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Madiha Kamoun Mhiri et al.
(silica gel, Petroleum ether / Ethyl ether: 20/80 for the
2. Experimental
compound 2, Ethyl ether/Ethyl acétate: 90/10 for the
compound 3, Petroleum ether /Ethyl ether: 50/40 for the
compound 4).
2.1 Materials, methods and instruments
The infrared spectra were recorded in CH2Cl2 on a
Bruker spectrometer IFS66V/S -IR 420 (between 400
2.3 Analytical data
1
and 4000 cm−1). The H NMR spectra were recorded
1
in CDCl3 on a Bruker AC spectrometer (300 MHz H
N-propanoyl-2,2-dimethylaziridine (1a). IR (CH2Cl2,
frequency). The 13C NMR spectra were recorded in
CDCl3 on a Bruker AC spectrometer (75 MHz 13C fre-
quency). Chemical shifts are reported in ppm from
internal TMS. Silica gel (70–230 mesh, Merck) was
used for the separation by column chromatography.
1
cm−1): ν (C=O) 1678. H NMR (300 MHz, CDCl3,
ppm): δ 1.15 (3H, q, J = 6 Hz, CH3), 1.35 (6H, s,
2CH3), 2.12 (2H, s, CH2N), 2.35 (2H, t, J = 6 Hz, CH2).
13C NMR (75 MHz, CDCl3, ppm): δ 9.32 (CH3), 23.06
(CH3), 30.92 (CH2), 36.82 (CH2N), 40.65 (Cq), 185.32
(C=O).
2.2 Synthesis
5,5-dimethyl-2-propyloxazoline (2a). IR: (CH2Cl2,
1
cm−1): ν (C=N) 1662. H NMR (300 MHz, CDCl3,
2.2a Synthesis of N-acylaziridines: N-acyl-2,2-di-
methylaziridines 1a-e were prepared from 2,2-
dimethylaziridine and various acyl chorides with an
excess of triethylamine in dry benzene according to
ppm): δ 1.18 (3H, t, J = 6 Hz, CH3), 1.40 (6H, s,
2CH3), 2.28 (2H, q, J = 6 Hz, CH2), 3.55 (2H, s, CH2N).
13C NMR (75 MHz, CDCl3, ppm): δ 10.02 (CH3),
21.91 (CH2), 27.33 (2CH3), 66.43 (CH2N), 83.41 (Cq),
168.34 (C=N).
N-(2-hydroxy-2-methylpropyl)propylamide (3a). IR
(CH2Cl2, cm−1): ν (C=O) 1657, (NH) 3443, (OH)
2.2b Typical procedure of the rearrangement of N-
acylaziridines 1:
1
3585. H NMR (300 MHz, CDCl3, ppm): δ 1.12 (2H,
t, J = 6 Hz, CH2), 1.28 (6 H, s, 2CH3), 2.28 (2H,
q, J = 6 Hz, CH2), 2.56 (1H, s, OH), 3.27 (2H, s,
CH2N), 6.22 (1H, s, NH). 13C NMR (75 MHz, CDCl3,
ppm): δ 10.06 (CH3), 27.21 (2CH3), 29.59 (CH2), 50.36
(CH2N), 70.77 (Cq), 175.13 (C=O).
2.2b1 Reaction of conc. H2SO4 with N-acylaziridines
1: A cold 30 mL of conc. sulfuric acid was added to
2 mmol of aziridine 1 at a low temperature and then
stirred at room temperature for 2 h 30 min. The reaction
was quenched with 10% NaOH and the aqueous mix-
ture was extracted with ether (3×100 mL). The organic
extracts were combined, dried over anhydrous MgSO4,
filtered and concentrated to give oxazoline 2.
N-(2-methylprop-2-enyl)-propylamide (4a). IR
(CH2Cl2, cm−1): ν (C=C) 1648, (C=O) 1665, (NH)
3333, 3445. 1H NMR (300 MHz, CDCl3, ppm): δ 1.19
(3H, q, J = 6 Hz, CH3), 1.73 (3H, s, CH3), 2.28 (2H,
t, J = 6 Hz, CH2), 3.70 (2H, d, J = 6 Hz, CH2N) ;
4.83 (2H, s, CH2 =C), 5.84 (1H, s, NH). 13C NMR
(75 MHz, CDCl3, ppm): δ 10.01 (CH3), 20.34 (CH3),
29.74 (CH2), 44.95 (CH2N), 110.74 (CH2 =), 142.17
(C=), 173.80 (C=O).
2.2b2 Reaction of ultrapure water with N-acyla-
ziridines 1: A mixture of 2 mmol of aziridine 1, 2 mL
of ether and 10 mL of ultrapure water was stirred at
room temperature for 96 h. The mixture was extracted
with ether (3 × 100 mL). The organic extracts were
combined, dried over anhydrous MgSO4, filtered and
concentrated to give amidoalcohol 3.
N-benzyloyl-2,2-dimethylaziridine (1b). IR (CH2Cl2,
1
cm−1): ν (C=O) 1675. H NMR (300 MHz, CDCl3,
ppm): δ 1.20 (6H, s, 2CH3), 2.05 (2H, s, CH2N), 3.60
(2H, s, CH2Ph), 7.10-7.25 (5H, m, C6H5). 13C NMR (75
2.2b3 Reaction of N-acylaziridines 1 with a mixture of MHz, CDCl3, ppm): δ 23.69 (2CH3), 36.97 (CH2N),
water and sulfuric acid in different concentration: 41.35 (Cq), 45.22 (CH2Ph), 126.83 (C, Ph), 127.29 (2C,
cold solution of 9% or 48% H2SO4 by wt. in water was Ph), 128.62 (2C, Ph), 134.73 (Cq), 181.69 (C=O).
added to a mixture of 2 mmol of aziridine 1 in 2 mL of 2-benzyl-5,5-dimethyloxazoline (2b). IR (CH2Cl2,
A
1
ether at a low temperature and then stirred at room tem- cm−1): ν (C=N) 1659. H NMR (300 MHz, CDCl3,
perature for 96 h. The crude reaction was quenched with ppm): δ 1.28 (6H, s, 2CH3), 3.40 (2H, s, CH2Ph),
10% NaOH to neutral pH, and the aqueous mixture was 3.45 (2H, s, CH2N), 7.12-7.21 (5H, s, C6H5). 13C
extracted with ether (3 × 100 mL). The organic layers NMR (75 MHz, CDCl3, ppm): δ 27.83 (2CH3), 43.46
were combined, dried over anhydrous MgSO4, filtered (CH2Ph), 66.09 (CH2N), 84.20 (Cq), 126.82 (C, Ph),
and concentrated to give a mixture of compounds 2-4. 128.67 (2C, Ph), 129.10 (2C, Ph), 134.05 (Cq), 166.03
The products were purified by column chromatography (C=N).