EXPERIMENTAL
1H NMR spectra were taken on a Mercury-300 (300 MHz) instrument using DMSO-d6 and with TMS as
internal standard. IR spectra were recorded on a UR-20 instrument (vaseline oil paste). Monitoring of the course
of the reaction and the purity of the compounds obtained was carried out by TLC using Silufol UV-254 plates
and eluent acetone–hexane (2:1).
3,4-Dimethyl-2-thioxothiazoline-5-carboxylic Acid Arylsulfonylhydrazides 2a-e. Hydrazide 1
(2.03 g, 10 mmol) was added in small portions with stirring to a solution of the arylsulfochloride (10 mmol) in
pyridine (5 ml) at 0°C. The mixture was held for 2 days at 20-25°C, diluted with iced water (20 ml), and the
separated crystals of compounds 2a-e were filtered off and recrystallized from 25% EtOH.
3,4-Dimethyl-2-thioxothiazoline-5-carboxylic Acid Thiosemicarbazide (3). A mixture of the
hydrazide 1 (2.03 g, 10 mmol), NH4SCN (1.25 g, 15 mmol), and 36% HCl (1.2 ml, 15 mmol) was refluxed in
EtOH (10 ml) for 1 h. The EtOH was distilled off and the residue was treated with H2O (10 ml). The precipitated
crystals were filtered off to give compound 3 (1.6 g).
3,4-Dimethyl-2-thioxothiazoline-5-carboxylic Acid Benzoylthiosemicarbazide (4). PhCOCl (1.4 g,
10 mmol) was added portionwise to a solution of NH4SCN (0.84 g, 11 mmol) in dry dioxane (10 ml). The
mixture obtained was refluxed for 15 min and the hydrazide 1 (2.03 g, 10 mmol) was added to it at such a rate
that gentle refluxing continued. After cooling, the reaction product was treated with water (20 ml) and the
precipitate was filtered off to give compound 4 (2.88 g).
3,4-Dimethyl-2-thioxothiazoline-5-carboxylic Acid Azide (5). NaNO2 (1.75 g, 25 mmol) was added to
a suspension of the hydrazide 1 (2.03 g, 10 mmol) in water (30 ml) and AcOH (1.50 g, 25 mmol) was added
portionwise slowly at 0°C. The mixture was stirred for 3 h at 20-25°C. The precipitate was filtered off, washed
on the filter with water (30 ml), and dried in air to give the azide 5 (1.95 g).
Esters of 3,4-Dimethyl-2-thioxothiazoline-5-carbamic Acid (6a-g), N-Alkyl(aryl, heteryl)-N'-
(3,4-dimethyl-2-thioxothiazolin-5-yl)ureas
(7a-k),
and
4-Acetyl-(arylsulfonyl)-1-(3,4-dimethyl-2-
thioxothiazolin-5-yl)semicarbazides (8a-d). A suspension of azide 5 (2.14 g, 10 mmol) and the nucleophile
(alcohol, amine, or substituted hydrazine) (10 mmol) in absolute toluene (10 ml) (in the case of aliphatic
alcohols the latter are the solvent) was held in the presence of a catalytic amount of pyridine at 100-120°C for
2 h. After cooling the reaction mixture the precipitated product was filtered off and washed with petroleum ether.
Most of the products 7 were additionally purified by recrystallization (solvent given in Table 2).
REFERENCES
1.
V. V. Dovlatyan, K. A. Eliazyan, V. A Pivazyan, and A. P. Engoyan, Khim. Geterotsikl. Soedin., 1409
(2003).
2.
3.
4.
M. D. Mashkovskii, Drugs [in Russian], Vol. 2, Novaya Volna, Moscow (1996), p. 319.
N. N. Mel'nikov, Pesticides [in Russian], Khimiya, Moscow (1987), p. 326.
V. A. Mamedov, I. Kh. Rizvanov, I. A. Nuretdinov, and Yu. Ya. Efremov, Khim. Geterotsikl. Soedin.,
987 (1994).
388