Cyclocondensation of unsymmetrical perfluoroalkyl-substituted β-diketones with urea, thiourea, and guanidine

Article abstract of DOI:10.1134/S1070428008040039

The reactions of unsymmetrical perfluoroalkyl-substituted β-diketones with guanidine, urea, and thiourea gave the corresponding 2-amino-, 2-hydroxy-, and 2-sulfanyl-6-perfluoroalkyl-4-methylpyrimidines.

Full text of DOI:10.1134/S1070428008040039

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 4, pp. 489–494. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © L.M. Popova, A.I. Ginak, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 4, pp. 494–499.
Cyclocondensation of Unsymmetrical Perfluoroalkyl-Substituted
β-Diketones with Urea, Thiourea, and Guanidine
L. M. Popova and A. I. Ginak
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 190013 Russia
e-mail: lorapopova@mail.ru
Received June 28, 2007
Abstract—The reactions of unsymmetrical perfluoroalkyl-substituted β-diketones with guanidine, urea, and
thiourea gave the corresponding 2-amino-, 2-hydroxy-, and 2-sulfanyl-6-perfluoroalkyl-4-methylpyrimidines.
DOI: 10.1134/S1070428008040039
The subjects of the present study are fluorine-con-
taining pyrimidine derivatives which constitute a new
class of potential biologically active substances and
compounds possessing anticorrosion properties. De-
spite the fact that some fluoropyrimidines have long
been known [1–11] and have found wide applpication
(e.g., 5-fluorouracil and Ftorafur), methods of syn-
thesis and chemical properties of fluorine-containing
nitrogen heterocycles have been studied fairly poorly,
so that relevant studies remain strongly desirable.
Taking the above stated into account, the goal of the
present work was to develop an acceptable procedure
for the synthesis of functionally substituted perfluoro-
alkylpyrimidines.
starting compounds. The reactions were performed by
treatment of perfluorinated carboxylic acid fluorides
with 3–5 equiv of acetone in the presence of sodium
fluoride as hydrogen fluoride acceptor on heating at
the boiling point over a period of 10–15 h. As a result,
we obtained the corresponding unsymmetrical per-
fluoroalkyl-containing β-diketones Ia–If (Scheme 1).
Scheme 1.
O
O
O
O
+
RF
F
Me
Me
RF
Me
Ia–If
RF = C6F13 (a), C8F17 (b), C3F7OCF(CF3) (c), C3F7OCF(CF3)-
CF2OCF(CF3) (d), C3F7O[CF(CF3)CF2O]2CF(CF3) (e),
C3F7O[CF(CF3)CF2O]9CF(CF3) (f).
Nitrogen-containing heterorings can be built up via
intramolecular dehydrogenation, dehydration, and de-
amination, as well as by intermolecular condensations
of amino, imino, carbonyl, and hydroxy compounds
[1–11]. One of the main methods for the synthesis of
pyrimidine derivatives is based on cyclocondensation
of β-dicarbonyl compounds with urea and its deriv-
atives. We now propose a procedure on the basis of
reactions of perfluoroalkyl-substituted β-diketones
with guanidine, urea, and thiourea. Perfluorinated
1,3-diketones can be obtained by different methods,
such as Claisen condensation [12–14], Meerwein re-
action [15], and reaction of fluorinated olefins with
acid fluorides under pressure in the presence of anti-
mony pentafluoride at 20°C (ratio RCOF–SbF5 6:1,
yield 40%) [16]. We synthesized fluorinated 1,3-di-
ketones by one-step procedure according to Meerwein
[15] using large-scale intermediate products, perfluoro-
acyl fluorides C6F13COF, C8F17COF, and C3F7O-
[CF(CF3)CF2O]nCF(CF3)COF (n = 1, 2, 3, 9), as
The structure of β-diketones Ia–If was confirmed
by the IR spectra and elemental analyses. The IR spec-
tra of Ia–If contained absorption bands in the region
3450–2985 cm–1 due to stretching vibrations of C–H
bonds, bands at 1350–950 cm–1 were attributed to
stretching vibrations of C–F and C–O (ether) bonds,
and ketone carbonyl bands were observed at 1780–
1770 cm–1, in keeping with published data [17]. The
spectra of all compounds Ia–If lacked absorption in
the region 1890–1880 cm–1, which is typical of initial
perfluoroacyl fluorides.
Condensations of 1,3-diketones or their analogs
with various guanidine and urea derivatives are widely
used for the synthesis of pyrimidine compounds
[1–11]. For example, fusion of guanidine carbonate
with 1,1,1-trifluoropentane-2,4-dione derivatives (140–
150°C, 1 h) was reported to give 4-substituted 2-amino-
489

POPOVA, GINAK
490
pyrimidines (yield 79–90%) [4], cyclization of ethyl-
guanidine with 1,3-diketones in a mixture of diethyl
ether with ethanol at room temperature (14 h) gave
6-trifluoromethyl- and 6-heptafluoropropylpyrimidines
(25–63%) [5], 4-trifluoromethylpyrimidine derivatives
were synthesized by reaction of fluorinated β-di-
ketones with 4-tolylguanidine (90–115°C, 8–12 h) [6]
and N-(2-hydroxyethyl)-N-methylguanidine sulfate [7]
in the presence of sodium carbonate, while guanidine
carbonate gave rise to 6-perfluoroalkylpyrimidines
(ethanol, 10–14 h, yield 73–82%) [8, 9]. Kucerovy
et al. [10] reported on the synthesis of mono- and
bis(trifluoromethyl)- and p-fluorophenyl-substituted
2-aminopyrimidines by condensation of aminoguani-
dine derivatives with various fluorine-containing β-di-
ketones (12 h, yield 54–82%). Urea, N-methylurea,
N,N′-dimethylurea, and thiourea reacted with 1,1,1-tri-
fluoropentane-2,4-dione in the presence of hydro-
chloric acid to produce the corresponding 2-hydroxy-
and 2-sulfanylpyrimidine derivatives [11]. Analysis of
published data [1–11] led us to select acid-catalyzed
cyclocondensation of β-dicarbonyl compounds with
urea and its analogs for the synthesis of the desired
fluorine-containing pyrimidine derivatives, taking into
account relatively mild conditions of the process and
high yield.
condensation products at only one carbonyl group
were detected.
Compounds II–IV were isolated by neutralization
of the reaction mixture with a solution of alkali or
sodium carbonate, followed by removal of the solvent
and reprecipitation from water (IIa, IIb), vacuum
sublimation (IIIa, IIIb), extraction with diethyl ether
(IVa–IVf), or recrystallization from ethanol (IIc–IIf,
IIIc–IIIf, IVc–IVf) or acetone (IIa, IIb, IVa, IVb).
The products were crystalline, amorphous, or viscous
oily substances. Compound IVb underwent decom-
position upon attempted purification by vacuum dis-
tillation. Pyrimidine-2-thiols IVa–IVf were charac-
terized by a specific odor. The structure of compounds
II–IV was confirmed by their elemental analyses and
UV, IR, and 1H and 19F NMR spectra.
The IR spectra of compounds IIa–IIf largely
resemble those of 2-amino-substituted pyrimidines
[3, 11], which are characterized by the presence of
absorption bands in the region 3330–3480 cm–1 due to
stretching vibrations of the amino group. Pyrimidin-2-
ol derivatives IIIa–IIIf displayed in the IR spectra
absorption bands belonging to stretching vibrations of
the hydroxy group at 3300–3500 cm–1, and the band at
1770–1780 cm–1 is likely to arise from tautomeric di-
hydropyrimidin-2-one structure. In the spectra of pyri-
midine-2-thiols IVa–IVf we observed medium-intens-
ity bands at 2500–2600 and 665 cm–1, which were
assigned to stretching vibrations of the S–H and C–S
bonds. All 6-perfluoroalkylpyrimidines II–IV were
characterized by IR absorption bands due to stretching
vibrations of the methyl C–H bonds (2310–3220 cm–1),
stretching vibrations of the C=C and C=N bonds in the
pyrimidine ring, bending vibrations of the N–H bonds,
skeletal vibrations of the pyrimidine ring (1440–
1680 cm–1), and stretching vibrations of the C–F and
C–O bonds (900–1340 cm–1) [18].
The reactions were carried out in a polar solvent
(propan-2-ol) using equimolar amounts of β-diketone
Ia–If and guanidine carbonate, urea, or thiourea in the
presence of hydrochloric acid on heating (70–80°C;
3–5 h). As a result, we obtained 6-perfluoroalkyl-sub-
stituted 4-methylpyrimidines IIa–IIf, IIIa–IIIf, and
IVa–IVf, respectively, in 68–95% yield (Scheme 2).
Compounds IIa–IVa were also obtained in propan-2-ol
at room temperature, but the reaction time was three
days, and the yields of IIa, IIIa, and IVa were 68, 72,
and 72%, respectively. The progress of the reactions
was monitored by thin-layer chromatography, follow-
ing disappearance of the initial diketone. In no case
The UV spectra of 6-perfluoroalkyl-2-aminopyri-
midines IIa–IIf in aqueous alcohol at pH 7 contained
one (IIa, IIb, IId, IIe) or two absorption maxima (IIc,
IIf) arising from the first (IIa–IIf, λmax 217–228 nm,
logε 3.04–4.15) and second π–π* transitions (IIc, IIf,
λmax 202–205 nm, logε 3.98–3.05); these bands con-
firm the presence of multiple bonds in the heteroring
[19]. Compounds IIIa, IIIc, IIId, and IIIf in aqueous
propan-2-ol at pH 7 showed two absorption maxima at
λ 202–218 nm (logε 2.72–3.30) and λ 217–270 nm
(logε 3.00–3.31), while only the first maximum was
present in the UV spectra of IIIb and IIIe. Pyrimidine-
2-thiol derivatives IVe and IVf were characterized by
Scheme 2.
Me
X
H+
N
Ia–If
+
H2N
NH2
XH
N
RF
IIa–IIf, IIIa–IIIf, IVa–IVf
II, X = NH; III, X = O; IV, X = S; RF = C6F13 (a), C8F17 (b),
C3F7OCF(CF3) (c), C3F7OCF(CF3)CF2OCF(CF3) (d), C3F7O-
[CF(CF3)CF2O]2CF(CF3) (e), C3F7O[CF(CF3)CF2O]9-
CF(CF3) (f).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

CYCLOCONDENSATION OF UNSYMMETRICAL PERFLUOROALKYL-SUBSTITUTED
491
two absorption maxima at λ 202 (logε 2.74–3.14) and
217 nm (logε 3.01–3.35), compounds IVa and IVc
displayed only one band at λ 235 nm (logε 3.92–4.29),
and a shoulder at λ 212 nm was observed in the spec-
trum of IVb.
purity of products were monitored by TLC on Silufol
UV-254 plates using chloroform−ethanol (1:1, 3:2, or
4:1) as eluent.
5,5,6,6,7,7,8,8,9,9,10,10,10-Tridecafluorodecane-
2,4-dione (Ia). Tridecafluoroheptanoyl fluoride, 200 g
(0.55 mol), was added dropwise to a mixture of 23.5 g
(0.56 mol) of sodium fluoride in 210 ml of acetone.
The mixture was kept for 10–15 h at 70°C, washed
with water to pH 6–7, and extracted with 1,1,2-tri-
chloro-1,2,2-trifluoroethane. The extract was filtered,
and the solvent was distilled off. Yield 46.7 g (21%),
yellow oily liquid, bp 176–177°C, nD20 = 1.3160. IR
spectrum (film), ν, cm–1: 1000–1350 (C–F), 1450,
1600, 1660, 1780 (C=O), 2950 (C–H), 3500 (O–H).
Found, %: C 28.53; F 62.91. C10H5F13O2. Calculated,
%: C 29.72; F 61.11.
1
The NH proton appeared in the H NMR spectra of
IIa and IIc–IIe as a broadened signal in the region
δ 10.25–10.90 ppm, indicating the presence of two
tautomers, amino and imino. The broadened signal at
δ 8.95–9.20 ppm in the spectra of compounds IIIc and
IIId was assigned to the NH proton of pyrimidin-2-
one tautomer. The thione tautomers of IVa, IVc, and
IVe gave rise to a broadened NH signal in the region
δ 8.45–8.88 ppm. In addition, compounds IIa, IIc–IIe,
IIIc, IIId, IVa, IVc, and IVe characteristically dis-
played a singlet at δ 6.90–7.47 ppm (IIa, IId, IVa,
IVc, IVe) or a doublet at δ 7.00 (JHF = 50 Hz, IIe),
7.47 (JHF = 34.4 Hz, IIIc), 7.70 (JHF = 50 Hz), or
7.75 ppm (JHF = 34.4 Hz) from the 5-H proton in
the pyrimidine ring. The SH proton resonated in the
1H NMR spectra of IVa, IVc, and IVe at δ 4.75–
4.92 ppm. Upfield three-proton signals in the region
δ 1.20–3.34 ppm were assigned to protons in the
4-methyl group. Signals from the fluorine nuclei in the
undecafluoro-1-(trifluoromethyl)-2-oxapentyl substit-
uent of compounds IIc and IIIc were located in the
region δF 34.00–83.19 ppm of the 19F NMR spectrum.
Compounds Ib–If were synthesized in a similar
way.
5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Hepta-
decafluorododecane-2,4-dione (Ib). Yield 15%,
bp 139–141°C (25 mm), nD20 = 1.3095. IR spectrum
(film), ν, cm–1: 980–1350 (C–F), 1455, 1590, 1650,
1770 (C=O), 2940, 2985 (C–H). Found, %: C 27.73;
F 62.91. C12H5F17O2. Calculated, %: C 28.59; F 65.96.
5,6,6,6-Tetrafluoro-5-(heptafluoropropoxy)-
hexane-2,4-dione (Ic). Yield 18%, bp 78–80°C, nD20 =
1.3048. IR spectrum (film), ν, cm–1: 980–1350 (C–F,
C–O), 1430, 1650, 1770 (C=O), 2500, 3000 (C–H),
3450 (O–H). Found, %: C 28.33; F 57.91. C9H5F11O3.
Calculated, %: C 29.21; F 56.46.
Thus we have shown that cyclocondensations of
unsymmetrical fluorinated β-diketones with guanidine
carbonate, urea, and thiourea in propan-2-ol in the
presence of a catalytic amount of hydrochloric acid
lead to the formation of the corresponding 6-per-
fluoroalkyl-substituted 2-amino-, 2-hydroxy-, and
2-sulfanyl-4-methylpyrimidines.
5,7,7,8,10,10,11,11,12,12,12-Undecafluoro-5,8-bis-
(trifluoromethyl)-6,9-dioxadodecane-2,4-dione (Id).
Yield 22%, bp 115–117°C, nD20 = 1.2980. IR spectrum
(film), ν, cm–1: 950–1350 (C–F, C–O), 1440, 1590,
1770 (C=O), 2450, 2990 (C–H), 3410 (O–H). Found,
%: C 25.83; F 61.44. C12H5F17O4. Calculated, %:
C 26.88; F 0.24.
EXPERIMENTAL
The UV spectra were measured from aqueous and
alcoholic solutions with a concentration of 10–4 M (in
propan-2-ol) on an SF-26 spectrophotometer using
1-cm cells. The IR spectra were recorded on IKS-29
and Shimadzu IR-470 instruments from samples pre-
5,7,7,8,10,10,11,13,13,14,14,15,15,15-Tetradeca-
fluoro-5,8,11-tris(trifluoromethyl)-6,9,12-trioxapen-
tadecane-2,4-dione (Ie). Yield 23%, bp 156–160°C,
nD20 = 1.2950. IR spectrum (film), ν, cm–1: 950–1350
(C–F, C–O), 1450, 1620, 1670, 1770 (C=O), 2960
(C–H), 3480 (O–H). Found, %: C 24.63; F 63.47.
C15H5F23O5. Calculated, %: C 25.66; F 62.23.
1
pared as thin films or KBr pellets. The H NMR spec-
tra were obtained on Bruker WM-250 (250 MHz),
Tesla-BS 487C (80 MHz), and Bruker WF-200 spec-
trometers (200 MHz) from solutions in CD3OD using
hexamethyldisiloxane as internal reference. The
19F NMR spectra were measured on a WF-200 instru-
ment at 200 MHz relative to hexafluorobenzene as
external reference. The progress of reactions and the
5,7,7,8,10,10,11,13,13,14,16,16,17,19,19,20,22,22,
23,25,25,26,28,28,29,31,31,32,34,34,35,35,36,36,36-
Pentatriacontafluoro-5,8,11,14,17,20,23,26,29,32-
decakis(trifluoromethyl)-6,9,12,15,18,21,24,27,30,33-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

POPOVA, GINAK
492
1
3380, 3480 (N–H). H NMR spectrum, δ, ppm: 1.90 t
(3H, CH3), 7.60 d.d (1H, 5-H, JHF = 6 Hz), 10.75 br.s
(1H, NH). Found, %: F 57.79; N 7.47. C13H6F17N3O2.
Calculated, %: F 57.76; N 7.52.
decaoxahexatriacontane-2,4-dione (If). Yield 23%,
bp 180°C (0.1 mm), nD20 = 1.3070. IR spectrum (film),
ν, cm–1: 950–1350 (C–F, C–O), 1430, 1720, 1770
(C=O), 2300, 2910 (C–H), 3300 (O–H).
4-Methyl-6-[perfluoro(1,4,7-trimethyl-2,5,8-
trioxaundecyl)]pyrimidin-2-amine (IIe). Yield 80%,
amorphous substance, Rf 0.80 (CHCl3−EtOH, 1:1).
UV spectum: λmax 217 nm (logε 3.05). IR spectrum
(KBr), ν, cm–1: 990–1300 (C–F, C–O); 1635, 1665,
1755 (C=C, C=N, C=O, δNH); 3165 (C–H); 3360,
4-Methyl-6-perfluorohexylpyrimidin-2-amine
(IIa). Guanidine carbonate salt, 7.04 g (0.04 mol), was
dispersed in propan-2-ol, 1 ml of concentrated hydro-
chloric acid and 32.3 g (0.08 mol) of diketone Ia were
added, and the mixture was heated for 3 h at 70°C. The
mixture was then neutralized with a 5% solution of
sodium carbonate, the organic layer was separated and
dried over Na2SO4, the solvent was distilled off, and
the residue was dissolved in acetone and reprecipitated
with water. The precipitate was filtered off and dried
over phosphoric anhydride. Yield 17.0 g (50%), color-
less crystals, mp 126–128°C (from acetone), Rf 0.87
(CHCl3−EtOH, 1:1). UV spectrum: λmax 228 nm
(logε 3.85). IR spectrum (KBr), ν, cm–1: 1145–1350
(C–F); 1580, 1610, 1680, 1740 (C=C, C=N, C=O,
δNH); 2960, 3280 (C–H); 3390, 3480 (N–H). 1H NMR
spectrum, δ, ppm: 1.90 t (3H, CH3), 7.25 s (1H, 5-H),
8.18 br.s (1H, NH). Found, %: F 57.80; N 9.89.
C11H6F19N3. Calculated, %: F 57.82; N 9.84.
1
3480 (N–H). H NMR spectrum, δ, ppm: 1.90 t (3H,
CH3), 7.05 s (1H, 5-H), 8.40 s (1H, NH). Found, %:
F 60.38; N 5.79. C16H6F23N3O3. Calculated, %:
F 60.25; N 5.80.
4-Methyl-6-[perfluoro(1,4,7,10,13,16,19,22,25,28-
decamethyl-2,5,8,11,14,17,20,23,26,29-decaoxadotri-
acontyl)]pyrimidin-2-amine (IIf). Yield 80%, oily
substance, Rf 0.95 (CHCl3−EtOH, 1:1). UV spectrum,
λmax, nm (logε): 202 (3.05), 217 (3.27). IR spectrum
(film), ν, cm–1: 980–1320 (C–F, C–O); 1440, 1560,
1620, 1680 (C=C, C=N, C=O, δNH); 2990, 3030
(C–H); 3330 (N–H).
4-Methyl-6-perfluorohexylpyrimidin-2-ol (IIIa).
Compound Ia, 15.0 g (0.04 mol), was added to a mix-
ture of 2.23 g (0.04 mol) of urea and 1 ml of concen-
trated hydrochloric acid in propan-2-ol, and the mix-
ture was heated for 3–5 h at 80°C. It was then
neutralized with a 5% solution of sodium carbonate,
the organic layer was separated and dried over sodium
sulfate, the solvent was distilled off, and the residue
was subjected to vacuum sublimation. Yield 10.0 g
(68%), colorless crystals, mp 98–100°C (from ace-
Compounds IIb–IIf were synthesized in a similar
way.
4-Methyl-6-perfluorooctylpyrimidin-2-amine
(IIb). Yield 75%, oily substance, Rf 0.86 (CHCl3−EtOH,
1:1). UV spectrum: λmax 218 nm (logε 3.04). IR spec-
trum (film), ν, cm–1: 1110–1360 (C–F); 1440, 1515,
1620, 1665 (C=C, C=N, C=O, δNH); 2910, 3150
(C–H); 3330, 3480 (N–H). Found, %: F 61.35; N 7.91.
C13H6F19N3. Calculated, %: F 61.26; N 7.97.
tone), Rf 0.94 (CHCl3−EtOH, 3:2). UV spectrum: λmax
,
4-Methyl-6-[1,2,2,2-tetrafluoro-1-(heptafluoro-
propoxy)ethyl]pyrimidin-2-amine (IIc). Yield 90%,
colorless crystals, mp 104–106°C (from EtOH),
Rf 0.91 (CHCl3–EtOH, 1:1). UV spectrum, λmax, nm
(logε): 205 (3.98), 225 (4.15). IR spectrum (KBr), ν,
cm–1: 1280–1300 (C–F, C–O); 1440, 1540, 1620, 1680
(C=C, C=N, C=O, δNH); 3180, 3200 (C–H); 3400
nm (logε): 203 (2.77), 217 (3.00). IR spectrum (KBr),
ν, cm–1: 950–1320 (C–F); 1540, 1640, 1720, 1780
(C=C, C=N, C=O, δNH); 2350, 2900, 3200 (C–H);
1
3400 (OH). H NMR spectrum, δ, ppm: 2.02 t (3H,
CH3), 7.47 s (1H, 5-H), 10.35 br.s (1H, NH). Found,
%: F 57.70. C11H5F13N2O. Calculated, %: F 57.69.
1
(N–H). H NMR spectrum, δ, ppm: 2.02 t (3H, CH3),
Compounds IIIb–IIIf were synthesized in a similar
7.47 s (1H, 5-H), 10.35 br.s (1H, NH). Found, %:
F 53.27; N 10.67. C10H6F11N3O. Calculated, %:
F 53.15; N 10.60.
way.
4-Methyl-6-perfluorooctylpyrimidin-2-ol (IIIb).
Yield 60%, colorless crystals, mp 98–100°C (from
acetone), Rf 0.93 (CHCl3−EtOH, 4:1). UV spectrum:
λmax 210 nm (logε 3.85). IR spectrum (KBr), ν, cm–1:
920–1370 (C–F); 1590, 1660, 1700, 1780 (C=C, C=N,
C=O, δNH); 3190, 3220 (C–H); 3350, 3500 (O–H).
Found, %: F 61.24. C13H5F17N2O. Calculated, %:
F 61.15.
4-Methyl-6-[perfluoro(1,4-dimethyl-2,5-dioxa-
octyl)]pyrimidin-2-amine (IId). Yield 77%, amor-
phous substance, Rf 0.88 (CHCl3−EtOH, 1:1). UV
spectrum: λmax 223 nm (logε 3.71). IR spectrum (KBr),
ν, cm–1: 1000–1320 (C–F, C–O); 1540, 1640, 1680,
1770 (C=C, C=N, C=O, δNH); 2900, 3220 (C–H);
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

CYCLOCONDENSATION OF UNSYMMETRICAL PERFLUOROALKYL-SUBSTITUTED
493
665, 790 (C=S); 1020–1320 (C–F); 1540, 1600, 1680,
4-Methyl-6-[1,2,2,2-tetrafluoro-1-(heptafluoro-
propoxy)ethyl]pyrimidin-2-ol (IIIc). Yield 60%,
colorless crystals, mp 178–180°C (from acetone),
Rf 0.93 (CHCl3−EtOH, 4:1). UV spectrum, λmax, nm
(logε): 218 (3.30), 270 (3.18). IR spectrum, ν, cm–1:
1100–1380 (C–F, C–O); 1540, 1620, 1660, 1700
(C=C, C=N, C=O, δNH); 2650, 2850, 3200 (C–H),
1690 (C=C, C=N, δNH); 2350, 2500 (S–H); 2900,
1
3100, 3250, 3380 (C–H). H NMR spectrum, δ, ppm:
2.80 t (3H, CH3), 7.05 br.s (1H, 5-H), 8.45 br.s (1H,
NH). Found, %: F 55.62; S 7.20. C11H5F13N2S. Cal-
culated, %: F 55.60; S 7.12.
Compounds IVb–IVf were synthesized in a similar
way.
1
3450 (O–H). H NMR spectrum, δ, ppm: 1.55 t (3H,
CH3), 7.47 d.d (1H, 5-H, JHF = 10 Hz), 8.95 br.s (1H,
NH). Found, %: F 53.07. C10H5F11N2O2. Calculated,
%: F 53.02.
4-Methyl-6-perfluorooctylpyrimidine-2-thiol
(IVb). Yield 51%, amorphous substance, Rf 0.67
(CHCl3−EtOH, 1:1). UV spectrum: λmax 212 nm, sh.
IR spectrum (KBr), ν, cm–1: 635, 805 (C=S); 970–1390
(C–F); 1430, 1450, 1590, 1770 (C=C, C=N, δNH);
2310 (S–H); 2760, 2980 (C–H). Found, %: F 59.35;
S 5.88. C13H5F17N2S. Calculated, %: F 59.34; S 5.89.
4-Methyl-6-[perfluoro(1,4-dimethyl-2,5-dioxa-
octyl)]pyrimidin-2-ol (IIId). Yield 72%, amorphous
substance, Rf 0.92 (CHCl3−EtOH, 3:2). UV spectrum,
λmax, nm (logε): 202 (2.72), 217 (3.02). IR spectrum
(KBr), ν, cm–1: 950–1350 (C–F, C–O); 1520, 1580,
1680, 1770 (C=C, C=N, C=O, δNH); 2520, 2850,
4-Methyl-6-[1,2,2,2-tetrafluoro-1-(heptafluoro-
propoxy)ethyl]pyrimidine-2-thiol (IVc). Yield 39%,
colorless crystals, mp 94–96°C (from EtOH), Rf 0.67
(CHCl3−EtOH, 1:1). UV spectrum: λmax 235 nm
(logε 4.29). IR spectrum (KBr), ν, cm–1: 666, 769
(C=S); 990–1380 (C–F, C–O); 1540, 1610, 1640, 1660,
1770 (C=C, C=N, δNH); 2400 (S–H); 3130, 3200,
1
3200 (C–H); 3400 (OH). H NMR spectrum, δ, ppm:
1.25 t (3H, CH3), 7.25 d.d (1H, 5-H, JHF = 11 Hz),
9.20 br.s (1H, NH). Found, %: F 57.71. C13H5F17N2O3.
Calculated, %: F 57.66.
4-Methyl-6-[perfluoro(1,4,7-trimethyl-2,5,8-tri-
oxaundecyl)]pyrimidin-2-ol (IIIf). Yield 97%, oily
substance, Rf 0.91 (CHCl3−EtOH, 4:1). UV spectrum:
λmax 210 nm (logε 3.95). IR spectrum (film), ν, cm–1:
950–1340 (C–F, C–O); 1450, 1560, 1680, 1780 (C=C,
C=N, C=O, δNH); 2500, 2880, 3150 (C–H); 3340
(O–H). Found, %: F 60.28. C16H5F23N2O4. Calculated,
%: F 60.17.
1
3350 (C–H). H NMR spectrum, δ, ppm: 2.68 t (3H,
CH3), 7.15 br.s (1H, 5-H), 8.88 br.s (1H, NH). Found,
%: F 50.98; S 7.84. C10H5F11N2SO. Calculated, %:
F 50.94; S 7.82.
4-Methyl-6-[perfluoro(1,4-dimethyl-2,5-dioxa-
octyl)]pyrimidine-2-thiol (IVd). Yield 45%, amor-
phous substance, Rf 0.92 (CHCl3−EtOH, 1:1). UV
spectrum: λmax 206 nm (logε 3.80). IR spectrum (KBr),
ν, cm–1: 709, 744 (C=S); 1107–1330 (C–F, C–O);
1526, 1558, 1640, 1668, 1777 (C=C, C=N, δNH);
2490 (S–H); 2993, 3170, 3340 (C–H). Found, %:
F 56.12; S 5.59. C13H5F17N2SO2. Calculated, %:
F 56.05; S 5.57.
4-Methyl-6-[perfluoro(1,4,7,10,13,16,19,22,25,28-
decamethyl-2,5,8,11,14,17,20,23,26,29-decaoxadotri-
acontyl)]pyrimidin-2-ol (IIIf). Yield 95%, oily
substance, Rf 0.81 (CHCl3−EtOH, 4:1). UV spectrum,
λmax, nm (logε): 202 (3.13), 217 (3.31). IR spectrum
(film), ν, cm–1: 930–1370 (C–F, C–O); 1440, 1690,
1770 (C=C, C=N, C=O, δNH); 2310, 2910, 2970
(C–H); 3300 (O–H).
4-Methyl-6-[perfluoro(1,4,7-trimethyl-2,5,8-tri-
oxaundecyl)]pyrimidine-2-thiol (IVe). Yield 57%,
oily substance, Rf 0.79 (CHCl3−EtOH, 1:1). UV spec-
trum, λmax, nm (logε): 202 (2.74), 217 (3.01). IR spec-
trum (film), ν, cm–1: 610, 715 (C=S); 995–1330 (C–F,
C–O); 1540, 1660, 1770 (C=C, C=N, δNH); 2500
(S–H); 3200, 3300 (C–H). 1H NMR spectrum, δ, ppm:
2.25 t (3H, CH3), 7.10 br.s (1H, 5-H), 8,80 br.s (1H,
NH). Found, %: F 58.92; S 4.34. C16H5F23N2SO3. Cal-
culated, %: F 58.87; S 4.32.
4-Methyl-6-perfluorohexylpyrimidine-2-thiol
(IVa). Compound Ia, 28.28 g (0.07 mol), was added to
a solution of 6.08 g (0.08 mol) of thiourea and 2 ml of
concentrated hydrochloric acid in propan-2-ol, and the
mixture was heated for 3–5 h at 70°C. The mixture
was then neutralized with a 5% solution of sodium
carbonate, the organic phase was separated and dried
over sodium sulfate, the solvent was distilled off, and
the residue was recrystallized from acetone. Yield
33.0 g (60%), light red crystals, mp 114–116°C (from
acetone), Rf 0.59 (CHCl3−EtOH, 1:1). UV spectrum:
λmax 235 nm (logε 3.92). IR spectrum (KBr), ν, cm–1:
4-Methyl-6-[perfluoro(1,4,7,10,13,16,19,22,25,29-
decamethyl-2,5,8,11,14,17,20,23,26,29-decaoxado-
triacontyl)]pyrimidine-2-thiol (IVf). Yield 70%, oily
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

POPOVA, GINAK
494
10. Kucerovy, A., Mattner, P.G., Hathaway, J.S., and
substance, Rf 0.91 (CHCl3−EtOH, 1:1). UV spectrum,
λmax, nm (logε): 202 (3.14), 217 (3.35). IR spectrum
(film), ν, cm–1: 770, 810 (C=S); 950–1390 (C–F, C–O);
1450, 1550, 1718, 1776 (C=C, C=N, δNH); 2352
(S–H); 2528, 2944, 2992, 3308 (C–H).
Repic, O., Synth. Commun., 1990, vol. 20, p. 913.
11. Butter, A.R. and Leich, E., J. Chem. Soc., Perkin
Trans. 2, 1976, p. 832.
12. Vatsuro, K.V. and Mishchenko, G.L., Imennye reaktsii v
organicheskoi khimii (Name Reactions in Organic
Chemistry), Moscow: Khimiya, 1976, p. 212.
REFERENCES
13. Peshkova, V.M. and Mel’chakova, N.V., β-Diketony
(β-Diketones), Moscow: Nauka, 1986.
1. Brown, D.J., The Pyrimidines, New York: Interscience,
1962.
14. Pashkevich, K.I., Saloutin, V.I., and Postovskii, I.Ya.,
Zh. Org. Khim., 1977, vol. 13, p. 49.
2. Brown, D.J., The Pyrimidines. Supplement I, New York:
Interscience, 1970.
3. Brown, D.J., The Pyrimidines. Supplement II, New York:
Interscience, 1985.
4. Nishiwaki, T., Bull. Chem. Soc. Jpn., 1970, vol. 43,
15. Weygand–Hilgetag Organisch-chemische Experimen-
tierkunst, Hilgetag, G. and Martini, A., Eds., Leipzig:
Johann Ambrosius Barth, 1964, 3rd ed. Translated
under the title Metody eksperimenta v organicheskoi
khimii, Moscow: Khimiya, 1968, p. 792.
p. 937.
16. Belen’kii, G.G. and German, L.S., Izv. Akad. Nauk SSSR,
Ser. Khim., 1974, p. 942.
5. Kreutzberger, A. and Leyke-Rohing, S., J. Fluorine
Chem., 1979, vol. 14, p. 55.
6. Kreutzberger, A. and Gillessen, J., J. Fluorine Chem.,
17. Joshi, K.C., Pathak, V.N., and Grover, V., J. Fluorine
Chem., 1980, vol. 15, p. 527.
1985, vol. 29, p. 385.
7. Kreutzberger, A. and Burger, A., J. Fluorine Chem.,
18. Bellamy, L.J., The Infra-red Spectra of Complex Mole-
cules, London: Methuen, 1958.
1993, vol. 60, p. 257.
8. Pathak, V.N., Sareen, V., and Joshi, K.C., J. Fluorine
Chem., 1985, vol. 29, p. 202.
9. Sareen, V. and Jain, S., J. Fluorine Chem., 1993, vol. 63,
19. Kazitsina, L.A. and Kupletskaya, N.B., Primenenie UF,
IK i YaMR spektroskopii v organicheskoi khimii
(Application of UV, IR, and NMR Spectroscopy in
Organic Chemistry), Moscow: Vysshaya Shkola, 1971.
p. 265.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008