Molecules 2020, 25, 4271
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ion [C14H19N5O6 + Na]+ as expected from its calculated m/z = 376.12330. IR (KBr; cm−1): 3300 (N-H),
3050 (C-H arom), 2940 (C-H aliph), 1650 (C=O), 1600 (C=C), 1450 (C=N), 1100 (C-O).
1H-NMR (400MHz, DMSO-d6):
δ ppm = 3.71 (s, 6H), 3.80 (s, 3H), 4.29 (bs, 4H, NH2), 4.50 (d, 1H,
J = 6.8 Hz), 5.05 (d, 1H, J = 6.8 Hz), 6.23 (s, 2H), 9.14 (bs, 1H, NH), 9.50 (bs, 1H, NH). 13C-NMR (100 MHz,
DMSO-d6): δ ppm = 55.4, 55.9, 58.7, 81.3, 90.9, 97.7, 150.5, 159.4, 162.2, 165.8, 166.9.
3.6. Preparation of
trans-3-(2,4,6-Trimethoxyphenyl)4,5-dihydroisoxazolo-4,5-bis[carbonyl-(40phenyl)thiosemicarbazide] 9
Phenyl isothiocyanate (0.82 g, 6 mmol) was added to a solution of hydrazinocarbonyl (3.1 g,
5 mmol) in absolute ethanol (30 mL). The reaction mixture was stirred at room temperature for
approximately 20 h. The mixture was poured into cold water. The resulting precipitate was filtered
and recrystallized from ethanol, affording 2.5 g (80%) of product
3028-3363 (N-H), 1703 (C=O), 1200-1256 (C=S).
9
; mp: 192–194 ◦C, IR (KBr; cm−1):
1H-NMR (400 MHz, DMSO-d6):
J = 7.8 Hz), 6.20 (s, 2H), 7.15-7.44 (m, 10H), 9.75 (bs, 4H, NH), 10.34 (bs, 1H, NH), 10.52 (bs, 1H, NH).
13C NMR (100MHz, DMSO-d6):
ppm = 55.3, 56.0, 58.1, 81.6, 91.0, 97.3, 124.1, 125.2, 125.8, 128.0, 128.2,
δ ppm = 3.72 (s, 6H), 3.74 (s, 2H), 4.85 (d, 1H, J = 7.8 Hz), 5.40 (d, 1H,
δ
138.6, 138.8, 139.0, 150.5, 159.4, 162.4, 180.3.
3.7. Preparation of trans-3-(2,4,6-Trimethoxyphenyl)-4,5-dihydroisoxazolo-4,5-bis(aroylcarbohydrazide) 10a–c
To a solution of acid dihydrazide (1.12 g, 2 mmol) and potassium carbonate (4 mmol) in aq.
tetrahydrofuran (160 mL 1:3), a solution of benzoyl chloride (4 mmol) in tetrahydrofuran (20 mL)
was added dropwise with stirring at 25 ◦C. The reaction mixture was stirred for 3–6 h, during which
time a precipitate was formed. The precipitate was collected by filtration and washed with water,
then recrystallized from dimethylsulfoxide (DMSO)/water (1:1).
For
compound
10a
,
trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydroisoxazolo-4,5-
bis(phenylcarbohydrazide):
Yield: 1.48g (83%); mp: 202–204 ◦C, the HRMS displayed a molecular ion peak at m/z 560.17869
corresponding to the ion [C28 H27N5O8-H]-, as expected from its calculated m/z = 560.17814.
IR (KBr; cm−1): 3145 (N-H), 3026 (C-H aromatic), 1675 (C=O), 1471 (C=N).
1H-NMR (400 MHz, DMSO-d6):
J = 7.8 Hz), 6.32 (s, 2H), 6.93-7.97 (m, 10H), 10.27 (bs, 1H, NH),10.44 (bs, 1H, NH), 10.59 (bs, 2H, NH).
13C-NMR (100 MHz, DMSO-d6):
ppm = 55.4, 55.9, 58.2, 81.4, 91.0, 97.5, 124.9, 127.4, 127.5, 128.3, 128.5,
131.7, 131.9, 132.3, 132.4, 139.2, 150.2, 159.6, 162.3, 165.0, 165.2, 166.3, 167.4.
δ ppm = 3.41 (s, 6H), 3.83 (s, 3H), 5.02 (d, 1H, J = 7.8 Hz), 5.31 (d, 1H,
δ
For compound 10b trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydroisoxazolo-4,5-
bis(aroylcarbohydrazide):
Yield: 0.86g (73%); mp: 225–227 ◦C. IR (KBr; cm−1): 3145 (N-H), 3026 (C-H aromatic), 1675 (C=O),
1471 (C=N).
1H-NMR (400 MHz, DMSO-d6):
5.24 (d, 1H, J = 7.8 Hz), 6.27 (s, 2H), 7.11-7.50 (m, 8H), 10.22 (bs, 1H, NH), 10.37 (bs, 1H, NH),
10.53 (bs, 2H, NH). 13C-NMR (100 MHz, DMSO-d6):
ppm = 55.2, 55.3, 55.4, 55.9, 58.2, 81.5, 91.0, 97.5,
,
δ
ppm = 3.76 (s, 6H), 3.79 (s, 3H), 3.83 (s, 6H), 4.97 (d, 1H, J = 7.8 Hz),
δ
112.4, 112.4, 117.8, 119.7, 119.7, 129.5, 129.7, 133.7, 133.7, 150.2, 159.0, 159.2, 159.6, 162.3, 164.7, 163.9,
166.4, 167.3.
For
compound
10c,
trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydroisoxazolo-4,5-
bis(aroylcarbohydrazide):
Yield: 0.63g (52%) of product; mp: 255–257 ◦C, IR (KBr; cm−1): 3145 (N-H), 3026 (C-H aromatic),
1608 (C=O), 1471 (C=N), 1535 (NO2).