1512
PILYUGIN et al.
Analysis of the starting compounds, crude prod-
sulfide ions were separated by adding 125.23 g of zinc
sulfate. The mixture was stirred, and the precipitate
of zinc sulfide (75.57 g) was filtered off. Then the
mixture was acidified with HCl to pH 3.5 4.5. To the
resulting solution of methyl cyanocarbamate we added
67.72 g of tetraamine IX; the mixture was heated to
90 95 C with stirring. The molar ratio sodium cyan-
ucts, and tetraaminodiphenyl ether IX is based on
their separation by HPLC on an Rsil or Ultraspher
ODS reversed-phase column in the eluent system
methanol (65 vol %) water (35 vol %), with addition
of 25 ml of a 10% solution of 18-crown-6 in methanol
per liter of the eluent. The content of components was
determined from the peak areas using the internal
normalization procedure.
amide : methyl
chloroformate : tetraaminodiphenyl
ether IX was 2.6 : 2.6 : 1.0. Under these conditions,
the reaction was complete in 6 7 h. To bind the re-
leased ammonia, we gradually added hydrochloric
acid to the reaction mixture, keeping pH 3.5 4.5. The
resulting precipitate of I was thoroughly washed on
the filter to remove salts and dried on a vacuum roller
drier. Yield of I 96.44 g (82%), main substance con-
tent 96%.
N-[4-(4-Nitrophenoxy)phenyl]acetamide IV. To
1.2 l of DMF we added with vigorous stirring
338.24 g of 4-acetylaminophenol, 378.00 g of 4-nitro-
chlorobenzene, and 241.80 g of anhydrous potassium
carbonate. The mixture was heated to 145 150 C and
vigorously stirred at this temperature for 10 h. The
reaction completion was judged from the disappear-
ance of 4-nitrochlorobenzene. When residual amounts
of 4-nitrochlorobenzene were detected, the mixture
was alkalized with a small amount of 44% aqueous
NaOH and stirred for 1 h. After the complete conver-
sion of 4-nitrochlorobenzene, the mixture was placed
in a crystallizer filled with water and was cooled to
room temperature. The precipitate of nitro acetamide
IV was filtered off, washed with 0.5 N alkali and
water, and dried. Nitro acetamide IV was obtained in
93% yield; mp 153 154 C, Rf 0.36 (benzene hexane,
Ether II was prepared similarly.
ACKNOWLEDGMENTS
The study was financially supported by the Russian
Foundation for Basic Research (project no. 02-03-
97911).
REFERENCES
1. Bessonov, A.S., Veterinariya, 1990, no. 4, p. 3.
3 : 7). Found, %: C 61.78; H 4.45; N 10.22. C14H12
N2O4. Calculated, %: C 61.76; H 4.44; N 10.29.
2. FRG Patent 2332343, 1973, Ref. Zh. Khim., 1975,
17O130.
Di(methoxycarbonylamino-1H-benzimidazol-5-
yl) ether I was prepared starting from commercially
available calcium cyanamide or from sodium cyan-
amide which was synthesized from thiourea. Solid
thiourea was mixed with solid NaOH (molar ratio
1 : 4), and the mixture was stirred in a Z-shaped worm
mixer at 90 95 C. The reaction occurred within 20
25 min, after which the mixture was gradually cooled,
with the stirring continued. Below 80 C, the mixture
crystallized and was ground by the moving worms;
then it was additionally ground in a centrifugal mixer.
The resulting fine powder of a mixture of sodium
cyanamide and sodium sulfide was used for preparing
methyl cyanocarbamate sodium salt.
3. FRG Patent 2332398, 1973, Ref. Zh. Khim., 1975,
16O185.
4. FRG Patent 2332486, 1973, Ref. Zh. Khim., 1975,
23O165.
5. FRG Patent 2332487, 1973, Ref. Zh. Khim., 1975,
17O131.
6. FRG Patent 2348104, 1973, Ref. Zh. Khim., 1975,
24O112.
7. FRG Patent 2348120, 1973, Ref. Zh. Khim., 1975,
24O111.
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Belen’kii, L.I., and Demidov, N.V., USSR Inventor’s
Certificate no. 1207114, 1984, Byull. Izobret., 1986,
no. 3.
To 1.0 l of water we added with stirring 140 g of
the finely dispersed crude product containing 48.77%
sodium cyanamide. To the resulting suspension we
gradually added with vigorous stirring at 20 30 C
73.33 g of methyl chloroformate, avoiding overheat-
ing of the reaction mixture above 30 C. The molar
ratio of sodium cyanamide to methyl chloroformate
was 1 : 1. After adding the whole amount of methyl
chloroformate, the mixture was vigorously stirred at
30 35 C for an additional 15 20 min to complete for-
mation of methyl cyanocarbamate sodium salt. The
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Novik, T.S., Berezkina, S.V., Pilyugin, V.S., Vali-
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Chukina, S.I., Novik, T.S., Berezkina, S.V., Volko-
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 10 2005