2-(N-Alkylamino)-1-(trifluoroacetimidoyl)vinyl ketone derivatives as potential reagents in heterocyclic synthesis

Article abstract of DOI:10.1007/s11172-008-0336-9

A reaction of 3-acetyl-4-amino-5,5,5-trifluoropent-3-en-2-one diphenylboron chelate and ammonia or primary amines affords 4-amino-or 4-alkylamino-3- trifluoroacetimidoylpent-3-en-2-ones, new reagents which can be used for the synthesis of pyrimidines with trifluoromethyl group.

Full text of DOI:10.1007/s11172-008-0336-9

Russian Chemical Bulletin, International Edition, Vol. 57, No. 11, pp. 2359—2363, November, 2008
2359
2ꢀ(NꢀAlkylamino)ꢀ1ꢀ(trifluoroacetimidoyl)vinyl ketone derivatives
as potential reagents in heterocyclic synthesis
L. S. Vasil´ev, M. A. Prezent, A. V. Ignatenko, and V. A. Dorokhov
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5328. Eꢀmail: vador@ioc.ac.ru
A reaction of 3ꢀacetylꢀ4ꢀaminoꢀ5,5,5ꢀtrifluoropentꢀ3ꢀenꢀ2ꢀone diphenylboron chelate
and ammonia or primary amines affords 4ꢀaminoꢀ or 4ꢀalkylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ
3ꢀenꢀ2ꢀones, new reagents which can be used for the synthesis of pyrimidines with trifluoroꢀ
methyl group.
Key words: 4ꢀaminoꢀ, 4ꢀalkylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀones, 4ꢀacetylꢀ
3ꢀmethylꢀ5ꢀ(trifluoromethyl)pyrazole, CF3ꢀcontaining pyrimidines, diphenylboron chelates.
Earlier, we have found1 that acetylacetone smoothly
adds to trifluoroacetonitrile in the presence of catalytic
amounts of Ni acetylacetonate (Ni(acac)2) to form
aminovinyl diketone 1, which can be easily converted to
diphenylboron complex2 2 (Scheme 1).
It should be noted that in the case of aminovinyl ketone
diphenylboron chelates containing no trihalomethyl fragment,
a replacement of the carbonyl group with imino group
failed.4,5 Apparently, the presence of the electronꢀwithꢀ
drawing CF3 group in chelate 3 facilitates attack of the nucleoꢀ
philic agent (amine) at the coordinated carbonyl group.
In complexes 3, the chelateꢀforming ligands are the
earlier unknown compounds, viz., 2ꢀ(Nꢀalkylamino)ꢀ
1ꢀ(trifluoroacetimidoyl)vinyl ketone derivatives. We
were interested in isolation of compounds of this type in
the free form for their further use as building blocks in the
heterocyclic synthesis.
Scheme 1
F3C
These ligands turned out to be unavailable by the
reaction of primary amines with enamino ketone 1, since
the deacetylation product, enamino ketone 4, and the
corresponding Nꢀalkylacetamide are formed in this case.
In addition, 4ꢀ(Nꢀalkylamino)pentꢀ3ꢀenꢀ2ꢀone has been
identified in the reaction mixture (Scheme 2).
F3C
F3C
Scheme 2
The complex compound 2 significantly differs in reacꢀ
tivity from the free ligand, enamino ketone 1. Thus,
dimethylformamide dimethyl acetal (DMF DMA) easily
forms the condensation product at the CH3 group directly
bonded to the chelate ring of compound 2, and this reacꢀ
tion opens the way to the functionally substituted 2ꢀ
(trifluoromethyl)pyridines.3 Another important property
of compound 2 is the possibility of its conversion on heatꢀ
ing with primary amines to βꢀdiiminate chelates 3, the
reactions of which with DMF DMA were also used in
the schemes suggested by us for the construction of funcꢀ
tionally substituted pyridines and naphthyridines with
trifluoromethyl group.2,3
F3C
The deacetylation process does not proceed noticeꢀ
ably only under the action of hydrazine hydrate on
enamino ketone 1, and heterocyclization occurs instead
giving rise to 4ꢀacetylꢀ5ꢀmethylꢀ3ꢀ(trifluoromethyl)ꢀ
pyrazole 5 (Scheme 3).
Therefore, we have studied the reaction of chelate 2
with primary amines in more details and found that the
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2313—2317, November, 2008.
1066ꢀ5285/08/5711ꢀ2359 © 2008 Springer Science+Business Media, Inc.

2360
Russ.Chem.Bull., Int.Ed., Vol. 57, No. 11, November, 2008
Vasil´ev et al.
Scheme 3
At first glance, compounds 7 should be close in strucꢀ
ture to the starting 3ꢀacetylꢀ4ꢀaminoꢀ5,5,5ꢀtrifluoropentꢀ
3ꢀenꢀ2ꢀone (1), i.e., structure B seemed more preferable.
1
But actually, H, 13C, and 19F NMR spectral data testify
in favor of structure A, in which the trifluoroacetimidoyl
group is bonded to the Hꢀchelate form of aminovinyl
ketone.
1
Thus, in the H NMR spectrum (CDCl3) of comꢀ
pound 7b (R = Me), the signal for the MeN fragment
resonates as a doublet at 2.98 ppm, whereas one of the
signals for the NH fragment, as a quartet at 11.9 ppm.
This indicates the presence of the MeNH fragment in the
molecule (structure A), and the downfield position of
the NH signal indicates involvement of this group into
process takes place already at 15—20 °C. Apparently, the
amine first adds to the carbonyl group of the chelate folꢀ
lowed by the cleavage of the C—O bond to form unstable
intermediates 6, which decompose to Ph2BOH and ligands
7a—f during column chromatography (SiO2). When the
reaction mixture is stored for several hours, complex 6 is
gradually converted to diiminate 3. Elevated temperaꢀ
tures also facilitate the process. To avoid the chelation,
Ph2BOH should be removed from the reaction mixture.
This was achieved by the addition of equimolar amount
of monoethanolamine to combine with diphenylborinic
acid into the stable intramolecular complex 8 which was
filtered off, whereas ligands 7a—f were isolated from the
filtrate in almost quantitative yields (Scheme 4).
Aminovinylimine 7a was isolated as a white crystalline
substance, whereas compounds 7b—f, as oily substances
well soluble in most organic solvents, excluding light
petroleum. The purities of free bases 7a—f (1H NMR
data) reached 92—95%, and this was confirmed by satisꢀ
factory elemental analysis data. In their mass spectra, the
peaks of molecular ions are present.
...
the intramolecular N—H O bonding. In the spectrum
of enamino ketone 7a (R = H), two signals for the NH2
group are present at 5.45 ppm (free NH) and 10.65 ppm
...
(N—H O). It is appropriate to compare the spectra of
compounds 7a and 1. For the latter, the signal for the
NH2 is observed1 as a singlet at 7.89 ppm.
In the spectrum of 7a in CDCl3, the proton of the
imino group gives two signals at 10.50 and 11.18 ppm in
the ratio 2 : 1. In DMSOꢀd6, these signals are downfield
shifted (11.98 and 12.25 ppm) with their ratio changing to
10 : 1. Similar picture was also observed in the spectra
of other compounds 7 synthesized. These data suggest the
existence of a dynamic E,Zꢀisomerism (relatively to
the C=N bond), that is also confirmed by the 19F NMR
spectral data. Thus, in the spectrum of compound 7a
(in CDCl3), two signals are observed: the more intensive
doublet with 4JF,NH = 2.5 Hz at –70.8 ppm and the minor
signal at –73.5 ppm (the spinꢀspin coupling constant,
apparently, is very low and could not be measured). In
DMSOꢀd6, both signals are downfield shifted and the
ratio of their intensities corresponds to the 1H NMR data,
i.e., ~2 : 1 (in CDCl3) and ~10 : 1 (in DMSOꢀd6). The
intensive signal with J = 2.5 Hz should be assigned to the
Eꢀisomer, whereas the minor signal, to the Zꢀisomer.
The heating of 7a in DMSOꢀd6 changes the ratio
of E,Zꢀisomers and at 100 °C, it is 5 : 1 (19F NMR data).
For compounds 7, a choice should be made between
the two most probable structures A and В, stabilized by
the intramolecular hydrogen bond.
F3C
F3C
1
In the H NMR spectrum of compound 7a in DMSOꢀd6
Scheme 4
F3C
F3C
F3C
R = H (a), Me (b), Prn (c), Bun (d), PhCH2 (e),
(f)

NꢀAlkylaminovinyl ketones trifluoroacetimidoyl derivatives Russ.Chem.Bull., Int.Ed., Vol. 57, No. 11, November, 2008 2361
pyrimidine ring is involved into the condensation with
DMF DMA. In the mass spectra of compounds 9 and 10,
the intensive peaks of molecular ions are observed.
Experimental
1H NMR spectra were recorded on a Bruker WMꢀ250 and
Bruker AMꢀ300 spectrometers, 11В, 13C, and 19F NMR spectra
were recorded on a Bruker Aꢀ200 spectrometer (the F chemical
shifts were measured relatively to CFCl3, the B, relatively to
BF3•Et2O). IR spectra for a solutions in CHCl3 were recorded
on a SpecordꢀM80 spectrometer, mass spectra, on a Kratos
MSꢀ30 instrument (EI, 70 eV, direct inlet of the substance).
Enamino ketone 1 and its diphenylboron complex were obtained
according to the described procedures.1,2 Starting amines
and dimethylformamide dimethyl acetal were purchased from
Lancaster. Solvents were purified according to the standard
procedures.6 Silica gel (Merkꢀ60, 0.063—0.200 mm) was used
for column chromatography.
at 65 °C, both signals for the NH2 group coalesce into one
broad signal centering at 9 ppm, that indicates their rapid
exchange.
Compounds 7 obtained can be used as building blocks
for the synthesis of nitrogenꢀcontaining heterocycles. Thus,
enamino ketone 7a reacts with DMF DMA in the ratio
1 : 1 under mild conditions to form 5ꢀacetylꢀ6ꢀmethylꢀ
4ꢀ(trifluoromethyl)pyrimidine 9 (58% yield) and dimethylꢀ
aminovinylpyrimidine 10 (22%), which were separated
on a column with SiO2 (Scheme 5).
Reaction of enamino ketone 1 with methylamine. A solution
of MeNH2 in THF (3.2 M, 4.5 mL) was added to a solution of 1
(1.33 g, 6.8 mmol) in THF (10 mL) under cooling, the mixture
was stirred for 0.5 h. The solvent was evaporated in vacuo
(30—50 Torr), the residue was chromatographed on a column
with SiO2 (eluent: first, benzene—light petroleum (1 : 1), then,
benzene—acetone (from 10 : 1 to 4 : 1)). The following comꢀ
pounds were sequentially isolated: (1) enamino ketone 4 (0.14 g,
13%) (the low yield results from its high volatility with the
solvent); (2) 4ꢀmethylaminopentenꢀ3ꢀenꢀ2ꢀone (0.17 g, 22%);
Scheme 5
F3C
1
(3) Nꢀmethylacetamide (0.27 g, 54%). H NMR of enamine 4
(CDCl3), δ: 2.20 (s, 3 H, Me); 5.52 (d, CH=, J = 5.5 Hz);
1
7.50—8.10 (br.s, 2 H, NH2). H NMR of 4ꢀmethylaminopentꢀ
3ꢀenꢀ2ꢀone (CDCl3), δ: 1.88 (s, 3 H, Me); 1.95 (s, 3 H, Me);
2.90 (d, 3 H, MeNH, J=5.5 Hz); 4.97 (s, 1 H, CH=); 10.7 (br.s,
1 H, NH). MS, m/z: 113 [M]+. 1H NMR of Nꢀmethylacetamide
(CDCl3), δ: 1.95 (s, 3 H, Me); 3.10 (s, 3 H, MeN); 5.85 (br.s,
1 H, NH). Compound 1 reacts in the same manner with
propylamine and slower, with ammonia.
When the ratio 7 : DMF DMA = 1 : 2.2, the yield of
compound 10 reaches 57%, whereas that of pyrimidine 9
decreases to 8%. Pyrimidine 9 is a colorless mobile liquid,
whereas dimethylaminovinylpyrimidine 10, a yellow
crystalline powder well soluble in most organic solvents
and poorly, in light petroleum.
4ꢀAcetylꢀ5ꢀmethylꢀ3ꢀ(trifluoromethyl)pyrazole (5). Hydrazine
hydrate (0.25 mL) was added dropwise to a solution of enamino
ketone 1 (1.0 g, 5.1 mmol) in THF (10 mL) with stirring and
cooling and the mixture was kept for 16 h. The solvent was
evaporated on a rotary evaporator, the residue was chromatoꢀ
graphed on a column with SiO2 (eluent: first, benzene—
chloroform (1 : 1), then, chloroform) to obtain pyrazole 5 (0.52 g,
53%), m.p. 114—115 °C (benzene—hexane). IR, ν/cm–1: 3432
(NH), 1672 (CO), 1260—1140 (CF). MS, m/z: 192 [M]+.
4ꢀAminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone (7a). A mixꢀ
ture of chelate 2 (2.22 g, 6.1 mmol) and a solution of NH3 in
THF (0.55 N, 44.5 mL) was kept for 1 h, then, monoethanolꢀ
amine (0.37 mL) was added and the solvent was evaporated
in vacuo. Diethyl ether (75 mL) and light petroleum (150 mL)
were added to the residue, a precipitate of 8 was filtered off,
washed 3 times with a mixture of diethyl ether (5 mL) and
light petroleum (10 mL). The filtrate was concentrated
on a rotary evaporator to obtain compound 7a (1.17 g, 97.5%),
The structures of pyrimidines 9 and 10 were confirmed
by the 1H, 13C, and 19F NMR, IR and mass spectral data. Thus,
1
in the H NMR spectrum of compound 9 in DMSOꢀd6,
three signals at 2.45 ppm, 2.46 ppm (Me and MeCO), and
9.12 ppm (CH=) are present, whereas in the spectrum of
dimethylaminovinylpyrimidine 10, two singlets at 2.52 ppm
(Me) and 8.72 ppm (CH=) are observed, as well as signals
for the enamine fragment: a broad signal at 2.80—3.35 ppm
for the Me2N group and two doublets at 4.72 ppm
(CH=CHN) and 8.10 ppm (=CHN). In the 13C NMR
spectrum of compound 10 in CDCl3, the signal for the
Me group from the MeCO (31.74 ppm) is present, whereas
the signal for the Me group directly bonded to the pyrimiꢀ
dine ring is absent. This indicates that the Me group of the
m.p. 118—119 °C (benzene—light petroleum). IR, ν/cm–1
:
3480 (NH), 3360—3008 (NH), 1620 (CO), 1360—1140 (CF).
MS, m/z: 194 [M]+, 179 [M – Me]+, 174 [M – HF]+. 13C NMR
(DMSOꢀd6), δ: 20.13 (MeC); 27.79 (MeCO); 103.00 (C—CMe);

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Vasil´ev et al.
Table 1. Elemental analysis data and 1H NMR spectra of compounds 5, 7a—f, 9, and 10
Comꢀ
pound
Found
Calculated
(%)
N
Molecular
formula
1H NMR (δ, J/Hz)
CDCl3
DMSOꢀd6
C
H
5
44.09
43.75
3.87
3.67
14.28
14.28
C7H7F3N2O
C7H9F3N2O
—
2.50, 2.58 (both s, 2 Н, Ме + МеСО),
10.65 (br.s, 1 Н, NH)
7a
43.43
43.34
4.76
4.67
14.42
14.13
1.93 (s, 3 Н, Ме); 2.03 (s, 3 Н,
МеСО); 5.48, 10.65 (both br.s,
2 Н, NH2); 10.5 (к, 0.68 Н,
=NH, JF,NH = 2.4); 11.18 (br.s,
1.83 (s, 3 Н, Ме); 1.86 (s, 3 Н,
МеСО); 8.15, 10.35 (both br.s, 2 Н,
NH2); 11.97 (q, 0.92 Н, =NH,
JF,NH = 2.4); 12.30 (br.s, 0.08 Н,
0.32 Н, =NH)
=NH)
7b
7c
46.36
46.15
5.48
5.33
13.51
13.46
C8H11F3N2O
1.93 (s, 3 Н, Ме); 2.01 (s, 3 Н,
МеСО); 2.98 (d, 3 Н, MeNH,
J = 5); 10.42 (q, 0.7 Н, =NH,
JF,NH = 2.4); 11.15 (br.s, 0.3 Н,
=NH); 11.90 (q, 1 Н, NHMe,
J = 5)
1.84 (s, 3 Н, Ме); 1.87 (s, 3 Н,
МеСО); 2.94 (d, 3 Н, MeNH,
J = 5); 11.60 (q, 1 Н, NHMe,
J = 5); 11.95 (q, 0.86 Н, =NH,
JF,NH = 2.5); 12.3 (br.s, 0.14 Н,
=NH)
50.56
50.82
6.17
6.40
11.80
11.85
C10H15F3N2O
0.95 (t, 3 Н, Ме, J = 7.0);
1.52—1.65 (m, 2 Н, СН2);
0.92 (t, 3 Н, Ме, J = 7.0);
1.52—1.72 (m, 2 Н, СН2);
1.90 (s, 3 Н, Ме); 2.00 (s, 3 Н,
МеСО); 3.15—3.25 (m, 2 Н,
CH2N); 10.42 (q, 0.73 Н, =NH,
JF,NH = 2.4); 11.15 (br.s, 0.27 Н,
=NH); 12.05 (br.s, 1 Н, NH)
1.82 (s, 3 Н, Ме); 1.84 (s, 3 Н, Ме);
3.15—3.30 (m, 2 Н, CH2N);
11.9 (t, 1 Н, NHCH2, J = 5.5);
11.98 (q, 0.9 Н, =NH, JF,NH = 2.4);
12.25 (br.s, 0.1 Н, =NH)
7d
52.69
52.79
6.83
6.84
11.57
11.19
C11H17F3N2O
0.95 (t, 3 Н, Ме, J = 7.0);
1.35—1.45 (m, 2 Н, СН2);
0.90 (t, 3 Н, Ме, J = 7.0);
1.35—1.40 (m, 2 Н, СН3СН2);
1.45—1.55 (m, 2 Н, СН2СН2N);
1.85 (s, 3 Н, Ме); 1.88 (s, 3 Н,
МеСО); 3.22—3.33 (m, 2 Н, CH2N);
11.88 (t, 1 Н,CH2NH, J = 5.5);
11.97 (q, 0.9 Н, =NH, JF,NH = 2.5);
12.28 (br.s, 0.1 Н, =NH)
1.50—1.60 (m, 2 Н, СН2СН2N);
1.92 (s, 3 Н, Ме); 2.02 (s, 3 Н,
МеСО); 3.20—3.35 (m, 2 Н,
CH2N); 10.42 (q, 0.7 Н, =NH,
JF,NH = 2.5); 11.15 (br.s, 0.3 Н,
=NH); 12.10 (br.s, 1 Н, CH2NH)
7e
7f
58.86
59.15
5.33
5.28
9.56
9.85
C14H15F3N2O
1.95 (s, 3 Н, Ме); 2.05 (s, 3 Н,
МеСО); 4.52 (d, 2 Н, CH2N,
J = 6.0); 7.20—7.50 (m, 5 Н, Ph),
10.50 (q, 0.68 Н, =NH, JF,NH
= 2.4); 11.20 (br.s, 0.32 Н, =NH);
12.30 (t, 1 Н, CH2NH, J = 6.0)
1.85 (s, 3 Н, Ме); 1.92 (s, 3 Н,
МеСО); 4.58 (d, 2 Н, CH2N,
J = 6.0); 7.30—7.50 (m, 5 Н, Ph);
12.03 (q, 0.9 Н, =NH, JF,NH = 2.4);
12.06 (t, 1 Н, CH2NH, J = 6.0);
12.30 (br.s, 0.1 Н, =NH)
49.70
49.65
4.49
4.51
9.83
9.65
C12H13F3N2O
1.95 (s, 3 Н, Ме); 2.02 (s, 3 Н,
МеСО); 4.66 (d, 2 Н, CH2NH,
J = 5.5); 6.95—7.10 (br.s, 2 Н,
Н(3´)+H(4´)); 7.28 (d, 1 Н,
Н(5´), J = 5); 10.50 (q, 0.65 Н,
=NH, JF,NH = 2.4); 11.20 (br.s,
0.35 Н, =NH); 12.30 (br.s, 1 Н,
CH2NH)
1.86 (s, 3 Н, Ме); 1.97 (s, 3 Н,
МеСО); 4.84 (d, 2 Н, CH2NH,
J = 5.5); 7.00—7.10 (m, 2 Н,
Н(3´)+H(4´)); 7.51 (d, 1 Н, Н(5´),
J = 5); 11.85 (t, 1 Н, CH2NH,
J = 5.5); 12.09 (q, 0.9 Н, =NH,
JF,NH = 2.4); 12.38 (br.s, 0.1 Н,
=NH)
9
46.90
47.07
3.22
3.46
13.65
13.72
C8H7F3N2O
2.58 (s, 3 Н, Ме); 2.59 (s, 3 Н, Ме);
9.25 (s, 1 Н, СН=)
2.45 (s, 3 Н, Ме); 2.46 (s, 3 Н,
МеСО); 9.12 (s, 1 Н, СН=)
10
50.84
50.93
4.51
4.67
16.28
16.21
C11H12F3N3O
—
2.52 (s, 3 Н, Ме); 2.80—3.35
(br.s, 6 Н, Ме2N); 4.72 (d, 1 Н,
СН=СНN, J = 12.5); 8.10 (d,
1 Н, СН=СНN, J = 12.5); 8.72
(s, 1 Н, СН=)

NꢀAlkylaminovinyl ketones trifluoroacetimidoyl derivatives Russ.Chem.Bull., Int.Ed., Vol. 57, No. 11, November, 2008 2363
1
120.68 (q, CF3, JC,F = 281 Hz); 162.80 (C—NH2); 166.97 (q,
5ꢀAcetylꢀ6ꢀ(2ꢀdimethylaminovinyl)ꢀ4ꢀ(trifluoromethyl)pyriꢀ
midine (10). A mixture of compound 7a (1.44 g, 7.4 mmol)
and DMF DMA (2.2 mL, 16.5 mmol) in benzene (15 mL) was
refluxed for 3.5 h. Benzene and excess DMF DMA were
evaporated on a rotary evaporator, the residue was chromatoꢀ
graphed on a column with SiO2 (eluent: first, benzene, then,
benzene—acetone (from 10 : 1 to 2 : 1)). The following comꢀ
pounds were sequentially isolated: pyrimidine 9 (0.12 g, 8%)
and dimethylaminovinylpyrimidine 10 (1.09 g, 57%). A dark
resinꢀlike compound (0.43 g) of unknown structure was addiꢀ
tionally obtained.
2
C—CF3, JC,F = 33 Hz); 191.20 (C=O). Signals for the minor
isomer were also observed in the 13C NMR spectrum in CDCl3,
δ: 101.96 (C—CMe, 118.26 (CF3), 162.42 (C—NH2), 167.15
(C—CF3, 194.03 (C=O).
4ꢀMethylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone (7b),
4ꢀnꢀpropylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone (7c),
and 4ꢀnꢀbutylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone (7d)
were obtained similarly, only in ethereal solution. In the case of
4ꢀbenzylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone (7e) and 4ꢀ
(2ꢀthienyl)methylaminoꢀ3ꢀtrifluoroacetimidoylpentꢀ3ꢀenꢀ2ꢀone
(7f), a short column with SiO2 was used to remove the excess
amine (needed to bring the reaction to completion). When
monoethanolamine was not used under the same conditions,
compounds 7b—f can be isolated by chromatography on a
column with SiO2, rather in lower yields (70—80%). In this
case, diphenylborinic acid was also obtained and identified. 11В
This work was financially supported by the Russian
Academy of Sciences (the Presidium of RAS Program
for Basic Research “Development of Methodology of
Organic Synthesis and Creation of Compounds with
Valuable Applied Properties”).
1
NMR (CDCl3), δ: –45.0. H NMR (CDCl3), δ: 5.70 (s, 1 H,
OH); 7.25—7.85 (m, 10 H, 2 Ph).
The elemental analysis and 1H NMR spectroscopic data for
all the compounds obtained are given in Table 1.
References
5ꢀAcetylꢀ6ꢀmethylꢀ4ꢀ(trifluoromethyl)pyrimidine (9). A soluꢀ
tion of compound 7a (0.9 g, 4.6 mmol), DMF DMA (0.8 mL)
in benzene (20 mL) was refluxed for 3 h and kept for 16 h. The
volatile products were evaporated on a rotary evaporator, the
residue was chromatographed on a column with SiO2 (eluent:
first, benzene, then, benzene—acetone (from 10 : 1 to 4 : 1)).
The following compounds were sequentially isolated: (1) pyriꢀ
midine 9 (0.55 g, 58%) and (2) pyrimidine 10 (0.20 g, 22%),
m.p. 125—126 °C. Compound 9. IR (CHCl3), ν/cm–1: 1712
(C=O), 1320—1156 (C—F). 13C NMR (CDCl3), δ: 22.04 (Me);
31.47 (MeCO); 120.34 (q, CF3, 1JC,F = 276 Hz); 126.25 (C(5));
1. V. A. Dorokhov, A. V. Komkov, L. S. Vasil´ev, O. G. Azarevich,
M. F. Gordeev, Izv. Akad. Nauk SSSR, Ser. Khim., 1991,
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2
149.48 (q, C(4), JC,F = 36 Hz); 157.75 (C(2)); 165.29 (C(6));
199.50 (C=O). 19F NMR (CDCl3), δ: –65.19. MS, m/z: 204
[M]+, 189 [M – Me]+, 162. 121. Compound 10. IR, ν/cm–1
:
1708 (C=O), 1344—1108 (C—F). 13C NMR (CDCl3), δ: 31.74
(MeCO); 37.20, 45.10 (Me2N); 89.04 (CH=CHN); 121.86 (q, CF3,
1JC,F = 261 Hz); 125.43 (C(5)); 147.94 (q, C(4), 2JC,F = 34 Hz);
150.53 (CH=CHNMe2); 157.10 (C(2)); 162.51 (C(6)); 202
(C=O). 19F NMR (CDCl3), δ: –65.4. MS, m/z: 259 [M]+, 244
[M – Me]+, 216.
6. A. J. Gordon, R. A. Ford, The Chemist´s Companion, Wiley,
New York—London—Sydney—Toronto, 1972.
Received June 10, 2008