BEHAVIOR OF BENZOINSAND HYDROXYKETONES INACID MEDIA: I.
89
to ketones can be combined into a one-pot process. We
succeeded in excluding the stage of isolation of sulfides
IVg, VIIe, and XIe, and the corresponding ketones were
thus obtained in 8295% yield.
CH3), 2.30 s (3H, CH3), 2.40 s (3H, CH3), 2.65 s (3H,
CH3), 5.40 s (1H, CH), 6.65 s (1H, thienyl), 6.70 s (1H,
thienyl), 7.15 d (2H, Harom, J = 7.0 Hz), 7.30 d (2H, Harom
,
J = 7.0 Hz). Found, %: C 58.85; H 4.75; Cl 8.65; S 23.48.
C20H19ClOS3. Calculated, %: C 59.02; H 4.71; Cl 8.71;
S 23.63.
Thus the proposed combination of the addition and
reductive cleavage can be regarded as a convenient
method for the transformation of hydroxyethanones into
ethanones.
2-(5-Amino-1,3,4-thiadiazol-2-ylsulfanyl)-1,2-
bis(2,5-dimethylthiophen-3-yl)ethanone (IVd). Yield
1
73%. H NMR spectrum (CDCl3), d, ppm: 2.35 s (9H,
CH3), 2.65 s (3H, CH3), 5.60 s (2H, NH2), 6.10 s (1H,
CH), 6.60 s (1H, thienyl), 6.80 s (1H, thienyl). Found, %:
C 48.35; H 4.37; N 10.48; S 32.48. C16H17N3OS4.
Calculated, %: C 48.58; H 4.33; N 10.62; S 32.42.
EXPERIMENTAL
The 1H NMR spectra were recorded on Bruker AM-
300 (300 MHz) and Bruker WM-250 (250 MHz)
spectrometers using DMSO-d6 or CDCl3 as solvent. The
melting points were determined on a Boetius device and
were not corrected. The reaction mixtures were analyzed,
and the purity of products was checked, by TLC on Silica
gel 60 F254 plates (Merck); eluent hexaneethyl acetate.
1,2-Bis(2,5-dimethylthiophen-3-yl)-2-(1-methyl-
1H-imidazol-2-ylsulfanyl)ethanone (IVe). Yield 71%.
1H NMR spectrum (CDCl3), d, ppm: 2.00 s (3H, CH3),
2.35 s (6H, CH3), 2.65 s (3H, CH3), 3.25 s (3H, NCH3),
5.80 s (1H, CH), 6.60 s (1H), 6.70 s (1H), 6.90 s (1H),
7.10 s (1H). Found, %: C 57.55; H 5.44; N 7.38; S 25.64.
C18H20N2OS3. Calculated, %: C 57.41; H 5.35; N 7.44;
S 25.54.
1,2-Bis(2,5-dimethylthiophen-3-yl)-2-(4-fluoro-
phenylsulfanyl)ethanone (IVa). Hydroxy ketone I, 0.1 g
(0.36 mmol), was added to a solution of 0.2 g (1.2 mmol)
of 4-fluorobenzenethiol in 2 ml of trifluoroacetic acid. The
mixture was kept for 15 min at room temperature, diluted
with diethyl ether, neutralized with an aqueous solution
of sodium hydroxide, and extracted with diethyl ether.
The extract was washed with water, 20% aqueous sodium
hydroxide, and water again, dried over MgSO4, and
evaporated. The residue was recrystallized from
1,2-Bis(2,5-dimethylthiophen-3-yl)-2-[5-(4-meth-
oxyphenyl)-1,2,4-triazin-3-ylsulfanyl]ethanone (IVf).
Yield 63%. 1H NMR spectrum (CDCl3), d, ppm: 2.30 s
(3H, CH3), 2.40 s (3H, CH3), 2.50 s (6H, CH3), 3.85 s
(3H, OCH3), 6.50 s (1H, CH), 6.60 s (1H), 6.95 d
(2H, Harom, J = 7.0 Hz), 7.30 s (1H), 8.05 d (2H, Harom
,
J = 7.0 Hz), 9.70 s (1H). Found, %: C 59.73; H 4.70;
N 8.91; S 19.84. C24H23N3O2S3. Calculated, %: C 59.85;
H 4.81; N 8.72; S 19.97.
1
methanol. Yield 0.1 g (76%), mp 6769°C. H NMR
spectrum (CDCl3), d, ppm: 1.95 s (3H, CH3), 2.30 s (3H,
CH3), 2.40 s (3H, CH3), 2.70 s (3H, CH3), 5.40 s (1H,
CH), 6.65 s (1H, thienyl), 6.70 s (1H, thienyl), 6.90
7.00 m (2H, Harom), 7.207.30 m (2H, Harom). Found, %:
C 61.40; H 4.96; F 4.74. C20H19FOS3. Calculated, %:
C 61.51; H 4.90; F 4.86.
Methyl [1,2-bis(2,5-dimethylthiophen-3-yl)-2-
oxoethylsulfanyl]acetate (IVg). Hydroxy ketone I,
0.2 g (0.7 mmol), was added to a solution of 0.4 g
(3.8 mmol) of methyl sulfanylacetate in 2 ml of tri-
fluoroacetic acid. The mixture was kept for 5 min, diluted
with diethyl ether, treated with a solution of 2 g of NaOH
in 5 ml of water, and extracted with three portions of
diethyl ether. The combined extracts were washed with
water, 20% aqueous alkali, and water again, dried over
MgSO4, and evaporated. Yield 0.23 g (90%), oily
Compounds IVbIVf were synthesized in a similar
way.
1,2-Bis(2,5-dimethylthiophen-3-yl)-2-phenyl-
sulfanylethanone (IVb). Yield 0.1 g (85%), oily
substance. H NMR spectrum (CDCl3), d, ppm: 2.05 s
(3H, CH3), 2.30 s (3H, CH3), 2.45 s (3H, CH3), 2.70 s
(3H, CH3), 5.50 s (1H, CH), 6.70 s (1H, thienyl), 6.80 s
(1H, thienyl), 7.207.40 m (5H, Harom). Found, %:
C 64.27; H 5.45; S 25.68. C20H20OS3. Calculated, %:
C 64.48; H 5.41; S 25.82.
1
1
substance. H NMR spectrum (CDCl3), d, ppm: 2.30 s
(3H, CH3), 2.40 s (3H, CH3), 2.45 s (3H, CH3), 2.65 s
(3H, CH3), 3.10 d (1H, CH2, J = 18.0 Hz), 3.20 d (1H,
CH2, J = 18.0 Hz), 3.70 s (3H, OCH3), 5.65 s (1H,
CH), 6.65 s (1H, thienyl), 6.90 s (1H, thienyl). Found,
%: C 55.51; H 5.34; S 26.15. C17H20O3S3. Calculated,
%: C 55.41; H 5.47; S 26.10.
2-(4-Chlorophenylsulfanyl)-1,2-bis(2,5-dimethyl-
thiophen-3-yl)ethanone (IVc). Yield 78%, mp 105
107°C. 1H NMR spectrum (CDCl3), d, ppm: 2.00 s (3H,
Methyl [1-(2,5-dimethylthiophen-3-yl)-2-oxo-2-
phenylethylsulfanyl]acetate (VIIe). Hydroxy ketone
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 1 2005