N- and C-acylation in β-enamino ketones: Structural effects on regiocontrol

Article abstract of DOI:10.1055/s-2007-992382

The acylation reaction of secondary (R¹ = H) β-enamino ketones [RCOCH=CHNR¹R², where R = CF₃, CCl ₃, Ph, 4-FC₆H₄, 4-NO₂C ₆H₄, thien-2-yl; R¹

Full text of DOI:10.1055/s-2007-992382

LETTER
3165
N- and C-Acylation in b-Enamino Ketones: Structural Effects on Regiocontrol
N
-
and C-Acy
e
lation in
b
-E
r
namino
n
K
etones anda A. Rosa, Pablo Machado, Marcelo Rossatto, Pâmela S. Vargas, Helio G. Bonacorso, Nilo Zanatta,
Marcos A. P. Martins*
Núcleo de Química de Heterociclos (NUQUIMHE), Departamento de Química, Universidade Federal de Santa Maria,
97105-900 Santa Maria, RS, Brazil
Fax +55(55)32208031; E-mail: mmartins@base.ufsm.br
Received 4 September 2007
for enamino ketones than for enamino esters. This phe-
Abstract: The acylation reaction of secondary (R1 = H) b-enamino
ketones [RCOCH=CHNR1R2, where R = CF3, CCl3, Ph, 4-FC6H4,
4-NO2C6H4, thien-2-yl; R1 = H, Me; R2 = Me, Bn, Ph, 4-NO2C6H4]
with trifluoroacetic anhydride or ethyl oxalyl chloride in pyridine
nomenon has been explained by the fact that the partial
negative charge on this carbon atom is decreased due to
the higher electron-withdrawing effect of the ketonic car-
led regiospecifically to a series of 14 N-acylated enaminones in bonyl than that observed with an ester carbonyl group.5
Valés et al.5 observed the influence of the carboxylic acid
good yields (72–88%). On the other hand, when tertiary enamino-
nes (R1, R2 = Me) were used, the acylation reaction led to a series of
chloride structure on the regiochemistry of the reaction.
12 C-acylated enaminones in good to excellent yields (75–92%).
The authors obtained two different compounds: the N-
acylated enaminones, with low to good yields (14–71%);
and the a-C-acylated enaminones, with low yields (10–
41%). The same report showed the effect of the amino
Key words: ketones, enones, acylation, regioselectivity, substitu-
ent effects
fragment on the acylation reaction of b-enamino ketones.
The reactivity scope associated with the conjugated sys-
tem O=C–C=C–N makes b-enaminones valuable reagents
with wide applications in organic synthesis.1,2 The versa-
tility of b-enaminones as synthetic intermediates has been
exemplified by their applications as 1,3-dielectrophilic
(carbonylic carbon and b-carbon) and as nucleophilic (ni-
trogen and/or a-carbon) building blocks in synthetic or-
ganic chemistry.1,2 Reactions between b-enamino
compounds and electrophiles such as acyl chloride and tri-
fluoroacetic anhydride have been reported in the litera-
ture.3–7 These reactions are known as the acylation of b-
enamino compounds and the products obtained have been
utilized as precursors in the synthesis of new heterocyclic
compounds, e.g., pyrimidines4,8–10 and pyrazoles.11 Re-
cently, Hogenkamp et al.12 reported the synthesis of a se-
ries of enamino esters and amides from the acylation
reaction of b-enamino compounds. The new enamino es-
ters and amides have been identified as novel positive al-
losteric modulators of the GABAA receptor. These
compounds were orally active in mice with profound cen-
tral nervous system depressant effects.12
When the nucleophilicity of the nitrogen atom was weak,
the a-C-acylation reaction occurred, leading to a mixture
of a-C-acylated and N-acylated compounds.5
The influence of the reaction conditions on the acylation
of b-enamino ketones has also been reported in the litera-
ture.7,16,17 For instance, the acylation of b-enamino ke-
tones with carboxylic acid chloride in the presence of
Et3N and DBU led to a mixture of a-C- and N-acylated
compounds, in low yields. In some of the cases, only N-
acylated products were obtained, but also only in low
yields. In order to give exclusively N-acylated com-
pounds, the classical acylation reaction in pyridine was
tested, leading to the N-acylated compounds (in low
yields, 26–40%), when primary enaminones were used.16
On the other hand, Venkov et al.7 reported the acylation
reaction of b-enamino compounds in an attempt to obtain
N-acyl derivatives. However, the acylation of enamino
ketones, enamino amides, and enamino esters in the pres-
ence of bases such as Et3N or pyridine led to a-C-acylated
products. These experiments show that the structures both
of b-enamino compounds and carboxylic acid chlorides
did not significantly change the reactivity pattern. Be-
sides, the nucleophilicity of the a-carbon in b-enamino
compounds diminished considerably when the ketone
substituent was an electron-withdrawing group, such as a
trichloromethyl group, and no acylation took place under
the conditions investigated. In addition, the acylation re-
action of b-enamino ketones containing an activated N-
benzene ring, under Friedel–Crafts-type conditions, after
seven days at room temperature, led to the benzene-acy-
lated product with good yields.17
Data from the literature have demonstrated that the regi-
oselectivity of the acylation of b-enamino compounds de-
pends on their structure, on the reactivity of the reagents
and on the reaction conditions.5,13 These data have shown
that, in general, enamino esters have led exclusively to a-
C-acylation.6,12,14,15 However, when the reaction was per-
formed with enamino ketones instead of enamino esters,
the N-acylated compounds or a mixture of both N- and a-
C-acylated products were observed.5 It seems clear that
the nucleophilic character of the a-carbon atom is weaker
Considering the importance of N-acyl and a-C-acyl en-
amino compounds as synthetic precursors and the diffi-
culties in terms of regiocontrol with b-enamino ketone
acylation, e.g., the limited scope and low yields of prod-
SYNLETT 2007, No. 20, pp 3165–3171
Advanced online publication: 21.11.2007
DOI: 10.1055/s-2007-992382; Art ID: S06707ST
© Georg Thieme Verlag Stuttgart · New York
x
x
.x
x
.2
0
0
7

3166
F. A. Rosa et al.
LETTER
ucts, the aim of this study is to extend the reactivity scope nes were obtained in good to excellent yields (72–92%)
by obtaining the a-C-acylation or N-acylation of enami- with the exception of entry 6 (Tables 1, 52%) where 21%
nones, with regiospecific control, mild conditions, and of starting material was recovered.
good yields.
Although the reaction of trifluoroacetic anhydride with
The enaminones used in this study were prepared accord- enaminone (entry 16) has been described in the litera-
ing to the experimental procedures described previous- ture,3,4 it required a great excess of acylating agent and a
ly.18–21
long reaction time (3 d).
The acylation reactions of enaminones (entries 1–26,
Table 1) were carried out in CH2Cl2, in the presence of
pyridine, at 25–40 °C.22 In general, the acylated enamino-
Table 1 Reaction Conditions and Yields of N-Acyl and a-C-Acyl Enaminones
pyridine,
(CF3CO)2O or ClC(O)CO2Et,
CH2Cl2, 25–40 °C
O
O
O
O
N
O
R1
R
N
R2
R
N
R2
R3
R
R3
or
72–92%
R1
R2
Entry
1
R
R1
H
R2
R3
Product
Temp (°C) Time (h) Isolated yield (%)
O
O
O
CF3
Bn
CO2Et
CF3
40
40
40
40
15
15
15
15
78
78
82
77
OEt
F3C
N
Bn
O
O
2
3
4
CF3
CF3
CF3
H
H
H
Bn
Ph
Ph
F3C
N
CF3
Bn
O
O
CO2Et
CF3
OEt
F3C
N
Ph
O
O
O
O
F3C
N
CF3
Ph
O
OEt
5
6
CF3
CF3
H
H
4-NO2C6H4
4-NO2C6H4
CO2Et
CF3
40
40
24
48
79
F3C
N
O
4-NO2H4C6
O
O
52a
F3C
N
CF3
4-NO2H4C6
O
O
OEt
7
8
CF3
CF3
Me
Me
Me
Me
CO2Et
CF3
40
40
15
15
81
76
F3C
O
Me2N
O
O
F3C
Me2N
CF3
O
O
O
9
CCl3
CCl3
H
H
Ph
Ph
CO2Et
CF3
40
40
24
15
72
77
OEt
Cl3C
Cl3C
N
Ph
O
O
10
N
CF3
Ph
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

LETTER
N- and C-Acylation in b-Enamino Ketones
3167
Table 1 Reaction Conditions and Yields of N-Acyl and a-C-Acyl Enaminones (continued)
pyridine,
(CF3CO)2O or ClC(O)CO2Et,
CH2Cl2, 25–40 °C
O
O
O
O
O
R1
R
N
R2
R
N
R2
R3
R
R3
or
72–92%
N
R1
R2
Entry
11
R
R1
R2
R3
Product
O
Temp (°C) Time (h) Isolated yield (%)
O
OEt
CCl3
CCl3
Me
Me
CO2Et
CF3
40
40
24
15
80
75
Cl3C
O
Me2N
O
O
12
Me
Me
Cl3C
CF3
O
Me2N
O
OEt
13
14
Ph
Ph
H
H
Ph
Ph
CO2Et
CF3
25
40
5
80
85
Ph
N
Ph
O
O
O
15
Ph
N
CF3
Ph
O
O
O
OEt
15
16
Ph
Ph
Me
Me
Me
Me
CO2Et
CF3
40
40
15
15
84
85
Ph
O
Me2N
O
Ph
CF3
Me2N
O
O
O
17
18
4-FC6H4
4-FC6H4
H
H
Ph
Ph
CO2Et
CF3
25
40
5
84
83
OEt
N
4-FH4C6
4-FH4C6
4-FH4C6
Ph
O
O
O
15
N
CF3
Ph
O
O
OEt
19
20
21
22
4-FC6H4
Me
Me
Me
Me
Me
Me
Me
Me
CO2Et
CF3
40
40
40
40
15
15
15
15
76
80
92
79
O
Me2N
O
4-FC6H4
CF3
O
4-FH4C6
Me2N
O
OEt
4-NO2C6H4
4-NO2C6H4
CO2Et
CF3
4-NO2H4C6
O
Me2N
O
O
CF3
4-NO2H4C6
Me2N
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

3168
F. A. Rosa et al.
LETTER
Table 1 Reaction Conditions and Yields of N-Acyl and a-C-Acyl Enaminones (continued)
pyridine,
(CF3CO)2O or ClC(O)CO2Et,
CH2Cl2, 25–40 °C
O
O
O
O
O
R1
R
N
R2
R
N
R2
R3
R
R3
or
72–92%
N
R1
R2
Entry
23
R
R1
H
R2
Ph
R3
Product
Temp (°C) Time (h) Isolated yield (%)
O
O
O
O
O
thien-2-yl
thien-2-yl
CO2Et
CF3
25
40
5
75
88
OEt
N
S
S
S
Ph
O
24
25
H
Ph
15
N
CF3
Ph
O
O
OEt
thien-2-yl
thien-2-yl
Me
Me
CO2Et
CF3
40
40
15
15
80
80
O
Me2N
O
26
Me
Me
CF3
S
Me2N
a 21% starting material was recovered.
1
The compound structures were determined by H NMR
and 13C NMR spectroscopy, MS spectrometry, and ele-
mental analysis.22 Moreover, X-ray crystallography data
have confirmed the structure of entries 10 and 22
(Figure 1 and Figure 2, respectively).23 It was possible to
completely modify the direction of the reaction in order to
obtain a-C-acylated or N-acylated enaminones in accor-
dance with the structure of the amino fragment present in
the enamino ketones. Thus, for substrates containing a
secondary amino fragment, N-acylated compounds were
obtained exclusively (Table 1, entries 1–6, 9, 10, 13, 14,
17, 18, 23, and 24). However, the regiochemistry of the
reaction was not modified for enaminones containing a
secondary amino fragment attached to phenyl or nitro-4-
phenyl substituents, and N-acylated compounds were ob-
tained. Furthermore, for the reaction shown in entry 6,
Table 1, (R = CF3, R1 = H, R3 = 4-NO2C6H4, R4 = CF3), it
was observed that 48 hours were necessary for partial con-
version into the product (52% of product and 21% of start-
ing material). On the other hand, for substrates containing
a tertiary amino fragment, C-acylated compounds were
obtained exclusively (Table 1, entries 7, 8, 11, 12, 15, 16,
19–22, 25, and 26). The structure of the acylating reagent
seemed not to interfere in the regiochemistry of the reac-
tion, rather only in the reaction time. When ethyl oxalyl
chloride was used as the acylating reagent (Table 1, en-
tries 13, 17, and 23), the reaction time was shorter than
when anhydride trifluoroacetic was used (Table 1, entries
14, 18, and 24). In addition, even when the nucleophilicity
of the a-carbon in enaminones was diminished consider-
ably for electron-withdrawing groups [Table 1, entries 7
Figure 1 The ORTEP diagram of entry 10, N-acylated enaminone
Figure 2 The ORTEP diagram of entry 22, a-C-acylated enaminone
and 8 (CF3) and entries 11, 12 (CCl3)], it was observed
that a-C-acylation nevertheless occurred for entries 21
and 22 (4-NO2C6H4). The wide scope of the reaction dem-
onstrates that diacylation is possible for a variety of b-
enamino ketones and not only for trifluoromethyl enami-
no ketones as has been described up to now in the litera-
ture.3
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

LETTER
N- and C-Acylation in b-Enamino Ketones
3169
A solution of b-enamino ketones (2 mmol), anhyd CH2Cl2 (6
mL), and pyridine (1.7 ml, 2 mmol) was added dropwise to
a stirred solution of ethyl oxalyl chloride (0.22 mL, 2 mmol)
or TFAA (0.28 mL, 2 mmol) in CH2Cl2 (8 mL) at 0 °C under
nitrogen atmosphere. After warming to r.t. the solution was
stirred at the temperature and time showed in Table 1. The
organic layer was then washed with a solution of H2O–HCl
(10:1; 1 × 20 mL) and with distilled H2O (3 × 20 mL).
Finally, the organic layer was dried over Na2SO4 and
evaporated under vacuum to afford the N-acyl or a-C-acyl
enaminones. When necessary, the products were
In summary, the methods proposed in this study allow for
the preparation of a wide scope of regiospecific N-acylat-
ed and a-C-acylated enaminones. The simplicity, wide
scope, and good yields of this method and the possible ap-
plication of the N-acyl and a-C-acyl enaminones in the
synthesis of new heterocyclic compounds make this reac-
tion highly attractive. We have already investigated the
use of these compounds in the construction of heterocy-
clic molecules and the preliminary results have shown that
N-acyl enaminones could be used in the synthesis of sub-
stituted pyrroles, while a-C-acyl enaminones could lead
to different heterocycles, such as isoxazoles and pyra-
zoles. These data will be communicated hereafter.
recrystallized from hexane.
N-Benzyl-N-(4,4,4-trifluoro-3-oxobut-1-enyl)oxalamic
Acid Ethyl Ester (Entry 1)
Oil. 1H NMR (200 MHz, CDCl3): d = 1.39 (br, 3 H, OCCH3),
4.48 (br, 2 H, OCH2), 4.96 (s, 2 H, CH2Ph), 6.01 (d, 1 H, J =
14 Hz, H2), 7.21–7.36 (m, 5 H, Ph), 8.15 (br, 1 H, H3). 13
C
Acknowledgment
NMR (100 MHz, CDCl3): d = 13.7 (OCCH3), 47.1 (CH2Ph),
63.7 (OCH2), 102.0 (C2), 116.0 (q, 1JC–F = 290 Hz, CF3),
126.6, 128.3, 129.1, 133.1 (Ph), 145.0 (C3), 160.2 (C4),
161.8 (C5), 179.1 (q, 2JC–F = 36 Hz, C1). MS: m/z (%) = 329
(10) [M+], 260 (9) [M – CF3], 228 (85) [M – C(O)CO2Et], 91
(100) [CH2Ph], 69 (5) [CF3]. Anal. Calcd for C15H14F3NO4:
C, 54.72; H, 4.29; N, 4.25. Found: C, 54.86; H, 4.53, N, 4.49.
N-Benzyl-2,2,2-trifluoro-N-(4,4,4-trifluoro-3-oxobut-1-
enyl)acetamide (Entry 2)
The authors thank the Conselho Nacional de Desenvolvimento
Científico e Tecnológico (CNPq/PADCT) and Fundação de Am-
paro à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) for
financial support. The fellowships from CNPq, CAPES, and FA-
PERGS are also acknowledged.
References and Notes
Oil. 1H NMR (200 MHz, CDCl3): d = 5.05 (s, 2 H, CH2Ph),
6.09 (d, 1 H, J = 14 Hz, H2), 7.18–7.38 (m, 5 H, Ph), 8.32 (d,
1 H, J = 14 Hz, H3). 13C NMR (100 MHz, CDCl3): d = 48.8
(CH2Ph), 103.9 (C2), 115.6 (q, 1JC–F = 288 Hz, CF3), 115.9
(q, 1JC–F = 290 Hz, CF3), 126.3, 128.5, 129.3, 132.7 (Ph),
143.5 (C3), 157.2 (q, 1JC–F = 38 Hz, C4), 179.0 (q, 1JC–F = 36
Hz, C1). MS: m/z (%) = 325 (28) [M], 256 (29) [M – CF3],
228 (76) [M – C(O)CF3], 91 (100) [CH2Ph], 69 (53) [CF3].
Anal. Calcd for C13H9F6NO2: C, 48.01; H, 2.79; N, 4.31.
Found: C, 48.20; H, 2.98, N, 4.58.
(1) Elassar, A. Z. A.; El-Khair, A. A. Tetrahedron 2003, 59,
8463.
(2) Stanovnik, B.; Svete, J. Chem. Rev. 2004, 104, 2433.
(3) Sanin, A. V.; Nenajdenko, V. G.; Smolko, K. I.; Denisenko,
D. I.; Balenkova, E. S. Synthesis 1998, 842.
(4) Soufyane, M.; van den Broek, S.; Khamliche, L.; Mirand, C.
Heterocycles 1999, 51, 2445.
(5) Valès, M.; Lokshin, V.; Pèpe, G.; Samat, A.; Guglielmetti,
R. Synthesis 2001, 2419.
(6) Braibante, M. E. F.; Braibante, H. T. S.; Costa, C. C.;
Martins, D. B. Tetrahedron Lett. 2002, 43, 8079.
(7) Venkov, A. P.; Angelov, P. A. Synthesis 2003, 2221.
(8) Soufyane, M.; Mirand, C.; Lévy, J. Tetrahedron Lett. 1993,
34, 7737.
(9) Berber, H.; Soufyane, M.; Mirand, C.; Schmidt, S.;
Aubertin, A.-M. Tetrahedron 2001, 57, 7369.
(10) Berber, H.; Soufyane, M.; Santillana-Hayat, M.; Mirand, C.
Tetrahedron Lett. 2002, 43, 9233.
N-Phenyl-N-(4,4,4-trifluoro-3-oxobut-1-enyl)oxalamic
Acid Ethyl Ester (Entry 3)
Oil. 1H NMR (200 MHz, CDCl3): d = 1.02 (br, 3 H, OCCH3),
4.06 (br, 2 H, OCH2), 5.59 (d, 1 H, J = 14 Hz, H2), 7.30–7.56
(m, 5 H, Ph), 8.77 (d, 1 H, J = 14 Hz, H3). 13C NMR (100
MHz, CDCl3): d = 13.4 (OCCH3), 62.6 (OCH2), 103.9 (C2),
116.0 (q, 1JC–F = 291 Hz, CF3), 128.2, 130.3, 130.7, 134.6
(Ph), 144.5 (C3), 159.9 (C4), 160.4 (C5), 179.5 (q, 2JC–F = 35
Hz, C1). MS: m/z (%) = 315 (6) [M+], 242 (8) [M – CO2Et],
218 (29) [M – C(O)CF3], 146 (100), 104 (49), 77 (81) [Ph],
69 (13) [CF3]. Anal. Calcd for C14H12F3NO4: C, 53.34; H,
3.84; N, 4.44. Found: C, 53.35; H, 4.10; N, 4.70.
(11) Touzot, A.; Soufyane, M.; Berber, H.; Toupet, L.; Mirand,
C. J. Fluorine Chem. 2004, 125, 1299.
(12) Hogenkamp, D. J.; Johnstone, T. B. C.; Huang, J.-C.; Li, W.-
Y.; Tran, M.; Whittemore, E. R.; Bagnera, R. E.; Gee, K. W.
J. Med. Chem. 2007, 50, 3369.
2,2,2-Trifluoro-N-phenyl-N-(4,4,4-trifluoro-3-oxobut-1-
enyl)acetamide (Entry 4)
Mp 30–32 °C. 1H NMR (200 MHz, CDCl3): d = 5.44 (d, 1 H,
J = 14 Hz, H2), 7.27–7.60 (m, 5 H, Ph), 8.79 (d, 1 H, J = 14
Hz, H3). 13C NMR (100 MHz, CDCl3): d = 105.6 (C2), 115.4
(q, 1JC–F = 288 Hz, CF3), 115.9 (q, 1JC–F = 288 Hz, CF3),
(13) Barun, O.; Chakrabarti, S.; Ila, H.; Junjappa, H. J. Org.
Chem. 2001, 66, 4457.
(14) Grohe, K.; Heitzer, H. Liebigs Ann. Chem. 1987, 29.
(15) Grohe, K.; Heitzer, H. Liebigs Ann. Chem. 1987, 871.
(16) Valès, M.; Lokshin, V.; Pèpe, G.; Guglielmetti, R.; Samat,
A. Tetrahedron 2002, 58, 8543.
(17) Ivanov, I.; Nikolova, S.; Angelov, P.; Statkova-Abeghe, S.;
Kochovska, E. ARKIVOC 2007, (xv), 11.
(18) Hojo, M.; Masuda, R.; Okada, E. Tetrahedron Lett. 1989,
30, 6173.
(19) Al-Saleh, B.; El-Apasery, M. A.; Abdel-Aziz, R. S.; Elnagdi,
M. H. J. Heterocycl. Chem. 2005, 42, 563.
(20) Al-Omram, F.; Elassar, A.-Z. A.; El-Khair, A. A.
Tetrahedron 2001, 57, 10163.
(21) Martins, M. A. P.; Rossatto, M.; Rosa, F. A.; Machado, P.;
Zanatta, N.; Bonacorso, H. G. ARKIVOC 2007, (i), 205.
(22) Typical Procedure for Synthesis of N-Acyl and a-C-Acyl
Enaminones
128.3, 130.2, 130.9, 133.8 (Ph), 145.8 (C3), 156.2 (q, 1JC–F
=
38 Hz, C4), 179.5 (q, 1JC–F = 36 Hz, C1). MS: m/z (%) = 311
(39) [M+], 242 (85) [M – CF3], 214 (47) [M – C(O)CF3], 172
(42), 145 (44), 117 (37), 77 (100) [Ph], 69 (43) [CF3]. Anal.
Calcd for C12H7F6NO2: C, 46.32; H, 2.27; N, 4.50. Found: C,
46.44; H, 2.36; N, 4.67.
N-(4-Nitrophenyl)-N-(4,4,4-trifluoro-3-oxobut-1-
enyl)oxalamic Acid Ethyl Ester (Entry 5)
Mp 93–95 °C. 1H NMR (200 MHz, CDCl3): d = 1.19 (t, 3 H,
OCCH3), 4.19 (q, 2 H, OCH2), 5.56 (d, 1 H, J = 14 Hz, H2),
7.53–8.44 (m, 4 H, C6H4), 8.71 (br, 1 H, H3). 13C NMR (100
MHz, CDCl3): d = 13.5 (OCCH3), 63.4 (OCH2), 104.1 (C2),
115.8 (q, 1JC–F = 290 Hz, CF3), 125.6, 129.5, 144.1, 148.7
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

3170
F. A. Rosa et al.
LETTER
(C6H4), 140.3 (C3), 159.2 (C4), 159.2 (C5), 179.1 (q, 2JC–F
=
d = 13.6 (OCCH3), 43.3 (NMe2), 48.5 (NMe2), 61.5 (OCH2),
96.3 (C3), 98.0 (CCl3), 161.7 (C4), 164.5 (C1), 179.5 (C2),
182.5 (C3¢). MS: m/z (%) = 315 (1) [M+], 280 (3) [M – Cl],
242 (85) [M – CO2Et], 214 (12) [M – C(O)CO2Et], 198 (6)
[M – CCl3], 170 (97) [M – C(O)CCl3], 92 (100). Anal. Calcd
for C10H12Cl3NO4: C, 37.94; H, 3.82; N, 4.42. Found: C,
38.23; H, 4.16; N, 4.61.
36 Hz, C1). MS: m/z (%) = 360 (3) [M+], 291 (17) [M – CF3],
287 (12) [M – CO2Et], 263 (50) [M – C(O)CF3], 191 (100),
145 (49), 116 (51), 76 (51), 69 (40) [CF3]. Anal. Calcd for
C14H11F3N2O6: C, 46.68; H, 3.08; N, 7.78. Found: C, 46.66;
H, 3.28; N, 7.87.
2,2,2-Trifluoro-N-(4-nitrophenyl)-N-(4,4,4-trifluoro-3-
oxobut-1-enyl)acetamide (Entry 6)
1,1,1-Trichloro-3-dimethylaminomethylene-5,5,5-
trifluoropentane-2,4-dione (Entry 12)
Mp 112–114 °C. 1H NMR (200 MHz, CDCl3): d = 5.44 (d,
1 H, J = 14 Hz, H2), 7.54–8.49 (m, 4 H, C6H4), 8.75 (d, 1 H,
J = 14 Hz, H2). 13C NMR (100 MHz, CDCl3): d = 105.9
(C2), 115.2 (q, 1JC–F = 288 Hz, CF3), 115.7 (q, 1JC–F = 290
Hz, CF3), 125.8, 130.0, 144.8, 149.1 (C6H4), 139.2 (C3),
155.5 (q, 1JC–F = 39 Hz, C4), 180.7 (q, 1JC–F = 35 Hz, C1).
MS: m/z (%) = 356 (13) [M+], 287 (72) [M – CF3], 259 (47)
[M – C(O)CF3], 217 (100), 116 (38), 69 (62) [CF3]. Anal.
Calcd for C12H6F6N2O4: C, 40.47; H, 1.70; N, 7.86. Found:
C, 40.64; H, 1.98; N, 8.02.
Mp 94–96 °C. 1H NMR (200 MHz, CDCl3): d = 2.87 (s, 3 H,
NMe2), 3.42 (s, 3 H, NMe2), 7.93 (s, 1 H, H4). 13C NMR
(100 MHz, CDCl3): d = 42.3 (NMe2), 48.9 (NMe2), 95.5
(CCl3), 100.1 (C3), 116.5 (q, 1JC–F = 291 Hz, CF3), 157.9
2
(C4), 178.6 (q, JC–F = 34 Hz, C2), 184.2 (C3¢). MS: m/z
(%) = 312 (4) [M + 2], 276 (7) [M – Cl], 242 (5) [M – CF3],
194 (100) [M – CCl3], 166 (6) [M – C(O)CCl3], 144 (92),
116 (13), 69 (24) [CF3]. Anal. Calcd for C8H7Cl3F3NO2: C,
30.75; H, 2.26; N, 4.48. Found: C, 30.77; H, 2.48; N, 4.57.
N-(3-Oxo-3-phenylpropenyl)-N-phenyloxalamic Acid
Ethyl Ester (Entry 13)
3-Dimethylaminomethylene-5,5,5-trifluoro-2,4-dioxo-
pentanoic Acid Ethyl Ester (Entry 7)
Oil. 1H NMR (200 MHz, CDCl3): d = 1.37 (t, 3 H, OCCH3),
2.98 (s, 3 H, NMe2), 3.47 (s, 3 H, NMe2), 4.35 (q, 2 H,
OCH2), 7.82 (s, 1 H, H4). 13C NMR (100 MHz, CDCl3): d =
13.6 (OCCH3), 43.5 (NMe2), 48.7 (NMe2), 61.9 (OCH2),
Mp 56–58 °C. 1H NMR (200 MHz, CDCl3): d = 1.00 (br, 3
H, OCCH3), 4.02 (br, 2 H, OCH2), 6.13 (d, 1 H, J = 14 Hz,
H2), 7.34–7.73 (m, 10 H, 2 Ph), 8.62 (br, 1 H, H3). 13C NMR
(100 MHz, CDCl3): d = 13.3 (OCCH3), 62.1 (OCH2), 109.6
(C2), 127.8, 128.3, 128.4, 129.9, 130.0, 132.5, 135.4, 137.6
(2 Ph), 140.3 (C3), 160.4 (C4), 160.5 (C5), 189.5 (C1). MS:
m/z (%) = 323 (10) [M+], 322 (26), 250 (30) [M – CO2Et),
222 (53) [M – C(O)CO2Et], 218 (41) [M – C(O)Ph], 105 (94)
[C(O)Ph], 77 (100) [Ph]. Anal. Calcd for C19H17NO4: C,
70.58; H, 5.30; N, 4.33. Found: C, 70.76; H, 5.53; N, 4.13.
2,2,2-Trifluoro-N-(3-oxo-3-phenylpropenyl)-N-phenyl-
acetamide (Entry 14)
102.4 (C3), 116.7 (q, 1JC–F = 291 Hz, CF3), 160.8 (q, 4JC–F
=
3 Hz, C4), 164.1 (C1), 177.6 (q, 2JC–F = 34 Hz, C3¢), 182.3
(C2). MS: m/z (%) = 267 (2) [M+], 194 (100) [M – CO2Et],
144 (78), 69 (10) [CF3]. Anal. Calcd for C10H12F3NO4: C,
44.95; H, 4.53; N, 5.24. Found: C, 45.28; H, 4.85; N, 5.48.
3-Dimethylaminomethylene-1,1,1,5,5,5-hexafluoro-
pentane-2,4-dione (Entry 8)
Mp 54–56 °C. 1H NMR (200 MHz, CDCl3): d = 2.81 (s, 3 H,
NMe2), 3.45 (s, 3 H, NMe2), 7.74 (s, 1 H, H4). 13C NMR
(100 MHz, CDCl3): d = 43.1 (NMe2), 48.9 (NMe2), 100.3
(C3), 116.2 (q, 1JC–F = 291 Hz, 2 CF3), 159.4 (C4), 179.5 (q,
2JC–F = 34 Hz, C2, C3¢). MS: m/z (%) = 263 (19) [M+], 194
(86) [M – CF3], 144 (100), 69 (31) [CF3]. Anal. Calcd for
C8H7F6NO2: C, 36.52; H, 2.68; N, 5.32. Found: C, 36.80; H,
3.01; N, 5.62.
Mp 110–112 °C. 1H NMR (200 MHz, CDCl3): d = 5.99 (d, 1
H, J = 14 Hz, H2), 7.33–7.70 (m, 10 H, 2 Ph), 8.65 (d, 1 H,
J = 14 Hz, H3). 13C NMR (100 MHz, CDCl3): d = 111.3
(C2), 115.6 (q, 1JC–F = 288 Hz, CF3), 128.0, 128.4, 128.5,
130.0, 130.4, 132.8, 134.8, 137.5 (2 Ph), 141.9 (C3), 155.8
(q, 2JC–F = 38, C4), 189.3 (C1). MS: m/z (%) = 319 (52) [M+],
318 (100), 222 (8) [M – C(O)CF3], 214 (23) [M – C(O)Ph],
105 (21) [C(O)Ph], 77 (50) [Ph], 69 (9) [CF3]. Anal. Calcd
for C17H12F3NO2: C, 63.95; H, 3.97; N, 4.39. Found: C,
63.74; H, 4.14; N, 4.58.
N-Phenyl-N-(4,4,4-trichloro-3-oxobut-1-enyl)oxalamic
Acid Ethyl Ester (Entry 9)
Mp 82–84 °C. 1H NMR (200 MHz, CDCl3): d = 1.04 (t, 3 H,
OCCH3), 4.07 (q, 2 H, OCH2), 5.92 (d, 1 H, J = 14 Hz, H2),
3-Benzoyl-4-dimethylamino-2-oxobut-3-enoic Acid
Ethyl Ester (Entry 15)
7.32–7.55 (m, 5 H, Ph), 8.76 (d, 1 H, J = 14 Hz, H3). 13
C
NMR (100 MHz, CDCl3): d = 13.4 (OCCH3), 62.5 (OCH2),
96.0 (CCl3), 103.1 (C2), 128.2, 130.2, 130.5, 135.0 (Ph),
144.1 (C3), 160.1 (C4), 160.3 (C5), 180.0 (C1). MS: m/z
(%) = 246 (51) [M+ – CCl3], 218 (6) [M – C(O)CCl3], 146
(100), 117 (55) [CCl3], 104 (66), 77 (77) [Ph]. Anal. Calcd
for C14H12Cl3NO4: C, 46.12; H, 3.32; N, 3.84. Found: C,
46.11; H, 3.67; N, 4.09.
Oil. 1H NMR (200 MHz, CDCl3): d = 1.09 (t, 3 H, OCCH3),
2.81 (s, 3 H, NMe2), 3.35 (s, 3 H, NMe2), 3.89 (q, 2 H,
OCH2), 7.42–7.75 (m, 5 H, Ph), 7.87 (s, 1 H, H4). 13C NMR
(100 MHz, CDCl3): d = 13.0 (OCCH3), 42.1 (NMe2), 47.4
(NMe2), 60.7 (OCH2), 106.9 (C3), 127.8, 128.4, 131.6,
139.4 (Ph), 159.0 (C4), 164.3 (C1), 182.9 (C2), 192.9 (C3¢).
MS: m/z (%) = 275 (4) [M+], 202 (36) [M – CO2Et], 174 (2)
[M – C(O)CO2Et], 105 (100) [C(O)Ph], 77 (60) [Ph]. Anal.
Calcd for C15H17NO4: C, 65.44; H, 6.22; N, 5.09. Found: C,
65.45; H, 6.37; N, 5.18.
2,2,2-Trifluoro-N-phenyl-N-(4,4,4-trichloro-3-oxobut-1-
enyl)acetamide (Entry 10)
Mp 85–87 °C. 1H NMR (200 MHz, CDCl3): d = 5.77 (d, 1 H,
J = 14 Hz, H2), 7.30–7.59 (m, 5 H, Ph), 8.79 (d, 1 H, J = 14
Hz, H3). 13C NMR (100 MHz, CDCl3): d = 95.8 (CCl3),
105.1 (C2), 115.4 (q, 1JC–F = 287 Hz, CF3), 128.3, 130.2,
130.8, 134.2 (Ph), 145.3 (C3), 156.0 (q, 2JC–F = 38 Hz, C4),
179.7 (C1). MS: m/z (%) = 359 (1) [M+], 242 (100) [M –
CCl3], 214 (4) [M – C(O)CCl3], 172 (23), 145 (21)
[C(O)CCl3], 117 (19) [CCl3], 77 (53) [Ph], 69 (12) [CF3].
Anal. Calcd for C12H7Cl3F3NO2: C, 39.98; H, 1.96; N, 3.88.
Found: C, 40.04; H, 2.12; N, 3.99.
2-Dimethylaminomethylene-4,4,4-trifluoro-1-phenyl-
butane-1,3-dione (Entry 16)
Oil. 1H NMR (200 MHz, CDCl3): d = 2.71 (s, 3 H, NMe2),
3.31 (s, 3 H, NMe2), 7.50–7.85 (m, 5 H, Ph), 7.76 (s, 1 H,
H4). 13C NMR (100 MHz, CDCl3): d = 41.1 (NMe2), 47.6
(NMe2), 105.3 (C3), 117.1 (q, 1JC–F = 291 Hz, CF3), 128.3,
128.8, 132.7, 138.6 (Ph), 157.0 (C4), 176.6 (q, 2JC–F = 33 Hz,
C2), 194.0 (C3¢). MS: m/z (%) = 271 (9) [M+], 202 (32)
[M – CF3], 174 (7) [M – C(O)CF3], 105 (100) [C(O)Ph], 77
(63) [Ph], 69 (4) [CF3]. Anal. Calcd for C13H12F3NO2: C,
57.57; H, 4.46; N, 5.16. Found: C, 57.69; H, 4.79; N, 5.27.
N-[3-(4-Fluorophenyl)-3-oxopropenyl]-N-phenyl-
oxalamic Acid Ethyl Ester (Entry 17)
5,5,5-Trichloro-3-dimethylaminomethylene-2,4-dioxo-
pentanoic Acid Ethyl Ester (Entry 11)
Mp 93–95 °C. 1H NMR (200 MHz, CDCl3): d = 1.38 (t, 3 H,
OCCH3), 3.05 (s, 3 H, NMe2), 3.46 (s, 3 H, NMe2), 4.35 (q,
2 H, OCH2), 8.31 (s, 1 H, H4). 13C NMR (100 MHz, CDCl3):
Mp 87–89 °C. 1H NMR (200 MHz, CDCl3): d = 1.01 (br, 3
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

LETTER
H, OCCH3), 4.03 (br, 2 H, OCH2), 6.08 (d, 1 H, J = 14 Hz,
N- and C-Acylation in b-Enamino Ketones
3171
Mp 100–102 °C. 1H NMR (200 MHz, CDCl3): d = 2.76 (s, 3
H, NMe2), 3.40 (s, 3 H, NMe2), 7.81 (s, 1 H, H4), 7.94–8.28
(m, 4 H, C6H4). 13C NMR (100 MHz, CDCl3): d = 42.5
(NMe2), 48.4 (NMe2), 105.2 (C3), 117.1 (q, 1JC–F = 291 Hz,
CF3), 123.7, 129.7, 143.9, 149.8 (C6H4), 158.5 (q, 4JC–F = 3
Hz, C4), 177.2 (q, 2JC–F = 33 Hz, C2), 192.0 (C3¢). MS: m/z
(%) = 316 (17) [M+], 247 (75) [M – CF3], 219 (13) [M –
C(O)CF3], 150 (100) [C(O)C6H4 (4-NO2)], 104 (49), 76 (43),
69 (6) [CF3]. Anal. Calcd for C13H11F3N2O4: C, 49.38; H,
3.51; N, 8.86. Found: C, 49.39; H, 3.67; N, 8.95.
H2), 7.07–7.76 (m, 4 H, C6H4), 7.34–7.55 (m, 5 H, Ph); 8.60
(br, 1 H, H3). 13C NMR (100 MHz, CDCl3): d = 13.5
(OCCH3), 62.3 (OCH2), 109.3 (C2), 115.5 (d, 2JC–F = 22 Hz,
C6H4), 128.5, 130.1, 130.2, 135.6 (Ph), 130.6 (d, 3JC–F = 9
Hz, C6H4), 134.2 (d, 4JC–F = 3 Hz, C6H4), 140.9 (C3), 160.5
(C4), 160.6 (C5), 165.4 (d, 1JC–F = 254 Hz, C6H4), 188.1
(C1). MS: m/z (%) = 341 (6) [M+], 340 (27), 268 (49) [M –
CO2Et), 240 (49) [M – C(O)CO2Et], 218 (55) [M –
C(O)C6H4 (4-F)], 123 (100) [C(O)C6H4 (4-F)], 95 (49) [C6H4
(4-F)], 77 (30) [Ph]. Anal. Calcd for C19H16FNO4: C, 66.86;
H, 4.72; N, 4.10. Found: C, 66.46; H, 4.90; N, 4.12.
2,2,2-Trifluoro-N-[3-(4-fluorophenyl)-3-oxopropenyl]-
N-phenylacetamide (Entry 18)
N-(3-Oxo-3-thiophen-2-yl-propenyl)-N-phenyloxalamic
Acid Ethyl Ester (Entry 23)
Mp 83–85 °C. 1H NMR (200 MHz, CDCl3): d = 1.02 (br, 3
H, OCCH3), 4.05 (br, 2 H, OCH2), 6.02 (d, 1 H, J = 14 Hz,
H2), 7.05, 7.44, 7.60 (m, 3 H, thien-2-yl), 7.34–7.54 (m, 5 H,
Ph), 8.64 (br, 1 H, H3). 13C NMR (100 MHz, CDCl3): d =
13.4 (OCCH3), 62.3 (OCH2), 109.4 (C2), 128.5, 130.0,
130.1, 135.6 (Ph), 128.0, 131.3, 133.6, 145.0 (thien-2-yl),
139.8 (C3), 160.4 (C4), 160.6 (C5), 181.4 (C1). MS: m/z
(%) = 329 (1) [M+], 328 (4), 256 (9) [M – CO2Et], 228 (24)
[M – C(O)CO2Et], 212 (100), 111 (80) [C(O)thien-2-yl], 77
(31) [Ph]. Anal. Calcd for C17H15NO4S: C, 61.99; H, 4.59; N,
4.25. Found: C, 61.63; H, 4.86; N, 4.28.
Mp 99–101 °C. 1H NMR (200 MHz, CDCl3): d = 5.96 (d, 1
H, J = 14 Hz, H2), 7.06–7.73 (m, 4 H, C6H4), 7.34–7.60 (m,
5 H, Ph), 8.65 (d, 1 H, J = 14 Hz, H3). 13C NMR (100 MHz,
CDCl3): d = 110.8 (C2), 115.6 (q, 1JC–F = 288 Hz, CF3),
115.6 (d, 2JC–F = 22 Hz, C6H4), 128.6, 130.1, 130.5, 134.8
(Ph), 130.7 (d, 3JC–F = 9 Hz, C6H4), 133.9 (d, 4JC–F = 3 Hz,
C6H4), 142.1 (C3), 155.9 (q, 2JC–F = 38 Hz, C4), 165.5 (d,
1JC–F = 255 Hz, C6H4), 187.6 (C1). MS: m/z (%) = 337 (13)
[M+], 336 (50), 268 (10) [M – CF3], 240 (7) [M – C(O)CF3],
123 (100) [C(O)C6H4 (4-F)], 95 (58) [C6H4 (4-F)], 77 (22)
[Ph], 69 (5) [CF3]. Anal. Calcd for C17H11F4NO2: C, 60.54;
H, 3.29; N, 4.15. Found: C, 60.60; H, 3.90; N, 4.46.
4-Dimethylamino-3-(4-fluorobenzoyl)-2-oxobut-3-enoic
Acid Ethyl Ester (Entry 19)
2,2,2-Trifluoro-N-(3-oxo-3-thiophen-2-ylpropenyl)-N-
phenylacetamide (Entry 24)
Mp 81–83 °C. 1H NMR (200 MHz, CDCl3): d = 5.87 (d, 1 H,
J = 14 Hz, H2), 7.05, 7.40, 7.59 (m, 3 H, thien-2-yl), 7.33–
7.59 (m, 5 H, Ph), 8.66 (d, 1 H, J = 14 Hz, H3). 13C NMR
(100 MHz, CDCl3): d = 111.1 (C2), 115.6 (q, 1JC–F = 288 Hz,
CF3), 128.6, 130.0, 130.1, 131.6 (Ph), 128.1, 130.4, 134.0,
144.8 (thien-2-yl), 141.2 (C3), 155.9 (q, 2JC–F = 38 Hz, C4),
181.2 (C1). MS: m/z (%) = 325 (2) [M+], 324 (13), 212 (100),
111 (41) [C(O)thien-2-yl], 83 (7) [thien-2-yl], 69 (16) [CF3].
Anal. Calcd for C15H10F3NO2S: C, 55.38; H, 3.10; N, 4.31.
Found: C, 55.41; H, 3.47; N, 4.70.
Oil. 1H NMR (200 MHz, CDCl3): d = 1.12 (t, 3 H, OCCH3),
2.81 (s, 3 H, NMe2), 3.36 (s, 3 H, NMe2), 3.94 (q, 2 H,
OCH2), 7.10–7.78 (m, 4 H, C6H4), 7.86 (s, 1 H, H4). 13
C
NMR (100 MHz, CDCl3): d = 13.4 (OCCH3), 42.5 (NMe2),
47.8 (NMe2), 61.3 (OCH2), 107.5 (C3), 115.3 (d, 2JC–F = 22
Hz, C6H4), 131.4 (d, 3JC–F = 9 Hz, C6H4), 136.3 (d, 4JC–F = 3
Hz, C6H4), 159.1 (C4), 164.4 (C1), 164.9 (d, 1JC–F = 253,
C6H4), 183.0 (C2), 191.8 (C3¢). MS: m/z (%) = 293 (6) [M+],
220 (68) [M – CO2Et], 192 (4) [M – C(O)CO2Et], 123 (100)
[C(O)C6H4 (4-F)], 95 (40) [C6H4 (4-F)]. Anal. Calcd for
C15H16FNO4: C, 61.43; H, 5.50; N, 4.78. Found: C, 61.58; H,
5.78; N, 4.94.
4-Dimethylamino-2-oxo-3-(thiophene-2-carbonyl)but-3-
enoic Acid Ethyl Ester (Entry 25)
Oil. 1H NMR (200 MHz, CDCl3): d = 1.14 (t, 3 H, OCCH3),
2.87 (s, 3 H, NMe2), 3.35 (s, 3 H, NMe2), 3.99 (q, 2 H,
OCH2), 7.06, 7.45, 7.62 (m, 3 H, thien-2-yl), 7.84 (s, 1 H,
H4). 13C NMR (100 MHz, CDCl3): d = 13.5 (OCCH3), 42.3
(NMe2), 48.0 (NMe2), 61.6 (OCH2), 108.0 (C3), 127.6,
133.1, 133.6, 146.9 (thien-2-yl), 158.2 (C4), 164.3 (C1),
182.6 (C2), 184.9 (C3¢). MS: m/z (%) = 281 (7) [M+], 208
(65) [M – CO2Et], 180 (4) [M – C(O)CO2Et], 111 (100)
[C(O)thien-2-yl], 83 (9) [thien-2-yl]. Anal. Calcd for
C13H15NO4S: C, 55.50; H, 5.37; N, 4.98. Found: C, 55.61; H,
5.65; N, 5.27.
2-Dimethylaminomethylene-4,4,4-trifluoro-1-(4-fluoro-
phenyl)butane-1,3-dione (Entry 20)
Mp 56–58 °C. 1H NMR (200 MHz, CDCl3): d = 2.71 (s, 3 H,
NMe2), 3.32 (s, 3 H, NMe2), 7.12–7.87 (m, 4 H, C6H4), 7.76
(s, 1 H, H4). 13C NMR (100 MHz, CDCl3): d = 41.3 (NMe2),
47.9 (NMe2), 105.4 (C3), 115.5 (d, 2JC–F = 21 Hz, C6H4),
117.2 (q, 1JC–F = 291 Hz, CF3), 131.6 (d, 3JC–F = 9 Hz, C6H4),
135.2 (d, 4JC–F = 3 Hz, C6H4), 157.2 (C4), 165.4 (d, 1JC–F
254 Hz, C6H4), 176.6 (q, 2JC–F = 33 Hz, C2), 192.5 (C3¢).
=
2-Dimethylaminomethylene-4,4,4-trifluoro-1-thiophen-
2-ylbutane-1,3-dione (Entry 26)
MS: m/z (%) = 289 (9) [M+], 220 (32) [M – CF3], 192 (7) [M
– C(O)CF3], 123 (100) [C(O)C6H4 (4-F)], 95 (49) [C6H4 (4-
F)], 69 (6) [CF3]. Anal. Calcd for C13H11F4NO2: C, 53.99; H,
3.83; N, 4.84. Found: C, 54.07; H, 3.89; N, 4.83.
4-Dimethylamino-3-(4-nitrobenzoyl)-2-oxobut-3-enoic
Acid Ethyl Ester (Entry 21)
Oil. 1H NMR (200 MHz, CDCl3): d = 2.80 (s, 3 H, NMe2),
3.30 (s, 3 H, NMe2), 7.12, 7.56, 7.69 (m, 3 H, thien-2-yl),
7.73 (s, 1 H, H4). 13C NMR (100 MHz, CDCl3): d = 40.4
(NMe2), 47.5 (NMe2), 105.2 (C3), 117.0 (q, 1JC–F = 291 Hz,
CF3), 127.9, 133.7, 134.3, 145.7 (thien-2-yl), 156.2 (C4),
175.8 (q, 2JC–F = 33 Hz, C2), 185.7 (C3¢). MS: m/z (%) = 277
(5) [M+], 208 (7) [M – CF3], 180 (1) [M – C(O)CF3], 111
(100) [C(O)thien-2-yl], 83 (8) [thien-2-yl], 69 (6) [CF3].
Anal. Calcd for C11H10F3NO2S: C, 47.65; H, 3.64; N, 5.05.
Found: C, 47.67; H, 3.87; N, 5.26.
Oil. 1H NMR (200 MHz, CDCl3): d = 1.16 (t, 3 H, OCCH3),
2.87 (s, 3 H, NMe2), 3.42 (s, 3 H, NMe2), 4.00 (q, 2 H,
OCH2), 7.87 (s, 1 H, H4), 7.89–8.26 (m, 4 H, C6H4). 13
C
NMR (100 MHz, CDCl3): d = 13.4 (OCCH3), 43.0 (NMe2),
48.2 (NMe2), 61.6 (OCH2), 107.2 (C3), 123.4, 129.6, 144.9,
149.2 (C6H4), 160.3 (C4), 164.2 (C1), 182.8 (C2), 191.1
(C3¢). MS: m/z (%) = 320 (7) [M+], 247 (100) [M – CO2Et],
219 (4) [M – C(O)CO2Et], 150 (69) [C(O)C6H4 (4-NO2)],
104 (47). Anal. Calcd for C15H16N2O6: C, 56.25; H, 5.03; N,
8.75. Found: C, 56.50; H, 5.22; N, 8.63.
(23) Crystallographic data for entries 10 and 22, reported in this
paper, have been deposited with the Cambridge Crystallog-
raphic Data Center (CCDC 654351 and CCDC 654350,
respectively). Copies of the data can be obtained, free of
charge, on application to CCDC 12 Union Road, Cambridge
CB2 1EZ, UK [fax: +44 (1223)336033 or e-mail:
deposit@ccdc.cam.ac.uk].
2-Dimethylaminomethylene-4,4,4-trifluoro-1-(4-nitro-
phenyl)butane-1,3-dione (Entry 22)
Synlett 2007, No. 20, 3165–3171 © Thieme Stuttgart · New York

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