Reaction of 3-trifluoroacetylchromones with diamines

Article abstract of DOI:10.1007/s11172-007-0251-5

Reaction of 3-(trifluoroacetyl)chromones with ethylenediamine and o-phenylenediamine depending on the nature of substituents and the reaction conditions afforded either mono-adducts, 3-[(2-aminoethyl)aminomethylidene]-and 3-[(2-aminophenyl)aminomethyliden

Full text of DOI:10.1007/s11172-007-0251-5

Russian Chemical Bulletin, International Edition, Vol. 56, No. 8, pp. 1608—1611, August, 2007
1608
Reaction of 3ꢀtrif luoroacetylchromones with diamines
V. Ya. Sosnovskikh,ꢀ R. A. Irgashev, and I. A. Khalymbadzha
A. M. Gor'kii Ural State University,
51 prosp. Lenina, 620083 Ekaterinburg, Russian Federation.
Fax: +7 (343) 261 5978. Eꢀmail: Vyacheslav.Sosnovskikh@usu.ru
Reaction of 3ꢀ(trifluoroacetyl)chromones with ethylenediamine and oꢀphenylenediamine
depending on the nature of substituents and the reaction conditions afforded either monoꢀ
adducts, 3ꢀ[(2ꢀaminoethyl)aminomethylidene]ꢀ and 3ꢀ[(2ꢀaminophenyl)aminomethylidene]ꢀ
2ꢀhydroxyꢀ2ꢀ(trifluoromethyl)chromanꢀ4ꢀones, or bisꢀadducts, N,N´ꢀethylenebisꢀ and
N,N´ꢀoꢀphenylenebis[3ꢀaminomethylideneꢀ2ꢀhydroxyꢀ2ꢀ(trifluoromethyl)chromanꢀ4ꢀones].
Key words: 3ꢀ(trifluoroacetyl)chromones, imines, ethylenediamine, oꢀphenylenediamine,
organofluorine compounds, heterocyclization.
Recently,1—3 we described the synthesis of 3ꢀ(polyꢀ
fluoroacyl)chromones, the highly reactive compounds,
which due to the presence of three electrophilic centers
(С(2), С(4), and RFCO atoms) can serve as the starting
materials in the synthesis of a broad variety of new
RFꢀcontaining heterocycles.4,5 (Polyfluoroacyl)chromoꢀ
nes react with aliphatic and aromatic amines by the
mechanism of nucleophilic 1,4ꢀaddition, accompanied
by the opening of the pyranone ring and cyclization
to 3ꢀalkylꢀ and 3ꢀarylaminоmethylideneꢀ2ꢀhydroxyꢀ2ꢀ
(polyfluoroalkyl)chromanꢀ4ꢀones.2—4 The present work
deals with the reaction of 3ꢀ(trifluoroacetyl)chromones
with diamines, such as ethylenediamine and оꢀpheꢀ
nylenediamine. It is known6ꢀ10 that 3ꢀformylchromones
react with these diamines to form compounds 1—4.
Results and Discussion
Taking into account that CF3 group stabilizes the cyꢀ
clic hemiꢀketal form, making the dehydration step diffiꢀ
cult, it can be assumed that, in comparison with 3ꢀformylꢀ
chromones, the reaction of ethylenediamine and оꢀpheꢀ
nylenediamine with 3ꢀ(trifluoroacetyl)chromones 5 would
stop at a stage of 3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ2ꢀ
(trifluoromethyl)chromanꢀ4ꢀones, as it occurred in case
of primary aliphatic and aromatic monoamines described
earlier.2—4 In fact, we found that the reaction of 3ꢀ(triꢀ
fluoroacetyl)chromones 5a—d with ethylenediamine
and оꢀphenylenediamine, depending on the reaction conꢀ
ditions and the nature of the substituents in benzene
ring of chromones, afforded either monoꢀadducts, viz.,
3ꢀ[(2ꢀaminоethyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ2ꢀ(triꢀ
fluoromethyl)chromanꢀ4ꢀones (6b,d) and 3ꢀ[(2ꢀaminоꢀ
phenyl)aminоmethylidene)]ꢀ2ꢀhydroxyꢀ2ꢀ(trifluoroꢀ
methyl)chromanꢀ4ꢀones (7a,b), or bisꢀadducts, viz.,
N,N´ꢀethyleneꢀbis(3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀones)
(8a,c)
and
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1548—1551, August, 2007.
1066ꢀ5285/07/5608ꢀ1608 © 2007 Springer Science+Business Media, Inc.

3ꢀ(Trifluoroacetyl)chromones and diamines
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1609
Scheme 1
R = H (a), 6ꢀMe (b), 6ꢀCl (c), 7ꢀOMe (d)
N,N´ꢀоꢀphenyleneꢀbis(3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀones) (9a,b) (Scheme 1).
The reaction with the more basic ethylenediamine was
carried out in methanol at –10 °C, nevertheless, even
under such mild conditions, a remarkable cleavage of
chromones 5 to the corresponding 2ꢀhydroxyacetoꢀ
phenones was observed, resulting in no more than
32% yield of products 6 and 8. Chromones 5b,d with
electronꢀdonating groups gave monoꢀadducts 6b,d only,
whereas under similar conditions, unsubstituted chromone
5а and 6ꢀchlorochromone 5с afforded only bisꢀadducts
8a,c, which points to the significant influence of substituꢀ
ents in benzene ring of chromones 5 on the reactivity of
С(2) atom, an attack of which triggers these transformaꢀ
tions. All attempts to obtain bisꢀadducts from chromones
5b,d, as well as monoꢀadducts from 5a,c failed. Treatꢀ
ment of chromones 5b,c with trimethylenediamine gave
the negative results, too.
In contrast to ethylenediamine, the reaction course of
the less basic оꢀphenylenediamine with chromones 5а,b
can be easily controlled by the reaction conditions. Thus
monoꢀadducts 7a,b are formed by the reaction with the
excess of оꢀphenylenediamine in methanol at ~20 °C,
whereas a reflux in methanol with the excess of chromone
gave bisꢀadducts 9a,b (the yields were 62—65%). Comꢀ
pounds 8a,c and 9a,b are formed as mixtures of two diaꢀ
stereomers in the ratio 1 : 1, this follows from the 1Н NMR
spectra, in which the two sets of signals, mostly overꢀ
lapped, are observed (see Experimental).
It should be finally noted that functionalized amines
and amines of naphthalene series, such as aminoacetꢀ
aldehyde dimethyl acetal and αꢀnaphthylamine, react with
chromones 5а,с to form 3ꢀaminоmethylidenechromanꢀ
4ꢀones 10 and 11, which are of interest for further transꢀ
formations in this series.
In conclusion, the reaction of ethylenediamine and
оꢀphenylenediamine with 3ꢀ(trifluoroacetyl)chromoꢀ
nes stops at the stage of reꢀcyclization to 3ꢀaminоꢀ
methylideneꢀ2ꢀhydroxyꢀ2ꢀ(trifluoromethyl)chromanꢀ
4ꢀones and, depending on the structure of the subꢀ
strate and the reaction conditions, can lead both to the
monoꢀ and to the bisꢀadducts. Due to the presence of CF3
group, the dehydration to the corresponding aldimines,
as it occurred in case of 3ꢀformylchromones, does not
take place.

1610
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sosnovskikh et al.
(d, 1 H, H(8), Jo = 8.3 Hz); 7.33 (dd, 1 H, H(7), Jo = 8.3 Hz,
Jm = 2.2 Hz); 7.62 (br.s, 1 H, H(5), Jm = 1.7 Hz); 7.86 (d, 1 H,
=CH, J = 12.8 Hz); 8.96 (s, 1 H, OH); 12.41 (d, 1 H, NH, J =
12.8 Hz).
Experimental
IR spectra were recorded on a PerkinꢀElmer Spectrum BXꢀII
spectrometer in KBr pellets. 1Н NMR spectra were recorded on
a Bruker DRXꢀ400 spectrometer (400.1 MHz) in DMSOꢀd6
with Me4Si as the internal standard. Chromones 5a—d were
obtained according to the described earlier procedure.3
N,N´ꢀEthyleneꢀbis[3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ2ꢀ(triꢀ
fluoromethyl)chromanꢀ4ꢀone] (8a). Ethylenediamine (90 mg,
1.5 mmol) was added to a cooled to –10 °C solution of chromone
5а (250 mg, 1.0 mmol) in methanol (4 mL) and the mixture was
kept at this temperature for 2 days. Then, the mixture was poured
into water (15 mL), acidified with conc. HCl (0.5 mL). The
formed precipitate was filtered off, washed with methanol, and
dried to obtain compound 8а (90 mg, 32%) as colorless powder,
m.p. 243—245 °C (decomp.). Found (%): C, 53.20; H, 3.27;
N, 5.05. C24H18F6N2О6. Calculated (%): C, 52.95; H, 3.33;
N, 5.15. IR, ν/cm–1: 3248, 1648, 1610, 1592, 1546, 1469.
1Н NMR, δ: 3.60—3.64 (m, 4 H, 2 CH2); 6.97 (d, 1 H, H(8),
Jo = 7.8 Hz); 6.98 (d, 1 H, H(8´), Jo = 7.8 Hz); 7.05—7.10 (m,
2 Н, H(6), H(6´), Jo = 7.5 Hz); 7.42—7.48 (m, 2 Н, H(7),
H(7´)); 7.54 (d, 1 H, =CH, J = 13.1 Hz); 7.57 (d, 1 H, =CH,
J = 13.1 Hz); 7.75 (br.s, 2 H, H(5), H(5´), Jo = 7.6 Hz); 8.70
(br.s, 2 H, 2 OH); 10.74 (br.d, 1 H, NH, J = 13.1 Hz); 10.76
(br.d, 1 H, NH, J = 13.1 Hz).
3ꢀ[(2ꢀAminоethyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ6ꢀmethylꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀone (6b). Ethylenediamine (90 mg,
1.5 mmol) was added to a cooled to –10 °C solution of chromone
5b (250 mg, 1.0 mmol) in methanol (4 mL) and the mixture was
kept at this temperature for 2 days. The formed precipitate was
filtered off, washed with methanol, and dried to obtain comꢀ
pound 6b (90 mg, 30%) as colorless crystals, m.p. 161—162 °C.
Found (%): C, 53.26; H, 4.71; N, 8.79. C14H15F3N2О3. Calcuꢀ
lated (%): C, 53.17; H, 4.78; N, 8.86. IR, ν/cm–1: 3359, 3270,
3210, 1649, 1619, 1595, 1558, 1526, 1485. 1Н NMR, δ: 2.27 (s,
3 H, Me); 2.71 (t, 2 H, CH2, J = 5.9 Hz); 2.8—4.0 (br.s, 3 H,
NH2, OH); 3.33—3.39 (m, 2 H, CH2); 6.87 (d, 1 H, H(8), Jo =
8.3 Hz); 7.24 (dd, 1 H, H(7), Jo = 8.3 Hz, Jm = 2.0 Hz); 7.50 (d,
1 H, =CH, J = 13.3 Hz); 7.53 (d, 1 H, H(5), Jm = 2.0 Hz);
10.8—10.9 (br.m, 1 H, NH).
3ꢀ[(2ꢀAminоethyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ7ꢀmethoxyꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀone (6d) was obtained similarly
to compound 6b. The yield was 28%, m.p. 167—168 °C,
light yellow powder. Found (%): C, 50.42; H, 4.56; N, 8.31.
C14H15F3N2О4. Calculated (%): C, 50.61; H, 4.55; N, 8.43. IR,
ν/cm–1: 3352, 3278, 1648, 1640, 1614, 1591, 1555. 1Н NMR, δ:
2.69 (t, 2 H, CH2, J = 5.9 Hz); 2.8—4.0 (br.s, 3 H, NH2, OH);
3.30—3.37 (m, 2 H, CH2); 3.79 (s, 3 H, MeО); 6.51 (d, 1 H,
N,N´ꢀEthyleneꢀbis[3ꢀaminоmethylideneꢀ6ꢀchloroꢀ2ꢀhydrꢀ
oxyꢀ2ꢀ(trifluoromethyl)chromanꢀ4ꢀone] (8c) was obtained simiꢀ
larly to compound 8а. The yield was 27%, m.p. 204—205 °C,
colorless powder. Found (%): C, 46.97; H, 2.66; N, 4.51.
C24H16Cl2F6N2О6. Calculated (%): C, 47.00; H, 2.63; N, 4.57.
1
IR, ν/cm–1: 3249, 1645, 1606, 1593, 1540, 1469. Н NMR, δ:
3.62—3.66 (m, 4 H, 2 CH2); 7.04 (d, 1 H, H(8), Jo = 8.7 Hz);
7.05 (d, 1 H, H(8´), Jo = 8.7 Hz); 7.48 (dd, 1 H, H(7), Jo =
H(8), Jo = 2.4 Hz); 6.64 (dd, 1 H, H(6), Jo = 8.7 Hz, Jm
=
8.7 Hz, Jm = 2.5 Hz); 7.50 (dd, 1 H, H(7´), Jo = 8.7 Hz, Jm =
2.4 Hz); 7.45 (d, 1 H, =CH, J = 13.3 Hz); 7.65 (d, 1 H, H(5),
Jo = 8.7 Hz); 10.7—10.8 (br.m, 1 H, NH).
2.5 Hz); 7.56 (d, 1 H, =CH, J = 13.4 Hz); 7.60 (d, 1 H, =CH,
J = 13.4 Hz); 7.65—7.67 (m, 2 H, H(5), H(5´)); 8.88 (br.s, 2 H,
2 OH); 10.74 (br.d, 1 H, NH, J = 13.3 Hz); 10.76 (br.d, 1 H,
NH, J = 13.3 Hz).
3ꢀ[(2ꢀAminоphenyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ2ꢀ(triꢀ
fluoromethyl)chromanꢀ4ꢀone (7a). оꢀPenylenediamine (160 mg,
1.5 mmol) was added to a solution of chromone 5a (250 mg,
1.0 mmol) in methanol (4 mL) and the mixture was kept at room
temperature for 1 day. The formed precipitate was filtered off,
washed with methanol, and dried to obtain compound 7а
(220 mg, 63%) as orange crystals, m.p. 197—198 °C. Found (%):
C, 58.18; H, 3.68; N, 7.92. C17H13F3N2О3. Calculated (%):
C, 58.29; H, 3.74; N, 8.00. IR, ν/cm–1: 3421, 3358, 3252, 1651,
1608, 1592, 1533, 1479, 1465. 1Н NMR, δ: 5.09 (s, 2 H, NH2);
6.75 (ddd, 1 H, H(5´), Jo = 7.1 Hz, Jm = 1.3 Hz); 6.89 (dd, 1 H,
H(3´), Jo = 8.0 Hz, Jm = 1.3 Hz); 6.99 (ddd, 1 H, H(4´), Jo =
8.0 Hz, 7.1 Hz, Jm = 1.3 Hz); 7.07 (d, 1 H, H(6´), Jo = 8.2 Hz);
7.14 (ddd, 1 H, H(6), Jo = 7.9 Hz, J = 7.2 Hz, Jm = 1.0 Hz); 7.19
(d, 1 H, H(8), Jo = 8.3 Hz); 7.53 (ddd, 1 H, H(7), Jo = 8.3 Hz,
Jo = 7.2 Hz, Jm = 1.7 Hz); 7.85 (dd, 1 H, H(5), Jo = 7.8 Hz, Jm =
1.6 Hz); 7.89 (d, 1 H, =CH, J = 12.8 Hz); 9.06 (s, 1 H, OH);
12.45 (d, 1 H, NH, J = 12.8 Hz).
N,N´ꢀоꢀPhenyleneꢀbis[3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀone] (9a). оꢀPenylenediamine
(55 mg, 0.5 mmol) was added to a solution of chromone 5a
(250 mg, 1.0 mmol) in methanol (4 mL) and the mixture was
refluxed for 2 h. The formed precipitate was filtered off, washed
with methanol, and dried to obtain compound 9а (190 mg, 62%)
as fine bright yellow crystals with m.p. 242—243 °C. Found (%):
C, 56.72; H, 2.99; N, 4.57. C28H18F6N2О6. Calculated (%):
C, 56.76; H, 3.06; N, 4.73. IR, ν/cm–1: 3307, 1637, 1606,
1
1589, 1566, 1551. Н NMR, δ: 7.09 (d, 2 H, Н(8), H(8´), Jo =
8.2 Hz); 7.14 (t, 2 H, Н(6), H(6´), Jo = 7.5 Hz); 7.35–7.46 (m,
4 H, С6Н4); 7.56 (ddd, 2 Н, Н(7), Н(7´), Jо = 8.2 Hz, Jo =
7.3 Hz, Jm = 1.7 Hz); 7.80–7.85 (m, 4 H, 2 =CH, Н(5), Н(5´));
9.14 (s, 1 H, OH); 9.15 (s, 1 H, OH); 12.48 (d, 2 H, 2 NH, J =
12.5 Hz).
N,N´ꢀоꢀPhenyleneꢀbis[3ꢀaminоmethylideneꢀ2ꢀhydroxyꢀ6ꢀ
methylꢀ2ꢀ(trifluoromethyl)chromanꢀ4ꢀone] (9b) was obtained
similarly to compound 9а. The yield was 65%, m.p. >250 °C
(decomp.), fine bright yellow crystals. Found (%): C, 58.05;
H, 3.56; N, 4.30. C30H22F6N2О6. Calculated (%): C, 58.07;
H, 3.57; N, 4.51. IR, ν/cm–1: 3412, 3196, 1642, 1620, 1600,
1568, 1552, 1489. 1Н NMR, δ: 2.30 (s, 6 H, 2 Me); 6.99 (d, 2 H,
Н(8), H(8´), Jo = 8.3 Hz); 7.34—7.45 (m, 6 Н, H(7), H(7´),
С6Н4); 7.60 (d, 1 H, H(5), Jm = 1.8 Hz); 7.62 (d, 1 H, H(5´),
Jm = 1.8 Hz); 7.81 (d, 2 H, 2 =CH, J = 12.4 Hz); 9.08 (s, 1 H,
OH); 9.09 (s, 1 H, OH); 12.46 (d, 2 H, 2 NH, J = 12.4 Hz).
3ꢀ[(2ꢀAminоphenyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ6ꢀmethylꢀ
2ꢀ(trifluoromethyl)chromanꢀ4ꢀone (7b) was obtained similarly to
compound 7а. The yield was 65%, m.p. 193—194 °C, orange
crystals. Found (%): C, 59.29; H, 4.11; N, 7.57. C18H15F3N2О3.
Calculated (%): C, 59.34; H, 4.15; N, 7.69. IR, ν/cm–1: 3422,
1
3356, 3255, 1650, 1611, 1604, 1534, 1480, 1453. Н NMR, δ:
2.30 (s, 3 H, Me); 5.06 (s, 2 H, NH2); 6.74 (ddd, 1 H, H(5´),
Jo = 8.3 Hz, Jo = 7.1 Hz, Jm = 1.3 Hz); 6.88 (dd, 1 H, H(3´), Jo =
8.0 Hz, Jm = 1.3 Hz); 6.95 (d, 1 H, H(6´), Jo = 8.3 Hz); 6.98
(ddd, 1 H, H(4´), Jo = 8.0 Hz, Jo = 7.1 Hz, Jm = 1.2 Hz); 7.17

3ꢀ(Trifluoroacetyl)chromones and diamines
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1611
3ꢀ[(2,2ꢀDimethoxyethyl)aminоmethylidene]ꢀ2ꢀhydroxyꢀ2ꢀ
(trifluoromethyl)chromanꢀ4ꢀone (10). The product was obtained
from chromone 5a according to the described earlier proceꢀ
dure.2,3 The yield was 60%, m.p. 115—116 °C, colorless crystals.
Found (%): C, 51.92; H, 4.54; N, 3.74. C15H16F3NО5. Calcuꢀ
lated (%): C, 51.88; H, 4.64; N, 4.03. IR, ν/cm–1: 3173, 1648,
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 06ꢀ03ꢀ
32388).
References
1
1610, 1594, 1543, 1470. Н NMR (CDCl3), δ: 3.09 (ddd, 1 H,
СНН, J = 13.8 Hz, J = 5.8 Hz, J = 6.8 Hz); 3.21 (dt, 1 H, СНН,
J = 13.8 Hz, J = 5.3 Hz); 3.37 (s, 3 Н, OMe), 3.38 (s, 3 Н,
OMe), 4.31 (t, 1 H, СН, J = 5.3 Hz); 5.47 (br.s, 1 Н, ОН); 6.95
(dd, 1 H, H(8), Jo = 8.3 Hz, Jm = 1.0 Hz); 7.04 (td, 1 H, H(6),
Jo = 7.6 Hz, Jm = 1.0 Hz); 7.28 (d, 1 H, =СН, J = 13.3 Hz); 7.39
(ddd, 1 H, H(7), Jo = 8.3 Hz, Jo = 7.3 Hz, Jm = 1.7 Hz); 7.85
(dd, 1 H, H(5), Jo = 7.8 Hz, Jm = 1.7 Hz); 10.79 (dt, 1 H, NH,
J = 13.0 Hz, J = 6.4 Hz).
1. V. Ya. Sosnovskikh and R. A. Irgashev, Synlett, 2005, 1164.
2. V. Ya. Sosnovskikh, R. A. Irgashev, M. A. Barabanov,
and V. S. Moshkin, Izv. Akad. Nauk, Ser. Khim., 2006,
572 [Russ. Chem. Bull., Int. Ed., 2006, 55, 593 (Engl.
Transl.)].
3. V. Ya. Sosnovskikh, R. A. Irgashev, and M. A. Barabanov,
Synthesis, 2006, 2707.
4. V. Ya. Sosnovskikh and R. A. Irgashev, Heteroat. Chem.,
2006, 17, 99.
5. V. Ya. Sosnovskikh, V. S. Moshkin, and R. A. Irgashev,
Tetrahedron Lett., 2006, 47, 8543.
6. A. O. Fitton, P. G. Houghton, and H. Suschitzky, Synthesis,
1979, 337.
7. C. K. Ghosh and S. Khan, Synthesis, 1980, 701.
8. I. Sigg, G. Haas, and T. Winkler, Helv. Chim. Acta, 1982,
65, 275.
9. G. Rihs, I. Sigg, G. Haas, and T. Winkler, Helv. Chim. Acta,
1985, 68, 1933.
6ꢀChloroꢀ2ꢀhydroxyꢀ3ꢀ[(1ꢀnaphthylaminо)methylidene]ꢀ2ꢀ
(trifluoromethyl)chromanꢀ4ꢀone (11). The product was obtained
from chromone 5c according to the described earlier proceꢀ
dure.2,3 The yield was 95%, m.p. 216—217 °C, yellow crystals.
Found (%): C, 60.03; H, 2.97; N, 3.13. C21H13ClF3NО3. Calꢀ
culated (%): C, 60.08; H, 3.12; N, 3.34. IR, ν/cm–1: 3265, 1637,
1
1603, 1582, 1557, 1479. Н NMR, δ: 7.18 (d, 1 H, H(8), Jo =
8.8 Hz); 7.61 (t, 1 H, arom., Jo = 7.8 Hz); 7.62 (dd, 1 H, H(7),
Jo = 8.8 Hz, Jm = 2.7 Hz); 7.67 (ddd, 1 H, arom., Jo = 8.0 Hz,
Jo = 7.1 Hz, Jm = 1.0 Hz); 7.71 (d, 1 H, arom., Jo = 7.2 Hz); 7.77
(ddd, 1 H, arom., Jo = 8.2 Hz, Jo = 7.0 Hz, Jm = 1.3 Hz); 7.87
(d, 1 H, H(5), Jm = 2.7 Hz); 7.88 (d, 1 H, arom., Jо = 8.2 Hz);
8.06 (d, 1 Н, arom., J = 8.1 Hz); 8.09 (d, 1 Н, arom., J =
8.4 Hz); 8.29 (d, 1 Н, =СН, J = 12.4 Hz); 9.36 (s, 1 Н, ОН);
13.59 (d, 1 H, NH, J = 12.4 Hz).
10. F. Ristiano, G. Grassi, and F. Foti, Heterocycl. Chem., 2001,
38, 1083.
Received March 26, 2007