It has therefore been shown that malonic acid dihydrazide, its N'-isopropylidene and N'-acetyl
derivatives, and also ethoxycarbonylacethydrazide react with 3-acyl(3-ethoxycarbonyl or 3-cyano)coumarins in
a similar manner to cyanoacetylhydrazine. It was discovered that these reactions proceed under milder conditions
than the reaction with analogous derivatives of acetamide. It has been established that the product of the
interaction of coumarin with cyanoacetamide exists in the form of a derivative of benzopyrano[3,4-c]-pyridine.
EXPERIMENTAL
The mass spectra were recorded on a Finnigan SSQ 710 chromato-mass spectrometer with direct
insertion of samples into the ion source. The energy of the ionizing electrons was 70 eV, and ion source
temperature was 150°C. The IR spectra were recorded on a Perkin-Elmer 457 instrument in nujol. The 1H NMR
spectrum of compound 10 was recorded on a Varian Unity 400 spectrometer (400 MHz), internal standard was
TMS.
Reaction mixtures, the compositions of which were studied by mass spectrometry, were obtained by the
interaction of malonic acid hydrazide derivatives with 3-substituted coumarins under the conditions indicated
previously in [3] after evaporation of the ethanol used as solvent.
Isopropylidene Derivative of 6-Methoxycoumarin-3-carboxylic Acid Hydrazide (5a). Piperidine
(1 drop) was added to a suspension of 3-cyano-6-methoxycoumarin (0.17 g, 7.5 mmol) and malonic acid
dihydrazide (0.1 g, 7.5 mmol) in ethanol (10 ml) and the mixture boiled with stirring for 10 min. After cooling to
room temperature the precipitated solid was filtered off, washed on the filter with cold ethanol (2 × 5 ml), and a
light yellow substance (0.1 g) was obtained with mp >300°C (shrivels and darkens at 150°C). The substance
obtained was boiled in acetone (15 ml) for 1 h, the solvent was evaporated, and the residue recrystallized from
ethanol. A finely crystalline substance (0.05 g, 42%), light yellow with a greenish tinge, was obtained;
mp 230-232°C. IR spectrum, ν, cm-1: 1690 (C=O), 1650 (C=N). Found, %: C 60.93; H 4.81; N 10.35. M+ 274.
C14H14N2O4. Calculated, %: C 61.31; H 5.11; N 10.22. M 274.
Isopropylidene Derivative of 7-Methoxycoumarin-3-carboxylic Acid Hydrazide (5b). Under
conditions analogous to those described above a light yellow substance (0.25 g) of mp >300° C was obtained
from 7-methoxycoumarin-3-carboxylic acid (0.2 g, 8 mmol) and malonic acid dihydrazide (0.1 g, 7.5 mmol) on
boiling the reaction mixture for 1 h. The substance was boiled in acetone (20 ml) for 1 h, the solvent evaporated,
and the residue recrystallized from ethanol. A light yellow finely crystalline substance (0.15 g, 51%) of
mp 239-241°C was obtained. IR spectrum, ν, cm-1: 1685 (C=O), 1660 (C=N). Found, %: C 61.12; H 4.85;
N 9.95. M+· 274. C14H14N2O4. Calculated, %: C C 61.31; H 5.11; N 10.22. M 274.
Isopropylidene Derivative of Coumarin-3-carboxylic Acid Hydrazide (5c). Piperidine (1 drop) was
added to a mixture of 3-ethoxycarbonylcoumarin (2 g, 9.2 mmol) and N, N'-diisopropylidene malonic acid
dihydrazide (0.19 g, 9.2 mmol) in ethanol (15 ml) and the reaction mixture was stirred for 1 h at room
temperature. The resulting solid was filtered off, recrystallized from ethanol, and a white crystalline substance
(0.14 g, 62.5%) was obtained; mp 200-201°C. IR spectrum, ν, cm-1: 2725 (NH), 1708 (CO), 1608 (C=N). Found,
%: C 63.72; H 4.68; N 11.27. M+· 244. C13H12N2O3. Calculated, %: C 63.93; H 4.92; N 11.47. M 244.
The yield of compound 5 obtained under analogous conditions from 3-acetylcoumarin was 77%, from
3-cyanocoumarin 53%, and from 3-benzoylcoumarin 77%. All the samples obtained gave no depression of
melting point when mixed with a sample obtained previously.
N'-Acetyl Derivative of Coumarin-3-carboxylic Acid Hydrazide (6). Piperidine (1 drop) was added to
a mixture of 3-ethoxycarbonylcoumarin (0.2 g, 9.2 mmol) and the N,N'-diacetyl derivative of malonic acid
dihydrazide (0.19 g, 9.2 mmol) in ethanol (15 ml) and the reaction mixture was stirred at room temperature for
2 h. The resulting solid was filtered off, recrystallized from ethanol, and a white finely crystalline substance was
1265