Synthesis of 6-(5-sulfanyl-1H-tetrazol-1-yl)-2H-chromen-2-one and 5-methyl-1-(2-oxo-2H-chromen-6-yl)-1H-1,2,3-triazole-4-carboxylic acid

Full text of DOI:10.1134/S1070428010110242

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 11, pp. 1748−1749. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © N.T. Pokhodylo, N.D. Obushak, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 11, pp. 1737−1738.
SHORT
COMMUNICATIONS
Synthesis
of 6-(5-Sulfanyl-1H-tetrazol-1-yl)-2H-chromen-2-one
and 5-Methyl-1-(2-oxo-2H-chromen-6-yl)-1H-1,2,3-triazole-4-
carboxylic Acid
N. T. Pokhodylo and N. D. Obushak
Ivan Franko L’vov National University, L’vov, 79005 Ukraine
e-mail: obushak@in.lviv.ua
Received March 4, 2010
DOI: 10.1134/S1070428010110242
The constant interest to syntheses of coumarin deriva-
tives to a large extent is due to the biological activity of
this class compounds [1]. Coumarins are also used in
practice owing to their photochemical and photophysi-
cal characteristics [2] as fluorophores in the fluorescence
spectroscopy of the resonance energy transfer [3]. In this
connection new approaches to the molecular design of
coumarin derivatives are of considerable interest.
tions at the use of weakly basic amines. It was established
that amine II reacted with CS2 to form a thiocarbamate
salt that after acylation was decomposed by treating with
HCl giving isothiocyanate III. By the 1,3-dipolar cyclo-
addition of an azide ion to isothiocyanate III in water
medium we obtained tetrazole IV.
Azide V was obtained by treating with sodium azide
the diazonium salt prepared from amine II. It was es-
tablished that this azide reacted with ethyl acetoacetate
in the presence of sodium methylate to give 1H-1,2,3-
triazole-4-carboxylic acid VI. It should be noted that the
reaction is accompanied by tarring.Apparently under the
reaction conditions the partial opening of the chromen
ring occurred resulting in competing reactions. Triazole
VI was isolated in a moderate yield.
In this report we describe the methods of the synthesis
of coumarin derivatives with tetrazole and 1,2,3-triazole
rings that can be used as convenient linkers for intro-
duction of a coumarin fragment. As the initial reagent
6-aminocoumarin (II) was used obtained by reduction
of nitro derivative I, and we studied the possibility of its
conversion into isothiocyanate III and azide V. The iso-
thiocyanate was synthesized by method [4] having limita-
Hence we demonstrated the possibility of converting
O
O
O
O
O
O
Fe
NaNO2, H2SO4
NaN3
H2O, EtOH
N3
NH2
NO2
V
II
I
(1) CS2, Et3N
MeONa, MeOH
MeCOCH2COOEt
Me
(2) ClCOOEt, Et3N
(3) HCl
SH
O
O
O
O
O
O
NaN3
H2O
COOH
N
N
N
N N
N N
NCS
IV
VI
III
1748

SYNTHESIS OF 6-(5-SULFANYL-1H-TETRAZOL-1-YL)-2H-CHROMEN-2-ONE
1749
the amino group of 6-aminocoumarin into the isothiocya-
nate and the azide functions which further were applied
to the syntheses of tetrazole and triazole derivatives.
obtained 1.4 g (75%) of azide V that was used without
further purification.
In 7 ml of anhydrous methanol was dissolved 0.15 g
(6.5 mmol) of sodium. To the cooled solution of the
sodium methylate was added 0.64 ml (5 mmol) of ethyl
acetoacetate, and at cooling with ice water was slowly
added 0.94 g (5 mmol) of azide V. The mixture was
maintained at cooling with ice bath for 30 min, then it
was slowly heated to boiling and boiled for 1 h. To the
formed precipitate was added 15–20 ml of hot water till
its dissolution, and the boiling was continued for 1 h. The
hot solution was poured into 10 ml of concn. HCl and
left for crystallization. The formed crystals were filtered
off, washed on the filter with a little water, and recrystal-
lized from aqueous ethanol. Yield 31%, mp 179–180°C.
1H NMR spectrum, δ, ppm: 2.46 s (3H, CH3), 6.45 d
(1H, H4, J 9.6Hz), 7.25 d.d (1H, H7, 3J 8.8, 4J 2.6 Hz),
6-Isothiocyanato-2H-chromen-2-one (III). In
a minimal quantity of benzene was dissolved 1.6 g
(0.01 mol) of 6-amino-2H-chromen-2-one (II), it was
mixed with 0.66 ml of carbon disulfide and 1.4 ml of
triethylamine, and the mixture was cooled to 0°C. After
4–5 h the formed triethylammonium dithiocarbamate was
filtered off, washed with anhydrous ether, and dried in
air for 10 min. The salt obtained was dissolved in 20 ml
of chloroform and mixed with 14 ml of triethylamine,
and the solution was cooled to 0°C. To the solution was
added dropwise at stirring within 15 min 1.02 ml of
ethyl chlorocarbonate, the mixture was stirred at 0°C for
10 min and left standing at room temperqature for 1 h.
The solution in chloroform was washed with 3M solution
of HCl, twice with water, and dried with Na2SO4. Chlo-
roform was distilled off, the residue was recrystallized
from ethanol. Yield 1.48 g (73%), mp 176°C. 1H NMR
spectrum, δ, ppm: 6.57 d (1H, H4, J 10.1 Hz), 7.45 d (1H,
H8, J 8.6 Hz), 7.62 d (1H, H7, J 8.6 Hz), 7.82 s (1H, H5),
7.99 d (1H, H3, J 10.1 Hz). Mass spectrum: m/z 204 [M +
H]+. Found, %: C 59.01; H 2.32; N 6.62. C10H5NO2S.
Calculated, %: C 59.10; H 2.48; N 6.89.
3
7.37 d (1H, H8, J 8.8 Hz), 7.47 d (1H, H5, 4J 2.6 Hz),
8.00 d (1H, H3, 3J 9.6 Hz). Mass spectrum: m/z 272 [M +
H]+. Found, %: C 57.31; H 3.45; N 15.40. C13H9N3O4.
Calculated, %: 57.57; H 3.34; N 15.49.
1H NMR spectra were registered on a spectrometer
Varian Mercury (400 MHz) in DMSO-d6, internal refer-
ence TMS. Mass spectra were obtained on a GC-MS
instrument Agilent 1100 LC/MSD at the chemical ion-
ization.
6-(5-Sulfanyl-1H-tetrazol-1-yl)-2H-chromen-2-one
(IV). A mixture of 1.02 g (5 mmol) of isothiocyanate III
and 0.39 g (6 mmol) of NaN3 in 10 ml of water was boiled
at stirring till complete dissolution of solid. The reaction
mixture was cooled to room temperature, and HCl was
added till acid reaction. The precipitate was filtered off,
washed with water on the filter, and dried in air. Yield
85%, mp 204°C. 1H NMR spectrum, δ, ppm: 6.54 d (1H,
H4, J9.6 Hz), 7.58 d (1H, H8, J 8.8 Hz), 8.13 d.d (1H, H7,
3J 8.8, 4J 2.6 Hz), 8.16 d (1H, H3, J9.6 Hz), 8.29 d (1H,
H5, 4J 2.5 Hz). Mass spectrum: m/z 247 [M + H]+. Found,
%: C 48.37; H 2.42; N 22.86. C10H6N4O2S. Calculated,
%: C 48.78; H 2.46; N 22.75.
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triazole-4-carboxylic acid (VI). In a mixture of 2.5 ml
of concn. H2SO4 and 7 ml of water was dissolved 1.6 g
(10 mmol) of amine II, and the solution was cooled
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(12 mmol) of NaNO2 was added maintaining the tempera-
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 11 2010