Synthesis of 1,3-thioxoketones from salicylaldehyde

Article abstract of DOI:10.1007/s11172-013-0135-9

A method for the synthesis of monothiodibenzoylmethanes was developed. The method involves a reaction of potassium thioacetate with 1-(2-hydroxyphenyl)-3- phenylpropynone prepared from salicylaldehyde.

Full text of DOI:10.1007/s11172-013-0135-9

Russian Chemical Bulletin, International Edition, Vol. 62, No. 4, pp. 1022—1025, April, 2013
1022
Synthesis of 1,3ꢀthioxoketones from salicylaldehyde*
I. S. Semenova,a V. N. Yarovenko,a K. S. Levchenko,b and M. M. Krayushkina
aN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Eꢀmail: mkray@ioc.ac.ru; irisemyonova@gmail.ru
bCentral Research Technological Institute "Tekhnomash",
4 ul. Ivana Franko, 121108 Moscow, Russian Federation
A method for the synthesis of monothiodibenzoylmethanes was developed. The method
involves a reaction of potassium thioacetate with 1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropynone
prepared from salicylaldehyde.
Key words: 1,3ꢀthioxoketones, chelates, chromones, propynones, tautomers.
Interest in 1,3ꢀthioxoketones is due to their structural
features (they can exist as four tautomers 1a—d (see
Refs 1—4)) and good chelating properties.
Our experiments showed that 2ꢀhydroxyacetophenone
does not react with ethyl benzenecarbodithioate in the
presence of NaH or ButOK.
An alternative way in which we tried to construct
a thioxo group involved replacement of vinylic halogens in
chalcones.
To do this, we used salicylaldehyde 4 in a reaction
with phenylacetylene to give propargyl alcohol 5, which
then was oxidized with MnO2 into phenylpropynone 6
(Scheme 1).
Scheme 1
For instance, metal complexes with monothiodibenzꢀ
oylmethane 2 have been reported.5—7
It is clear that their properties will largely depend on
orthoꢀsubstituents of the aromatic rings. However, comꢀ
pounds of the type 3 are not documented, probably beꢀ
cause the most obvious synthetic routes to these derivaꢀ
tives are complicated by possible cyclization into the
chromone system involving the hydroxy or ether group.
In the present work, we propose a method for the synꢀ
thesis of monothiodibenzoylmethanes 3 containing an
ether group in the orthoꢀposition.
i. 1) BuLi, THF, –78 C; 2) HCCPh; ii. MnO2, CH2Cl2.
Reactions of phenylpropynone 6 with halogens afford
diꢀ and trihalides 7—9 (Scheme 2). Monobromide 10
was obtained by a reaction of HBr with compound 6 in
acetic acid.
However, it turned out that compounds 7—9 readily
undergo baseꢀ or acidꢀcatalyzed cyclization into the corꢀ
responding 2ꢀphenylchromones 11—13. For instance,
compounds 7 and 8 yield dibromochromone 11 and
* Dedicated to Academician of the Russian Academy of Sciences
I. P. Beletskaya on the occasion of her anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1021—1024, April, 2013.
1066ꢀ5285/13/6204ꢀ1022 © 2013 Springer Science+Business Media, Inc.

Synthesis of 1,3ꢀthioxoketones
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 4, April, 2013
1023
Scheme 2
For this purpose, starting from salicylaldehydes 15a—c
with the OH group protected by methyl, benzyl, and
tertꢀbutyl(dimethyl)silyl groups, we obtained the correꢀ
sponding phenylpropynones 17a—c (Scheme 5).
Scheme 5
R = X = Br (7); R = H, X = Br (8); R = H, X = I (9)
bromochromone 12, respectively. Treatment of comꢀ
pounds 9 and 10 with K2CO3 in DMF gave 2ꢀphenylꢀ
chromone 13 (Scheme 3). Obviously, this strategy is unꢀ
suitable for subsequent functionalization of compounds
7—10 via nucleophilic substitution of a mercapto group
for the Br atom.
17: R = Me (a), PhCH2 (b), ButMe2Si (c)
Scheme 3
i. 1) BuLi, THF, –78 C; 2) HCCPh; ii. MnO2, CH2Cl2.
Indeed, we found that reactions of ethers 17a—c with
potassium thioacetate (Scheme 6) give earlier unknown
monothiodiketones 18a—c containing an ether group in
the orthoꢀposition.
Scheme 6
Comꢀ
pound
7
8
R
X
X´
Comꢀ
pound
11
12
13
R
X
Br
H
H
Br
Br
I
Br
Br
I
Br
H
H
Br
Br
H
9
10
H
H
Br
To prevent possible cyclization, we protected the OH
group in monobromide 10 by its conversion into acetate
14 (Scheme 4). The reaction was successfully carried out
in acetic anhydride in the presence of HBr; with H2SO4 as
a catalyst, a complex mixture of products was formed.
18: R = Me (a), PhCH2 (b), ButMe2Si (c)
The structures and chelating properties of the ꢀthioxoꢀ
ketones obtained will be described elsewhere.
Experimental
Scheme 4
1
H NMR spectra were recorded on Bruker ACꢀ200 (200 MHz)
and Bruker AMꢀ300 instruments (300 MHz) in CDCl3. 13C NMR
spectra were recorded on Bruker AMꢀ300 (75 MHz) and Bruker
ACꢀ200 instruments (50 MHz) in CDCl3. The carbon atom and
residual protons of the solvent served as the internal standard.
Mass spectra were measured on a Varian MAT CHꢀ6 instrument
(direct inlet probe, ionizing energy 70 eV, control voltage
1.75 kV). Melting points were determined on a Boetius hot stage
and are given uncorrected. All the reaction mixtures were anaꢀ
lyzed and the purity of the products obtained were checked by
TLC on Silica gel 60 F254 UVꢀ254 plates (Merck).
Attempted replacement of the Br atom in compound 14
by using Na2S in DMF, NaHS in DMF, and potassium
thioacetate failed: the reaction always produced chromone 13.
This failure prompted us to provide more stable proꢀ
tection to the OH group under these reaction conditions.
Synthesis of phenylpropꢀ2ꢀynꢀ1ꢀols (general procedure).
A 2.2 M solution of BuLi (1.2 equiv.) in hexane was slowly added

1024
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 4, April, 2013
Semenova et al.
at –78 C to a solution of freshly distilled phenylacetylene
(1.2 equiv.) in dry THF. The reaction mixture was warmed to
–40 C, stirred for 10 min, and cooled again to –78 C. A soluꢀ
tion of dry salicylaldehyde (or its Oꢀsubstituted analogs 15a—c)
(1 equiv.) in THF was slowly infused through a syringe. The
reaction mixture was stirred at –78 C for 4.5 h and neutralized
with a saturated solution of NH4Cl. The tetrahydrofuran was
removed from the aqueous solution under reduced pressure. The
product was extracted with ethyl acetate. The combined organic
fractions were washed with brine, dried with anhydrous Na2SO4,
and concentrated. The resulting solid or oil was purified by flash
chromatography.
J = 8.0 Hz); 7.49—7.59 (m, 3 H); 7.38—7.48 (m, 3 H); 7.27—7.38
(m, 5 H); 7.05—7.11 (m, 2 H); 5.23 (s, 2 H). 13C NMR (75.47
MHz, CDCl3), : 176.4, 158.7, 136.2, 134.8, 132.7 (2 C); 132.0,
130.2, 128.5 (2 C); 128.4 (2 C); 127.8, 127.3, 127.1 (2 C); 120.6,
120.5, 113.5, 91.8, 89.5, 70.6. MS, m/z (Irel (%)): 312 [M]+ (36), 221
[M – PhCH2]+ (12), 121 [Ph(CO)O]+ (94), 91 [PhCH2]+ (100).
1ꢀ[2ꢀ(tertꢀButyldimethylsilyloxy)phenyl]ꢀ3ꢀphenylpropꢀ2ꢀynꢀ
1ꢀone (17c). Yield 2.01 g (80%), oil. 1H NMR (300.13 MHz,
CDCl3), : 8.04 (dd, 1 H, J = 7.7 Hz, J = 1.6 Hz); 7.63 (d, 2 H,
J = 7.1 Hz); 7.3—7.49 (m, 4 H); 7.08 (t, 1 H, J = 7.5 Hz); 6.93
(d, 1 H, J = 8.2 Hz); 1.07 (s, 9 H); 0.29 (s, 6 H). 13C NMR
(50.32 MHz, CDCl3), : 177.8, 156.1, 134.2, 132.9 (2 C); 132.6,
130.4, 129.5, 128.5 (2 C); 121.5, 121.0, 120.6, 91.4, 88.8, 25.8
(3 C); 18.4, –4.1 (2 C). MS, m/z (Irel (%)): 336 [M]+ (5), 321
[M – Me]+ (14), 279 [M – But]+ (83), 249 [M – But – 2 Me]+ (37),
221 [M – C6H14Si]+ (7), 159 [C6H14SiOCHCH2]+ (100).
2,3ꢀDibromoꢀ1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀone
(8). A solution of 1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀ
one (6) (0.3 g, 1.35 mmol) in dichloroethane was stirred with
bromine (0.23 g, 1.45 mmol) at room temperature for 8 h (monꢀ
itoring by TLC). The solvent was removed, and the residue was
purified by column chromatography with light petroleum as an
eluent. Yield 46%, m.p. 136—138 C. 1H NMR (CDCl3), : 11.44
(s, 1 HOH); 7.78 (d, 1 H, J = 8.1 Hz); 7.55—7.68 (m, 3 H);
7.41—7.52 (m, 3 H); 7.11 (d, 1 HCHCOH, J = 8.4 Hz); 7.11 (t, 1 H,
J = 7.6 Hz). MS, m/z (Irel (%)): 380 [M]+ (9), 302 [M – Br]+
(68), 221 [M – 2 Br]+ (40), 194 [M – Br2C2H2]+ (21), 180
[M – Br2C2H2O]+ (15), 165 [M – Br2C2H2O2]+ (19), 129
[M – Br2PhO]+ (18), 121 [Ph(CO)O]+ (100), 102 [PhCCH]
(35), 93 [PhO]+ (67), 76 [Ph]+ (44). Found (%): C, 47.21;
H, 2.72; Br, 41.74. C15H10Br2O2. Calculated (%): C, 47.16;
H, 2.64; Br, 41.83.
1ꢀ(2ꢀHydroxyphenyl)ꢀ2,3ꢀdiiodoꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀone
(9). A solution of 1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀ
one (6) (0.3 g, 1.35 mmol) in diethyl ether was stirred with
excess iodine (0.65 g, 2.55 mmol) at room temperature. After
completion of the reaction (monitoring by TLC), the solvent
was removed and the precipitate that formed was purified by
column chromatography with light petroleum as an eluent. Yield
28%, m.p. 167—169 C. 1H NMR (CDCl3), : 11.51 (s, 1 HOH);
7.81 (d, 1 H, J = 8.0 Hz); 7.58 (t, 1 H, J = 7.3 Hz); 7.38—7.51
(m, 5 H); 7.10 (d, 1 H, CHCOH, J = 8.4 Hz); 7.11 (t, 1 H,
J = 7.6 Hz). 13C NMR (50.32 MHz, CDCl3), : 197.1, 164.3, 144.0,
137.6, 132.4, 129.4, 128.7 (2 C); 128.3 (2 C); 119.7, 119.0, 115.0,
97.3, 90.6. MS, m/z (Irel (%)): 476 [M]+ (21), 349 [M – I]+ (30),
253 [M – PhIO]+ (30), 222 [M – 2 I]+ (40), 194 [M – I2C2H2]+
(14), 129 [M – I2PhO]+ (30), 121 [Ph(OH)CO]+ (100), 93
[PhO]+ (82), 77 [Ph]+ (16). Found (%): C, 37.90; H, 2.16.
C15H10I2O2. Calculated (%): C, 37.85; H, 2.12.
1ꢀ(2ꢀHydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀol (5). Yield
76%, m.p. 87—88 C (cf. Refs 8, 9: m.p. 88 C).
1ꢀ(2ꢀMethoxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀol (16a).10 Yield
2.23 g (70%), oil. 1H NMR (300.13 MHz, CDCl3), : 7.68 (dd, 1 H,
J = 7.5 Hz, J = 1.3 Hz); 7.46—7.55 (m, 2 H); 7.29—7.41 (m, 4 H);
7.03 (t, 1 H, J = 7.5 Hz); 6.95 (d, 1 H, J = 8.2 Hz); 5.97 (d, 1 H,
J = 5.9 Hz); 3.92 (s, 3 H); 3.21 (d, 1 H, OH, J = 5.9 Hz).
13C NMR (75.45 MHz, CDCl3), : 156.8, 131.7 (2 C); 129.6,
128.3, 128.2, 128.1 (2 C); 127.9, 122.7, 120.8, 110.9, 88.5, 85.9,
61.4, 55.5. MS, m/z (Irel (%)): 238 [M]+ (30), 222 [M – OH]+
(100), 207 [M – OMe]+ (37).
1ꢀ(2ꢀBenzyloxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀol (16b). Yield
3.56 g (96%), oil. 1H NMR (300.13 MHz, CDCl3), : 7.72 (dd, 1 H,
J = 7.5 Hz, J = 1.2 Hz); 7.50—7.62 (m, 4 H); 7.31—7.42 (m, 7 H);
7.07 (t, 1 H, J = 7.5 Hz); 7.01 (d, 1 H, J = 8.4 Hz); 6.02 (s, 1 H);
5.21 (s, 2 H); 3.32 (s, 1 H, OH). 13C NMR (50.32 MHz, CDCl3),
: 155.9, 136.6, 131.7 (2 C); 129.5, 129.3, 128.6 (2 C); 128.3,
128.2, 128.0 (3 C); 127.2 (2 C); 122.8, 121.1, 112.2, 88.8, 85.7,
70.2, 61.8. MS, m/z (Irel (%)): 314 [M]+ (21), 297 [M – OH]+
(28), 223 [M – PhCH2]+ (74), 205 [M – PhCH2O]+ (80), 91
[PhCH2]+ (100).
1ꢀ[2ꢀ(tertꢀButyldimethylsilyloxy)phenyl]ꢀ3ꢀphenylpropꢀ2ꢀynꢀ
1ꢀol (16c). Yield 2.55 g (89%), oil. 1H NMR (300.13 MHz,
CDCl3), : 7.71 (d, 1 H, J = 7.6 Hz); 7.46—7.53 (m, 2 H); 7.30—7.38
(m, 3 H); 7.26 (t, 1 H, J = 7.7 Hz); 7.04 (t, 1 H, J = 7.5 Hz); 6.91
(d, 1 H, J = 8.1 Hz); 5.98 (m, 1 H); 2.94 (s, 1 H, OH); 1.09 (s, 9 H);
0.34 (s, 6 H). 13C NMR (75.45 MHz, CDCl3), : 152.9, 131.6
(2 C); 131.1, 129.3, 128.29, 128.1 (2 C); 128.0, 122.7, 121.4, 118.4,
88.8, 85.9, 61.2, 25.7 (3 C); 18.2, –4.1 (2 C). MS, m/z (Irel (%)):
338 [M]+ (2), 281 [M – But]+ (91), 251 [M – But – 2 Me]+
(100), 224 [M – C6H14Si]+ (8), 201 [M – C6H14SiO]+ (12).
Oxidation of phenylpropꢀ2ꢀynꢀ1ꢀols (general procedure).
Manganese dioxide (4.3 g) was added in portions to a solution of
phenylpropꢀ2ꢀynꢀ1ꢀol 5 or its derivatives 16a—c (8.45 mmol) in dry
CH2Cl2 (20 mL). The reaction mixture was stirred at room temperꢀ
ature until the reaction was completed (monitoring by TLC).
Manganese oxide was filtered off, and the resulting solution was
concentrated. The product was purified by flash chromatography.
1ꢀ(2ꢀHydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀone (6). Yield
65%, m.p. 66 C (cf. Refs 8, 9: m.p. 65 C).
3ꢀBromoꢀ1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀone (10).
A 48% aqueous solution of HBr (0.2 mL, d = 1.49) was added to
a solution of 1ꢀ(2ꢀhydroxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀone (6)
(0.2 g, 0.9 mmol) in glacial acetic acid. The reaction mixture was
stirred at 60 C until the reaction was completed (monitoring by
TLC). The solvent was removed, and the residue was purified by
column chromatography with light petroleum as an eluent. Yield
1ꢀ(2ꢀMethoxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀone (17a).10
Yield 2.17 g (96%), oil. 1H NMR (300.13 MHz, CDCl3), : 8.18
(d, 1 H, J = 7.7 Hz); 7.62 (d, 2 H, J = 7.2 Hz); 7.53 (t, 1 H,
J = 7.8 Hz); 7.35—7.44 (m, 3 H); 7.00—7.08 (m, 2 H); 3.95 (s, 3 H).
13C NMR (75.45 MHz, CDCl3), : 176.5, 159.7, 134.9, 132.8
(2 C); 132.4, 130.3, 128.5 (2 C); 126.7, 120.6, 120.2, 112.2, 91.4,
89.2, 55.8. MS, m/z (Irel (%)): 236 [M]+ (92), 219 [M – OH]+
(11), 207 [M – OMe]+ (85), 129 [M – C7H7O]+ (95), 115 (100).
1ꢀ(2ꢀBenzyloxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀone (17b). Yield
3.42 g (97%), oil. 1H NMR (300.13 MHz, CDCl3), : 8.19 (d, 1 H,
1
64%, m.p. 82—84 C. H NMR (CDCl3), : 12.15 (s, 1 HOH);
7.79 (d, 1 H, J = 8.0 Hz); 7.69—7.75 (m, 2 H); 7.43—7.57 (m, 5 H);
7.05 (d, 1 H, J = 8.4 Hz); 6.93 (t, 1 H, J = 7.6 Hz). 13C NMR
(50.32 MHz, CDCl3), : 195.5, 163.2, 138.7, 136.7, 134.8, 130.5,
130.4, 128.5 (2 C); 127.9 (2 C); 124.3, 119.8, 118.9, 118.5. MS,
m/z (Irel (%)): 302 [M]+ (5), 223 [M – HBr]+ (100), 194

Synthesis of 1,3ꢀthioxoketones
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 4, April, 2013
1025
[M – C2H2]+ (5), 165 [M – COH – C2H2]+ (17), 129 [M – PhO]+
(11), 121 [Ph(CO)O]+ (68), 102 [PhCCH] (33), 93 [PhO]+ (51).
Found (%): C, 59.59; H, 3.81; Br, 26.22. C15H11BrO2. Calculatꢀ
ed (%): C, 59.43; H, 3.66; Br, 26.36.
Synthesis of 3ꢀmercaptoꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀones (general
procedure). Thioacetic acid (1.6 mL, 1.71 g, 22.4 mmol) was
stirred with ButOK (0.3 g, 2.38 mmol) for 20 min. Then an
appropriate phenylpropynone 17a—c (1.19 mmol) was added.
The reaction mixture was stirred at room temperature for 2 h and
poured into water. The product from the aqueous layer was exꢀ
tracted with ethyl acetate. The extract was concentrated and
passed through a short column with silica gel. Elution with light
petroleum gave a dark cherry oily liquid.
3ꢀMercaptoꢀ1ꢀ(2ꢀmethoxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀone
(18a). Yield 59%. 1H NMR (300.13 MHz, CDCl3), : 15.92
(s, 1 HSH); 7.93 (dd, 1 H, J = 1.5 Hz, J = 7.8 Hz); 7.83 (d, 2 H,
J = 7.8 Hz); 7.74 (s, 1 H); 7.41—7.53 (m, 4 H); 7.09 (t, 1 H,
J = 7.6 Hz); 7.03 (d, 1 H, J = 8.3 Hz); 3.95 (s, 3 H). 13C NMR (50.32
MHz, CDCl3), : 200.4 (C=O); 179.6, 158.1, 145.4, 133.3, 130.8,
130.5, 128.4 (2 C); 126.9 (2 C); 125.5, 120.9, 116.2, 111.9, 55.9.
MS, m/z (Irel (%)): 270 [M]+ (29), 239 [M – MeO]+ (68), 135
[Ph(CS)CH2]+ (92), 120 [Ph(CO)O]+ (51). Found (%): C, 70.79;
H, 5.05. C16H14O2S. Calculated (%): C, 71.08; H, 5.22.
1ꢀ(2ꢀBenzyloxyphenyl)ꢀ3ꢀmercaptoꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀ
one (18b). Yield 68%. 1H NMR (300.13 MHz, CDCl3), : 15.36
(s, 1 HSH); 8.06 (d, 1 H, J = 8.1 Hz); 7.79 (s, 1 H); 7.11—7.54
(m, 13 H); 5.20 (s, 2 H). MS, m/z (Irel (%): 345 [M]+ (37), 255
[M – PhCH2OCCH]+ (100), 121 [Ph(CO)OH]+ (74). Found (%):
C, 75.98; H, 5.12. C22H18O2S. Calculated (%): C, 76.27; H, 5.24.
1ꢀ[2ꢀ(tertꢀButyldimethylsilyloxy)phenyl]ꢀ3ꢀmercaptoꢀ3ꢀphenꢀ
ylpropꢀ2ꢀenꢀ1ꢀone (18c). Yield 84%. 1H NMR (300.13 MHz,
CDCl3), : 14.86 (s, 1 HSH); 7.72—7.84 (m, 3 H); 7.32—7.57
(m, 5 H); 7.01—7.12 (m, 1 H); 6.82—6.99 (m, 1 H); 0.88 (s, 9 H);
0.24 (s, 6 H). MS, m/z (Irel (%)): 370 [M]+ (48), 355 [M – Me]+
(68), 313 [M – But]+ (98), 255 [M – SiMe2But]+ (12), 135
[Ph(CS)CH2]+ (86), 120 [Ph(CO)O]+ (100). Found (%): C, 67.83;
H, 6.98. C21H26O2SiS. Calculated (%): C, 68.06; H, 7.07.
3,6ꢀDibromoꢀ2ꢀphenylchromone (11). Excess bromine was
added to a solution of compound 6 (0.1 g, 0.45 mmol) in dry
dichloroethane. The reaction mixture was stirred at room temꢀ
perature until the reaction was completed (monitoring by TLC).
The solvent was removed to give product 7 (0.12 g), which was
dissolved in ethanol (5 mL). Sodium acetate (0.074 g, 0.92 mmol)
was added to the solution. The reaction mixture was refluxed for
1 h and poured into water. The precipitate that formed was
filtered off and dissolved in CH2Cl2. The resulting solution was
passed through a short column with silica gel and concentrated.
Yield 61%, m.p. 190 C (cf. Ref. 11: m.p. 190 C). 1H NMR
(CDCl3), : 8.4 (d, 1 H, J= 1.8 Hz); 7.78—7.92 (m, 3 H); 7.50—7.64
(m, 3 H); 7.42 (d, 1 H, J = 8.9 Hz). 13C NMR (50.32 MHz,
CDCl3), : 171.8, 162.1, 154.3, 137.1, 132.4, 131.2, 129.7 (2 C);
128.9, 128.3 (2 C); 122.9, 119.7, 118.9, 109.1. MS, m/z (Irel (%)):
380 [M]+ (100), 301 [M – Br]+ (5), 200 [BrPh(CO)O]+ (46), 91
[PhO]+ (74). Found (%): C, 47.46; H, 2.20; Br, 42.23. C15H8Br2O2.
Calculated (%): C, 47.41; H, 2.12; Br, 42.05.
3ꢀBromoꢀ2ꢀphenylchromone (12). A mixture of compound 8
(0.07 g, 0.183 mmol) and excess NaOAc (0.045 g, 0.55 mmol)
was refluxed in ethanol for 4 h (monitoring by TLC) and then
poured into water. The precipitate that formed was filtered off
and dissolved in CH2Cl2. The resulting solution was passed
through a short column with silica gel and concentrated. Yield
0.041 g (74%), m.p. 119—120 C (cf. Ref. 12: m.p. 124—125 C).
1H NMR (CDCl3), : 8.32 (d, 1 H, J = 7.7 Hz); 7.82—7.96 (m, 2 H);
7.74 (t, 1 H, J = 7.4 Hz); 7.41—7.64 (m, 5 H). 13C NMR (50.32
MHz, CDCl3), : 167.9, 156.8, 150.5, 128.9, 127.7, 125.9, 124.1
(2 C); 123.1 (2 C); 121.4, 120.6, 116.6, 112.7, 104.1. MS, m/z
(Irel (%)): 300 [M]+ (33), 300 [M – H]+ (77), 274 [M – C2H2]+
(29), 221 [M – Br]+ (33), 180 [M – BrC2H2O]+ (14), 165 [M –
– BrC2H2O2]+ (13), 137 [M – BrC4H4O2] (24), 121 [Ph(CO)O]+
(100), 101 [PhCO]+ (23), 92 [PhO]+ (72), 74 [C6H4]+ (67).
Found (%): C, 59.85; H, 3.03; Br, 26.59. C15H9BrO2. Calculatꢀ
ed (%): C, 59.83; H, 3.01; Br, 26.53.
References
1. L. Carlsen, F. Duus, J. Chem. Soc., Perkin Trans. 2, 1980,
1768.
2. A. Gorski, Y. Posokhov, B. K. V. Hansen, J. SpangetꢀLarsꢀ
en, J. Jasny, F. Duus, P. E. Hansen, J. Waluk, Chem. Phys.,
2006, 328, 205.
3. R. M. Claramunt, C. López, M. D. Santa María, D. Sanz,
J. Elguero, Prog. Nucl. Magn. Reson. Spectrosc., 2006, 49,169.
4. Y. Posokhov, A. Gorski, J. SpangetꢀLarsen, F. Duus, P. E.
Hansen, J. Waluk, Chem. Phys. Lett., 2001, 350, 502.
5. T. Honjo, H. Freiser, Anal. Chem., 1981, 53, 1258.
6. B. Andresen, F. Duus, S. Bolvig, P. E. Hansen, J. Mol.
Struct., 2000, 552, 45.
7. R. T. LaLonde, J. Chem. Soc., Chem. Commun., 1982, 401.
8. H. Harkat, A. Blanc, J.ꢀM. Weibel, P. Pale, J. Org. Chem.,
2008, 73, 1620.
9. M. Yoshida, Y. Fujino, T. Doi, Org. Lett., 2011, 13, 4526.
10. C. Zhou, A. V. Dubrovsky, R. C. Larock, J. Org. Chem.,
2006, 71, 1626.
2ꢀPhenylchromone (13). Compound 9 (0.074 g, 0.15 mmol)
was dissolved in dry DMF (1 mL). Then K2CO3 (0.0083 g,
0.6 mmol) was added, and the reaction mixture was stirred at 60 C
for 1 h and poured into water. The precipitate that formed was
filtered off and dissolved in CH2Cl2. The resulting solution was
passed through a short column with silica gel and concentrated.
Yield 39%, m.p. 98—99 C (cf. Ref. 13: m.p. 97—99 C).
2ꢀ(3ꢀBromoꢀ3ꢀphenylpropꢀ2ꢀenoyl)phenyl acetate (14). Comꢀ
pound 10 (0.05 g, 0.165 mmol) was heated in acetic anhydride in
the presence of HBr until the reaction was completed (monitorꢀ
ing by TLC). The reaction mixture was poured into water. The
product was extracted with CH2Cl2 and purified by column chroꢀ
matography. Yield 0.034 g (61%), m.p. 68—70 C. 1H NMR
(300.13 MHz, CDCl3), : 7.82 (d, 1 H, J = 6.9 Hz); 7.71 (s, 2 H);
7.57 (t, 1 H, J = 6.5 Hz); 7.33—7.46 (m, 5 H); 7.17 (d, 1 H,
J = 7.3 Hz); 2.26 (s, 3 H). 13C NMR (50.32 MHz, CDCl3), : 189.4,
169.4, 149.1, 138.9, 134.4, 133.7, 131.4, 130.5, 130.1, 128.7
(2 C); 128.1 (2 C); 127.2, 126.2, 123.8, 121.1. MS, m/z (Irel (%)):
345 [M]+ (5), 265 [M – Br]+ (68), 223 [M – Br – COMe)]+
(84), 165 [Ph(CO)OCOMe]+ (43), 120 [Ph(CO)O]+ (100), 92
[PhO]+ (76), 77 [Ph]+ (43). Found (%): C, 59.23; H, 3.89; Br,
23.30. C17H13BrO3. Calculated (%): C, 59.15; H, 3.80; Br, 23.15.
11. M. Hoshino, Nippon Kagaku Zasshi, 1957, 78, 1754.
12. K. Jakhar, J. K. Makrandi, Indian J. Chem., Sect. B, 2012,
51, 770.
Received February 11, 2013;
in revised form March 14, 2013