NCH ),
3
2
1
9
23.4 (4C, br s, CH ). F NMR d = À72.8 (t, J = 9 Hz, CF ).
3
3
3
1
P NMR d = 4.3. IR nmax = 3201 (NH), 2981, 2939, 1469,
389, 1281, 1236 (P O), 1151, 1109, 993, 897, 852, 829,
1
777, 663, 548 cm . HRMS: calculated for C H F NO P
À1
3
.1.1. Dimethyl N-(2,2,2-trifluoroethyl)-
phosphoramidate 1
8
17
3
3
+
263.196 ([M À F] = 244.198), found 244.193 (error
1
Bp 72 8C/0.03 mmHg. Mp 54 8C. H NMR d = 3.76 (6H,
d, J = 11 Hz, OCH ), 3.51 (2 H, br m, NCH ), 3.32 (1 H, br
1.8 ppm).
3
2
1
m, NH). C NMR d = 124.5 (q, J = 278 Hz, CF ), 53.5 (d,
3
3.3. N-(2,2,2-Trifluoroethyl)phosphoramidic dichloride
(5)
3
1
J = 6 Hz, OCH ), 43.5 (q, J = 35 Hz, NCH ). F NMR
9
3
2
3
1
d = À73.2 (t, J = 9 Hz, CF ).
P NMR d = 8.6. IR
= 3176 (NH), 1479, 1405, 1298, 1271, 1232 (P O),
3
n
1
A solution of 2,2,2-trifluoroethylamine (5.9 g, 60 mmol)
and triethylamine (8.4 ml, 60 mmol) in ether (50 ml) was
added dropwise to a stirred solution of phosphorus
oxychloride (9.1 g, 60 mmol) in ether (50 ml) at 0–5 8C.
After addition, the mixture was allowed to warm to room
temperature and was left for 14 h. The precipitate of
triethylamine hydrochloride was filtered off and the filtrate
concentrated to reveal a liquid. Bulb-to-bulb distillation
under reduced pressure gave the title compound as a
max
À1
146, 1057, 962, 881, 839, 768, 654, 474 cm . HRMS:
+
calculated for C H F NO P 207.088 ([M À F] = 188.090),
4
9
3
3
found 188.088 (error 1.1 ppm).
3
.1.2. Dimethyl N-(2,2,3,3,3-pentafluoropropyl)-
phosphoramidate 2
Bp 69 8C/0.02 mmHg. Mp 42 8C. H NMR d = 3.68 (6H,
1
1
3
d, J = 11 Hz, OCH ), 3.48 (3 H, br m, NHCH ). C NMR
d = 116.9 (tq, J = 286 and 35 Hz, CF ), 110.1 (tq, J = 254
3
2
1
colourless liquid (5.6 g, 43%). Bp 62 8C/0.02 mmHg. H
NMR d = 5.73 (1 H, br m, NH), 3.71 (2H, ‘septet’, J = 9 Hz,
3
and 5 Hz, CF ), 53.3 (d, J = 6 Hz, OCH ), 41.5 (t, J = 24 Hz,
2
3
1
9
13
NCH2). C NMR d = 123.3 (dq, J = 8 and 278 Hz, CF ),
NCH ). F NMR d = À123.3 (2F, m, CF ), À83.6 (3F, m,
2
2
3
3
CF3). P NMR d = 8.8. IR n
1
19
= 3178 (NH), 1462, 1348,
292, 1238 (P O), 1190, 1157, 1136, 1045, 955, 839, 795,
43.4 (q, J = 36 Hz, NCH ). F NMR d = À71.9 (t, J = 9 Hz,
max
2
3
CF3). P NMR d = 15.5. IR (film) n = 3180 (NH), 2903,
1
1
7
2
3
À1
+
21, 594, 534 cm . HRMS: calculated for C H F NO P
5
1460, 1439, 1395, 1299, 1280, 1264, 1158 (P O), 1089,
À1
5
9
3
57.095 ([M À F] = 238.097), found 238.094 (error
995, 963, 865, 832, 662, 570, 544 cm . HRMS: calculated
+
.2 ppm).
for C H Cl F NOP 215.926 ([M À Cl] = 180.473), found
2
3
2 3
180.472 (error 4.2).
3.2. Dipropyl and diisopropyl N-(fluoroalkyl)-
phosphoramidates (3 and 4)
3.4. Bis(fluoroalkyl) N-(fluoroalkyl)phosphoramidates
6–11)
(
The same method as described above was used but a
catalytic amount of DMAP (5% mol) was added. Kugelrohr
distillation under reduced pressure gave compound 3 as a
colourless liquid and compound 4 as a white solid.
A solution of fluorinated amine (40 mmol) and triethy-
lamine (5.6 ml, 40 mmol) in ether (10 ml) was added
dropwise by cannula to a stirred solution of the bis(fluor-
oalkyl) phosphorochloridate (40 mmol) in ether (40 ml) at
0–5 8C. After addition, the mixture was allowed to warm to
room temperature and was left for 14 h. The precipitate of
triethylamine hydrochloride was filtered off and the filtrate
concentrated to reveal a viscous liquid or white solid
depending on the fluorinated amine and phosphorochlor-
idate used. The liquids were distilled under reduced pressure
using a Kugelrohr apparatus; in most cases, a white
crystalline solid sublimed in the receiver bulb. Physical
constants for the title compounds appear in Table 1.
3.2.1. Di-n-propyl N-(2,2,2-trifluoroethyl)-
phosphoramidate 3
1
Bp 72 8C/0.02 mmHg. H NMR d = 3.98 (2 H, complex
m, CH CF ), 3.59 (1 H, br m, NH), 3.50 (4 H, br m, OCH ),
2
3
2
1
CH3). C NMR d = 124.5 (tq, J = 278 and 35 Hz, CF ), 68.3
.71 (4 H, sextet, J = 7 Hz, CH ), 0.96 (6 H, t, J = 7 Hz,
2
1
3
3
(
d, J = 6 Hz, OCH ), 43.5 (q, J = 35 Hz, NCH ), 23.5 (d,
2 2
1
9
J = 7 Hz, CH ), 10.0 (s, CH ). F NMR d = À73.1 (t,
2
3
3
J = 11 Hz, CF3). P NMR d = 6.3. IR n
1
= 3199 (NH),
max

Table 1
F 2 3
Analytical data for bis(fluoroalkyl) N-(fluoroalkyl)phosphoramidates (R O) P(O)NHR 6–11 (NMR data measured in CDCl )
1
13
1
C{ H} NMR d, J (Hz)
19
31
1
P{ H} IR n (cm )
À1
Compound R
F
R
Bp
H NMR d, J (Hz)
F NMR d, J (Hz)
HRMS analysis
(
8C/mm Hg)
NMR d
6
7
C
C
2
F
5
CF
3
59/0.015
4.46 (4 H, m, 8, OCH
2
),
125–111 (br m, CF
and CF ), 62.3 (dt,
J = 4, 29, OCH ),
3.2 (q, J = 35, NCH
2
À124.5 (4F, t, J = 11,
6.0
3203 (NH), 1460, 1356, Calc. for
3
1302, 1205 (P O), 1159, C 13NO P 443.096,
4
3
.31 (1 H, br m, NH),
.52 (2 H, br m, NCH
3
CF
CF
2
), À83.4 (6F, m,
), À74.1 (3F, t,
8
H
7
F
2
)
2
3
1128, 1070, 1030, 968,
937, 881
found 443.094
(error 2 ppm)
4
2
)
)
2 3
J = 8, NCH CF )
3
F
7
CF
3
69/0.04
4.46 (4 H, m, 13, OCH
2
),
127–106 (br m, CF
and CF ), 62.6 (dt,
J = 4, 29, OCH ),
3.4 (q, J = 36, NCH
2
À126.8 (4F, m, CF
2
),
),
6.3
6.9
3207 (NH), 1460, 1356, Calc. for
4
3
.3 (1 H, br m, NH),
.52 (2 H, br m, NCH
3
À120.9 (4F, m, CF
2
1302, 1232 (P O),
1182, 1132, 1080,
1016, 968, 930
10 7 3
C H F17NO P 543.11,
2
)
2
À80.1 (6F, m, CF
3
),
found 543.061
(error 10 ppm)
4
2
À73.5 (3F, t, J = 8,
NCH CF
2
3
)
8
(CF
3
)
2
CH CF
3
50/0.015,
5.05 (2 H, m, OCH),
4.11 (1 H, br m, NH),
124–116 (br m, CF
71.5 (dsept, J = 4, 36,
OCH), 43.2 (q, J = 36,
NCH
3
),
À73.2 and À73.4
(15F, m, CF ),
3212 (NH), 1470,
1403, 1383, 1370,
1296, 1210 (P O),
1200, 1182, 1160,
Calc. for
Mp 44 8C
3
8 5 3
C H F15NO P 479.076,
3
.57 (2 H, m, 18, NCH
2
)
found 479.078
(error 5 ppm)
2
)
1
094, 970, 907
3172 (NH), 1460, 1406, Calc. for
1375, 1350, 1200 (P O), C 15NO
1149, 1109, 1090, 1028, found 493.098
958, 935, 885 (error 12 ppm)
3184 (NH), 1458, 1406, Calc. for
1348, 1230, 1201 (P O), C11 19NO
1132, 1088, 1032, 1016, found 593.111
9
0
C
C
2
F
5
C
C
2
F
5
Mp 76 8C
4.53–4.35 (4 H, m, OCH
2
), 124–108 (br m, CF
2
and CF
),
3
), À124.6 (4F, t, J = 14, CF
2
2
),
),
6.3
6.3
4
3
.25 (1 H, m, NH),
.54 (2 H, m, NCH
62.1 (dt, J = 4, 29, OCH
2
À123.5 (2F, t, J = 14, CF
9
H
7
F
3
P 493.103,
2
)
41.2 (t, J = 24, NCH
2
)
À84.4 (6F, m, CF
3
),
À74.6 (3F, t, J = 8, NCH
2
3
CF )
1
3
F
7
2
F
5
73/0.1,
4.46 (4 H, m, OCH
2
),
123–106 (br m, CF
and CF ), 62.5
(t, J = 28, OCH
2
À126.7 (4F, m, OCH
À122.7 (2F, m, NCH
À120.8 (4F, m, OCH
2
CF
2
CF
2
CF
2
2
2
),
),
Mp 49 8C
4.28 (1 H, br m, NH),
.57 (2 H, m, NCH
3
H
7
F
3
P 593.117,
3
2
)
2
),
1.6 (t, J = 24, NCH
2
CF ),
4
2
)
À83.1 (3F, m, CF
3
),
)
964, 928, 885
(error 20 ppm)
À78.9 (6F, m, CF
3
11
(CF
3
)
2
CH C
2
F
5
83/0.03,
5.06 (2 H, m, OCH),
3.81 (1 H, br s, NH),
124–116 (br m, CF
3
),
À122.5 (2F, d, J = 14, CF
À83.2 (3F, m, CF ),
À73.2 (12F, m, CF ),
2
),
7.0
1371, 1292, 1236,
1209 (P O), 1147,
1113, 1090, 1034,
908, 735, 652
Calc. for
Mp 58 8C
71.7 (dsept, J = 4, 35,
3
9 5 3
C H F17NO P 529.083,
3
.62 (2 H, m, NCH
2
)
OCH), 41.7 (t,
3
found 529.051
(error 4 ppm)
2
J = 23, NCH )

C.M. Timperley, M. Waters / Journal of Fluorine Chemistry 126 (2005) 1144–1149
1149
3.5. Reaction of 2,2,2-trifluoroethylamine with
phosphorus oxychloride
mixture of the desired product 14b and a by-product,
probably structure 15. This mixture decomposed on
attempted Kugelrohr distillation under reduced press-
ure (5 mmHg) and on passage through a chromatog-
raphy column of silica gel eluting with hexane–acetone
mixtures.
A solution of 2,2,2-trifluoroethylamine (2 g, 20.2 mmol)
and triethylamine (2.8 ml, 20.2 mmol) in ether (25 ml) was
added dropwise to a stirred solution of phosphorus
oxychloride (1.54 g, 10.1 mmol) in ether (35 ml) at 0–
5
8C. Reaction was instantaneous and a white precipitate
formed. After 12 h, the precipitate was filtered off and the
filtrate concentrated to reveal an oily solid, which was shown
by GC–MS analysis to contain a variety of obscure products,
but a small amount of the desired product 12. The solid
decomposed on attempted bulb-to-bulb vacuum distillation
Acknowledgements
We wish to thank Ian Morton for obtaining the HRMS
data and the Ministry of Defence UK for funding this work.
# Crown Copyright 2005 published with the permission of
the Controller HMSO.
(5 mmHg) and on chromatography on silica gel eluting with
hexane–acetone mixtures.
References
3.6. Reaction of 2,2,2-trifluoroethylamine with methyl
or ethylphosphonic dichloride
[
[
1] H.J. Emel e´ us, T. Onak, J. Chem. Soc. (A) (1966) 1291–1292.
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A solution of 2,2,2-trifluoroethylamine (1 g, 10.1
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[
[
[
[
(
8 ml) was added dropwise to a stirred solution of methyl
or ethylphosphonic dichloride (5 mmol) in ether (15 ml) at
–5 8C. Reaction was instantaneous and a white precipitate
4] E.S. Kozlov, A.A. Kisilenko, A.I. Sedlov, A.V. Kirsanov, J. Gen.
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0
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formed. After 12 h, the precipitate was filtered off and the
filtrate concentrated to reveal an oily solid, which was
shown by GC–MS analysis to contain about 25% of the
desired product (13a and b) and two other unidentified
products. The solid decomposed during heating on
attempted Kugelrohr distillation under reduced pressure
6] B.L. Dyatkin, E.P. Mochalina, Yu S. Konstantinov, S.R. Sterlin, I.L.
Knunyants, Izv. Akad. Nauk. SSSR, Ser. Khim. (1967) 2200–2207
(
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[
4
[
[
8] A.L. Henne, J.J. Stewart, J. Am. Chem. Soc. 77 (1955) 1901–1902.
9] H. Gilman, R.G. Jones, J. Am. Chem. Soc. 65 (1943) 1458–1460.
(
5 mmHg). Analysis of the liquid distillate by GC–MS
revealed a small amount of the desired product plus three
uncharacterised products. The solid also decomposed on
attempted chromatography over silica gel eluting with
hexane–acetone mixtures.
[10] T.S. Reid, US Patent 2,706,733 (1955).
[
[
[
[
11] C.M. Timperley, M. Bird, J.F. Broderick, I. Holden, I.J. Morton, M.J.
Waters, J. Fluorine Chem. 104 (2000) 215–223.
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(
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13] K.V. Nikonorov, E.A. Gurylev, A.V. Chernova, Izv. Akad. Nauk.
SSSR, Ser. Khim. (1968) 569–573 (English translation).
3.7. Reaction of 2,2,2-trifluoroethylamine with 2,2,2-
trifluoroethyl phosphorodichloridate
14] E. Fluck, W. Haubold, Phosphorus(V)-nitrogen compounds with
phosphorus in coordination number 4, in: G.M. Kosolapoff, L. Maier
(
Eds.), Organic Phosphorus Compounds, vol. 6, Wiley-Interscience,
A solution of 2,2,2-trifluoroethylamine (1.38 g, 13.9
mmol) and triethylamine (1.93 ml, 13.9 mmol) in ether
London, 1973 , pp. 592–593 (Chapter 16).
15] H. McCombie, B.C. Saunders, G.J. Stacey, J. Chem. Soc. (1945) 380–
382.
[
[
[
[
(
20 ml) was added dropwise to a stirred solution of 2,2,2-
trifluoroethyl phosphorodichloridate (5 mmol) in ether
30 ml) at 0–5 8C. Reaction was instantaneous and a white
16] B. Fiszer, J. Michalski, Roczniki Chem. 26 (1952) 688–689 (English
translation).
(
17] C.M. Timperley, R.E. Arbon, S.A. Saunders, M.J. Waters, J. Fluorine
Chem. 113 (2002) 65–78.
precipitate formed. After 12 h, the precipitate was filtered
off and the filtrate concentrated to reveal a liquid, which
was shown by GC–MS analysis to contain about a 1:2
18] C.M. Timperley, I.J. Morton, M.J. Waters, J.L. Yarwood, J. Fluorine
Chem. 96 (1999) 95–100.