Transformation of Cyclic Ketones
Chin. J. Chem.
(125 MHz, DMSO-d6) δ: 18.6 (2C), 23.0, 25.9, 28.2, 28.8, 32.5, 35.8, 336.2298; found: 336.2297.
55.4, 111.5, 114.0, 122.4, 124.2, 126.7, 127.8, 128.0 (2C), 135.6
(2C), 135.8, 136.1, 138.5, 158.4, 171.2; HRMS calcd for
[C24H29NNaO2]+ (M+Na+): 386.2091; found: 386.2096.
5-(3,4-Dihydronaphthalen-2-yl)-N-(2,6-dimethylphenyl)pen-
tanamide (15). Flash chromatography on silica gel (eluent:
EtOAc/n-Hexane = 1 : 2) gave compound 15 as a colorless oil (1.04
g, yield: 73%); IR (film) vmax: 3438, 2916, 2848, 1959, 1681, 1573,
1196, 1180, 1132, 1076 cm–1; 1H NMR (500 MHz, CDCl3) δ:
1.46—1.54 (m, 2H), 1.61—1.68 (m, 2H), 2.08 (s, 6H), 2.11—2.20
(m, 4H), 2.25 (t, J = 7.4 Hz, 2H), 2.76 (t, J = 8.1 Hz, 2H), 6.16 (s, 1H),
6.90—6.96 (m, 3H), 6.96—7.00 (m, 1H), 7.03—7.07 (m, 2H),
7.08—7.12 (m, 1H), 7.42 (s, 1H); 13C NMR (125 MHz, CDCl3) δ:
18.2 (2C), 25.5, 27.0, 27.1, 28.0, 35.9, 37.0, 122.1, 125.2, 125.9,
126.2, 126.8, 127.0, 127.8 (2C), 134.0, 134.2, 134.7, 135.2 (2C),
141.6, 171.7; HRMS calcd for [C23H27NNaO]+ (M+Na+): 356.1985;
found: 356.1976.
N-(2,6-Dimethylphenyl)-5-(7-methoxy-3,4-dihydronaphtha-
len-1-yl)pentanamide (10). Flash chromatography on silica gel
(eluent: EtOAc/n-Hexane = 1 : 2) gave compound 10 as a colorless
oil (1.20 g, yield: 78%); IR (film) vmax: 3435, 2917, 2848, 1958,
1659, 1650, 1537, 1469, 1383, 1195, 1132, 1076, 611 cm–1; 1H
NMR (500 MHz, DMSO-d6) δ: 1.51—160 (m, 2H), 1.66—1.73 (m,
2H), 2.10 (s, 6H), 2.12—2.18 (m, 2H), 2.34 (t, J = 7.3 Hz, 2H), 2.45
(t, J = 7.3 Hz, 2H), 2.59 (t, J = 7.9 Hz, 2H), 3.72 (s, 3H), 5.89 (t, J =
4.3 Hz, 1H), 6.71 (dd, J = 2.4, 8.2 Hz, 1H), 6.81 (d, J = 2.4 Hz, 1H),
7.03 (s, 3H), 7.06 (d, J = 8.2 Hz, 1H), 9.16 (s, 1H); 13C NMR (125
MHz, DMSO-d6) δ: 19.6 (2C), 23.4, 25.9, 27.4, 28.2, 32.3, 35.8,
55.4, 109.7, 111.4, 125.7 (2C), 126.7, 128.0 (3C), 128.6, 128.7,
135.6, 135.8, 136.4, 158.5, 171.2; HRMS calcd for [C24H29NNaO2]+
(M+Na+): 386.2091; found: 386.2095.
N-(2,6-Dimethylphenyl)-5-(7-nitro-3,4-dihydronaphthalen-
1-yl)pentanamide (11). Flash chromatography on silica gel (eluent:
EtOAc/n-Hexane = 1 : 2) gave compound 11 as a colorless oil (1.37
g, yield: 90%); IR (film) vmax: 3434, 2916, 2848, 1619, 1536, 1467,
1384, 1196, 1076 cm–1; 1H NMR (500 MHz, DMSO-d6) δ:
1.54—1.63 (m, 2H), 1.66—1.75 (m, 2H), 2.08 (s, 6H), 2.24—2.30
(m, 2H), 2.35 (t, J = 7.2 Hz, 2H), 2.54 (t, J = 7.2 Hz, 2H), 2.82 (t, J =
8.0 Hz, 2H), 6.06—6.11 (m, 1H), 7.03 (s, 3H), 7.46 (d, J = 8.2 Hz,
1H), 7.99—8.06 (m, 2H), 9.17 (s, 1H); 13C NMR (125 MHz,
DMSO-d6) δ: 18.5 (2C), 22.4, 25.8, 27.7, 28.1, 31.8, 35.7, 117.1,
122.0, 126.7, 128.0 (3C), 129.2, 134.9, 135.6 (2C), 135.8, 136.2,
145.1, 147.1, 171.1; HRMS calcd for [C23H26N2NaO3]+ (M+H+):
379.2016; found: 379.2023.
5-(2H-Chromen-4-yl)-N-(2,6-dimethylphenyl)pentanamide
(12). Flash chromatography on silica gel (eluent: EtOAc/n-Hexane
= 1 : 2) gave compound 12 as a colorless oil (1.30 g, yield: 91%); IR
(film) vmax: 3434, 2917, 2849, 1650, 1575, 1537, 1464, 1384, 1214,
1141, 1076, 1032, 163, 612 cm–1; 1H NMR (500 MHz, DMSO-d6) δ:
1.51—1.60 (m, 2H), 1.66—1.74 (m, 2H), 2.11 (s, 6H), 2.35 (t, J =
7.2 Hz, 2H), 2.42 (t, J = 7.3 Hz, 2H), 4.68 (d, J = 3.4 Hz, 2H), 5.68 (t,
J = 3.4 Hz, 1H), 6.75—6.80 (m, 1H), 6.88 (m, 1H), 7.04 (s, 3H), 7.09
(m, 1H), 7.21—7.25 (m, 1H), 9.17 (s, 1H); 13C NMR (125 MHz,
DMSO-d6) δ: 18.6 (2C), 25.8, 27.7, 30.8, 35.7, 65.2, 116.2, 118.7,
121.6, 123.6, 123.8, 126.7, 128.0 (2C), 129.2, 133.8, 135.6 (2C),
135.8, 154.5, 171.2; HRMS calcd for [C22H25NNaO2]+ (M+Na+):
358.1778; found: 358.1780.
N-(2,6-Dimethylphenyl)-5-(1H-inden-3-yl)pentanamide (13).
Flash chromatography on silica gel (eluent: EtOAc/n-Hexane = 1 : 2)
gave compound 13 as a colorless oil (1.11 g, yield: 81%); IR (film)
vmax: 3368, 2916, 2297, 1577, 1384, 1076, 483 cm–1; 1H NMR (500
MHz, DMSO-d6) δ: 1.68—1.78 (m, 4H), 1.96—2.09 (m, 2H), 2.11 (s,
6H), 2.38 (t, J = 6.4 Hz, 2H), 2.48—2.51 (m, 2H), 6.26—6.29 (m,
1H), 7.04 (s, 3H), 7.16—7.20 (m, 1H), 7.25—7.30 (m, 1H), 7.39 (d,
J = 7.4 Hz, 1H), 7.46 (d, J = 7.4 Hz, 1H), 9.20 (s, 1H); 13C NMR (125
MHz, DMSO-d6) δ: 18.6 (2C), 25.9, 27.4, 27.8, 35.7, 37.7, 119.3,
124.2, 124.9, 126.4, 126.7, 128.0 (2C), 128.4, 135.6 (2C), 135.8,
144.2, 144.6, 145.4, 171.2; HRMS calcd for [C22H25NNaO]+
(M+Na+): 342.1828; found: 342.1829.
General procedure for the cyclic enimines
To a cooled (0 °C ) solution of amide (0.60 mmol) and 2-F-Pyr.
(62 µL, 0.72 mmol) in CH2Cl2 (5 mL) was added dropwise Tf2O (111
µL, 0.66 mmol). The reaction was allowed to warm to 40 °C and
stirred for additional 2 h. The resulting solution was concentrated
under reduced pressure. The residue was purified by flash column
chromatography on silica gel to afford the corresponding cyclic
enimine.
(E)-N-(2,6-Dimethylphenyl)-3,4,9,10-tetrahydrophenanth-
ren-1(2H)-imine (16). Flash chromatography on silica gel (eluent:
EtOAc/n-Hexane = 1 : 20) gave compound 16 as a yellow oil (152
mg, yield: 84%); IR (film) vmax: 2916, 1958, 1712, 1659, 1650, 1383,
1196, 1076 cm–1; 1H NMR (500 MHz, CDCl3) δ: 1.86—1.94 (m, 2H),
1.99 (s, 6H), 2.09—2.13 (m, 2H), 2.68 (t, J = 5.8 Hz, 2H),
2.83—2.89 (m, 4H), 6.87 (t, J = 7.5 Hz, 1H), 7.02 (d, J = 7.5 Hz, 2H),
7.20—7.29 (m, 3H), 7.35—7.40 (m, 1H); 13C NMR (125 MHz, CDCl3)
δ: 18.0 (2C), 21.6, 22.0, 26.2, 28.0, 28.8, 122.3, 123.4, 125.5 (2C),
126.4, 127.5, 127.7 (2C), 128.1, 133.1, 135.5, 137.6, 141.1, 149.4,
166.2; HRMS calcd for [C22H24N]+ (M+H+): 302.1903; found:
302.1899.
(E)-N-(2,6-Dimethylphenyl)-3,4,5,6,7,8-hexahydronaphtha-
len-1(2H)-imine (17). Flash chromatography on silica gel (eluent :
EtOAc/n-Hexane = 1 : 20) gave compound 17 as a yellow oil (132
mg, yield: 87%); IR (film) vmax: 2916, 2848, 2359, 2340, 1651, 1504,
1494, 1384, 1195, 1131, 1076, 668 cm–1; 1H NMR (500 MHz, CDCl3)
δ: 1.66—1.74 (m, 6H), 19.8 (s, 6H), 1.99—2.03 (m, 2H), 2.11—2.19
(m, 4H), 2.45—2.52 (m, 2H), 6.84 (t, J = 7.5 Hz, 1H), 6.99 (d, J = 7.5
Hz, 2H); 13C NMR (125 MHz, CDCl3) δ: 18.1 (2C), 22.2, 22.4, 22.8,
24.0, 29.0, 31.5, 31.8, 122.1, 125.8 (2C), 127.6 (2C), 130.5, 146.8,
149.5, 166.6; HRMS calcd for [C18H23NNa]+ (M+Na+): 276.1723;
found: 276.1724.
(E)-N-(2,6-Dimethylphenyl)-1,2,3,4,6,7,8,9-octahydro-5H-
benzo[7]annulen-5-imine (19). Flash chromatography on silica gel
(eluent: EtOAc/n-Hexane = 1 : 20) gave compound 19 as a yellow
oil (150 mg, yield: 94%); IR (film) vmax: 2910, 2845, 2340, 1651,
1604, 1494, 1374, 1196, 1076, 663 cm–1; 1H NMR (500 MHz, CDCl3)
δ: 1.45—1.53 (m, 2H), 1.62—1.71 (m, 6H), 2.00 (s, 6H), 2.10—1.19
(m, 4H), 2.20—2.25 (m, 2H), 2.50—2.55 (m, 2H), 6.84 (t, J = 7.6 Hz,
1H), 7.00 (d, J = 7.6 Hz, 2H); 13C NMR (125 MHz, CDCl3) δ: 18.0
(2C), 22.7, 22.9, 23.2, 24.7, 27.2, 31.7, 33.2, 33.8, 122.1, 125.4,
127.8 (2C), 133.9 (2C), 143.8, 149.1, 173.1; HRMS calcd for
[C19H25NNa]+ (M+Na+): 290.1879; found: 290.1881.
5-(Cyclohex-1-en-1-yl)-N-(2,6-dimethylphenyl)pentanamide
(14). Flash chromatography on silica gel (eluent: EtOAc/n-Hexane
= 1 : 2) gave compound 14 as a colorless oil (1.22 g, yield: 91%); IR
(film) vmax: 3845, 3438, 2916, 2848, 1958, 1655, 1578, 1535, 1384,
1196,1132,1076, 609 cm–1; 1H NMR (500 MHz, DMSO-d6) δ:
1.39—1.51 (m, 10H), 1.57—1.65 (m, 2H), 2.00 (t, J = 7.5 Hz, 2H),
2.02—2.08 (m, 2H), 2.09—2.11 (m, 2H), 2.11 (s, 6H), 2.32 (t, J =
7.2 Hz, 2H), 5.32 (t, J = 8.1 Hz, 1H), 7.04 (s, 3H), 9.16 (s, 1H); 13C
NMR (125 MHz, DMSO-d6) δ: 18.6 (2C), 25.8, 26.2, 26.3, 26.5, 27.7,
28.9, 29.0, 30.0, 35.7, 37.4, 123.7, 126.7, 128.0 (2C), 135.6, 135.7
(2C), 140.7, 171.2; HRMS calcd for [C21H31NNaO]+ (M+Na+):
(E)-N-(2,6-Dimethylphenyl)-3-methoxy-5,6,8,9,10,11-hexa-
hydro-7H-cyclohepta[a]naphthalen-7-imine (20). Flash chroma-
tography on silica gel (eluent: EtOAc/n-Hexane = 1 : 20) gave
compound 20 as a yellow oil (186 mg, yield: 96%); IR (film) vmax
:
2917, 2848, 1614, 1573, 1538, 1464, 1384, 1293, 1198, 1047, 805
cm–1; 1H NMR (500 MHz, CDCl3) δ: 1.59 (m, 2H), 1.81 (m, 2H), 2.03
(s, 6H), 2.17—2.24 (m, 2H), 2.76 (t, J = 6.1 Hz, 2H), 2.83 (m, 4H),
3.83 (s, 3H), 6.78 (d, J = 7.5 Hz, 2H), 6.88 (t, J = 7.5 Hz, 1H), 7.03 (d,
J = 7.5 Hz, 2H), 7.35 (d, J = 7.7 Hz, 1H); 13C NMR (125 MHz, CDCl3)
δ: 18.0 (2C), 22.4, 24.8, 25.3, 27.7, 29.3, 31.7, 55.3, 111.4, 113.3,
Chin. J. Chem. 2019, 37, 315-322
© 2019 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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