Notes
J . Org. Chem., Vol. 64, No. 2, 1999 643
(100). Anal. Calcd for C7H19NOSi: C, 52.13; H, 11.88. Found:
C, 52.30; H, 11.47.
N-ter t-Bu tyl-4-m eth yla n ilin e (4l). The crude material was
purified by flash chromatography (ethyl acetate/light petroleum
ether 9:1) to give 0.212 g (65%) of a pale yellow oil whose
analytical data matched those previously reported in the litera-
ture.19
Gen er a l P r oced u r e for th e P r ep a r a tion of Secon d a r y
Am in es 4a -s. The cyanocuprates were prepared by rapidly
adding CuCN (2.00 mmol, 0.179 g) under N2 flow to the lithium
compound (4.00 mmol) in THF (15 mL), cooled at -40 °C. The
reaction mixture was stirred until dissolution of the salt, which
was generally complete after 20 min. The secondary amines were
prepared by adding dropwise the N-alkyl-O-(trimethylsilyl)-
hydroxylamines (2.00 mmol) to a THF solution of cyanocuprate
(2.00 mmol) at -50 °C. The temperature was allowed to rise to
rt, and after 2 h the dark reaction mixture was filtered through
a Celite pad. The solution was evaporated, and the residue was
purified by flash chromatography.
N-ter t-Bu tyl-3-m eth oxya n ilin e (4m ). The crude material
was purified by flash chromatography (benzene/ethyl ether 8:2)
to give 0.262 g (73%) of a low melting point solid whose analytical
data matched those previously reported in the literature.19
N-ter t-Bu t yl-4-flu or oa n ilin e (4n ). Following the usual
procedure and workup, the crude material was purified by flash
chromatography (benzene/ethyl ether 9:1) to give 0.150 g (45%)
of a white oil whose analytical data matched those previously
reported in the literature.19
2-Meth yla m in op yr id in e (4o).20 To 2 mmol of 2-pyridylcy-
anocuprate prepared as previously described10 was added 0.238
mL (2 mmol) of 1 at -60 °C, and the reaction mixture was slowly
allowed to reach rt. The dark mixture subjected to the usual
workup gave a dark oil that was purified by flash chromatog-
raphy (ethyl acetate), affording 0.140 g (65%) of a yellow oil. 1H
NMR (CDCl3): δ 8.09-8.06 (d, 1H, J ) 4.6 Hz), 7.47-7.39 (m,
1H), 6.60-6.53 (m, 1H), 6.40-6.36 (d, 1H, J ) 4.6 Hz), 2.90 (s,
3H). 13C NMR (50.3 MHz, CDCl3): δ 159.6, 148.0, 137.4, 112.7,
106.2, 29.1. MS m/z (relative intensity): 108 (M+, 100), 107 (56),
92 (2), 79 (93), 67 (11), 65 (6), 52 (35), 41 (5).
2-Isop r op yla m in op yr id in e (4p ).21 The crude material was
purified by flash chromatography (benzene/ethyl acetate 9:1) to
give 0.185 g (68%) of a yellow oil. 1H NMR (CDCl3): δ 8.12-7.96
(m, 1H), 7.42-7.30 (m, 1H), 6.58-6.21 (m, 2H), 4.49 (br, 1H),
3.95-3.70 (m, 1H), 1.21-1.18 (d, 6H, J ) 6.3 Hz). 13C NMR (50.3
MHz, CDCl3): δ 158.2, 148.1, 137.2, 112.3, 106.8, 43.0, 22.9. MS
m/z (relative intensity): 136 (M+, 28), 121 (100), 94 (34), 78 (36),
67 (21), 58 (27), 51 (12).
2-ter t-Bu tyla m in op yr id in e (4q).22 The crude material was
purified by flash chromatography (benzene/ethyl acetate 8:2) to
give 0.210 g (70%) of a brown oil. 1H NMR (CDCl3): δ 8.06-8.03
(m, 1H), 7.39-7.36 (m, 1H), 6.53-6.41 (m, 2H), 4.49 (br, 1H),
1.41 (s, 9H). 13C NMR (50.3 MHz, CDCl3): δ 158.5, 148.1, 136.7,
112.3, 108.6, 50.7, 29.6. MS m/z (relative intensity): 150 (M+,
24), 135 (100), 95 (33), 994 (98), 78 (28), 67 (49), 57 (7), 52 (7).
N-Meth yla n ilin e (4a ).16 The crude product was purified by
flash chromatography (benzene/ethyl acetate, 8:2), to give 0.124
g (58%) of a pale yellow liquid whose spectral data were identical
to those of the commercial product.
N-Meth yl-4-m eth yla n ilin e (4b).17 The residue was purified
by flash chromatography (petroleum ether/ethyl acetate 9:1) to
give 0.139 g (57%) of a yellow oil. The spectral data were
identical to those of the commercial product.
N-Meth yl-3-m eth oxya n ilin e (4c). The crude material was
purified by flash chromatography (light petroleum ether/ethyl
ether 1:1) to give 0.162 g (59%) of a pale yellow oil. 1H NMR
(CDCl3): δ 7.1-6.6 (m, 4H), 3.8 (s, 3H), 3.7 (s, 1H), 2.8 (s, 3H).
13C NMR (50.3 MHz, CDCl3): δ 147.0, 139.5, 121.4, 116.3, 109.4,
55.5, 30.4. HRMS: calcd for C8H11NO 137.0841, found 137.0840
N-Meth yl-4-m eth oxya n ilin e (4d ).16 The crude material was
purified by flash chromatography (benzene/ethyl acetate 8:2) to
give 0.241 g (88%) of a low melting point material. 1H NMR
(CDCl3): δ 6.84-6.79 (m, 2H), 6.64-6.57 (m, 2H), 3.76 (s, 3H),
3.32 (br, 1H), 2.81 (s, 3H). 13C NMR (50.3 MHz,CDCl3): δ 152.22,
143.8, 115.1, 113.7, 55.9, MS m/z (relative intensity): 137 (M+,
70), 122 (100), 94 (25), 77 (11), 65 (24), 52 (19).
N-Isop r op yla n ilin e (4e).18 Evaporation of the solvent led
to 0.173 g (64%) of a yellow oil whose analytical data matched
those of an authentic sample.
N-Isop r op yl-4-m eth yla n ilin e (4f).17 The crude material was
purified by flash chromatography (benzene) to give 0.200 g (67%)
of a yellow oil. 1H NMR (CDCl3): δ 7.10-6.59 (m, 4H), 3.78-
3.59 (m, 1H), 3.29 (br, 1H), 2.39 (s, 3H), 1.30-1.26 (d, 6H, J )
6.2 Hz). 13C NMR (50.3 MHz, CDCl3): δ 145.3, 129.7, 126.2,
113.6, 44.6, 23.1, 20.3. MS m/z (relative intensity): 149 (M+, 28),
134 (100), 119 (7), 106 (12), 91 (10), 77 (8), 65 (6), 51 (3).
N-Isop r op yl-4-m eth oxya n ilin e (4g). The crude material
was purified by flash chromatography (benzene/ethyl acetate 8:2)
2-Meth yla m in oth iop h en e (4r ). The dark violet residue was
purified by Kugelrohr distillation (80 °C/ 12 mmHg) to give 0.119
g (60%) of a pale yellow liquid that slowly darkened on exposure
to light. 1H NMR (CDCl3): δ 6.7-6.0 (m, 3H), 3.72 (br, 1H), 2.84
(s, 3H). 13C NMR (50.3 MHz, CDCl3): δ 156.5, 126.3, 110.3,
103.2, 34.4. HRMS: calcd for C5H7NS 113.0299, found 113.0297.
1
to give 0.241 g (73%) of a low melting solid. H NMR (CDCl3): δ
6.82-6.58 (m, 4H), 3.76 (s, 3H), 3.63-3.50 (m, 1H), 3.18 (br, 1H),
2-Isop r op yla m in oth iop h en e (4s). The solvent was evapo-
rated, and the dark violet residue was purified by Kugelrohr
distillation (100 °C/ 12 mmHg) to give 0.165 g (65%) of a pale
yellow liquid that slowly darkened on exposure to light. 1H NMR
(CDCl3): δ 6.74-6.02 (m, 3H), 3.59 (br, 1H), 3.50-3.38 (m, 1H),
1.24-1.20 (d, 6H, J ) 6.3 Hz). 13C NMR (50.3 MHz, CDCl3): δ
1.22-1.19 (d, 6H, J ) 6.3 Hz). 13C NMR (50.3 MHz, CDCl3): δ
152.0, 141.8, 114.9, 55.7, 45.2, 23.0. HRMS: calcd for C10H15
NO 165.1154, found 165.1155.
-
N-Isop r op yl-4-flu or oa n ilin e (4h ). The crude material was
purified by flash chromatography (,benzene/ethyl ether 9:1) to
1
give 0.138 g (45%) of a white oil. H NMR (CDCl3): δ 6.93-6.64
154.2, 126.1, 110.8, 105.4, 49.4, 22.9. HRMS: calcd for C7H11
NS 141.0612, found 141.0616.
-
(m, 2H), 6.56-6.49 (m, 2H), 3.59-3-53 (m, 1H), 3.14 (br, 1H),
1.21-1.18 (d, 6H, J ) 6.3 Hz). 13C NMR (50.3 MHz, CDCl3): δ
158.0, 144.0, 115.4, 114.3, 45.0, 23.0. HRMS: calcd for C9H12
NF 153.0954, found 153.0953.
-
Ack n ow led gm en t. The financial support of the
MURST (ex 60%-MPI) and of the National Research
Council of Italy (CNR) is gratefully acknowledged.
N-ter t-Bu tyla n ilin e (4i). The residue was purified by flash
chromatography (benzene/ethyl acetate 8:2) to give 0.158 g (53%)
of a yellow liquid whose analytical data matched those previously
reported in the literature.19
J O981412H