2192
Z. Yang et al. / Tetrahedron 72 (2016) 2186e2195
2.23 (s, 6H), 2.32 (s, 3H), 6.43 (s, 1H), 7.14 (d, J¼8.7 Hz, 2H), 7.21 (s,
calcd for C14H12F3N2O [MþH-tBuOH-CO]þ m/z: 281.0896, found
2H), 7.47 (d, J¼8.7 Hz, 2H). 13C NMR (75 MHz, CDCl3)
d
: 154.1, 148.0,
281.0900.
140.4, 134.3, 133.2, 128.9, 125.6, 121.6, 119.6, 103.7, 82.5, 27.9, 20.7,
19.0. IR (KBr)
n
(cmꢀ1): 3356, 2977, 2926, 2218, 1717.
4.4.8. tert-Butyl 2-(2,6-dimethylphenyl)-1-(4-nitrophenyl)hydrazi-
necarboxylate (15a). Orange crystals, 2.57 g, yield 18%, mp
4.4.2. tert-Butyl 2-(4-cyano-2-ethyl-6-methylphenyl)-1-(4-
153e154 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.27 (s, 9H), 2.17 (s, 6H),
6.27 (s, 1H), 6.82 (t, J¼7.4 Hz, 1H), 6.97 (d, J¼7.4 Hz, 2H), 8.07e8.12
(m, 2H), 8.19e8.25 (m, 2H). 13C NMR (75 MHz, CDCl3)
: 153.3,
149.3, 143.3, 142.8, 129.7, 124.8, 124.1, 121.9, 119.7, 83.7, 27.6, 19.0.
ethylphenyl)hydrazinecarboxylate (9b). Colorless crystals, 5.62 g,
yield 37%, mp 164e164.5 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.20 (t,
d
J¼7.5 Hz, 3H), 1.23 (t, J¼7.5 Hz, 3H), 1.33 (s, 9H), 2.24 (s, 3H), 2.59 (q,
J¼7.5 Hz, 2H), 2.64 (q, J¼7.5 Hz, 2H), 6.45 (d, J¼4.1 Hz, 1H), 7.17 (d,
J¼8.6 Hz, 2H), 7.23 (s, 1H), 7.28 (s, 1H), 7.49 (d, J¼8.6 Hz, 2H). 13
C
4.4.9. tert-Butyl
drazinecarboxylate (15b). Orange crystals, 2.38 g, yield 16%, mp
118e119 ꢁC. 1H NMR (300 MHz, CDCl3)
2-(2-ethyl-6-methylphenyl)-1-(4-nitrophenyl)hy-
NMR (75 MHz, CDCl3) d: 154.1, 147.6, 140.5, 140.5, 133.1, 131.5, 130.8,
127.6, 126.0, 121.6, 119.7, 103.8, 82.3, 28.0, 27.8, 24.3, 19.4, 15.3, 13.6,
8.7.
d
: 1.19 (t, J¼7.5 Hz, 3H), 1.26
(s, 9H), 2.15 (s, 3H), 2.56 (q, J¼7.5 Hz, 2H), 6.34 (s,1H), 6.85e7.03 (m,
3H), 8.06e8.12 (m, 2H), 8.20e8.25 (m, 2H). 13C NMR (50 MHz,
4.4.3. tert-Butyl 2-(2,4,6-trimethylphenyl)-1-(4-nitrophenyl)hydra-
CDCl3) d: 153.4, 149.4, 143.0, 142.8, 131.2, 129.8, 127.3, 125.3, 124.1,
zinecarboxylate (9c). Orange crystals, 2.53 g, yield 17%, mp
122.1, 119.8, 83.7, 27.6, 24.7, 19.5, 14.2.
127e129 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.29 (s, 9H), 2.14 (s, 6H),
2.22 (s, 3), 6.20 (s, 1H), 6.77 (s, 2H), 8.03e8.08 (m, 2H), 8.19e8.24
(m, 2H). 13C NMR (50 MHz, CDCl3)
: 153.4, 149.5, 142.9, 140.7, 131.1,
130.3, 124.9, 124.1, 119.9, 83.6, 27.7, 20.3, 18.9. IR (KBr)
(cmꢀ1):
4.4.10. tert-Butyl 2-(2,6-diethylphenyl)-1-(4-nitrophenyl)hydrazine-
d
carboxylate (15c). Orange crystals, 2.00 g, yield 13%, mp
n
164e165 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.15 (t, J¼7.5 Hz, 6H), 1.26
(s, 9H), 2.52 (q, J¼7.5 Hz, 4H), 6.37 (s, 1H), 6.94e7.04 (m, 3H),
8.07e8.12 (m, 2H), 8.21e8.26 (m, 2H). 13C NMR (50 MHz, CDCl3)
3358, 2978, 2928, 2857, 1720, 1591, 1511, 1455, 1308. HRMS (ESI)
calcd for C20H25N3O4 [MþH]þ m/z: 372.1918, found 372.1927.
d:
153.5, 149.4, 143.2, 142.3, 131.9, 127.3, 124.1, 122.6, 120.1, 83.8, 27.7,
24.9, 14.4.
4.4.4. tert-Butyl 2-(2,4,6-trimethylphenyl)-1-(4-trifluoromethylphenyl)
hydrazinecarboxylate (9d). Colorless crystals, 6.15 g, yield 39%, mp
101e102 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.31 (s, 9H), 2.15 (s, 6H),
4.4.11. tert-Butyl 2-(2,6-dimethylphenyl)-1-[4-(trifluoromethyl)phe-
nyl]hydrazinecarboxylate (15d). Colorless crystals, 5.63 g, yield 37%,
2.21 (s, 3H), 6.17 (s, 1H), 6.76 (s, 2H), 7.57 (d, J¼8.6 Hz, 2H), 7.90
(d, J¼8.6 Hz, 2H). 13C NMR (50 MHz, CDCl3)
d
: 153.9, 146.8, 141.0,
mp 105e106 ꢁC. 1H NMR (300 MHz, CDCl3)
d: 1.28 (s, 9H), 2.19 (s,
130.8, 130.4, 130.1, 125.5 (q, J1¼3.7 Hz), 125.3 (q, J2¼32.5 Hz),
125.2, 124.3 (q, J3¼270 Hz), 120.8, 120.1, 82.7, 27.7, 20.2, 18.9. IR
6H), 6.23 (s,1H), 6.80 (t, J¼7.5 Hz,1H), 6.95 (d, J¼7.5 Hz, 2H), 7.59 (d,
J¼8.7 Hz, 2H), 7.95 (d, J¼8.7 Hz, 2H). 13C NMR (50 MHz, CDCl3)
d:
(KBr)
n
(cmꢀ1): 3338, 2980, 1701, 1617, 1522, 1487, 1457, 1322.
153.8, 146.7, 143.6, 129.6, 125.3 (q, J1¼3.8 Hz), 125.2 (q, J2¼32.5 Hz),
125.0, 124.3 (q, J3¼270 Hz), 121.6, 120.4, 82.8, 27.6, 18.9.
HRMS (ESI) calcd for C21H25F3N2O2 [MþH]þ m/z: 395.1941, found
395.1958.
4.4.12. tert-Butyl 2-(2-ethyl-6-methylphenyl)-1-(4-trifluoro-
methylphenyl)hydrazinecarboxylate (15e). Colorless crystals, 7.10 g,
4.4.5. tert-Butyl 2-(4-methoxyphenyl)-1-(4-nitrophenyl)hydrazine-
1-carboxylate (9e). This reaction was performed on 5-mmol scale,
and the product was inseparable from its another isomers, with
a ratio 2:3 and a total yield 0.674 g (38%). For detail, see the 1H and
13C NMR spectra in ESI. Yellow oil, 0.27 g, yield 15%. 1H NMR
yield 45%, mp 121e121.5 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.18 (t,
J¼7.5 Hz, 3H), 1.28 (s, 9H), 2.17 (s, 3H), 2.56 (q, J¼7.5 Hz, 2H), 6.30 (s,
1H), 6.84e7.02 (m, 3H), 7.58e7.61 (m, 2H), 7.93e7.96 (m, 2H). 13
NMR (50 MHz, CDCl3) : 153.9,146.6,143.0,131.4,129.7,127.2,125.5,
C
d
(400 MHz, CDCl3)
J¼8.9, 2H), 6.72 (d, J¼8.9, 2H), 6.30 (s, 1H), 3.79 (s, 3H), 1.41 (s, 9H).
13C NMR (100 MHz, CDCl3)
: 154.9, 153.1, 151.9, 148.6, 143.3, 125.9,
124.4, 114.7, 114.5, 83.7, 55.6, 27.9. IR (KBr)
(cmꢀ1): 3359, 2978,
d
: 7.92 (d, J¼9.4, 2H), 7.70 (d, J¼9.3, 2H), 6.84 (d,
125.5 (q, J2¼32.5 Hz), 125.4 (q, J3¼3.7 Hz), 124.3 (q, J1¼270 Hz),
122.0, 120.7, 83.0, 27.7, 24.7, 19.5, 14.3.
d
n
4.4.13. tert-Butyl 2-(2,6-diethylphenyl)-1-[4-(trifluoromethyl)phe-
nyl]hydrazinecarboxylate (15f). Colorless crystals, 4.41 g, yield 27%,
2932, 1721, 1590, 1514, 1476, 1308. HRMS (ESI) calcd for C18H22N3O5
[MþH]þ m/z: 360.1554, found 360.1543.
mp 83e84 ꢁC. 1H NMR (300 MHz, CDCl3)
d
: 1.15 (t, J¼7.5 Hz, 6H),
1.27 (s, 9H), 2.54 (q, J¼7.5 Hz, 4H), 6.34 (s, 1H), 6.90e7.03 (m, 3H),
7.58e7.61 (m, 2H), 7.92e7.95 (m, 2H). 13C NMR (50 MHz, CDCl3)
4.4.6. tert-Butyl 1-(4-cyanophenyl)-2-(4-methoxyphenyl)hydrazine-
1-carboxylate (9f). This reaction was performed on 5-mmol scale.
Yellowish crystals, mp 127e129 ꢁC, 0.48 g, yield 28%. 1H NMR
d:
154.1, 146.7, 142.5, 132.1, 127.3, 125.7 (q, J2¼32.3 Hz), 125.4 (q,
J3¼3.7 Hz), 124.3 (q, J1¼270 Hz), 122.4, 120.9, 83.0, 27.8, 24.9, 14.5.
(400 MHz, CDCl3)
6.81 (d, J¼8.9 Hz, 2H), 6.68 (d, J¼8.9 Hz, 2H), 6.23 (s, 1H), 3.76 (s,
3H), 1.37 (s, 9H). 13C NMR (100 MHz, CDCl3)
: 154.8, 153.2, 146.8,
141.0,132.7,120.4,119.0,114.7,114.5,106.7, 83.4, 55.6, 27.9. IR (KBr)
d
: 7.84 (d, J¼8.9 Hz, 2H), 7.59 (d, J¼8.9 Hz, 2H),
4.5. General procedure for the acid-catalyzed rearrangements
d
of N,N0-diarylhydrazines 9 and 15
n
(cmꢀ1): 3356, 2977, 2926, 2218, 1717. HRMS (ESI) calcd for
To a round bottom flask were charged with an N,N0-diaryl hy-
drazine (9 or 15, 1 mmol), 95% ethanol (10 mL), and conc. HCl
(0.5 mL) under nitrogen at room temperature. The reaction mixture
was refluxed for 2 h, then cooled to room temperature, neutralized
with solid NaHCO3, filtered, concentrated. The residue was purified
by flash column chromatography.
C
19H22N3O3 [MþH]þ m/z: 340.1656, found 340.1652.
4.4.7. tert-Butyl 2-(4-methoxyphenyl)-1-(4-(trifluoromethyl)phenyl)
hydrazine-1-carboxylate (9g). This reaction was performed on 5-
mmol scale. Yellowish crystals, mp 79e81 ꢁC, 0.42 g, yield 22%.
1H NMR (400 MHz, CDCl3)
d
7.83 (d, J¼8.6 Hz, 2H), 7.59 (d,
J¼8.6 Hz, 2H), 6.84 (d, J¼8.9 Hz, 2H), 6.74 (d, J¼8.9 Hz, 2H), 6.30 (s,
1H), 3.79 (s, 3H), 1.41 (s, 9H). 13C NMR (50 MHz, CDCl3)
: 154.7,
The analytical data of compounds 10a,b, 13, 16, 17, and 18 are
identical with those reported in our group.8
d
153.5, 145.9, 141.4, 125.7 (q, JCeF¼31 Hz), 125.6 (q, JCeF¼3.8 Hz),
4.5.1. 4-[(2-Amino-5-methylphenyl)amino]-3,5-dimethylbenzonitrile
124.6 (q, JCeF¼270 Hz), 120.6, 114.7, 114.5, 83.0, 55.6, 28.0. 19F NMR
(10a). Pink crystals, 88 mg, yield 35%, mp 133e134 ꢁC, 1H NMR
(375 MHz, CDCl3)
d
ꢀ62.0. IR (KBr)
n
(cmꢀ1): 1715. HRMS (ESI)
(300 MHz, CDCl3) d: 2.13 (s, 9H), 3.65 (s, 2H), 5.02 (s, 1H), 6.17 (s,