ACYL DERIVATIVES OF 2-AMINOBENZIMIDAZOLE
743
3,5-Dichlorosalicylic acid. A suspension of 40 g
of salicylic acid in 250 ml of glacial acetic acid was
heated to 35 C on a water bath (the mixture gradually
became homogeneous), and gaseous chlorine was
passed through a bubbler over a period of 4 5 h.
Bubbling of chlorine was terminated, and the mixture
was cooled to room temperature while stirring, purged
with air to remove absorbed chlorine, and poured into
cold water. The precipitate was filtered off, thorough-
ly washed on a filter with acetic acid and water (in
succession), and dried. Yield of the crude product
95%; it contained no less than 99% of the main
substance.
to be tested (this amount corresponds to a dose of
5 kg/ton), and 0.1 ml of water and 10 g of seeds were
added. The flask was shaken for 5 8 min until the
sample was distributed completely on the seed surface,
i.e., until it was removed completely from the flask
walls. Laboratory tests were performed with Voro-
nezhskaya wheat seeds. The seeds were treated 3 days
prior to germination and were incubated in a moist
chamber (Petri dishes) on a filter paper at 24 C. The
germination capacity and the degree of affection with
root rots were determined in 7 days after germination
started. The technical (biological) activity of the
fungicides was determined using the known formula
[11].
Methylation of 2-hydroxybenzoic acids. A solu-
tion of 8 g of sodium hydroxide in 47 ml of water was
cooled to 0 C, and 0.1 mol of the corresponding
hydroxybenzoic acid was added under stirring. Di-
methyl sulfate, 10 ml, was quickly added on cooling,
and the mixture was heated to 35 C and stirred for
20 min at that temperature. An additional 10 ml of
dimethyl sulfate was added, the mixture was stirred
for 10 min at 45 C, heated to 95 100 C, and stirred
for 2 h at 95 100 C, a solution of 3.9 g of NaOH in
13.3 ml of water was added, and the mixture was
stirred for 2 h at 95 100 C. The mixture was cooled
to room temperature, and 2 ml of concentrated hydro-
chloric acid was added; the pH value changed from
7 to 1. The mixture turned turbid, and the product was
extracted into diethyl ether. Removal of the solvent
from the extract gave 76 99% of the corresponding
2-methoxybenzoic acid containing 93 98% of the
main substance.
REFERENCES
1. Spisok pestitsidov i agrokhimikatov, razreshennykh k
primeneniyu na territorii Rossiiskoi Federatsii.
2000 g. (List of Pesticides and Agrochemicals
Allowed to Application in the Russian Federation),
Suppl. to Zashchita i karantin rastenii, 2000, no. 3,
p. 103.
2. Mel’nikov, N.N., Novozhilov, K.V., and Belan, S.R.,
Pestitsidy i regulyatory rosta rastenii: Spravochnik
(Pesticides and Plant Growth Regulators: A Hand-
book), Moscow: Khimiya, 1995, pp. 239, 241, 251,
300.
3. Mel’nikov, N.N., Khimiya i tekhnologiya pestitsidov
(Chemistry and Technology of Pesticides), Moscow:
Khimiya, 1974, pp. 633, 635.
4. Kadyrov, Ch.Sh., Livshits, N.D., Khasanov, S.A.,
Atakuziev, A.A., Gordeeva, A.V., and Akbarova, M.,
Fungitsidy (Fungicides), Tashkent: FAN, 1980, p. 5.
5. Farinliolt, L.H. and Stuart, A.P., J. Am. Chem. Soc.,
1940, vol. 62, p. 1237.
Carboxylic acid chlorides were synthesized by
treatment of the corresponding acids in chloroform
with 1.5 2.0 equiv of thionyl chloride on heating for
5 8 h under reflux. Several drops of dimethylform-
amide as catalyst were added. When the reaction was
complete, excess thionyl chloride and the solvent were
distilled off under reduced pressure. The yields and
purity of the crude products were 95 99%.
6. Earle, R.B. and Jacrson, H.L., J. Am. Chem. Soc.,
1928, vol. 28, p. 109.
7. Anschutz, R. and Mehring, H., Justus Liebigs Ann.
Chem., 1906, vol. 346, p. 301.
8. Fuson, R.C., Reactions of Organic Compounds. A
Textbook for the Advanced Student, New York: Wiley,
1962. Translated under the title Reaktsii organiches-
kikh soedinenii, Moscow: Mir, 1966, p. 99.
9. Lopyrev, V.A., Larina, L.I, Vakulskaja, T.A., La-
rin, M.F., Nefedova, O.B., Shibanova, E.F., and
Voronkov, M.G., Org. Magn. Reson., 1981, vol. 15,
no. 3, p. 219.
10. Lopyrev, V.A., Larina, L.I., Vakulskaja, T.A., Shi-
banova, E.F., Titova, I.A., Voronkov, M.G., and
Liepinsh, E.E., Org. Magn. Reson., 1982, vol. 20,
no. 4, p. 212.
Acylation of 2-aminobenzimidazole. A mixture of
150 ml of acetone (or toluene), 9.31 g of 2-amino-
benzimidazole, and 9.94 ml of triethylamine was
heated to 50 55 C, and a solution of 9.31 g of 3,6-di-
chloro-2-methoxybenzoyl chloride [prepared from
technical grade 3,6-dichloro-2-methoxybenzoic acid
(from Novartis)] in 50 ml of acetone was added. The
mixture was heated for 2 h at 55 C and poured into
cold water, and the precipitate was filtered off and
dried. Yield 25.6 g. The other acyl derivatives of
2-aminobenzimidazole were synthesized in a similar
way.
11. Metodicheskie rekomendatsii po ispytaniyu khimiches-
kikh veshchestv na fungitsidnuyu aktivnost’ (Metho-
dical Recommendations for Testing Chemical Sub-
stances for Fungicide Activity), Cherkassy, 1990, p. 5.
Seed treatment. A flask was charged with a
sample (see above) containing 50 mg of a compound
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 74 No. 5 2004