Perspective approach to the synthesis of 4,5-dimercapto-1,3-oxazole derivatives

Full text of DOI:10.1023/A:1012312008448

Russian Journal of General Chemistry, Vol. 71, No. 4, 2001, pp. 644 645. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 4, 2001,
pp. 689 690.
Original Russian Text Copyright
2001 by Babii, Zyabrev, Drach.
LETTERS
TO THE EDITOR
Perspective Approach to the Synthesis
of 4,5-Dimercapto-1,3-oxazole Derivatives
S. B. Babii, V. S. Zyabrev, and B. S. Drach
Institute of Bioorganic and Coal Chemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received June 21, 2000
In the course of a systematic study of new trans-
formations of -sulfonyl-substituted enamides we
found that the available reagent I [1] reacts in an
unusual way with an excess of thiphenols in the pre-
sence of triethylamine. The intermediate products of
this reaction are, probably, functionalized enamides
II which are in equilibrium with the corresponding
N-acylimine tautomers III. The latter may well react
with thiophenol in mild conditions with elimination
of a tosyl residue to give new sulfur-containing
enamides IV which readily cyclize under the action of
thionyl chloride.
Ts
Ts
Ts
H
H
N
N
N
2ArSH, 2Et3N
SAr
SAr
Ph
Cl
Ph
Ph
OArS
OArS
O Cl
I
IIa, IIb
IIIa, IIIb
ArSH, Et3N
SAr
H
SAr
N
N
SOCl2
Ph
SAr
SAr
Ph
O
OArS
Va, IVb
I
Va, Vb
Ar = 4-ClC6H4 (a), 4-MeC6H4 (b).
1
The structure of cyclization products V was proved
by spectral methods. The field of application of the
IR spectrum (CH2Cl2), , cm : 1685 (C=O), 3390
(N H). Found, %: Cl 18.40; S 16.75. C27H18Cl3NOS3.
convenient synthetic approach to previously hardly Calculated, %: Cl 18.50; S 16.73. Compound IVb.
available 4,5-dimercapto-1,3-oxazole derivatives (cf.
[2]) will be considered at a later time.
Yield 85%, mp 84 85 C. 1H NMR spectrum (CDCl3),
, ppm: 2.25 s (3H, Me), 2.30 s (3H, Me), 2.33 s (3H,
Me), 7.00 7.44 m (17H, Ar H; 1H, NH). Found, %:
N 2.72; S 18.67. C30H27NOS3. Calculated, %: N 2.73;
S 18.72.
N-[1,2,2-Tri(arylthio)ethenyl]benzamides IVa,
IVb. Triethylamine, 0.03 mol, and 0.01 mol of
enamide I [3] were added to a solution of 0.03 mol of
p-chlorothiophenol or p-thiocresol in 50 ml of
ethanol. The mixture was stirred at 20 25 C for 24 h,
the precipitate was filtered off and recrystallized from
ethanol. Compound IVa. Yield 87%, mp 150 151 C.
4,5-Bis(arylthio)-2-phenyl-1,3-oxazoles Va, Vb.
A solution of 0.001 mol of enamide IVa or IVb in
6 ml of thionyl chloride was heated under reflux for
1.5 h, excess thionyl chloride was removed in a
1070-3632/01/7104-0644$25.00 2001 MAIK Nauka/Interperiodica

PERSPECTIVE APPROACH TO THE SYNTHESIS
645
vacuum, and the residue was crystallized from ethanol.
Compound Va. Yield 42%, mp 121 122 C. IR spec-
trum (CH2Cl2): in the ranges 1600 2000 and 3200
instrument, solvent CH2Cl2. The 1H NMR spectra
were measured on a Varian Gemini spectrometer
(200 MHz), internal reference TMS, solvent CDCl3.
1
3600 cm no bands are observed. Found, %: C 58.50;
REFERENCES
H 2.99; Cl 16.45; S 14.87. C21H13Cl2NOS2. Calcula-
ted, %: C 58.61; H 3.04; Cl 16.48; S 14.90. Com-
pound Vb. Yield 37%, mp 106 107 C. 1H NMR
spectrum (CDCl3), , ppm: 2.30 s (6H, 2Me), 7.05
7.45 m (11H, Ar H), 8.00 8.04 m (2H, Ar H). Found,
%: N 3.65; S 16.03. C23H19NOS2. Calculated, %: N
3.60; S 16.46.
1. Kharchenko, O.V., Dopov. Nat. Akad. Nauk Ukr., 1999,
no. 1, pp. 161 165.
2. Oxazoles: The Chemistry of Heterocyclic Compounds,
Turchi, I.J., Ed., New York: Wiley, 1986, pp. 66 74.
3. Chervonyi, V.A., Kharchenko, A.V., and Drach, B.S.,
The IR spectra were obtained on a Specord IR-71
Ukr. Khim. Zh., 1991, vol. 57, no. 4, pp. 415 418.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001