Desulfurizing reagent for thioamides
Russ. Chem. Bull., Int. Ed., Vol. 70, No. 2, February, 2021
385
1H NMR, δ: 3.90 (s, 4 H, 2 CH2); 4.30 (s, 4 H, 2 CH2); 8.20
(s, 2 H, Ar); 8.40 (s, 2 H, Ar); 8.65 (s, 1 H, Ar). MS, m/z: 219 [M]+.
2-Oxo-N,2-diphenylacetamide (11b). White crystals, the yield
was 69%, m.p. 62—63 °C (cf. Ref. 15: m.p. 62—63 °C). 1H NMR,
δ: 7.35 (s, 2 H, Ar); 7.60 (s, 2 H, Ar); 7.75 (s, 1 H, Ar); 7.90
(s, 1 H, Ar); 8.30 (s, 2 H, Ar); 8.45 (s, 2 H, Ar); 10.45 (s, 1 H, NH).
MS, m/z: 225 [M]+.
S-Methyl 2-oxo-2-(phenylamino)ethanethioate (14a). White
crystals, the yield was 74%, m.p. 241—243 °C. 1H NMR, δ: 2.35
(s, 3 H, Me); 7.60 (s, 1 H, Ar); 7.85 (s, 2 H, Ar); 8.00 (s, 1 H,
Ar); 8.15 (s, 1 H, Ar); 10.70 (s, 1 H, NH). MS, m/z: 195 [M]+.
Found (%): С, 55.44; H, 4.80; N, 7.10. С9H9NO2S. Calculat-
ed (%): С, 55.37; H, 4.65; N, 7.17.
S-Methyl 2-[(4-chlorophenyl)amino]-2-oxoethanethioate
(14b). White crystals, the yield was 67%, m.p. 168—170 °C.
1H NMR, δ: 2.30 (s, 3 H, Me); 7.65 (s, 1 H, Ar); 7.80 (s, 2 H,
Ar); 8.15 (s, 1 H, Ar); 10.60 (s, 1 H, NH). MS, m/z: 230 [M]+.
Found (%): С, 47.15; H, 3.42; Сl, 15.58; N, 6.15; S, 13.79.
С9H8ClNO2S. Calculated (%): С, 47.06; H, 3.51; Cl, 15.44;
N, 6.10; S, 13.96.
S-Methyl 2-[(4-bromophenyl)amino]-2-oxoethanethioate
(14с). White crystals, the yield was 70%, m.p. 184—186 °C.
1H NMR, δ: 2.33 (s, 3 H, Me); 7.70 (s, 1 H, Ar); 7.80 (s, 2 H,
Ar); 8.20 (s, 1 H, Ar); 10.85 (s, 1 H, NH). MS, m/z: 274 [M]+.
Found (%): С, 39.36; H, 2.98; Br, 29.02; N, 5.03; S, 11.84.
С9H8BrNO2S. Calculated (%): С, 39.43; H, 2.94; Br, 29.15;
N, 5.11; S, 11.70.
Experimental
1H NMR spectra were recorded on a Bruker AC-300 spectro-
meter in DMSO-d6. Mass spectra were recorded on a Varian
MAT CH-6 instrument (70 eV) with direct sample injection into
the radiation source, control voltage 1.75 kV. Melting points were
measured on a Boetius heating stage and were not corrected.
TLC on Merck Silica gel 60 F254 plates was used to analyze all
reaction mixtures and control the purity of the isolated products.
Synthesis of oxoacetamides (general procedure). Thioamide
(0.1 mmol) was dissolved in a minimal amount of an ionic
liquid (1-butyl-3-methylimidazolium hexafluorophosphate),
followed by the addition of thionyl chloride (0.15 mmol). After
2—4 min, the mixture was extracted with benzene or diethyl
ether (3×5 mL), the organic layer was washed with water, the
solvent was evaporated in vacuo. The product was purified
on a chromatographic plate (eluent petroleum ether—ethyl
acetate, 3 : 1).
2-Morpholin-4-yl-N-(2-nitrophenyl)-2-oxoacetamide (2a).
White crystals, the yield was 70%, m.p. 147—149 °C. 1H NMR,
δ: 3.60 (d, 2 H, СH2, J = 4.6 Hz); 3.80 (d, 4 H, 2 СH2, J = 4.4 Hz);
3.90 (s, 2 H, CH2); 7.45 (s, 1 H, Ar); 7.85 (s, 2 H, Ar); 8.05
(s, 1 H, Ar); 11.25 (s, 1 H, NH). MS, m/z: 279 [M]+. Found (%):
С, 51.74; H, 4.52; N, 15.21. С12H13N3O5. Calculated (%): С, 51.61;
H, 4.69; N, 15.05.
N-(4-Chlorophenyl-2-nitro)-N´-phenylethanediamide (2b).
White crystals, the yield was 73%, m.p. 163—165 °C. 1H NMR,
δ: 7.40 (s, 1 H, Ar); 7.60 (s, 3 H, Ar); 7.90 (s, 2 H, Ar); 8.20
(s, 1 H, Ar); 8.35 (s, 1 H, Ar); 10.90 (s, 1 H, NH); 11.60 (s, 1 H,
NH). MS, m/z: 319 [M]+. Found (%): С, 52.74; H, 3.10;
N, 13.27. С14H10ClN3O4. Calculated (%): С, 52.60; H, 3.15;
N, 13.14.
The authors express their gratitude to the program for
the development of scientific schools of the N. D. Zelinsky
Institute of Organic Chemistry of the Russian Academy
of Sciences.
N-(2-Nitrophenyl)-N´-phenylethanediamide (2c). White crys-
tals, the yield was 74%, m.p. 287—289 °C. 1H NMR, δ: 7.20
(s, 1 H, Ar); 7.45 (s, 3 H, Ar); 7.85 (s, 3 H, Ar); 8.15 (s, 1 H, Ar);
8.20 (s, 1 H, Ar); 10.80 (s, 1 H, NH); 11.75 (s, 1 H, NH). MS,
m/z: 285 [M]+. Found (%): С, 58.81; H, 3.94; N, 14.62.
С14H11N3O4. Calculated (%): С, 58.95; H, 3.89; N, 14.73.
2-Morpholin-4-yl-N-(5-nitropyridin-3-yl)-2-oxoacetamide
(2d). White crystals, the yield was 70%, m.p. 188—190 °C.
1H NMR, δ: 3.80 (s, 6 H, 3 СH2); 4.20 (s, 2 H, СH2); 8.00 (s, 1 H,
HPy); 8.35 (s, 1 H, HPy); 8.55 (s, 1 H, HPy); 11.80 (s, 1 H, NH).
MS, m/z: 280 [M]+. Found (%): С, 47.03; H, 4.37; N, 19.82.
С11H12N4O5. Calculated (%): С, 47.15; H, 4.32; N, 19.99.
2-Morpholinocarbonyl-1H-benzimidazole (5a). White crys-
tals, the yield was 68%, m.p. 181—183 °C (cf. Ref. 11: m.p.
181—182 °C). 1H NMR, δ: 3.90 (s, 2 H, CH2); 4.10 (s, 2 H,
CH2); 4.25 (s, 4 H, 2 CH2); 7.40 (s, 2 H, Ar); 7.80 (s, 2 H, Ar);
10.90 (s, 1 H, NH). MS, m/z: 231 [M]+.
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N-Phenyl-1H-benzimidazole-2-carboxamide (5b). White
crystals, the yield was 57%, m.p. 234—235 °C (cf. Ref. 12: m.p.
1
235—236 °C). H NMR, δ: 7.35 (s, 2 H, Ar); 7.45 (s, 1 H, Ar);
7.60 (s, 1 H, Ar); 7.80 (s, 2 H, Ar); 8.20 (s, 2 H, Ar, NH); 8.50
(s, 2 H, Ar); 10.35 (s, 1 H, NH). MS, m/z: 237 [M]+.
4-(Phenylacetyl)morpholine (8). White crystals, the yield was
75%, m.p. 73—74 °C (cf. Ref. 13: m.p. 73—76 °C). 1H NMR,
δ: 2.30 (s, 2 H, СH2); 3.90 (s, 2 H, CH2); 4.10 (s, 2 H, CH2);
4.30 (s, 4 H, 2 CH2); 7.40 (s, 2 H, Ar); 7.80 (s, 2 H, Ar); 7.90
(s, 1 H, Ar).
Received May 7, 2020;
in revised form August 19, 2020;
accepted October 1, 2020
1-Morpholino-2-phenylethane-1,2-dione (11a). White crys-
tals, the yield was 65%, m.p. 59—60 °C (cf. Ref. 14: m.p. 58—60 °C).