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Russ.Chem.Bull., Int.Ed., Vol. 63, No. 6, June, 2014
Nosova et al.
19F NMR spectra were detected on a Bruker Avance 400 spectroꢀ
meter with a working frequency of 376.43 MHz, and chemical
shifts were measured relatively to CFCl3 using C6F6 as a secondꢀ
ary standard ((19F) –162.9). Mass spectra were recorded on
a SHIMADZU GCMSꢀQP2010 Ultra instrument with electron
ionization (EI) of the sample. UV and FL spectra were obtained
on a Shimadzu UVꢀ2401PC spectrophotometer (Japan) and
a Varian Eclipse spectrofluorimeter (Australia), and solutions in
acetonitrile with a concentration of 10–4 mol L–1 were used for
spectra recording. The relative quantum yield was determined
using a known procedure17 using quinine bisulfate ( = 0.546)
and fluorescein for compound 6d ( = 0.92) as standards.
(d, 1 H, H(4), J = 8.3 Hz); 8.59 (s, 1 Н, СH=N); 12.1 (br.s, 1 Н,
NH). 19F{1H} NMR, : –135.49 (d, 1 F, F(7), J = 21.3 Hz);
–132.26 (d, 1 F, F(6), J = 21.3 Hz). MS, m/z (Irel (%)): 311 [M]+
(3), 206 [M–С6H5CO]+ (86), 178 [M–С6H5CO–N2]+ (41),
151 (35), 105 [С6H5CO]+ (100), 77 [С6H5]+ (66). Found (%):
С, 65.54; Н, 3.52; N, 13.57. С17H11F2N3O. Calculated (%):
C, 65.59; H, 3.56; N, 13.50.
Methyl pyrazinyl ketone benzoylhydrazone (5). The melting
point corresponds to the literature data.15 1Н NMR, : 2.47 (s, 3 Н,
Me); 7.5—7.8 (m, 3 Н, H(3´), H(4´), H(5´)); 7.97 (m, 2 Н,
H(2´), H(6´)), 8.54 (m, 2 Н, H(5), H(6)); 9.32 (d, 1 Н, H(3),
J = 1.3 Hz); 10.9 (br.s, 1 Н, NH).
Xꢀray diffraction study of compound 6b was carried out on an
Xcalibur S automated Xꢀray diffractometer using a standard proꢀ
cedure (MoK = 0.71073 Å, Т = 295(2) K, scan mode with
an increment of 1 and a crystal—detector distance of 50 mm).
The number of reflections collected on the scattering angles
1.64 < < 26.37 was 13 707, of which 7334 reflections were
independent (Rint = 0.0452), and 4516 reflections were with
I > 2(I). An empirical absorption correction was applied
( = 0.722 mm–1). The crystal was triclinic, space group Р–1,
a = 11.3242(5) Å, b = 13.0648(9) Å, c = 14.1811(8) Å,
= 116.518(6), = 99.331(4), = 91.845(4). The structure
was solved by a direct method and refined in the anisotropic
approximation using the SHELXTL program package.18 The
Zinc(II) complex of benzoic acid (quinolinꢀ2ꢀyl)methyleneꢀ
hydrazide (6а). A solution of zinc acetate dihydrate (0.084 g,
0.365 mmol) in water (3 mL) was added dropwise to hydrazone
3a (0.2 g, 0.73 mmol) in freshly distilled DMF (15 mL). The
reaction mixture was refluxed for 3 h and cooled, and the bright
yellow precipitate was filtered off and washed with ethanol. The
yield was 0.15 g (67%), m.p. >300 С. 1Н NMR, : 7.32 (m, 2 Н);
7.39 (m, 1 Н); 7.45 (m, 1 Н); 7.54 (m, 1 Н); 7.57 (m, 1 Н); 7.90
(m, 1 Н); 8.0—8.15 (m, 3 Н); 8.58 (d, 1 Н, Н(4), J = 8.4 Hz);
9.03 (s, 1 H, CH=N). MS, m/z (Irel (%)): 614 [M]+ (3), 457 (10),
170 (19), 142 (14), 128 (19), 115 (22), 105 (100), 77 (91).
Found (%): С, 66.43; Н, 3.81; N, 13.59. C34H24N6O2Zn. Calꢀ
culated (%): C, 66.51; H, 3.94; N, 13.69. The molecular weight
was 613.98.
parameters of the final refinement were R1 = 0.0611, wR2
=
= 0.1512 for reflections with I > 2(I) at the goodnessꢀofꢀfit
S = 1.002. The maximum and minimum of the residual electron
Compounds 6b,c and 7a were synthesized similarly. To obꢀ
tain complex 6b, the reaction mixture was heated at 150 С for
10 h, cooled, and filtered. The solution was slowly evaporated at
room temperature, and the precipitated orange crystals were
filtered off and used directly for Xꢀray diffraction analysis.
Zinc(II) complex of benzoic acid [6ꢀfluoroꢀ7ꢀ(dimethylamino)ꢀ
quinolinꢀ2ꢀyl]methylenehydrazide (6b). The yield was 59%, m.p.
density were 0.556 and –0.494 e Å–3
.
The results of Xꢀray diffraction analyses for compound 6b
were deposited with the Cambridge Crystallographic Data Cenꢀ
tre (CCDC 1000078). These data are free and can be available at
Melting points were determined on a Stuart SMP3 instꢀ
rument.
1
>300 С. Н NMR, : 2.88 (s, 6 H, NMe2); 6.76 (d, 1 Н, H(8),
J = 8.6 Hz); 7.33 (m, 2 Н, Ph); 7.36 (m, 1 Н, Ph); 7.48 (d, 1 Н,
H(5), J = 14.0 Hz); 7.69 (d, 1 H, H(3), J = 8.3 Hz); 8.09 (m, 2 Н,
Ph); 8.29 (d, 1 H, H(4), J = 8.3 Hz); 8.87 (s, 1 Н, СH=N).
19F{1H} NMR, : –118.28 (с, 1 F). MS, m/z (Irel (%)): 736 [M]+
(4), 247 (15), 246 (19), 242 (11), 217 (10), 215 (31), 214 (15), 203
(10), 189 (10), 188 (11), 121 (18), 111 (17), 106 (14), 105 (100),
103 (34), 97 (16), 77 (68). Found (%): С, 61.95; Н, 4.31; N, 15.29.
C38H32F2N8O2Zn. Calculated (%): C, 62.01; H, 4.38; N, 15.22.
The molecular weight was 736.10.
Zinc(II) complex of benzoic acid (quinoxalinꢀ2ꢀyl)methyleneꢀ
hydrazide (6c). The yield was 69%, m.p. >300 С. 1Н NMR,
: 7.41 (m, 2 Н); 7.45 (m, 1 Н); 7.64 (m, 1 Н); 7.71 (m, 2 Н); 8.00
(m, 1 Н); 8.13 (m, 1 Н); 8.15 (m, 1 Н); 9.17 (s, 1 Н, Н(3)); 9.39
(s, 1 Н, CH=N). MS, m/z (Irel (%)): 616 [M]+ (4), 614 (5), 458
(5), 155 (8), 130 (5), 129 (11), 105 (100), 103 (40), 77 (88).
Found (%): С, 62.08; Н, 3.78; N, 18.43. C32H22N8O2Zn. Calꢀ
culated (%): C, 62.40; H, 3.60; N, 18.19. The molecular weight
was 615.95.
2ꢀFormylbenzazines 2а—c were synthesized by the oxidaꢀ
tion of the corresponding 2ꢀmethyl derivatives by selenium diꢀ
oxide on reflux in dioxane.19 Ligand 5 was synthesized by reflux
of benzhydrazide 1 with 2ꢀacetylpyrazine 4 in ethanol according
to a described procedure.15
Benzoic acid (quinoxalinꢀ2ꢀyl)methylenehydrazide (3с).
A solution of benzhydrazide (1) (0.172 g, 1.27 mmol) in ethanol
(15 mL) was added to a solution of quinoxalineꢀ2ꢀcarbaldehyde
(2c) (0.2 g, 1.27 mmol) in ethanol (25 mL). The reaction mixꢀ
ture was refluxed for 10 h, then the solvent was distilled off to 1/4
volume, and the formed precipitate was filtered off. The yield
was 0.31 g (89%), m.p. 224—226 С. 1Н NMR, : 7.55 (m, 2 Н);
7.61 (m, 1 Н); 7.84 (m, 2 Н); 7.98 (m, 2 Н); 8.10 (m, 2 Н); 8.66
(s, 1 Н, Н(3)); 9.55 (s, 1 Н, CH=N); 12.2 (br.s, 1 Н, NH).
Found (%): С, 69.61; Н, 4.44; N, 20.22. C16H12N4O. Calculatꢀ
ed (%): C, 69.55; H, 4.38; N, 20.28.
Compounds 3а,b were synthesized similarly.
Benzoic acid (quinolinꢀ2ꢀyl)methylenehydrazide (3а). The
yield was 84%, m.p. 140—142 С. 1Н NMR, : 7.5—7.6 (m, 4 Н);
7.75 (m, 1 Н); 7.95 (m, 3 Н); 8.03 (m, 1 Н); 8.21 (m, 1 H, H(3));
8.30 (m, 1 H, H(4)); 8.60 (s, 1 Н, СH=N); 12.0 (br.s, 1 Н, NH).
Found (%): С, 74.13; Н, 4.71; N, 15.32. С17H13N3O. Calculatꢀ
ed (%): C, 74.17; H, 4.76; N, 15.26.
Benzoic acid (6,7ꢀdifluoroquinolinꢀ2ꢀyl)methylenehydrazide
(3b). The yield was 87%, m.p. 246—248 С. 1Н NMR, : 7.5—7.6
(m, 3 Н); 7.9—8.0 (m, 4 Н); 8.24 (d, 1 H, H(3), J = 8.3 Hz); 8.39
Zinc(II) complex of benzoic acid (1ꢀpyrazinꢀ2ꢀyl)ethylideneꢀ
hydrazide (7a). The yield was 76%, m.p. >300 С. 1Н NMR,
: 2.90 (s, 3 Н, Me); 7.40—7.48 (m, 3 Н, H(3´), H(4´), H(5´));
7.93 (m, 1 Н, H(6´)); 8.15 (m, 2 Н, H(5), H(6)); 8.68 (m, 1 Н,
H(2´)); 9.26 (d, 1 Н, H(3), J = 1.3 Hz). MS, m/z (Irel (%)): 544
[M]+ (30), 527 (13), 307 (18), 305 (25), 303 (42), 106 (15), 105
(100), 93 (11), 79 (39), 77 (52). Found (%): С, 57.34; Н, 4.12;
N, 20.51. C26H22N8O2Zn. Calculated (%): С, 57.42; Н, 4.08;
N, 20.60. The molecular weight was 543.89.