of the significantly larger nucleophilicity of the sulfur atom in comparison with oxygen and nitrogen atoms of
OH and NH functions in hydrazones obtained on using hydrazides of 2-hydroxy- and 2-aminobenzoic acids. In
this respect 2-mercaptobenzoylhydrazones 2a-g are close to the condensation products of aromatic aldehydes
with hydrazides of thiobenzoic and thioglycolic acids investigated by us previously, for which intramolecular
attack by the sulfur atom at the C=N bond of the hydrazone fragment leads to the formation of 1,3,4-thia-
diazoline [11] and 1,3,4-thiadiazine [12] rings respectively.
EXPERIMENTAL
1
The H NMR spectra were taken on a Bruker AV 400 (400 MHz) spectrometer in DMSO-d , internal
6
standard was HMDS. The quantitative content of the tautomeric forms was determined by integrating the
1
appropriate signals in the H NMR spectra, error of measurement was ± 1%. A check on the progress of
reactions and the purity of the obtained compounds was effected by TLC on Silufol UV-254 plates in the system
benzene–acetone, 4:1.
The hydrazide of 2-mercaptobenzoic acid 1 was obtained by the known procedure of [2].
2
-Mercaptobenzoylhydrazones of Aromatic Aldehydes 2a-g. A mixture of carbonyl compound
(
2
10 mmol) and 2-mercaptobenzoic acid hydrazide 1 (1.68 g, 10 mmol) in methanol (50 ml) was maintained at
o
5 C for 2 h. The precipitated crystals were filtered off, washed with ether, and dried.
,2'-Dithiobenzoylhydrazones of Aromatic Aldehydes 3a-g. A 5% solution of H O (0.5 ml) was
2
2
2
o
added to a solution of compound 2a-g (5 mmol) in methanol (5 ml) and the mixture maintained at 25 C for 2 h.
The precipitated crystals were filtered off, washed with ether, and dried.
REFERENCES
1
.
A. Yu. Ershov, I. V. Lagoda, M. V. Mokeev, S. I. Yakimovich, I. V. Zerova, V. V. Pakal'nis, and
V. V. Shamanin, Khim. Geterotsikl. Soedin., 460 (2008). [Chem. Heterocycl. Comp., 44, 356 (2008).
L. Katz, L. S. Karger, W. Schroeder, and M. S. Cohen, J. Org. Chem., 18, 1380 (1953).
Yu. P. Kitaev and B. I. Buzykin, Hydrazones [in Russian], Nauka, Moscow (1974), p. 381.
N. A. Parpiev, V. G. Yusupov, S. I. Yakimovich, and Kh. T. Sharipov, Acylhydrazones and Their
Complexes with Transition Metals [in Russian], Fan, Tashkent (1988), p. 163.
2
3
4
.
.
.
5
6
7
.
.
.
G. J. Karabatsos, J. D. Draham, and F. M. Vane, J. Am. Chem. Soc., 84, 753 (1962).
K. N. Zelenin, S. V. Oleinik, V. V. Alekseev, and A. A. Potekhin, Zh. Obshch. Khim., 71, 1182 (2001).
Yu. A. Zhdanov and V. I. Minkin, Correlation Analysis in Organic Chemistry [in Russian], Izd. Rost.
Univ., Rostov-on Don (1966), p. 470.
8
9
.
.
H. C. Brown and Y. Okamoto, J. Am. Chem. Soc., 80, 4979 (1958).
A. V. Dolgarev, V. V. Lukachina, and O. I. Karpova, Zh. Analit. Khim., 29, 721 (1974).
S. A. Flegontov, Z. S. Titova, A. P. Stolyarov, B. I. Buzykin, and Yu. P. Kitaev, Izv. Akad. Nauk SSSR,
Ser. Khim., 1014 (1979).
1
1
1
0.
1.
2.
K. N. Zelenin and V. V. Alekseev, Khim. Geterotsikl. Soedin., 571 (1992). [Chem. Heterocycl. Comp.,
2
8, 481 (1992)].
A. Yu. Ershov, I. V. Lagoda, S. I. Yakimovich, V. V. Pakal'nis, I. V. Zerova, A. V. Dobrodumov, and
V. V. Shamanin, Zh. Org. Khim., 45, 678 (2009).
1
137