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Yang
similar Schiff base compounds derived from
the condensation of 3-methoxysalicylaldehyde or
4-dimethylaminobenzaldehyde with isonicotinic
acid hydrazide in MeOH or in 95% EtOH.
Synthesis of isonicotinic acid [1-(4-
dimethylaminophenyl)methylidene]hydrazide
monohydrate (2)
Compound 2 was prepared by a sim-
ilar procedure as described for 1, with
3-methoxysalicylaldehyde replaced by 4-
Experimental
dimethylaminobenzaldehyde
(149.2
mg,
1.0 mmol), and with MeOH replaced by
95% EtOH. Yellow block-shaped crystals of 2
were formed after evaporating the solvent for 5
days. The crystals were isolated, washed three
times with cold EtOH and dried in a vacuum
desiccator containing anhydrous CaCl2. Yiled
196.8 mg (87.2%). Analysis calculated for
C15H18N4O2: C, 62.92; H, 6.34; N, 19.57%;
found: C, 62.71; H, 6.27; N, 19.72%. Selected
IR data (KBr, cm−1): 3612 (m), 3327 (w), 3067
(w), 2933 (w), 2861 (w), 1655 (s), 1632 (s), 755
(s). 1HNMR data (CD3COCD3, ppm): δ = 3.10
(s, 6H), 6.78 (d, 2H), 7.61 (d, 2H), 7.82 (d, 2H),
8.34 (s, 1H), 8.74 (d, 2H), 10.88 (s, 1H).
Materials and measurements
All chemicals (reagent grade) were com-
mercially available and used without further pu-
rification. C, H, and N elemental analyses were
performed on a Perkin-Elmer 240C elemental
analyzer. The IR spectra were measured with
a FT-IR 170-SX (Nicolet) spectrophotometer.
1
The HNMR spectra were recorded on Bruker
AVANCE 500 MHz spectrometer with tetram-
ethylsilane as the internal reference.
Synthesis of isonicotinic acid [1-(3-methoxy-2-
hydroxyphenyl)methylidene]hydrazide (1)
3-Methoxysalicylaldehyde (152.2 mg,
1.0 mmol) and isonicotinic acid hydrazide
(137.1 mg, 1.0 mmol) were dissolved in a MeOH
solution (50 cm3). The mixture was refluxed for
about 1 h and cooled to room temperature to give
a clear yellow solution. After keeping the solution
in air for 8 days, yellow block-shaped crystals of
the compound, suitable for X-ray single crystal
structural determination, formed at the bottom
of the vessel. The crystals were isolated, washed
three times with cold MeOH and dried in a
vacuum desiccator containing anhydrous CaCl2.
Yiled 225.7 mg (83.2%). Analysis calculated
for C14H13N3O3: C, 61.99; H, 4.83; N, 15.49%;
found: C, 61.83; H, 4.93; N, 15.54%. Selected
IR data (KBr, cm−1): 3573 (w), 3429 (w), 3066
(w), 2934 (w), 2859 (w), 1654 (s), 1635 (s), 1279
Crystallography
X-ray diffraction intensities were collected
using a Bruker SMART Apex 1000 CCD area
detector equipped with graphite-monochromated
ꢁ
Mo-Ka radiation (λ = 0.71073 Å) at 298(2) K.
Absorption corrections were applied by SAD-
ABS program.8 The structures were solved by
direct methods and refined on F2 by full-matrix
least-squares methods using the SHELXTL ver-
sion 5.1.9 All non-hydrogen atoms were refined
anisotropically. Atom H2 in 1 and atoms H2A,
H2B and H2C in 2 were located in difference
Fourier maps and refined isotropically, with the
Uiso(H) value fixed at 0.08 Å and the N H dis-
tances restrained to 0.90(1) Å, O H distances re-
strained to 0.85(1) Å, and H · · · H restrained to
1.37(2) Å. The other H atoms were placed in ideal-
ized positions and constrained to ride on their par-
ent atoms. The details of the crystallographic data
are summarized in Table 1. Selected bond lengths
2
–
–
1
(s), 753 (s). HNMR data (CD3COCD3, ppm):
δ = 3.88 (s, 3H), 6.90 (t, 1H), 7.06 (t, 2H), 7.88
(d, 2H), 8.65 (d, 2H), 8.82 (s, 1H), 11.21 (s, 1H),
11.46 (s, 1H).