Solventless Wittig olefination with fluorinated benzaldehydes

Article abstract of DOI:10.3184/030823407X225464

Fluorinated benzaldehydes undergo solventless Wittig olefination with stabilised phosphoranes. Even with less reactive, stabilised phosphoranes, such as acetylmethylidenetriphenylphosphorane, the reactions have been found to be exothermic.

Full text of DOI:10.3184/030823407X225464

3
36 RESEARCH PAPER
JUNE, 336–341
JOURNAL OF CHEMICAL RESEARCH 2007
Solventless Wittig olefination with fluorinated benzaldehydes
Thies Thiemann
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasuga-koh-en, Kasuga-shi 816-8580, Japan
Fluorinated benzaldehydes undergo solventless Wittig olefination with stabilised phosphoranes. Even with less
reactive, stabilised phosphoranes, such as acetylmethylidenetriphenylphosphorane, the reactions have been found
to be exothermic.
Keywords: solventless reaction, stabilised phosphoranes, fluorobenzaldehydes
The reduction of solvents used in organic transformations is
an intriguing and timely challenge. Such a reduction not only
has environmental benefits, but can also lead to simplified and
time-saving handling and work-up of the reactions. Within
this context, solventless reactions are of specal interest and
a number of procedures for solventless organic reactions have
upon addition of pure fluorinated benzaldehyde 1k to solid
2a an immediate warming of the mixture resulted in the
dissolution of the phosphorane in the benzaldehyde with
concurrent intimate mixing of the constituents. While the
reaction temperature intermittently rose to 70ºC and most of
the benzaldehyde was consumed in the process, the melt was
heated further externally to 100°C for 40–45 min to achieve
a complete transformation of the benzaldehyde. Most of the
reactions of the fluorinated benzaldehydes 1 with phosphorane
1
already been developed. In the following, the solventless
Wittig olefination is discussed for the very reactive fluorinated
benzaldehydes, which were found to react exothermically
with a range of stabilised phosphoranes.
2
a are found to be exothermic, with 1d and 1m providing the
Wittig olefination is an organic transformation for which
solvent-reduced or even solventless procedures have been
developed.2 In traditional procedures, Wittig reactions are
run in benzene, toluene, chloroform, dichloromethane, DME
least exothermic reactions within the series of fluorinated
benzaldehydes studied (Scheme 1). Nevertheless, all
fluorinated benzaldehydes that were reacted, were consumed
when the corresponding mixtures were heated at 100ºC for
-6
7
or THF, when stabilised phosphoranes are used. Due to the
4
5 min. While the reactions of benzaldehydes with 2a usually
low reactivity of some of the phosphoranes, an acd catalyst
are E-/Z-selective, apprecable amounts of Z-isomer (Z-3)
could be found in some cases, especally in the reactions with
benzaldehydes 1e and 1g–1i.
8
such as benzoic acd is often added. Solvent-reduced Wittig
6
reactions can be run in chloroform or similar solvents with
a variety of stabilised and semi-stabilised phosphoranes.
The solventless Wittig reactions reported thus far are
limited to a restricted number of phosphoranes, such as the
alkoxycarbonylmethylidenetriphenylphosphoranes 2b and 2c,
Fluorinated benzaldehydes 1 also reacted exothermically
with phosphoranes 2b and 2c. This characteristic is shared
with other benzaldehydes that also have been found to react
2
exothermicallywithalkoxycarbonylmethylidenephosporanes.
2
when classical heating is used. Microwave heating allows the
2
As is typical for other benzaldehydes, the reaction of
use of an expanded range of stabilised phosphoranes.2-5
Previously, the author has noted that simple mixing of
substituted benzaldehydes and ester substituted phosphoranes,
fluorinated 1 with 2b and 2c form mixtures of E- and Z-olefins
(Scheme2).Interestingly,however,for2,6-difluoro-substituted
2
benzaldehydes, such as for 2,6-difluorobenzaldehyde (1j) and
pentafluorobenzaldehyde (1k), the corresponding E-olefin is
obtained almost exclusively.
such as 2b and 2c, results in exothermic reactions. Further
heating of the mixtures at 100ºC leads to total transformation
2
of the educts. For the benzaldehydes studied previously a
Also, halomethylidenetriphenylphosphoranes can be used
in solventless Wittig olefination reactions with fluorinated
benzaldehydes, as is exemplified in the reaction of 2d with
1e and 1f to give 5a and 5b, respectively. When 1a and 1i
are reacted with 2e, cnnamaldehydes 6 are formed mostly,
although 6 can also undergo a Wittig olefination to the
dienals 7. When Wittig olefinations are carried out with non-
fluorinated benzaldehydes in a minimal amount of chloroform
as solvent, phenylpentadienals and even phenylheptatrienals
can be found as very significant by-products. Due to the
much higher reactivity of the fluorinated benzaldehydes
compared with the cnnamaldehydes 6, the Wittig reaction
of fluorobenzaldehydes with 2e can be controlled better to
produce the desired products 6 selectively (Scheme 3), even
under solventless conditions. However, the use of a larger
excess of phosphorane 2e and longer reaction times favours
the dienals 7, together with their homologues as by-products.
Fluorinated benzaldehydes 1 react with benzoylmethyl-
idenetriphenylphosphoranes 2f and 2g, where the reactions
between 1j/1k and 2f were found to be exothermic (Scheme 3).
The reactions show good E-selectivity.
similarly exothermic reaction of the benzaldehydes with other
stabilised phosphoranes was not noted, and for these cases a
minimal amount of solvent is always needed when classical
heating is used.2,6
When aldehydes and phosphoranes are reacted under
solventless conditions, an initial intimate mixing of the two
educts is necessary for the reaction to start. In the case of an
exothermic reaction gradual melting of the constituents will
then lead to further progression of the transformation until
near completion. This initial mixing of the starting materials
necessitates that the aldehyde component is a liquid or that it
has a low melting point as the phosphoranes themselves are
higher-melting solids. This prerequisite is satisfied by many
benzaldehydes. However, many of the reactive, electron poor
benzaldehydes, such as the nitrobenzaldehydes, have relatively
high melting points. One notable exception are the electron
poor, fluoro-substituted benzaldehydes, which are liquids or
solids with low melting points. The Wittig olefination of such
fluorinated benzaldehydes with stabilised phosphoranes 2
gives interesting olefins that have been used themselves, as
intermediates in bioactive materials, or screened as inhibitors
9
10
of angiogenesis, of the farnesyl protein transferase and of
Reactions of 1e/1j with cyanomethylidenetriphenyl-
phosphorane 2h were also found to be exothermic. Here,
however, apprecable amounts of separable Z-isomeric olefins
Z-10a and Z-10b were formed. This is in contrast to most
other reactions of 2,6-difluoro substituted benzaldehydes such
as 1a, 1j and 1k with stabilised phosphoranes, where only
11
b-amyloid protein production.
First experiments with the usually poorly reactive
acetylmethylidenetriphenylphosphorane 2a showed that
*
Correspondent. E-mail: thies@cm.kyushu-u.ac.jp
PAPER: 07/4575

JOURNAL OF CHEMICAL RESEARCH 2007 337
O
CHO
solvent-
less
+
Ph3P
1
00°C
CH3
Fx
O
Fx
2a
1
3
1
1
1
1
1
1
1
1
1
1
1
a: 2,3,6-F -(1)
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 40 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq. 2a, 100ºC, 45 min
1.6 eq, 2a, 100ºC, 45 min
1.6 eq, 2a, 100ºC, 60 min
3
3a: 2,3,6-F -(3) (91%, only E-isomer isolated)
3
b: 2,3,5,6-F -(1)
4
3b: 2,3,5,6-F -(3) (92%, only E-isomer isolated)
4
c: 2,3-F -(1)
2
3c: 2,3-F -(3) (90%, only E-isomer isolated)
2
d: 3,4-F -(1)
2
3d: 3,4-F -(3) (92%, only E-isomer isolated)
2
e: 3,5-F -(1)
2
3e: 3,5-F -(3) (94%, E/Z 92/8)
2
f: 2,3,5-F -(1)
3
3f: 2,3,5-F -(3) (90%, only E-isomer isolated)
3
g: 3,4,5-F -(1)
3
3g: 3,4,5-F -(3) (94%, E/Z 93/7)
3
h: 2,3,4-F -(1)
3
3h: 2,3,4-F -(3) (95%, E/Z 92/8)
3
i: 2,3,4,5-F -(1)
4
3i: 2,3,4,5-F -(3) (86%, E/Z 93/7)
4
j: 2,6-F -(1)
2
3j: 2,6-F -(3) (quant., only E-isomer)
2
k: F -(1)
5
3k: F -(3) (93%, only E-isomer)
5
Scheme 1 Solventless Wittig olefination of fluorinated benzaldehydes with acetylmethylidenetriphenylphosphorane (2a).
O
CHO
solvent-
less
+
Ph3P
OR
1
00°C
OR
1
5-30 min
Fx
O
Fx
1
2b: R = Et; 2c: R = Bzl
4
2
2
2
2
2
2
2
2
2
2
b
b
b
b
c
c
c
c
c
c
4a: 2,5-F -(4); R = Et (93%; E/Z = 92:8)
2
1
1
1
1
1
1
1
1
1
1
m: 2,5-F -(1)
2
4b: 2,3,6-F -(4); R = Et (95%; E/Z>98:2)
a: 2,3,6-F -(1)
3
3
4c: 2,6-F -(4); R = Et (97%; E/Z>98:2)
j: 2,6-F -(1)
2
2
4d: F -(4); R = Et (98%; E/Z>98:2)
k:F -(1)
5
5
4e: 2,3,6-F -(4); R = Bzl (96%; E/Z>98:2)
a: 2,3,6-F -(1)
3
3
4f: 2,3-F -(4); R = Bzl (96%; E/Z=92:8)
c: 2,3-F -(1)
2
2
4g: 2,4-F -(4); R = Bzl (97%; E/Z=86:14)
2
n: 2,4-F -(1)
2
4h: 3,5-F -(4); R = Bzl (97%; E/Z=89:11)
e: 3,5-F -(1)
2
2
4i: 2,6-F -(4); R = Bzl (98%; E/Z>98:2)
2
j: 2,6-F -(1)
2
4j: F -(4); R = Bzl (98%; E/Z>98:2)
k: F -(1)
5
5
Scheme 2 Solventless Wittig olefination of fluorinated benzaldehydes with alkoxycarbonylmethylidenetriphenylphosphorane 2b
and 2c.
E-configurated olefins are produced. Nevertheless, the amount
of Z-isomer obtained for 1j is smaller than for 1e (Scheme 3).
The reaction of 1j with 2i was found not to be exothermic.
Earlier experiments had shown phosphorane 2i to be
moderately sensitive to heat12 and 2i was found to be
unstable under microwave irradiation at 500W (2450 MHz).
Nevertheless, heating the solventless reaction mixture at 100ºC
produced the Wittig product 11, albeit in more moderate yield
triphenylphosphine oxide. For the procedure of a Wittig
reaction in a biphasic medium, which in many cases does not
necessitate a chromatographic separation of the product, see
ref.13.
2
Experimental
General
Melting points were measured on a Yanaco microscopic hot-stage and
are uncorrected. IR spectra were measured with JASCO IR-700 and
(Scheme 3).
In conclusion, a number of fluorinated benzaldehydes could
1
13
Nippon Denshi JIR-AQ2OM instruments. H and C NMR spectra
be reacted with stabilised phosphoranes under solventless
conditions, where in many cases the reactions were found
to be exothermic. It must be noted that the conditions
described lead to time-saving due to quicker reactions and
work-up procedures. Although there is also some reduction
in the solvents involved, including the crcumvention of
such solvents as benzene, it must be noted that solvents
still need to be used in the separation of the products from
1
were recorded with a JEOL EX-270 spectrometer ( H at 270 MHz,
C at 67.8 MHz). The chemical shifts are relative to TMS (solvent
13
CDCl , unless otherwise noted). Mass spectra were measured with
3
a JMS-01-SG-2 spectrometer. For the experiments, an electric
oven, EYELA NDO-450N, pre-heated at 100ºC, was used. Column
chromatography was carried out on Wakogel 300. The reactions were
carried out with 5–14 mmol of benzaldehyde using 1.6 mol equiv. of
phosphorane.
PAPER: 07/4575

3
38 JOURNAL OF CHEMICAL RESEARCH 2007
O
CHO
Br
solvent-
less
+
Ph3P
1
00°C
Br
9
0 min
Fx
O
Fx
1
5
2
d (1.6 eq.)
5
5
a:3,5-F -(5) (85%, Z-isomer)
b: 2,3,4,5-F4-(5) (87%, Z-isomer)
1
1
e: 3,5-F2-(1)
i: 2,3,4,5-F4-(1)
2
CHO
solvent-
less
CHO
CHO
+
Ph3P
1
00°C
+
H
4
0 min
Fx
O
Fx
Fx
1
2e (1.6 eq.)
6
7
1
1
a: 2,3,6-F -(1)
i: 2,3,4,5-F4-(1)
6a:2,3,6-F3-(6) (70%)
6b:2,3,4,5-F4-(6) (72%)
7
7
a:2,3,6-F3-(7) (18%)
b:2,3,4,5-F4-(7) (14%)
3
O
CHO
solvent-
less
+
Ph3P
1
00°C
9
0 min
Fx
O
Fx
1
8
2
f
8
8
a:3,5-F2-(8) (90% E-isomer)
1
1
j: 2,6-F -(1)
k: F5-(1)
2
b:F -(8) (92% E-isomer)
5
O
F
CHO
Br
solvent-
less
F
F
+
Ph3P
1
00°C
Br
F
70 min
O
F
F
9
1
g
2g
(
75%, yield based on Z-isomer)
CHO
solvent-
less
CN
+
3
Ph P
1
00°C
CN
4
0 min.
Fx
Fx
1
2h
10
1
1
0a: 2,6-F2-(10) (90%, E/Z 85:15)
0b: 3,5-F2-(10) (88%, E/Z 8:2)
1
1
j: 2,6-F2-(1)
e: 3,5-F -(1)
2
F
O
F
CHO
solvent-
less
O
Ph3P
+
N
100°C
F
1
h
F
N
O
1
j
2i
11
O
(
70%, based on E-isomer)
Scheme 3 Solventless Wittig olefination of fluorinated benzaldehydes with various stabilised phosphorances.
3
3
Chemicals
(q, 2H, J = 7.0 Hz), 6.50 (d, 1H, J = 15.9 Hz), 7.06 (m, 2H), 7.24
3
The fluorinated benzaldehydes 1 and triphenylphosphoranylidene-
acetaldehyde (2e) were acquired commercally (Aldrich). Phosphoranes
(m, 1H), 7.75 (d, 1H, J = 15.9 Hz); MS (EI, 70 eV) m/z (%) 212
(M , 44), 167 (100), 139 (34), 119 (37). HRMS Found: 212.0646.
Calcd. for C H O F : 212.0649.
+
1
4a
14b
14c
14d,e
14a
14d,e
14f,g
14h
2
a,
synthesised according to literature procedures.
E/Z)-Ethyl 3-(2,5-difluorophenyl)acrylate (4a): To 2b (3.69 g,
0.6 mmol) was added dropwise 2,5-difluorobenzaldehyde (1m)
1.0 g, 6.8 mmol). The reaction vessel was then heated at 100ºC for
0 min. Direct column chromatography on silica gel (hexane/ether/
2b,
2c,
2d,
2f,
2g,
2h,
and 2i
were
11
10
2 2
(
Further selected physical and spectroscopic data
(E)-4-(2,3,6-Trifluoro-phenyl)but-3-en-2-one
slowly solidifying oil; (Found: M 200.0450. C H OF requires M,
1
(3a):
Colourless
+
(
1
0
7
3
(KBr)/cm- 3042, 1667, 1495, 1446, 1278, 1256,
1
3
200.0449); n
max
1
5
CHCl 5: 1: 1) gave 4a as a colourless oil; IR (neat) n 2980, 1718,
1235, 1054, 984, 937, 832, 765, 616, 551; d NMR (270 MHz,
3
H
-
1
3
1
642, 1591, 1492, 1368, 1240, 1179, 1037, 982, 862, 816 cm ; for
CDCl ) 2.41 (3H, s, CH ), 6.89 (1H, m), 7.03 (1H, d, J = 16.7 Hz),
3
3
1
3
3
E-4a: H NMR (270 MHz, CDCl ) d 1.34 (t, 3H, J = 7.0 Hz), 4.28
7.15 (1H, m), 7.55 (1H, d, J = 16.7 Hz); MS (70 eV) m/z (%) = 200
3
PAPER: 07/4575

JOURNAL OF CHEMICAL RESEARCH 2007 339
+
(
55) [M ], 185 (100), 157 (51), 137 (37). (Found: C, 60.2; H, 3.4.
(Z)-4-(2,3,4,5-Tetrafluorophenyl)but-3-en-2-one (Z-3i): Colourless
+
C H F O requires C, 60.01; H, 3.5).
oil; (Found: M 218.0354. C H OF requires M, 218.0355); d (270
10
7
3
10
6
4
H
3
(
E)-4-(2,3,5,6-Tetrafluoro-phenyl)but-3-en-2-one (3b): Colourless
slowly solidifying oil; (Found: M 218.0355. C H OF requires M,
MHz, CDCl ) 2.28 (3H, s, CH ), 6.43 (1H, d, J = 12.4 Hz), 6.71
3
3
+
3
(1H, d, J = 12.4 Hz), 7.41 (1H, m); MS (70 eV) m/z (%) = 218 (35)
1
0
6
4
-1
+
2
1
18.0355); n
(KBr)/cm 3050, 1673, 1499, 1452, 1379, 1283,
[M ], 203 (100), 175 (30).
max
257, 1182, 1052, 981, 928, 880, 713, 692, 648, 546; d (270 MHz,
(E)-4-(2,3,4,5-Tetrafluorophenyl)but-3-en-2-one (E-3i): Colourless
H
3
+
CDCl ) 2.41 (3H, s, CH ), 7.03 (1H, d, J = 16.7 Hz), 7.11 (1H, m),
solid; m.p. 82ºC; (Found: M 218.0352. C H OF requires M,
3
3
10
6
4
3
+
-1
7
(
.53 (1H, d, J = 16.7 Hz); MS (70 eV) m/z (%) = 218 (78) [M ], 203
100), 175 (90), 155 (31). (Found: C, 54.6; H, 2.65. C H F O.0.1H O
requires C, 54.6; H, 2.8).
E)-4-(2,3-Difluoro-phenyl)but-3-en-2-one
slowly solidifying oil; (Found: M 182.0542. C H OF requires M,
218.0355); n
(KBr)/cm 3064, 1678, 1530, 1484, 1257, 1120,
max
1040, 987, 948, 892, 715, 700, 639, 544; d (270 MHz, CDCl ) 2.40
H 3
3
1
0
6
4
2
(3H, s, CH ), 6.73 (1H, d, J = 16.2 Hz), 7.18 (1H, m), 7.53 (1H, d,
3
3
+
(
(3c):
Colourless
J = 16.2 Hz); MS (70 eV) m/z (%) = 218 (58) [M ], 203 (100), 175
(56). (Found: C, 54.8; H, 2.7. C H F O requires C, 55.1; H, 2.8).
+
1
0
8
2
10
6 4
-1
17
1
1
82.0543); n
(KBr)/cm 1675, 1620, 1589, 1482, 1362, 1265,
(E)-4-(2,6-Difluorophenyl)but-3-en-2-one (3j) : Colourless solid,
m.p. 29ºC; (Found: M 182.0546. C H OF requires M, 182.0543);
max
+
070, 978, 820, 780, 737, 711; d (270 MHz, CDCl ) 2.41 (3H, s,
H
3
10
8
2
3
-1
CH ), 6.80 (1H, d, J = 16.2 Hz), 7.09–7.33 (3H, m), 7.63 (1H, d,
n
(KBr)/cm 1663, 1620, 1464, 1364, 1283, 1252, 1203, 1018,
3
max
3
+
J = 16.2 Hz); MS (70 eV) m/z (%) = 182 (59) [M ], 167 (100), 139
45), 119 (35).
985, 792, 719, 590, 525, 504; d (270 MHz, CDCl ) 2.39 (3H, s, CH ),
H 3 3
3
(
6.95 (2H, m), 7.01 (1H, d, J = 16.5 Hz), 7.34 (1H, m), 7.61 (1H, d,
1
6
3
(
E)-4-(3,4-Difluoro-phenyl)but-3-en-2-one + (3d) : Colourless,
J = 16.5 Hz); d (67.8 MHz, CDCl ) 27.9, 111.9 (2C, m), 112.5 (t,
C
3
slowly solidifying oil, m.p. 39ºC; (Found: M 182.0546. C H OF
J
= 14.0 Hz), 129.3 (t, J = 2.0 Hz), 131.3 (t, J = 11.2 Hz),
CF CF
1
0
8
2
CF
-1
requires M, 182.0543); n
358, 1296, 1275, 1183, 1145, 1117, 974, 810, 789, 745, 617, 582,
50, 509; d (270 MHz, CDCl ) 2.38 (3H, s, CH ), 6.63 (1H, d, J =
6.2 Hz), 7.14–7.40 (3H, m), 7.41 (1H, d, J = 16.2 Hz); MS (70 eV)
m/z (%) = 182 (45) [M ], 167 (100), 139 (47), 119 (30). (Found: C,
6.0; H, 4.3; C H F O requires: C, 65.9; H, 4.4).
Z)-4-(3,5-Difluoro-phenyl) but-3-en-2-one (Z-3e): Colourless oil;
Found: M 182.0539. C H OF requires M, 182.0543); n (neat)/
cm 2920, 1694, 1620, 1588, 1415, 1357, 1175, 1122, 996, 868, 758;
(KBr)/cm 1668, 1615, 1519, 1433,
132.4 (t, JCF = 8.4 Hz), 161.8 (2C, dd, JCF = –255 Hz, J = 6.7 Hz),
max
CF
+
1
5
1
198.5 (CO); MS (70 eV) m/z (%) = 182 (49) [M ], 167 (100), 139
3
(48), 119 (47).
H
3
3
3
(E)-4-Pentafluorophenylbut-3-en-2-one (3k): Colourless oil;
+
+
(Found: M 236.0262. C H OF requires M, 236.0261); n (KBr)/
1
0
5
5
max
cm- 2922, 1700, 1683, 1654, 1613, 1523, 1499, 1425, 1362, 1293,
1
6
10
8 2
1
(
1257, 1182, 1136, 1013, 983, 910, 734; d (270 MHz, CDCl ) 2.41
H
3
+
3
3
(
(3H, s, CH ), 6.88 (1H, d, J = 16.7 Hz), 7.47 (1H, d, J = 16.7 Hz);
1
0
8
2
max
3
-1
+
MS (70 eV) m/z (%) = 236 (M , 24), 221 (45), 193 (28), 58 (100).
3
d (270 MHz, CDCl ) 2.23 (3H, s, CH ), 6.28 (1H, d, J = 12.7 Hz),
(E)-Ethyl 3-(2,3,6-trifluorophenyl)acrylate (4b): Colourless oil;
H
3
3
3
+
6
.71 (1H, d, J = 12.7 Hz), 6.79 (1H, m), 7.07 (2H, m); d (67.8 MHz,
(Found: M , 230.0559. C H O F : requires M, 230.0555); n
C
11
9
2
3
max
(neat)/cm- 3092, 2986, 1719, 1639, 1493, 1367, 1312, 1292, 1183,
1048, 985, 926, 872, 810; d (270 MHz, CDCl ) 1.35 (3H, t, J = 7.0
Hz), 4.29 (2H, q, J = 7.0 Hz), 6.76 (1H, d, J = 16.2 Hz), 6.90 (1H,
1
CDCl ) 31.1, 104.4 (t, J = 25.2 Hz), 112.3 (2C, m), 130.6, 137.3 (t,
3
CF
3
JCF = 2.8 Hz), 138.1 (t, JCF = 9.5 Hz), 162.7 (2C, dd, JCF = –248 Hz,
JCF = 12.3 Hz), 197.7 (CO); MS (70 eV) m/z (%) = 182 (37) [M ],
67 (100), 139 (51), 119 (43).
E)-4-(3,5-Difluoro-phenyl)but-3-en-2-one (E-3e): Colourless
solid, m.p. 58ºC; (Found: M 182.0542. C H OF requires M,
H
3
+
3
3
3
1
m), 7.16 (1H, m), 7.65 (1H, d, J = 16.2 Hz); MS (70 eV) m/z (%) =
+
(
230 (39) [M ], 185 (100), 157 (40), 137 (35).
+
18
Ethyl (E)-3-(2,6-difluorophenyl)acrylate (4c) : Colourless oil;
1
0
8
2
-1
+
1
1
82.0543); n
(KBr)/cm 3070, 1672, 1589, 1440, 1365, 1315,
(Found: MH 213.0726. C H O F requires MH, 213.0727); n
max
11 11
2
2
max
(neat)/cm- 2982, 1718, 1639, 1621, 1467, 1314, 1273, 1239, 1203,
1
263, 1215, 1128, 978, 870, 835, 672, 579, 519, 507; d (270 MHz,
H
3
3
CDCl ) 2.39 (3H, s, CH ), 6.69 (1H, d, J = 16.2 Hz), 6.85 (1H, m),
1149, 1012, 869, 788, 743; d (270 MHz, CDCl ) 1.35 (3H, t, J =
3
3
H
3
3
3
3
7
(
1
1
1
4
.07 (2H, m), 7.40 (1H, d, J = 16.2 Hz); MS (70 eV) m/z (%) = 182
7.3 Hz, CH ), 4.28 (2H, q, J = 7.3 Hz, OCH ), 6.74 (1H, d, J =
3
2
+
3
42) [M ], 167 (100), 139 (47), 119 (40); d (67.8 MHz, CDCl ) 28.0,
16.5 Hz), 6.94 (2H, m), 7.30 (1H, m), 7.77 (1H, d, J = 16.5 Hz); d
C
(67.8 MHz, CDCl ) 14.3, 60.7, 111.8 (m), 112.5 (t, J = 15.1 Hz),
C
3
05.6 (t, J = 25.7 Hz), 110.8 (2C, m), 129.0, 137.7 (t, J = 9.5 Hz),
CF
CF
3
C
F
40.5 (t, JCF = 2.8 Hz), 163.2 (2C, dd, JCF = –249 Hz, JCF = 12.8 Hz),
97.7 (CO); (Found: C, 65.7; H, 4.4; C H F O requires C, 65.9; H,
.4).
E)-4-(2,3,5-Trifluoro-phenyl)but-3-en-2-one(3f):Colourlesssolid,
mp. 87ºC; (Found: M 200.0450; C H OF requires M, 200.0449);
d (270 MHz, CDCl ) 2.41 (3H, s, CH ), 6.77 (1H, d, J = 16.2 Hz),
.96–7.09 (2H, m), 7.58 (1H, d, J = 16.2 Hz); MW (70 eV) m/z (%)
200 (55) [M ], 185 (100), 157 (52), 137 (33). (Found: C, 59.85; H,
.4. C H F O requires C, 60.0; H, 3.5).
124.4 (t, JCF = 8.4 Hz), 130.6 (t, JCF = 2.2 Hz), 131.0 (t, JCF = 10.6
Hz), 161.7 (2C, dd, JCF = –255 Hz, JCF = 7.3 Hz), 166.9 (CO); MS
1
0
8 2
+
(FAB, 3-nitrobenzyl alcohol) m/z (%) = 213 (14) [MH ], 167 (24) [M
(
+ -OC H ]. (Found: C, 62.35; H, 4.75. C H F O requires C, 62.3;
2
5
11 10
2
2
+
H, 4.75).
1
0
7
3
3
Ethyl (E)-3-pentafluorophenylacrylate (4d)7f,19: Colourless oil;
H
3
3
3
+
6
=
3
(Found: M 266.0368. C H O F requires M, 266.0366); n
11
7
2
5
max
+
-1
(neat)/cm 2966, 1724, 1650, 1523, 1501, 1296, 1260, 1186, 1150,
1020, 984, 872, 675; d (270 MHz, CDCl ) 1.38 (3H, t, CH , J = 7.3
Hz), 4.30 (2H, q, OCH , J = 7.3 Hz), 6.74 (1H, d, J = 16.5 Hz), 7.64
(1H, d, J = 16.5 Hz). MS (70 eV) m/z (%) = 266 (34) [M ], 238 (18),
221 (100) [M -OC H ], 193 (50) [M -OCOC H ], 143 (25).
3
10
7
3
H
3
3
3
3
(
Z)-4-(3,4,5-Trifluorophenyl)but-3-en-2-one (Z-3g): Colourless
2
+
3
+
oil; (Found: M 200.0450. C H OF requires M, 200.0449); d (270
1
0
7
3
H
3
+
+
MHz, CDCl ) 2.26 (3H, s, CH ), 6.29 (1H, d, J = 12.7 Hz), 6.61
3
3
2 5 2 5
3
(
[
1H, d, J = 12.7 Hz), 7.31 (2H, m); MS (70 eV) m/z (%) 200 (28)
Benzyl (E)-3-(2,3,6-trifluorophenyl)acylate (4e): Colourless solid;
+
+
M ], 185 (66), 157 (33), 137 (20).
E)-4-(3,4,5-Trifluorophenyl)but-3-en-2-one (E-3g): Colourless
solid, m.p. 43ºC; (Found: M 200.0448. C H OF requires M,
(Found: M 292.0719. C H O F requires M, 292.0711); n
1
6
11
2
3
max
(KBr)/cm- 3074, 1704, 1634, 1495, 1455, 1315, 1250, 1170, 1050,
1
(
+
984, 916, 868, 818, 750, 700, 492; d (270 MHz, CDCl ) 5.27 (2H, s,
1
0
7
3
H
3
-1
3
2
1
00.0449); n
(KBr)/cm 3070, 1675, 1532, 1441, 1354, 1250,
OCH ), 6.81 (1H, d, J = 16.5 Hz), 6.91 (1H, m), 7.14 (1H, m), 7.34–
7.44 (5H, m), 7.48 (1H, d, J = 16.5 Hz); MS (70 eV) m/z (%) = 292
(10) [M ], 247 (26), 185 (31), 157 (15), 137 (20), 91 (43), 58 (100).
max
2
3
045, 984, 792, 704, 665, 628, 556; d (270 MHz, CDCl ) 2.38 (3H,
H
3
3
3
+
s, CH ), 6.63 (1H, d, J = 15.9 Hz), 7.17 (2H, t, J
= 6.5 Hz),
3
H-F
3
+
7
1
.34 (1H, d, J = 15.9 Hz); MS (70 eV) m/z (%) = 200 (47) [M ],
85 (100), 157 (45), 137 (28). (Found: C, 60.0; H, 3.4. Calcd. for
Benzyl (E)-3-(2,3-difluorophenyl)acrylate (4f): Slowly solidifying
+
colourless oil; (Found: M 274.0806. C H O F requires M,
1
6
12
2 2
C H F O: C, 60.0; H, 3.5.)
274.0805); n
(KBr)/cm- 1714, 1642, 1484, 1328, 1280, 1203,
1
10
7
3
max
(
Z)-4-(2,3,4-Trifluorophenyl)but-3-en-2-one (Z-3h): Colourless
oil; (Found: M 200.0447. C H OF requires M, 200.0449); n
neat)/cm 2926, 1702, 1621, 1510, 1474, 1357, 1311, 1175, 1037,
61, 814; dH (270 MHz, CDCl ) 2.23 (3H, s, CH ), 6.38 (1H, d, J
12.7 Hz), 6.77 (1H, d, J = 12.7 Hz), 6.96 (1H, m), 7.36 (1H, m);
MS (70 eV) m/z (%) = 200 (51) [M ], 185 (100), 157 (45), 137 (27),
01 (20).
E)-4-(2,3,4-Trifluorophenyl)but-3-en-2-one (E-3h): Colourless
1161, 782, 748, 698; d (270 MHz, CDCl ) 5.27 (2H, s, OCH ), 6.61
H 3 2
3 3
+
(1H, d, J = 16.2 Hz), 7.10–7.44 (8H, m), 7.82 (1H, d, J = 16.2 Hz);
1
0
7
3
max
-1
+
(
9
=
MS (70 eV) m/z (%) = 274 (20) [M ], 229 (41), 167 (62), 139 (29),
3
119 (46), 91 (100).
3
3
3
20
Benzyl (E)-3-(2,4-difluorophenyl)acrylate (4g) : Colourless oil;
+
+
(Found: M 274.0809. C H O F requires M, 274.0805); n
1
6
12
2
2
max
(neat)/cm- 3070, 3034, 2952, 1721, 1640, 1501, 1456, 1431, 1376,
1
1
(
1262, 1169, 1090, 968, 852, 813, 752, 697, 610, 572; d (270 MHz,
H
+
3
solid, m.p. 53ºC; (Found: M 200.0450. C H OF requires M,
CDCl ) 5.26 (2H, s, OCH ), 6.53 (1H, d, J = 16.2 Hz), 6.88 (2H, m),
7.32–7.43 (5H, m), 7.50 (1H, m), 7.79 (1H, d, J = 16.2 Hz); d (67.8
MHz, CDCl ) 66.5, 104.6 (t, J = 25.2 Hz), 111.1 (dd, J = 21.8
1
0
7
3
3
2
-1
3
2
1
5
00.0449); n
(KBr)/cm 3070, 1676, 1604, 1512, 1473, 1360,
max
C
313, 1293, 1253, 1214, 1176, 1070, 1040, 1018, 985, 957, 809, 696,
3
CF
CF
3
48; d (270 MHz, CDCl ) 2.41 (3H, s, CH ), 6.76 (1H, d, J = 16.2
Hz), 7.03 (1H, m), 7.29 (1H, m), 7.56 (1H, d, J = 16.2 Hz); MS (70
eV) m/z (%) = 200 (58) [M ], 185 (100), 157 (49), 137 (31). (Found:
C, 60.0; H, 3.4. C H F O requires C, 60.0; H, 3.5).
Hz, JCF = 3.9 Hz), 120.1 (dd, JCF = 6.7 Hz, JCF = 2.2 Hz), 118.9 (dd,
JCF = 11.7 Hz, JCF = 3.9 Hz), 128.3 (3C), 128.6 (2C), 130.2 (dd, JCF
H
3
3
3
=
+
10.0 Hz, JCF = 4.5 Hz), 135.9, 136.8 (t, JCF = 1.7 Hz), 161.7 (dd, JCF
= –256 Hz, JCF = 11.7 Hz), 163.9 (dd, JCF = –252 Hz, JCF = 12.9 Hz),
10
7 3
PAPER: 07/4575

3
40 JOURNAL OF CHEMICAL RESEARCH 2007
+
21
1
9
66.5 (CO); MS (70 eV) m/z (%) = 274 (34) [M ], 229 (54), 167 (75),
1 (100).
(E)-3-(2,6-Difluoro-phenyl)-1-phenyl-propenone (8a) : Pale
+
yellow solid, m.p. 64ºC; (Found: M 244.0702. C H OF requires
1
5
10
2
-1
Benzyl (E)-3-(3,5-difluorophenyl)acrylate (4h): Slowly solidifying
M, 244.0700); nmax (KBr)/cm 1668, 1622, 1472, 1319, 1288, 1240,
1212, 992, 885, 860, 785, 718, 681, 495;dH (270 MHz, CDCl3) 6.97
+
colourless oil; (Found: M 274.0802. C H O F requires M,
1
6
12
2 2
-1
3
2
1
74.0805); n
(KBr)/cm 3072, 2956, 1710, 1646, 1620, 1588,
453, 1432, 1316, 1279, 1169, 1116, 988, 850, 756, 699, 661; d
270 MHz, CDCl ) 5.26 (2H, s, OCH ), 6.83 (1H, m), 6.47 (1H, d,
(2H, m), 7.33 (1H, m), 7.48–7.63 (3H, m), 7.84 (1H, d, J = 15.9
max
3
Hz), 7.92 (1H, d, J = 15.9 Hz), 8.04 (2H, m); dC (67.8 MHz, CDCl3)
H
(
111.8 (m), 113.0 (t, JCF = 14.6 Hz), 127.5 (t, JCF = 8.3 Hz), 128.6
(2C), 128.7 (2C), 130.5 (t, JCF = 2.2 Hz), 131.2 (t, JCF = 10.6 Hz),
133.0, 137.8, 162.0 (2C, dd, JCF = –254 Hz, JCF = 6.7 Hz), 190.4
3
2
3
3
J = 15.9 Hz), 7.03 (2H, m), 7.33–7.41 (5H, m), 7.61 (1H, d, J =
1
5.9 Hz); d NMR (67.8 MHz, CDCl ) 66.66, 105.4 (t, J = 25.2
C 3 CF
+
Hz), 110.7 (2C, m), 120.6, 128.3 (2C), 128.3, 128.6 (2C), 137.6 (t,
(CO); MS (70 eV) m/z (%) = 244 (100) [M ], 225 (28), 216 (24), 167
(40), 119 (47), 105 (46). (Found: C, 73.8; H, 4.1. C15H10F2O requires
C, 73.76; H, 4.13).
E)-3-Pentafluorophenyl-1-phenylpropenone (8b) : Pale yellow
solid, m.p. 153ºC; (Found: M 298.0419. C H OF requires M,
1668, 1606, 1522, 1498, 1337, 1307,
1287, 1266, 1217, 1179, 1147, 1138, 1016, 980, 953, 781, 725, 692,
JCF = 9.5 Hz), 142.5 (t, JCF = 2.8 Hz), 163.2 (2C, dd, JCF = –249 Hz,
JCF = 12.9 Hz), 166.0 (CO); MS (70 eV) m/z (%) = 274 (12) [M ],
28 (68), 167 (70), 91 (100). (Found: C, 69.95; H, 4.30. C H F O
+
2
1
(
2
16 12 2 2
+
requires C, 70.07; H, 4.41).
15
7
5
1
2
98.0417); (KBr)/cm-
n
Benzyl (E)-3-(2,6-difluorophenyl)acrylate (4i): Colourless solid;
m.p. 58ºC; (Found: M 274.0806. C H O F requires M, 274.0805);
max
+
1
6
12
2 2
3
-1
611, 567; d (270 MHz, CDCl ) 7.51–7.64 (3H, m), 7.76 (1H, d, J =
H 3
3
n
1
(KBr)/cm 1702, 1632, 1467, 1322, 1285, 1240, 1209, 1169,
max
1
6.2 Hz), 7.87 (1H, d, J = 16.2 Hz), 8.03 (2H, m); MS (70 eV) m/z
018, 982, 916, 868, 784, 742, 700; d (270 MHz, CDCl ) 5.27 (2H,
H 3
3
+
(%) = 298 (100) [M ], 279 (17), 250 (17), 221 (25), 193 (24), 105
(54). (Found: C, 60.5; H, 2.3. C15H7F5O requires C, 60.41; H, 2.37).
s, OCH ), 6.80 (1H, d, J = 16.2 Hz), 6.92 (2H, m), 7.27–7.44 (6H,
2
3
+
m), 7.83 (1H, d, J 1= 6.2 Hz); MS (70 eV) m/z (%) = 274 (34) [M ],
29 (80), 167 (93), 139 (34), 119 (58), 91 (100); (Found: C, 70.0; H,
.35. C H F O requires C, 70.07; H, 4.41).
Benzyl (E)-3-(pentafluorophenyl)acrylate (4j): Colourless solid,
m.p. 79ºC; (Found: M 328.0529. C H O F requires M, 328.0523);
(
Z)-2-Bromo-3-(3,4,5-trifluoro-phenyl)-1-phenylpropenone
(9):
3
2
4
+
79
Colourless solid, m.p. 77ºC; (Found: MH 340.9789. C H O BrF
15
9
16
12
2
2
1
requires MH, 340.9789); n
(KBr)/cm- 1666, 1616, 1528,
max
+
1438, 1349, 1260, 1060, 1041, 865, 780, 723, 693; dH (270 MHz,
CDCl3) 7.49–7.56 (5H, m), 7.63 (1H, m), 7.80 (2H, m); MS (FAB,
-nitrobenzyl alcohol) m/z (%) = 343 (21) {[ Br]MH }, 341 (21)
1
6
9
2 5
-1
n (KBr)/cm 1725, 1641, 1523, 1501, 1443, 1381, 1328, 1300, 1265,
8
1
+
3
1
194, 1154, 1128, 1029, 1007, 983, 961, 865, 731, 694; d (270 MHz,
H
79
+
3
{[ Br]MH }, 263 (5), 261 (6).
CDCl ) 5.27 (2H, s, OCH ), 6.79 (1H, d, J = 16.5 Hz), 7.33–7.43
3
2
(E)-3-(2,6-Difluorophenyl)acrylonitrile (E-10a)22: Colourless
3
(
[
5
5H, m), 7.68 (1H, d, J = 16.5 Hz); MS (70 eV) m/z (%) = 328 (21)
M ], 283 (50), 221 (65), 193 (35), 143 (31), 91 (100). (Found: C,
8.6; H, 2.6. C H F O requires: C, 58.55; H, 2.76).
Z)-3-Bromo-4-(3,5-difluorophenyl)but-3-en-2-one(5a):Colourless
+
solid; m.p. 38ºC; (Found: M 165.0390. C H NF requires M,
+
9
5
2
1
1
1
65.0390); n
(KBr)/cm- 2214 (CN), 1625, 1471, 1234, 1206,
max
16 9 5 2
038, 972, 838, 779, 719, 555, 510; d (270 MHz, CDCl ) 6.25 (1H,
H
3
(
3
3
d, J = 16.3 Hz), 6.97 (2H, m), 7.37 (1H, m), 7.47 (1H, d, J = 16.3
Hz); d (67.8 MHz, CDCl ) 102.7 (t, J = 10.0 Hz), 111.7 (t, JCF
+
79
solid, m.p. 37ºC; (Found: M 259.9649. C H O BrF requires M,
1
0
7
2
=
-1
C
3
CF
2
1
(
8
=
1
(
1
2
69.9648); n
(KBr)/cm 3074, 1681, 1607, 1488, 1431, 1343,
259, 1216, 1148, 1089, 999, 965, 885, 813, 577, 548, 512, 484; d
270 MHz, CDCl ) 2.61 (3H, s, CH ), 6.94 (2H, m), 8.19 (1H, s),
max
1
=
4.5 Hz), 112.1 (2C, m), 118.0, 132.3 (t, J = 11.2 Hz), 137.1 (t, JCF
CF
H
2.2 Hz), 161.4 (2C, dd, J = –256 Hz, JCF = 6.7 Hz); MS (70 eV)
CF
m/z (%) = 165 (100) [M ], 145 (9.5), 138 (11). (Found: C, 65.55; H,
.0; N, 8.5. C H F N requires C, 65.46; H, 3.05; N, 8.48).
3
3
+
3
.25 (1H, dt, J = 8.6 Hz); d (67.8 MHz, CDCl ) 26.8, 104.2 (dd, J
C
3
CF
3
9
5 2
25.1 Hz, J = 25.1 Hz), 111.4 (dd, J = 21.3 Hz, J = 3.9 Hz),
CF
CF
CF
(
Z)-3-(2,6-Difluorophenyl)acrylonitrile (Z-10a): Colourless oil;
18.3 (dd, JCF = 11.8 Hz, JCF = 3.9 Hz), 125.6, 131.3 (2C, m), 161.4
dd, JCF = –255 Hz, JCF = 11.7 Hz), 164.0 (dd, JCF = 254 Hz, J
1.7 Hz), 192.5 (CO); MS (70 eV) m/z (%) = 262 (20) {[ Br]M },
60 (20) {[ Br]M }, 181 (100), 138 (64).
Z)-3-Bromo-4-(2,3,4,5-tetrafluorophenyl)but-3-en-2-one
+
(
Found: M 165.0390. C H NF requires M, 165.0390); n
(neat)/
9
5
2
max
=
-1
CF
cm 3070, 2222 (CN), 1630, 1581, 1463, 1279, 1237, 1012, 970,
8
1
+
3
9
(
42, 788, 762; d (270 MHz, CDCl ) 5.79 (1H, d, J = 12.2 Hz), 6.99
H 3
3 3
79
+
2H, t, J = 8.1 Hz), 7.14 (1H, d, J = 12.2 Hz), 7.39 (1H, m); d (67.8
C
(
(5b):
MHz, CDCl ) 104.1 (t, J = 2.2 Hz), 111.7 (t, J = 10.6 Hz), 111.8
3
CF
CF
+
79
Colourless oil; (Found: M 295.9461. C H O BrF requires M,
1
0
5
4
(2C, m), 115.6, 131.9 (t, JCF = 10.6 Hz), 136.4, 160.1 (2C, dd, J
–254 Hz, JCF = 6.7 Hz); MS (70 eV) m/z (%) = 165 (100) [M ], 145
(10), 138 (12).
(E)-3-(3,5-Difluorophenyl)acrylonitrile (E-10b): Colourless solid,
m.p. 92ºC; (Found: M 165.0389. C H NF requires M, 165.0390);
=
CF
-
1
2
1
95.9460); n
(neat)/cm 3096, 2918, 1694, 1628, 1525, 1477,
362, 1206, 1122, 1053, 718; d (270 MHz, CDCl ) 2.62 (3H, s,
CH ), 7.85 (1H, m), 8.03 (1H, s); MS (70 eV) m/z (%) = 298 (31)
[ Br]M }, 296 (32) {[ Br]M }, 217 (91), 174 (100).
E)-2,3,6-Trifluorocnnamaldehyde (6a): Pale yellow solid, m.p.
1ºC; (Found: M 186.0287. C H OF requires M, 186.0292); n
KBr)/cm 1686, 1635, 1492, 1446, 1329, 1306, 1267, 1224, 1126,
+
max
H
3
3
8
1
+
79
+
{
+
9
5
2
(
-1
n
(KBr)/cm 3096, 2214, 1620, 1589, 1439, 1343, 1321, 1270,
max
+
6
(
1
(
9
5
3
max
1127, 1005, 969, 860, 817, 691, 668; d (270 MHz, CDCl ) 5.91 (1H,
H 3
3 3
-1
d, J = 16.5 Hz), 6.86–7.02 (3H, m), 7.32 (1H, d, J = 16.5 Hz); d
C
043, 981, 935, 841, 775, 623, 607, 573; d (270 MHz, CDCl ) 6.85
H
3
(67.8 MHz, CDCl ) 99.5, 106.4 (t, J = 25.7 Hz), 110.2 (2C, m),
3 CF
3
3
1H, m), 7.02 (1H, dd, J = 16.5 Hz, J = 7.5 Hz), 7.24 (1H, m), 7.54
117.1, 136.5 (t, JCF = 9.5 Hz), 148.0 (t, JCF = 2.8 Hz), 163.3 (2C,
dd, J = –250 Hz, JCF = 12.3 Hz); MS (70 eV) m/z (%) = 165 (100)
[M ], 138 (22), 114 (13). (Found: C, 65.5; H, 3.0; N, 8.5. C H F N
3
3
4
(
1H, d, J = 16.5 Hz), 9.73 (1H, dd, J = 7.5 Hz, J = 0.8 Hz); MS (70
CF
+
+
eV) m/z (%) = 186 (100) [M ], 167 (30), 158 (73), 137 (53).
E)-2,3,4,5-Tetrafluorocnnamaldehyde (6b): Colourless needles,
m.p. 79ºC; (Found: M 204.0193. C H OF requires M, 204.0198);
(KBr)/cm 3074, 2858, 1694, 1530, 1487, 1375, 1126, 1049,
80, 953, 871, 841, 718, 644, 559; d (270 MHz, CDCl ) 6.72 (1H,
dd, J = 16.2 Hz, J = 7.3 Hz), 7.24 (1H, m), 7.54 (1H, d, J = 16.2
9
5 2
(
requires C, 65.46; H, 3.05; N, 8.48).
+
9
4
4
(Z)-3-(3,5-Difluorophenyl)acrylonitrile (Z-10b): Slowly solidifying
-1
+
n
9
oil; (Found: M 165.0396. C H NF requires M, 165.0390); n (KBr)/
max
9
5
2
max
-
1
H
3
cm 3088, 2212, 1621, 1585, 1438, 1314, 1127, 968, 861, 669; d (270
H
3
3
3
3
MHz, CDCl ) 5.58 (1H, d, J = 12.2 Hz), 6.87–7.34 (3H, m), 7.06 (1H,
3
3
3
+
Hz), 9.74 (1H, d, J = 7.3 Hz, CHO); MS (70 eV) m/z (%) = 204
100) [M ], 176 (79), 155 (33), 125 (33). (Found: C, 52.9; H, 2.0.
d, J = 12.2 Hz); MS (70 eV) m/z (%) = 165 (100) [M ], 138 (22).
(E)-3-(2,6-Difluorobenzylidene)-1-phenylpyrrolidine-2,5-
+
(
+
C H F O requires C, 52.96; H, 1.98).
dione (11): Colourless solid, m.p. 163ºC; (Found: M 299.0760.
9
4 4
1
(
E,E)-5-(2,3,6-Trifluorophenyl)penta-2,4-dienal (7a): Pale yellow
C H O NF requires M, 299.0758); n
(KBr)/cm- 3054, 1775,
1
7
11
2
2
max
+
solid; m.p. 104ºC; (Found: M 212.0453. C H OF requires M,
1706 (s), 1651, 1620, 1502, 1478, 1457, 1385, 1202, 1180, 980, 744,
696, 680; dH (270 MHz, CDCl3) 3.59 (2H, d, J = 2.4 Hz), 7.02 (2H,
m), 7.36–7.56 (6H, m), 7.77 (1H, t, J = 2.4 Hz); MS (70 eV) m/z (%)
1
1
7
3
-1
4
2
1
12.0449); n
(KBr)/cm 1687, 1614, 1488, 1299, 1244, 1201,
161, 1109, 1042, 1010, 990, 924, 816, 780, 623, 488; MS (70 eV)
m/z (%) = 212 (100) [M ], 183 (34), 165 (76), 164 (83). d (270 MHz,
CDCl ) 6.33 (1H, m), 7.00–7.38 (4H, m), 6.88 (1H, m), 9.66 (1H, d,
max
4
+
+
= 299 (88) [M ], 152 (100), 151 (79). (Found: C, 68.3; H, 3.6; N, 4.8.
H
C17H11F2NO2 requires C, 68.23; H, 3.70; N, 4.68).
3
3
J = 8.1 Hz, CHO). (Found: C, 62.3; H, 3.3. Calcd. for C H F O
11
7 3
requires C, 62.27; H, 3.33).
E,E)-5-(2,3,4,5-Tetrafluorophenyl)penta-2,4-dienal (7b): Pale
Part of this work has been carried out within the framework of
a CREST program. Financal support from the Japan Scence
andTechnology Corporation (JST) is gratefully acknowledged.
The author thanks Ms. Yasuko Tanaka, Institute of Materials
Chemistry and Engineering, Kyushu University, for the mass
and high resolution mass measurements. The elemental
analyses were carried out at the Centre of Analysis, Kyushu
University, Hakozaki Campus, Fukuoka.
(
+
yellow needles, m.p. 109ºC; (Found: M 230.0361. C H OF
11
6
4
requires M, 230.0355); (KBr)/cm-
1
n
3056, 2836, 1674, 1621,
max
1
(
(
525, 1479, 1372, 1159, 1127, 1042, 1012, 992, 950, 708, 565; d
H
3
3
270 MHz, CDCl ) 6.33 (1H, dd, J = 15.1 Hz, J = 7.8 Hz), 7.04
2H, m), 7.13–7.31 (2H, m), 9.66 (1H, d, J = 7.8 Hz, CHO); MS (70
3
3
+
eV) m/z (%) = 230 (100) [M ], 201 (36), 182 (76), 151 (96). (Found:
C, 57.4; H, 2.6. C H F O requires C, 57.40; H, 2.63).
11
6 4
PAPER: 07/4575

JOURNAL OF CHEMICAL RESEARCH 2007 341
Received 1 April 2007; accepted 20 June 2007
Paper 07/4575 doi: 10.3184/030823407X225464
11 T. Yasukochi, M. Ito, H. Kubota, S. Miyauchi and M. Saito (Daiichi
Pharmaceutical Co., Ltd., Japan), PCT Int. Appl. WO 2003055850 (July
1
0, 2003); Chem. Abs., 2003, 139, 101146.
M. Koszytkowka-Stawinska and W. Sas, J. Chem. Res., 1999, (S), 694;
M) 2945.
12
13
14
(
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1
0
PAPER: 07/4575