J. Poisson et al. / Journal of Molecular Structure 1116 (2016) 30e36
35
Table 5
Formal description of bonding in Ar2NNR2.
Type
N Hybridization states
Geometry
Relative bond strength
Contributing bonding interactions
1
sp3-sp3
Weak
s
s
s
s
only
only
and
2a
2b
3
sp2-sp2 (available lone pairs)
sp2-sp2 (delocalized lone pairs)
sp2-sp2 (no available lone pairs)
orthogonal
coplanar
Strong
Strong
Strong
p
only
bicarbonate (5% w/w) and then extracted (3 ꢂ 20 mL) with ether.
7.74 (dd, 1H); 13C-NMR (300 MHz, CDCl3)
d (ppm): 21.1, 24.6, 122.3,
The organic washings were dried (MgSO4) and left to crystallize at
122.6, 122.8, 124.3, 125.5, 129.5, 132.5, 142.5, 143.8, 146.1, 173.1; IR
(KBr, cmꢀ1): 419 (vw), 428 (vw), 437 (vw), 466 (vw), 497 (vw), 520
(w), 533 (w), 614 (vw), 640 (vw), 678 (vw), 705 (s), 713 (w), 741 (s),
751 (w), 770 (m), 776 (m), 841 (m), 850 (m), 906 (vw), 923 (vw),
942 (vw), 993 (vw),1004 (vw),1026 (vw),1050 (vw),1072 (w), 1093
(sh), 1156 (w), 1173 (w), 1205 (w), 1255 (m), 1272 (m), 1292 (m),
1309 (sh), 1324 (vw), 1363 (s), 1426 (vw), 1447 (w), 1486 (s), 1524
(vs), 1573 (w), 1591 (m), 1602 (m), 1630 (vw), 1644 (vw), 1955 (vw),
1972 (vw), 2915 (vw), 2951 (vw), 2991 (vw), 3034 (vw), 3064 (vw);
UVeVis (CHCl3): lmax ¼ 410 nm, ε ¼ 3681ꢀ1 cmꢀ1; HRMS calcd for
0
ꢁC, giving the dark red crystalline product (0.2506 g, 70% yield);
m.p. (DSC) onset 141.56 ꢁC (lit. 140.9 ꢁC), peak max 143.30 ꢁC (lit.
[13] 141.7 ꢁC); 1H-NMR (300 MHz, DMSO-d6)
d
(ppm) mixture of E-
and Z-isomers, Z-isomer: 1.89 (3H, s), 6.76 (d, 2H, J ¼ 7.80 Hz), 6.90
(1H, t, J ¼ 7.50 Hz), 7.21 (t, 2H, J ¼ 7.80 Hz), 7.35 (1H, t, J ¼ 8.10 Hz),
7.53 (d, 1H, J ¼ 8.10 Hz), 7.67 (t, 1H, J ¼ 8.40 Hz), 7.85 (d, 1H,
J ¼ 8.10 Hz), 10.49 (s, 1H); E-isomer: 1.94 (3H, s), 6.81 (d, 2H,
J ¼ 7.80 Hz), 7.02 (1H, t, J ¼ 7.50 Hz), 7.27 (t, 2H, J ¼ 7.80 Hz), 7.40
(1H, t, J ¼ 8.10 Hz), 7.57 (d, 1H, J ¼ 8.10 Hz), 7.78 (t, 1H, J ¼ 8.40 Hz),
7.92 (d, 1H, J ¼ 8.10 Hz), 10.09 (s, 1H); 13C-NMR (300 MHz, DMSO-
C
C
15H15N3O2Na: 292.1056, Found: 292.1052; Anal. Calcd for
15H15N3O2: C, 66.90%; H, 5.61%; N, 15.60%; Found: C, 66.62%; H,
d6)
d (ppm), only Z-isomer detectable: 20.7, 116.0, 121.9, 125.6,
125.9, 126.9, 129.4, 134.5, 138.6, 146.1, 157.8, 169.5; UVeVis (CHCl3):
lmax ¼ 418 nm, ε ¼ 1541 Мꢀ1 cmꢀ1; HRMS calcd for C14H12N3O3:
270.0884, Found: 270.0873; Anal. Calcd for C14H13N3O3: C, 61.99%;
H, 4.83%; N, 15.49%; Found: C, 61.91%; H, 4.78%; N, 15.59%.
5.48%; N, 15.63%.
4.1.4. (Z)-2-((2-(2-nitrophenyl)-2-phenylhydrazono)methyl)phenol
(4)
To a 250 mL round-bottomed flask under N2 (g) was added a
solution of 1-(2-nitrophenyl)-1-phenylhydrazine (0.1700 g,
0.44 mmol) in dry dichloromethane (20 mL) along with 2 drops
each of salicylaldehyde and hydrochloric acid. The red reaction
mixture was stirred for 12 h at room temperature, during which,
the solution adopted a lighter orange color. The product was ob-
tained as a crude solid by simple evaporation of the solvent under
reduced pressure and recrystallized from dichloromethane:ethanol
(1:2) to give red crystals in 0.2004 g (0.60 mmol, 81%) yield. m.p.
(DSC) onset 125.53 ꢁC, peak max 127.06 ꢁC; 1H-NMR (300 MHz,
4.1.2. N-acetyl-N'-(2-nitrophenyl)-N'-phenylacetohydrazide (2)
1-(2-nitrophenyl)-1-phenylhydrazine (150 mg, 0.65 mmol) was
dissolved in chloroform (50 mL) along with 5 mL of acetic anhy-
dride. The reactants were heated at 60 ꢁC for 2 days, at which point
TLC (dichloromethane) indicated consumption of the starting ma-
terial. The solution was reduced in vacuo and the residue was dis-
solved in ethanol (15 mL). After cooling for 24 h at ꢀ10 ꢁC, which
crystals of 2 began to form. Yield 0.173 g (0.55 mmol, 84% yield). A
sample was recrystallized from dichloromethane to yield red
prisms. m.p. (DSC) onset 172.05 ꢁC, peak max 173.75 ꢁC; 1H-NMR
CDCl3)
d
(ppm): 6.83 (t, 1H, J ¼ 8 Hz), 6.96 (t, 2H, J ¼ 8 Hz), 7.03 (d,
(300 MHz, CDCl3)
d
(ppm): 2.52 (6H, s), 6.97 (d, 2H, J ¼ 8.40 Hz),
2H, J ¼ 8 Hz), 7.11 (t, 1H, J ¼ 7 Hz), 7.22 (t, 1H, J ¼ 8 Hz), 7.35 (t, 2H,
J ¼ 8 Hz), 7.39 (s, 1H), 7.40 (d. 1H, 8 Hz) 7.56 (t, 1H, J ¼ 8 Hz), 7.76 (t,
1H, J ¼ 10 Hz), 8.04 (d, 1H, J ¼ 8 Hz), 10.90 (s, 1H); 13C-NMR
7.09 (1H, t, J ¼ 7.50 Hz), 7.12 (d, 1H, J ¼ 4.50 Hz), 7.19 (1H, t,
H ¼ 7.50 Hz), 7.27 (m, 2H), 7.54 (t, 1H, J ¼ 7.50 Hz), 7.77 (d, 1H,
J ¼ 8.10 Hz); 13C-NMR (300 MHz, CDCl3)
d
(ppm): 25.6, 118.6, 121.0,
(300 MHz, CDCl3) d (ppm): 116.8, 118.4, 118.8, 119.4, 123.9, 126.1,
123.7, 125.1, 125.9, 129.5, 129.6, 134.0, 136.9, 144.0, 172.8; IR (KBr,
cmꢀ1): 477 (vw), 525 (w), 587 (w), 596 (vw), 631 (m), 665 (vw), 701
(m), 744 (m), 758 (m), 776 (m), 828 (w) 857 (w), 903 (vw), 919 (vw),
938 (vw), 950 (vw), 991 (m), 1028 (vw), 1042 (vw), 1137 (sh), 1165
(w), 1203 (vs), 1234(s), 1261 (w), 1287 (w), 1301 (w), 1321 (vw),
1365 (s), 1415 (w), 1456 (w), 1482 (s), 1491 (s), 1530 (vs), 1597 (m),
1718 (vs), 1734 (vs), 3044 (vw); UVeVis (CHCl3): lmax ¼ 445 nm,
128.6, 129.7, 130.2, 130.4, 130.5, 134.5, 134.7, 142.3, 143.7, 147.2,
157.1; IR (KBr, cmꢀ1): 472 (w), 553 (w), 588 (w), 624 (vw), 657 (w),
667 (w), 688 (s), 712 (w), 746 (vs), 759 (s), 776 (w), 795 (w), 810
(vw), 848 (m), 1033 (w), 1071 (w), 1098 (vw), 1153 (w), 1220 (s),
1271 (s), 1296 (m), 1363 (s), 1387 (vw), 1413 (vw), 1496 (vs), 1527
(vs), 1594 (vs), 1620 (w), 2875 (vw), 3042 (vw); UVeVis (CHCl3):
lmax
¼
338 nm,
ε
¼
20471 Mꢀ1 cmꢀ1
;
lmax
¼
241 nm,
ε ¼ 1095 Мꢀ1 cmꢀ1
,
lmax ¼ 377 nm, ε ¼ 2952 Mꢀ1 cmꢀ1
ε ¼ 170,000 Mꢀ1 cmꢀ1 HRMS calcd for C19H15N3O3Na: 356.1002,
Found: 356.1006; Anal. Calcd for C19H15N3O3: C, 68.46%; H, 4.54%;
N, 12.61%; Found: C, 68.26%; H, 4.31%; N, 12.43%.
lmax
¼
259 nm,
ε
¼
17130 Mꢀ1 cmꢀ1
; HRMS calcd for
C
C
16H15N3O4Na: 336.0955, Found: 336.0944; Anal. Calcd for
16H15N3O4: C, 61.34; H, 4.83; N, 13.41; Found: C, 61.69; H, 4.80; N,
13.48.
4.1.5. (E)-2-Benzylidene-1-(2-nitrophenyl)-1-phenylhydrazine (5)
1-(2-nitrophenyl)-1-phenylhydrazine (145 mg, 0.63 mmol) was
dissolved in dichloromethane (50 mL) along with benzaldehyde
4.1.3. 1-(2-nitrophenyl)-1-phenyl-2-(propan-2-ylidene)hydrazine
(3)
(120 mL, 1.17 mmol) was added along with anhydrous magnesium
1-(2-nitrophenyl)-1-phenylhydrazine (0.0853 g, 0.373 mmol)
was dissolved in dry dichloromethane (50 mL). HPLC-grade acetone
(10 mL) was added, along with a catalytic amount of concentrated
sulfuric acid. The reaction was stirred for 15 h at room temperature.
Evaporation of the solvents and acid under high vacuum yielded
the crude product, which was recrystallized by slow evaporation
from dichloromethane to give 0.055 g of an orange crystalline
product (0.20 mmol, 54%); m.p. 81.2e82.0 ꢁC; 1H-NMR (300 MHz,
sulfate (0.23 g, 1.91 mmol). The yellow solution was stirred for
12 h at room temperature. The solvent was removed under reduced
pressure and the residue loaded onto a silica gel column with
dichloromethane as eluent. The first yellow band was collected and
the solvent evaporated to yield the pure product directly as a yellow
solid in 0.115 g (0.36 mmol, 57% yield). A sample was recrystallized
from dichloromethane to yield yellow prisms. m.p. (DSC) onset
109.22 ꢁC (lit. 102.6 ꢁC), peak max 109.64 ꢁC (lit. [13] 104.8 ꢁC); 1H-
CDCl3)
d
(ppm): 1.80 (s, 3H), 2.10 (s, 3H), 7.09 (m, 5H) 7.31 (tt, 3H),
NMR (500 MHz, CDCl3)
d
(ppm): 7.11 (1H, d, J ¼ 8.50 Hz), 7.17 (t, 4H,