O. G. Dediu et al. · The Coupling-Isomerization Approach to Enimines
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4-Methyl-N-[1-(thien-2-yl)-prop-2-ynyl]-benzenesulfon-
amide (2b)
in 4 ml of degassed triethylamine and 5 ml of THF under ni-
trogen was heated to reflux temperature for 24 – 48 h. After
cooling to room temperature 30 ml of diethyl ether was added
to the reaction mixture. After filtration the solvents were re-
moved in vacuo and the residue was washed with ethanol to
give the enimines 5. Further purification could be achieved
by recrystallization from ethanol or trituration with ethanol.
According to the GP from the reaction of 13.3 g
(50.0 mmol) of 4-methyl-N-(thiophen-2-ylmethylene)-benz-
enesulfonamide [12] and 123 ml (63 mmol) of a 0.5 M solu-
tion of ethynyl magnesium bromide in 70 ml of THF, 13.7 g
(94%) of 2b were o◦btained as colorless crystals.
M. p. 121 – 122 C. – IR (KBr): ν = 3269, 3118, 2940,
2122, 1596, 1493, 1432, 1330, 1290, 1229, 1165, 1092,
1058, 1039, 925, 815, 715, 673, 648, 587, 569, 550 cm−1. –
1H NMR (300 MHz, CDCl3): δ = 2.33 (d, J = 2.3 Hz, 1 H),
2.42 (s, 3 H, TolMe), 5.23 (d, J = 8.9 Hz, 1 H), 5.51 (d,
J = 8.9 Hz, 1 H), 6.87 – 6.90 (m, 1 H), 7.08 (d, J = 3.5 Hz,
1 H), 7.22 (dd, J = 7.8 Hz, J = 1.2 Hz, 1 H), 7.28 (d,
J = 8.2 Hz, 2 H), 7.77 (d, J = 8.4 Hz, 2 H). – 13C NMR
(75 MHz, CDCl3): δ = 21.5 (CH3, TolMe), 44.8 (CH), 74.0
(CH), 80.0 (Cquat.), 126.4 (CH), 126.5 (CH), 126.8 (CH),
127.4 (CH), 129.5 (CH), 137.1 (Cquat.), 140.7 (Cquat.), 143.7
(Cquat.). – MS (70 eV, EI): m/z (%) = 291 (M+, 2), 155
(C7H7SO2, 5), 136 (M+ - C7H7SO2, 100), 91 (C7H7, 21).
– C14H13NO2S2 (291.4): calcd. C 57.71, H 4.50, N 4.81,
S 22.01; found C 57.62, H 4.50, N 4.81, S 21.54.
N-[1-(4-Methoxyphenyl)-3-(4-nitrophenyl)-allylidene]-4-
methyl-benzenesulfonamide (3a)
According to the GP the reaction of 473 mg (1.90 mmol)
of 4-iodo-1-nitrobenzene (1a) and 631 mg (2.00 mmol) of 2a
furnished, after recrystallization from ethanol, 332 mg (40%)
of 3a as brown yellow crystals.
◦
M. p. 148 – 150 C. – IR (KBr): ν = 3070, 2936, 1599,
1516, 1420, 1344, 1309, 1259, 1176, 1152, 1092, 1025,
958, 870, 847, 834, 823, 776, 755, 683, 665, 596, 568,
544 cm−1. – 1H NMR (300 MHz, CDCl3): δ = 2.42 (s, 3 H,
TolMe), 3.87 (s, 3 H, OMe), 6.94 (d, J = 8.8 Hz, 2 H), 7.04
(d, J = 16.3 Hz, 1 H), 7.32 (d, J = 8.2 Hz, 2 H), 7.71 (d,
J = 8.6 Hz, 2 H), 7.72 (d, J = 8.7 Hz, 2 H), 7.90 (d, J =
8.3 Hz, 2 H), 8.03 (d, J = 16.3 Hz, 1 H), 8.24 (d, J = 8.7 Hz,
2 H). – 13C NMR (75 MHz, CDCl3): δ = 21.5 (CH3, TolMe),
55.5 (CH3, OMe), 114.0 (CH), 124.1 (CH), 127.1 (CH),
128.8 (CH, br), 129.4 (CH), 130.9 (Cquat.), 132.5 (CH), 138.5
(Cquat.), 140.8 (Cquat.), 142.4 (CH), 143.6 (Cquat.), 148.5
(Cquat.), 163.7 (Cquat.), 175.2 (Cquat., C=N). – MS (70 eV,
EI): m/z (%) = 436 (M+, 0.3), 280 (M+ - C7H7SO2, 100),
251 (M+ - C7H7SO2 - NH -N, 71), 155 (C7H7SO2, 5), 134
(C7H4NO2, 6), 91 (C7H7, 23). – C23H20N2O5S (436.5):
calcd. C 63.29, H 4.62, N 6.42, S 7.35; found C 63.02, H
4.73, N 6.55, S 7.48.
4-Methyl-N-[1-(4-phenoxyphenyl)-prop-2-ynyl]-benzenesul-
fonamide (2c)
According to the GP from the reaction of 2.73 g
(7.77 mmol) of 4-methyl-N-(4-phenoxy-benzylidene)-benz-
enesulfonamide [12] and 19 ml (9.8 mmol) of a 0.5 M solu-
tion of ethynyl magnesium bromide in 10 ml of THF, 2.4 g
(82%) of 2c were obtained as colorless crystals.
M. p. 96 – 97 ◦C. – IR (KBr): ν = 3281, 3065, 2929,
2119, 1657, 1581, 1506, 1490, 1415, 1333, 1262, 1158,
1091, 1053, 963, 842, 813, 693, 669, 545 cm−1. – 1H NMR
(300 MHz, CDCl3): δ = 2.31 (d, J = 0.7 Hz, 1 H), 2.41 (s,
3H, TolMe), 5.27 (br, 2 H), 6.90 (d, J = 8.7 Hz, 2 H), 6.97
(dd, J = 0.8, 8.7 Hz, 2 H), 7.11 (t, J = 7.4 Hz, 1 H), 7.26
(d, J = 8.1 Hz, 2 H), 7.31 (dd, J = 0.8, 8.0, 2 H), 7.35 – 7.40
(m, 2 H), 7.75 (d, J = 8.3 Hz, 2 H). – 13C NMR (75 MHz,
CDCl3): δ = 21.5 (CH3, TolMe), 48.4 (CH), 74.7 (CH), 80.4
(Cquat.), 118.6 (CH), 119.1 (CH), 123.6 (CH), 127.4 (CH),
128.7 (CH), 129.4 (CH), 129.8 (CH), 131.6 (Cquat.), 137.2
(Cquat.), 143.5 (Cquat.), 156.6 (Cquat.), 157.5 (Cquat.). – MS
(70 eV, EI): m/z (%) = 377 (M+, 2), 222 (M+ - C7H7SO2,
80), 207 (M+ - C7H7SO2 - NH, 28), 155 (C7H7SO2, 7), 91
(C7H7, 44). – C22H19NO3S (377.5): calcd. C 70.01, H 5.07,
N 3.71, S 8.49; found C 69.82, H 5.18, N 3.64, S 8.49.
4-Methyl-N-[3-(4-nitrophenyl)-1-(thien-2-yl)-allylidene]-
benzene sulfonamide (3b)
According to the GP the reaction of 453 mg (1.80 mmol)
of 4-iodo-1-nitrobenzene (1a) and 557 mg (1.90 mmol) of 2b
furnished, after recrystallization from ethanol, 368 mg (49%)
of 3b as light yellow crystals.
M. p. 180.7 – 181 ◦C. – IR (KBr): ν = 3084, 2925, 1624,
1598, 1519, 1413, 1346, 1303, 1152, 1089, 979, 840, 785,
747, 668, 552, 536 cm−1. – 1H NMR (300 MHz, CDCl3):
δ = 2.42 (s, 3 H, TolMe), 7.16 (t, J = 4.8 Hz, 1 H), 7.26
(d, J = 2.2 Hz, 1 H), 7.30 – 7.32 (m, 2 H), 7.69 (m, 2 H),
7.73 (d, J = 8.9 Hz, 2 H), 7.90 (d, J = 8.3 Hz, 2 H), 7.94 (d,
J = 16.2 Hz, 1 H), 8.25 (d, J = 8.7 Hz, 2 H). – 13C NMR
(75 MHz, CDCl3): δ = 21.5 (CH3, TolMe), 124.1 (CH),
126.1 (CH), 127.1 (CH), 128.5 (CH), 128.8 (CH), 129.4
(CH), 135.4 (CH), 135.6 (CH), 138.1 (Cquat.), 140.6 (Cquat.),
General procedure for the enimine synthesis
A magnetically stirred solution of 1 equiv. of (het)aryl 140.9 (Cquat.), 141.8 (Cquat.), 143.7 (CH), 148.5 (Cquat.),
halide 1, 1.05 equiv. of propargyl N-tosyl amine 2, 14 mg 168.293 (Cquat., C=N). – MS (70 eV, EI): m/z (%) = 412
(0.02 mmol) of Pd(PPh3)Cl2, and 2 mg (0.01 mmol) of CuI (M+, 0.2), 317 (M+ - C5H3S, 16), 256 (M+ - C7H7SO2,
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