2097
F. Blume et al.
Paper
Synthesis
FTIR (neat, ATR): 3105 (w), 2860 (w), 1637 (s), 1492 (m), 1145 (s),
1026 (s), 935 (s), 921 (m), 785 (m), 696 (s) cm–1
1H NMR (300 MHz, CDCl3): δ = 8.15 (s, 1 H), 7.31–7.33 (m, 8 H), 7.20–
7.25 (m, 2 H), 6.80 (d, J = 3.3 Hz, 1 H), 6.41 (d, J = 3.3 Hz), 5.59 (s, 1 H),
4.68 (s, 2 H), 4.58 (s, 2 H), 3.39 (s, 3 H).
dried over MgSO4, volatiles were removed in vacuo, and the crude
product was purified by bulb-to-bulb distillation (40–140 °C,
0.3 mbar).
.
1-(2-Furyl)but-3-enylamine (2a)
13C NMR (75 MHz, CDCl3): δ = 154.2, 152.1, 150.1, 143.3, 128.5, 128.0,
127.1, 114.7, 111.1, 95.7, 77.8, 61.2, 55.5.
Prepared according to the general procedure using allyl bromide (907
mg, 7.5 mmol).
GC-MS (tR = 17.2 min): m/z (%) = 335 (33) [M+], 274 (14), 167 (100),
Yield: 460 mg (3.36 mmol, 67%); colourless liquid.
152 (16), 139 (2), 115 (3), 96 (2), 77 (2), 51 (2).
FTIR (neat, ATR): 3369 (br w), 3076 (w), 2978 (w), 1639 (w), 1147
(m), 1008 (s), 916 (br s), 883 (s), 804 (s), 731 (s) cm–1
.
Anal. Calcd for C21H21NO3: C, 75.20; H, 6.31; N, 4.17. Found: C, 74.91;
H, 6.32; N, 4.09.
1H NMR (300 MHz, CDCl3): δ = 7.29 (dd, J = 1.8, 0.8 Hz, 1 H), 6.25 (dd,
J = 3.1, 1.8 Hz, 1 H), 6.10–6.09 (m, 1 H), 5.73 (ddt, J = 17.1, 10.0, 7.0 Hz,
1 H), 5.13–5.04 (m, 2 H), 3.96 (dd, J = 7.2, 5.8 Hz, 1 H), 2.49–2.59 (m,
1 H), 2.30–2.45 (m, 1 H), 1.54 (br s, 2 H).
N-5-(Benzyloxymethyl)furfurylidene-N-(diphenylmethyl)amine
(3e)
Yield: 2.42 g (6.34 mmol, 91%); beige solid; mp 74 °C; Rf = 0.36 (cyclo-
13C NMR (75 MHz, CDCl3): δ = 158.6, 141.3, 134.7, 117.8, 109.9, 104.3,
hexane–EtOAc, 3:1).
49.2, 40.9.
FTIR (neat, ATR): 3026 (w), 2852 (w), 1635 (s), 1492 (m), 1089 (s),
1070 (s), 948 (s), 810 (m), 736 (s), 696 (s) cm–1
.
1-(2-Furyl)ethylamine (2b)
1H NMR (300 MHz, CDCl3): δ = 8.13 (s, 1 H), 7.18–7.36 (m, 15 H), 6.78
(d, J = 3.3 Hz, 1 H), 6.39 (d, J = 3.3 Hz), 5.58 (s, 1 H), 4.55 (s, 2 H), 4.51
(s, 2 H).
Prepared by the general procedure using imine 3a (6.53 g, 25 mmol),
t-BuOK (3.37 g, 30 mmol), and iodomethane (5.30 g, 37.5 mmol).
Yield: 2.58 g (23.2 mmol, 93%); colourless liquid.
13C NMR (75 MHz, CDCl3): δ = 154.6, 151.9, 150.0, 143.3, 137.8, 128.5,
128.0, 127.8, 127.1, 114.8, 111.0, 77.8, 72.4, 64.2.
FTIR (neat, ATR): 2972 (w), 1583 (br m), 1147 (m), 1006 (m), 927 (m),
873 (br m), 806 (br m), 731 (s) cm–1
.
GC-MS (tR = 19.4 min): m/z (%) = 381 (10) [M+], 274 (2), 167 (100), 152
(16), 139 (2), 128 (2), 115 (3), 105 (3), 91 (24), 77 (13), 65 (12), 51
(13).
1H NMR (300 MHz, CDCl3): δ = 7.32 (d, J = 1.6 Hz, 1 H), 6.28 (dd, J =
3.2, 1.6 Hz, 1 H), 6.08 (d, J = 3.2 Hz, 1 H), 4.06 (q, J = 6.7 Hz, 1 H), 1.53
(br s, 2 H), 1.41 (d, J = 6.7 Hz, 3 H).
13C NMR (75 MHz, CDCl3): δ = 160.4, 141.3, 110.1, 103.3, 45.2, 22.2.
Anal. Calcd for C26H23NO2: C, 81.86; H, 6.07; N, 3.67. Found: C, 81.98;
H, 6.19; N, 3.65.
GC (Lipodex E): tR = 7.7 [(S)-2b], 8.2 [(R)-2b] min.
N-5-(Acetoxymethyl)furfurylidene-N-(diphenylmethyl)amine (3f)
1-(2-Furyl)propylamine (2c)
Yield: 1.55 g (4.64 mmol, 93%); colourless crystals; mp 97 °C; Rf = 0.64
(cyclohexane–EtOAc, 3:1).
Prepared according to the general procedure using bromoethane (817
mg, 7.5 mmol).
FTIR (neat, ATR): 3086 (w), 1734 (s), 1633 (m), 1226 (m), 1031 (m),
Yield: 390 mg (3.11 mmol, 62%); colourless liquid.
765 (m), 698 (s) cm–1
.
FTIR (neat, ATR): 2964 (w), 2875 (w), 1593 (br w), 1506 (w), 1147
1H NMR (300 MHz, CDCl3): δ = 8.16 (s, 1 H), 7.23–7.35 (m, 10 H), 6.67
(d, J = 3.4 Hz, 1 H), 6.07 (d, J = 3.3 Hz, 1 H), 5.61 (s, 1 H), 5.08 (s, 2 H),
2.08 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 170.5, 152.3, 152.0, 149.9, 143.2, 128.5,
128.0, 127.2, 114.9, 112.5, 77.9, 58.2, 20.9.
(m), 1074 (w), 1006 (m), 883 (br w), 731 (s) cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.32 (dd, J = 1.8, 0.8 Hz, 1 H), 6.29 (dd,
J = 3.3, 1.8 Hz, 1 H), 6.10 (d, J = 3.3 Hz, 1 H), 3.82 (t, J = 6.7 Hz, 1 H),
1.81 (ddq, J = 13.5, 7.3, 6.7 Hz, 1 H), 1.68 (ddq, J = 13.5, 7.3, 6.7 Hz,
1 H), 1.54 (br s, 2 H), 0.91 (t, J = 7.3 Hz, 3 H).
Anal. Calcd for C21H19NO3: C, 75.66; H, 5.74; N, 4.20. Found: C, 75.43;
H, 5.73; N, 4.20.
13C NMR (75 MHz, CDCl3): δ = 159.3, 141.3, 110.0, 104.3, 51.4, 29.6,
10.5.
Preparation of Furfurylamines; General Procedure
1-(2-Furyl)pentylamine (2d)
The corresponding imine (5.0 mmol) was dissolved in anhydrous
DMF (25 mL). At 0 °C, t-BuOK (673 mg, 6.0 mmol) was added and the
deep-red solution was stirred for 5 min. After addition of the alkyl
halide (7.5 mmol) stirring was continued for 15 min. The reaction
mixture was diluted with H2O (15 mL) and saturated sodium bicar-
bonate solution (25 mL), and extracted with Et2O (3 × 30 mL). The
combined organic layers were dried over MgSO4 and concentrated
under reduced pressure and excess DMF was removed under high
vacuum. The residue was redissolved in MeOH (25 mL) and HCl (1 M,
25 mL) was added. The solution was stirred at r.t. for 2 h, then extract-
ed with Et2O (3 × 50 mL). At 0 °C, the aqueous layer was brought to pH
>12 by addition of aqueous sodium hydroxide solution (5 M) and ex-
tracted with Et2O (3 × 50 mL). The combined organic extracts were
Prepared according to the general procedure using 1-bromobutane
(1.03 g, 7.5 mmol).
Yield: 610 mg (3.98 mmol, 80%); colourless liquid.
FTIR (neat, ATR): 2956 (m), 2858 (m), 2360 (w), 1593 (bw), 1147 (m),
1008 (m), 912 (m), 883 (m), 729 (s) cm–1
.
1H NMR (300 MHz, CDCl3): δ = 7.27 (dd, J = 1.7, 0.8 Hz, 1 H), 6.24 (dd,
J = 3.1, 1.7 Hz, 1 H), 6.05 (d, J = 3.1 Hz, 1 H), 3.83 (t, J = 6.9 Hz, 1 H),
1.61–1.80 (m, 4 H), 1.15–1.36 (m, 4 H), 0.84 (t, J = 6.9 Hz, 3 H).
13C NMR (75 MHz, CDCl3): δ = 159.4, 141.1, 109.9, 104.0, 49.8, 36.2,
28.3, 22.5, 13.9.
HRMS: m/z [M + H]+ calcd for C9H16NO: 154.1226; found: 154.1226.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 2093–2099