EXPERIMENTAL
The IR spectra were recorded in the region of 400–4000 cm−1 on a Perkin-Elmer Spectrum One Fourier
IR spectrometer with a diffuse reflection adapter. The 1H and 19F NMR spectra were obtained on a Bruker DRX-
400 spectrometer (400 and 376 MHz respectively) in CDCl3 solution with TMS and C6F6 respectively as internal
standard. Elemental analysis was conducted with a Perkin-Elmer PE 2400 Series 2 CHNS-O EA 1108.4
elemental analyzer. The melting points were determined in quartz capillaries on Stuart SMP3 apparatus for
melting point determination. The reactions were monitored by TLC on Alugram Sil G/UV-254 plates.
The 2,5-thiophenedicarbaldehyde (2a) and 2,6-pyridinedicarbaldehyde (2b) were Aldrich reagents.
Diethyl 2-[(2-Aminophenyl)aminomethylidene]malonate (1). Diethyl 2-ethoxymethylenemalonate
(2.16 g, 10 mmol) was added to a solution of o-phenylenediamine (1.08 g, 10 mmol) in ether (30 ml). The
mixture was stirred at room temperature for 1 h and was then evaporated. The residue was recrystallized from
hexane. We obtained 2.42 g (87%) of compound 1 in the form of a milky-colored powder; mp 96–97°C (mp of
unpurified product 78°C [10]). IR spectrum, ν, cm−1: 3409, 3351 (NH2), 3251 (N−H), 2986 (С−Н val.), 1697,
1
1655 (С=O), 1609, 1593 (С=С, N−H). H NMR spectrum, δ, ppm (J, Hz): 1.31; .38 (6Н, two t, J = 7.1,
2СН2СН3); 4.23, 4.32 (4Н, two q, J = 7.1, 2СН2СН3); 6.82 (1H, ddd, J = 7.8, J = 7.7, J = 1.1, H Ar); 6.87 (1H,
dd, J = 7.7, J = 1.1, H Ar); 7.04 (1H, ddd, J = 7.8, J = 7.7, J = 1.1, H Ar); 7.12 (1H, dd, J = 7.7, J = 1.1, H Ar);
7.27 (Н, s, НС=N); 8.42 (Н, d, J = 13.6, NH). Found, %: С 60.31; Н 6.45; N 9.91. С14Н18N2O4. Calculated, %:
С 60.42; Н 6.52; N 10.07.
Tetraethyl 2,2'-[2,5-Thienylbis(aminomethylidene-2-iminophenylene)]dimalonate (3a). A mixture
of the ester 1(1.95 g, 7 mmol), 2,5-thiophenedicarbaldehyde (2a) (0.42 g, 3 mmol), and glacial acetic acid
(2 ml) in benzene (40 ml) was boiled for 15 h with azeotropic distillation of the water. The reaction mixture was
then evaporated, and the precipitate was recrystallized from diethyl ether. Product 3a (1.56 g, 80%) was
obtained in the form of an orange-colored powder; mp 160–161°C. IR spectrum, ν, cm−1: 3251, 3070 (N–H),
2978 (С–Н val.), 1700, 1669 (С=O), 1646 (С=N), 1604, 1570 (С=С, N–H). 1H NMR spectrum, δ, ppm (J, Hz):
1.31; 1.33 (12Н, two t, J = 7.1, 4СН2СН3); 4.26, 4.33 (8Н, two q, J = 7.1, 4СН2СН3); 7.14 (2Н, ddd, J = 7.5,
J = 7.4, J = 1.6, Н Аr); 7.27–7.36 (6Н, m, Н Аr); 7.75 (2Н, s, thiophene); 8.61 (2Н, d, J = 14.1,
2HС=); 8.71 (2Н, s, 2H–С=N); 11.69 (2Н, br. d, J = 14.1, 2NH). Found, %: С 61.65; Н 5.38; N 8.29; S 5.11.
С34Н36N4O8S. Calculated, %: С 61.80; Н 5.49; N 8.48; S 4.85.
Tetraethyl 2,2'-[2,6-Pyridylbis(aminomethylidene-2-iminophenylene)]dimalonate (3b). A mixture
of the ester 1 (1.95 g, 7 mmol) and 2,6-pyridinedicarbaldehyde (2b) (0.41 g, 3 mmol) in absolute ethanol (40 ml)
was boiled for 4 h. The precipitate was filtered off and recrystallized from acetonitrile. Product 3b (1.63 g, 83%)
was obtained in the form of a bright-yellow powder; mp 199–200°C. IR spectrum, ν, cm−1: 3186, 3079 (N–H),
2980 (С–Н), 1712, 1678 (С=O), 1641 (С=N), 1605, 1588 (С=С, N–H). 1H NMR spectrum, δ, ppm (J, Hz): 1.35;
1.41 (12Н, two t, J = 7.1, 4СН2СН3); 4.27, 4.39 (8Н, two q, J = 7.1, 4СН2СН3); 7.17 (2Н, ddd, J = 7.3, J = 7.2,
J = 2.0, Н Аr); 7.34–7.40 (4Н, m, Н Аr); 7.46 (2Н, dd, J = 8.4, J = 0.7, Н Аr); 8.05 (1H, t, J = 7.8, Н Ру); 8.65
(2Н, d, J = 14.1, 2HС=); 8.76 (2Н, d, J = 7.8, Н Ру); 8.86 (2Н, s, 2HСN); 12.11 (2Н, d, J = 14.1, 2NH). Found,
%: С 63.95; Н 5.65; N 10.38. С35Н37N5O8. Calculated, %: С 64.11; Н 5.69; N 10.68.
X-Ray Crystallographic Analysis. Single crystals of 3a were obtained by slow evaporation from a 3:1
acetonitrile–chloroform solution. The crystal structure was investigated on an Xcalibur 3 diffractometer (ω/2θ
scan, MoKα radiation, graphite monochromator, CCD detector). The structure was solved by direct methods
followed by Fourier syntheses using SHELXS-97 software and were refined by least squares treatment in
anisotropic full-matrix approximation for all the hydrogen atoms using the SHELXL-97 program [11]. The
coordinates of the hydrogen atoms were determined by placing them in the calculated positions and refining
them by the “rider” model.
The full set of crystallographic data has been deposited at the Cambridge structural data bank (deposit
562