ACCEPTED MANUSCRIPT
6
Tetrahedron
1
128.5, 128.9, 130.4, 134.0, 151.9, 153.9 ppm. HRMS (ESI) Calcd
for C22H30ON [M+H]+ = 324.2322, Found = 324.2323.
IR (neat): ν = 2998, 1581, 1458, 1211 cm-1. H NMR (400 MHz,
CDCl3): δ = 5.07 (s, 2H), 7.40-7.45 (m, 7H), 7.49 (dd, 2H, J1 =
7.6 Hz, J2 = 2.0 Hz), 8.21 (dd, 2H, J1 = 5.7 Hz, J2 = 2.1 Hz) ppm.
13C NMR (100 MHz, CDCl3): δ =71.2, 128.4, 128.6, 129.0, 129.2,
130.3, 130.4, 133.2, 134.3 (2C) ppm. HRMS (ESI) Calcd for
C14H14ON [M+H]+ = 212.1070, Found = 212.1072.
4.2.6
N-(4-n-Butylphenyl)methyl-N-(4-n-butylphenyl)
-methyleneamine N-Oxide 2f: Yield: 131.2 mg (41%); white
solid; mp: 62-63 °C. IR (neat): ν = 2955, 1577, 1455, 1312 cm-1.
1H NMR (400 MHz, CDCl3): δ = 0.90 (t, 3H, J = 4.5 Hz), 0.93
(t, 3H, J = 4.5 Hz) 1.31-1.38 (m, 4H), 1.55-1.63 (m, 4H), 2.62 (t,
2H, J = 7.7 Hz), 2.62 (t, 2H, J = 7.7 Hz), 5.01 (s, 2H), 7.21 (d, 2H,
J = 8.4 Hz), 7.22 (d, 2H, J = 8.2 Hz), 7.32 (s, 1H), 7.38 (d, 2H, J =
7.9 Hz), 8.12 (d, 2H, J = 8.4 Hz) ppm. 13C NMR (100 MHz,
CDCl3): δ = 13.9, 22.2, 22.3, 33.2, 33.4, 35.3, 35.7, 70.7, 127.0,
127.9, 128.4, 128.6, 128.9, 129.2, 130.4, 134.2, 143.8, 145.8 ppm.
HRMS (ESI) Calcd for C22H30ON [M+H]+ = 324.2322, Found =
324.2317.
4.2.12
N-(4-Fluorophenyl)methyl-N-(4-fluorophenyl)
-methyleneamine N-Oxide 2l: Yield: 110.5 mg (45%); white
solid; mp: 88-89 °C. IR (neat): ν = 2974, 1597, 1436, 1230 cm-1.
1H NMR (400 MHz, CDCl3): δ = 5.02 (s, 2H), 7.06-7.14 (m, 4H),
7.39 (s, 1H), 7.48 (dd, 2H, J1 = 8.8 Hz, J2 = 5.4 Hz), 8.26 (dd, 2H,
J1 = 8.8 Hz, J2 = 5.5 Hz) ppm. 13C NMR (100 MHz, CDCl3): δ =
70.2, 115.5 (JC-F = 21.6 Hz), 115.8, 116.1, 128.7 (JC-F = 224.6 Hz),
130.8, 130.9, 131.2 (JC-F = 8.5 Hz), 133.0 (2C) ppm. HRMS (ESI)
Calcd for C14H12ONF2 [M+H]+ = 248.0881, Found = 248.0884.
4.2.7
N-(3-Methoxyphenyl)methyl-N-(3-methoxyphenyl)
-methyleneamine N-Oxide 2g: Yield:111.8 mg (41%); colorless
liquid; IR (neat): ν = 2939, 1584, 1318, 1263 cm-1. 1H NMR (400
MHz, CDCl3): δ = 3.826 (s, 3H), 3.834 (s, 3H), 5.03 (s, 2H),
6.92-6,99 (m, 2H), 7.02 (s, 1H), 7.06 (d, 1H, J = 7.5 Hz), 7.30 (t,
1H, J = 7.9 Hz), 7.33 (t, 1H, J = 7.9 Hz), 7.39 (s, 1H), 7.46 (d, 1H,
J = 7.70 Hz), 8.21 (s,1H) ppm. 13C NMR (100 MHz,CDCl3): δ =
55.3(2C), 71.3, 112.2, 114.5, 114.8, 117.5, 121.5, 121.7, 129.2,
130.0, 131.6, 134.4, 134.5, 159.4, 159.9 ppm. HRMS (ESI) Calcd
for C16H18O3N [M+H]+ = 272.1281, Found = 272.1278.
4.2.13
N-(4-Chlorophenyl)methyl-N-(4-chlorophenyl)
-methyleneamine N-Oxide 2m: Yield: 115.4 mg (41%); white
solid; mp: 124-125 °C. IR (neat): ν = 2963, 1585, 1410, 1307 cm-1.
1H NMR (400 MHz, CDCl3): δ =5.02 (s, 2H), 7.37-7.44 (m, 7H),
8.17 (d, 2H, J = 8.6 Hz) ppm. 13C NMR (100 MHz, CDCl3): δ =
70.3, 128.6, 128.7, 129.1, 129.7, 130.5 131.4, 133.2, 135.1, 136.0
ppm HRMS (ESI) Calcd for C14H12ONCl2 [M+H]+= 280.0290,
Found = 280.0294.
4.2.14
N-(4-Bromophenyl)methyl-N-(4-bromophenyl)
4.2.8
N-(4-Methoxyphenyl)methyl-N-(4-methoxyphenyl)
-methyleneamine N-Oxide 2n: Yield: 160.0 mg (43%); white
solid; mp: 159-161 °C. IR (neat): ν =2930, 1579, 1395, 1227 cm-1.
1H NMR (400 MHz, CDCl3): δ = 5.00 (s, 2H), 7.36 (d, 2H, J = 8.6
Hz), 7.38 (s, 1H), 7.53 (d, 2H, J = 6.1 Hz), 7.55 (d, 2H, J = 6.1
Hz,), 8.09 (d, 2H, J = 8.6 Hz) ppm. 13C NMR (100 MHz, CDCl3):
δ = 70.5, 123.4, 128.5, 129.0, 129.9, 130.9, 131.6, 131.7, 131.9,
-methyleneamine N-Oxide 2h4d: Yield: 119.2 mg (44%); white
solid; mp: 111-112 °C. IR (neat): ν = 2913, 1587, 1457, 1311 cm-1.
1H NMR (400 MHz, CDCl3): δ = 3.83 (d, 3H), 3.84 (s, 3H), 4.96
(s, 2H), 6.92 (d, 2H, J = 9.0 Hz), 6.94 (d, 2H, J = 6.9 Hz), 7.40 (d,
2H, J = 8.8 Hz), 8.20 (d, 2H, J = 8.8 Hz) ppm. 13C NMR (100
MHz, CDCl3): δ = 55.3(2C), 70.1, 113.7, 114.3, 123.4, 125.3,
130.5, 130.9, 133.4, 160.0, 161.0 ppm. HRMS (ESI) Calcd for
C16H18O3N [M+H]+ = 272.1281, Found = 272.1279.
132.2 ppm. HRMS (ESI) Calcd for C14H12ON79Br2 [M+H]+
=
367.9280, Found = 367.9285, Calcd for C14H12ON79Br81Br
[M+H]+ = 369.9260, Found = 369.9263. Calcd for C14H12ON81Br2
[M+H]+ = 371.9239, Found = 371.9244.
4.2.9
N-(4-Ethoxyphenyl)methyl-N-(4-ethoxyphenyl)
-methyleneamine N-Oxide 2i: Yield: 129.4 mg (43%); white
solid; mp: 115-117 °C. IR (neat): ν = 3002, 1603, 1396, 1246 cm-1.
1H NMR (400 MHz, CDCl3): δ = 1.42 (t, 3H, J = 7.0 Hz), 1.42 (t,
3H, J = 7.0 Hz), 4.02-4.09 (m, 4H), 5.00 (s, 2H), 6.89 (d, 2H, J =
10.8 Hz), 6.92 (d, 2H, J = 10.6 Hz), 7.23 (s, 1H), 7.38 (d, 2H, J =
8.5 Hz), 8.18 (d, 2H, J = 9.0 Hz) ppm. 13C NMR (100 MHz,
CDCl3): δ = 14.7, 14.8, 63.5(2C), 70.1, 114.2, 114.8, 123.3, 125.2,
130.6, 130.9, 133.5, 159.4, 160.4 ppm. HRMS (ESI) Calcd for
C18H22O3N [M+H]+ = 300.1594, Found = 300.1593.
4.2.15
N-(4-Iodophenyl)methyl-N-(4-iodophenyl)methylene
-amine N-Oxide 2o: Yield: 188.3 mg (41%); white solid; mp:
191-193 °C. IR (neat): ν = 2920, 1575, 1391, 1229 cm-1. 1H NMR
(400 MHz, CDCl3): δ= 4.97 (s, 2H), 7.22 (d, 2H, J = 8.4 Hz), 7.36
(s, 1H), 7.74 (d, 2H, J = 3.6 Hz), 7.76 (d, 2H, J = 3.4 Hz), 7.94 (d,
2H, J = 8.6 Hz) ppm. 13C NMR (100 MHz, CDCl3): δ = 70.8, 95.2,
96.7, 129.5, 129.8, 131.0, 132.5, 133.4, 137.7, 138.1 ppm. HRMS
(ESI) Calcd for C14H12ONI2 [M+H]+ = 463.9001, Found =
463.9003.
4.2.10
N-(3,5-Dimethoxyphenyl)methyl-N-(3,5-dimethoxy
4.3.
(p-methylphenyl)-2,3-dihydroisoxazole-4,5-dicarboxylate 3a:
To N-(4-methylphenyl)methyl-N-(4-methylphenyl)methylene
-amine N-oxide 2a (239.3 mg, 1.0 mmol) in a 50 mL two-necked
round-bottom flask was added solution of diethyl
acetylenedicarboxylate (230.4 mg, 1.3 mmol) in dichloromethane
(2.0 mL) under argon atmosphere. The mixture was stirred for 7
h at 40 ꢀ. The resulting mixture was quenched by the addition
of H2O (10.0 mL). The mixture was extracted with CHCl3 (3 ×
20.0 mL). The combined organic layers were dried over Na2SO4.
After filtration and removal of the solvent under reduced pressure,
the residue was purified by short column chromatography on
Preparation
of
Diethyl
2-(p-Methylbenzyl)-3-
-phenyl)methyleneamine N-Oxide 2j: Yield: 134.0 mg (40%);
white solid; mp: 111-112 °C. IR (neat): ν = 2939, 1589, 1346,
1291 cm-1. 1H NMR (400 MHz, CDCl3): δ = 3.81 (s, 6H), 3.81 (s,
6H), 5.00 (s, 2H), 6.48 (t, 1H, J = 2.3 Hz), 6.55 (t, 1H, J = 2.3 Hz),
6.61 (d, 2H, J = 2.3 Hz), 7.34 (s, 1H), 7.45 (d, 2H, J = 2.3 Hz)
ppm. 13C NMR (100 MHz, CDCl3): δ = 55.4, 55.5, 71.5, 100.8,
103.8, 106.2, 107.2, 131.9, 134.6, 135.0, 160.5, 161.1 ppm.
HRMS (ESI) Calcd for C18H22O5N [M+H]+ = 332.1492, Found =
332.1488.
a
a
4.2.11 N-Benzyl-N-phenylmethyleneamine N-Oxide 2k4d,6
Yield: 84.5 mg (40%); white solid; mp: 80-82 °C (mp: 82-83 °C)6.
:
silica
gel
(hexane/AcOEt,
5:1)
to
afford
diethyl