A New Synthesis of 2-Methyleneaziridines
J . Org. Chem., Vol. 62, No. 8, 1997 2451
in 300 mL of absolute methanol was treated portionwise with
0.3 mol of sodium borohydride. After the vigorous reaction
ceased, the solution was refluxed for 2 h. The cooled solution
was then poured in 500 mL of water, and extraction was
performed three times with dichloromethane. The combined
extracts were dried (MgSO4) and evaporated in vacuo to give
an oil, which consisted mainly of 2-(bromomethyl)aziridine 7
(>95%). Purification was performed by vacuum distillation
ArCH2N); 83.5 (t, CH2dC); 127.3 (d, Cpara); 128.2 and 128.4
(each d, Cortho and Cmeta); 137.0 and 138.2 (each s, Cquat). IR
(NaCl): 1780 cm-1 (CdC). MS m/ z (relative intensity): 145
(M+; 11); 144(33); 117(11); 105(44); 91(100); 77(11); 65(33);
54(88); 39(16). Anal. Calcd 82.72 C, 7.64 H. Found: 82.79
C, 7.73 H.
1-Ben zyl-2-(ter t-bu toxym eth yl)a zir id in e (9a ): bp 72-
78 °C/0.05 mmHg. Yield: 18%. 1H NMR (60 MHz, CDCl3) δ
1.14 (9H, s); 1.3-2.1 (3H, m); 3.1-3.7 (4H, m); 7.29 (5H, s).
13C NMR (20 MHz, CDCl3) δ 27.5 (q, Me3C); 32.3 (t, NCH2-
CH); 39.6 (d, CHN); 64.4 and 64.5 (each t, ArCH2N and CH2O);
72.9 (CO); 126.9 (d, Cpara); 128.0 and 128.3 (each d, Cortho and
Cmeta); 139.3 (s, Cquat). IR (NaCl): 2980, 1457, 1363, 1198,
1079, 1028 cm-1. MS m/ z (relative intensity): 219 (M+; 0.5);
204(1); 189(0.5); 174(1); 163(10); 162(14); 146(33); 134(4);
133(10); 132(7); 91(92); 72(49); 65(14); 57(100); 44(7); 42(14);
41(28). Anal. Calcd 76.67 C, 9.65 H, 6.39 N. Found: 76.81
C, 9.52 H, 6.49 N.
1-[(4-Me t h ylp h e n yl)m e t h yl]-2-m e t h yle n e a zir id in e
(8b): bp 48-52 °C/0.05 mmHg. Yield: 48%. 1H NMR (270
MHz, CDCl3) δ 2.09 (2H, s); 2.33 (3H, s); 3.64 (2H, s); 4.70
(2H, s); 7.14 and 7.23 (each 2H, each d, J ) 7.75 Hz). 13C NMR
(68 MHz, CDCl3) δ 21.1 (Me); 30.4 (CH2dCCH2N); 62.5
(ArCH2N); 83.4 (CH2dC); 128.2 and 129.1 (Carom); 135.1, 136.9
and 137.0 (CH2dC and 2 × Cquat). IR (NaCl): 1777 cm-1 (νCdC).
MS m/ z (relative intensity): 159 (M+; 9); 158(11); 144(5);
131(9); 119(21); 106(11); 105(100); 104(7); 103(12); 91(12);
79(25); 78(8); 77(25); 65(11); 63(7); 54(34); 51(13); 44(5); 41(9).
Anal. Calcd 82.97 C, 8.23 H. Found: 83.11 C, 8.18 H.
2-(ter t-Bu toxym eth yl)-1-[(4-m eth ylph en yl)m eth yl]azir -
id in e (9b): bp 78-79 °C/0.05 mmHg. Yield: 18%. 1H NMR
(270 MHz, CDCl3) δ 1.17 (9H, s); 1.44 (1H, d, J ) 6.26 Hz);
1.67-1.76 (2H, m); 2.32 (3H, s); 3.20 and 3.46 (each 1H, ABX,
J AB ) 9.90 Hz, J AX ) J BX ) 5.61 Hz); 3.38 and 3.43 (each 1H,
AB, J ) 13.36 Hz); 7.11 and 7.25 (each 2H, each d, J ) 7.76
Hz). 13C NMR (68 MHz, CDCl3) δ 21.1 (MeAr); 27.5 (Me3C);
32.3 (NCH2CH); 39.5 (NCH2CH); 64.1 (NCH2Ar); 64.5 (CH2O);
72.8 (CO); 127.9 and 128.9 (Carom); 136.2 and 136.3 (each Cquat).
1
affording pure compounds 7 (>98%; H NMR, GC).
1-Ben zyl-2-(br om om eth yl)a zir id in e (7a ): bp 72-75 °C/
0.05 mmHg. 1H NMR (270 MHz, CDCl3) δ 1.64 (1H, d, J )
6.27 Hz); 1.81 (1H, d, J ) 3.30 Hz); 1.91-2.00 (1H, m); 3.26-
3.35 (2H, m); 3.41 and 3.58 (each 1H, each d, J ) 13.19 Hz);
7.26-7.37 (5H, m). 13C NMR (20 MHz, CDCl3) δ 35.3 (t, CH2-
Br); 39.9 (d, CHN); 63.8 (t, ArCH2N); 126.9 (Cpara); 127.9 and
128.1 (d, Cortho and Cmeta); 138.5 (s, Cquat). IR (NaCl): 1496,
1455, 1357, 1223, 1157 cm-1
. MS m/ z (relative intensity):
225/7 (M+, 1); 146 (M+ - Br, 33); 91(100); 65(21); 55(10); 51(10);
44(12); 42(25). Anal. Calcd 53.12 C, 5.35 H. Found: 53.21
C, 5.43 H.
2-(Br om om e t h yl)-1-[(4-m e t h ylp h e n yl)m e t h yl]a zir i-
d in e (7b): bp 80-82 °C/0.08 mmHg. 1H NMR (60 MHz, CCl4)
δ 1.3-1.9 (3H, m); 2.27 (3H, s); 2.9-3.3 (2H, m); 3.13 and 3.33
(2H, each d, AB, J ) 13 Hz); 7.07 (4H, s). 13C NMR (20 MHz,
CDCl3) δ 21.0 (q, each Me); 35.1 and 35.4 (each t, NCH2CH
and CH2Br); 40.1 (d, NCH); 63.1 (t, NCH2Ar); 128.0 and 129.0
(each d, Cortho and Cmeta); 135.3 (s, dCMe); 136.6 (s, CH2Cd).
IR (NaCl): 1521, 1442, 1354, 1220, 1151, 1052, 1020 cm-1. MS
m/ z (relative intensity): 239/41 (M+, 1); 160 (M+ - Br, 18);
105(100); 79(11); 77(11); 65(3); 55(9); 44(9); 42(3); 41(4). Anal.
Calcd 55.02 C, 5.88 H. Found: 54.91 C, 5.93 H.
2-(Br om om e t h yl)-1-[4-(ch lor op h e n yl)m e t h yl]a zir i-
d in e (7c). Compound 7c decomposed during high vacuum
distillation. 1H NMR (60 MHz, CCl4) δ 1.4-2.0 (3H, m); 3.1-
3.3 (2H, m, CH2Br); 3.29 and 3.47 (each 1H, each d, AB, J )
13.6 Hz); 7.27 (4H, s). 13C NMR (20 MHz, CDCl3) δ 35.0 (d ×
d, NCH2CH); 35.7 (t, CH2Br); 40.3 (d, NCH); 63.5 (t, NCH2-
Ar); 128.5 and 129.5 (each d, Cortho and Cmeta); 133.0 (s, CCl);
137.1 (s, Cquat). IR (NaCl): 1594, 1490, 1407, 1350, 1220, 1085,
1012 cm-1. MS m/ z (relative intensity): 259/61 (M+, 1); 180/2
(M+ - Br); 125/7(100); 99(6); 90(11); 89(15); 83(4); 77(4); 75(5);
63(10); 55(16); 54(8); 51(7); 50(3); 49(6); 44(14); 42(34); 41(12).
Anal. Calcd 5.38 N. Found: 5.30 N.
IR (NaCl): 2971, 1361, 1252, 1232, 1197, 1080 and 1021 cm-1
.
MS m/ z (relative intensity): 233 (M+; 0.7); 232(0.5); 218(1);
203(0.5); 202(0.5); 198(0.6); 197(0.4); 172(5); 171(9); 161(3);
160(21); 158(3); 148(3); 147(5); 146(4); 119(3); 105(76); 103(3);
91(3); 79(4); 77(4); 72(58); 57(100). Anal. Calcd 6.00 N.
Found: 6.07 N.
2-(Br om om eth yl)-1-(2,2-d im eth yl-3-p h en ylp r op yl)a zir -
id in e (7d ): bp 120-124 °C/0.05 mmHg. 1H NMR (60 MHz,
CDCl3) δ 0.87 and 0.93 (each 3H, each s); 1.2-1.8 (3H, m);
1.87 and 2.25 (each 1H, each d, J ) 12 Hz); 2.61 and 2.72 (each
1H, each d, J ) 13 Hz); 3.1-3.5 (2H, m); 7.25 (5H, s). 13C
NMR (20 MHz, CDCl3) δ 25.5 and 25.9 (each q, Me2); 35.6 (t,
CH2Br); 36.2 (s, Me2C); 36.5 (t, NCH2CH); 39.7 (d, NCH2CH);
71.0 (t, NCH2C); 125.7 (d, Cpara); 127.5 and 130.6 (each d, Cortho
1-[(4-Ch lor op h e n yl)m e t h yl]-2-m e t h yle n e a zir id in e
(8c): bp 67-79 °C/0.01 mmHg. Yield: 40%. 1H NMR (270
MHz, CDCl3) δ 2.11 (2H, s, CH2dCCH2N); 3.63 (2H, s, ArCH2);
4.69-4.72 (2H, m, CH2dC); 7.89 (4H, s, C6H4). 13C NMR (68
MHz, CDCl3) δ 30.6 (CCH2N); 62.0 (ArCH2N); 83.8 (CH2));
128.5 and 129.5 (Carom); 133.1 and 136.7 (CH2dC and 2 × Cquat).
IR (NaCl): 1779 cm-1 (νCdC). MS m/ z (relative intensity): 179/
81 (M+; 17); 178/80(28); 151/3(13); 139/41(41); 140(7); 125/7(63);
126(11); 103(15); 99(11); 90(9); 89(29); 77(6); 75(8); 62(11);
54(100); 51(7). Anal. Calcd 7.80 N. Found: 7.73 N.
and Cmeta); 138.8 (Cquat). IR (NaCl): 3020 cm-1
. MS m/ z
(relative intensity): 281/83 (M+; 2); 202(3); 150(18); 148(18);
146(15); 131(13); 117(6); 105(4); 91(51); 70(100); 56(13); 55(20);
42(73); 41(24). Anal. Calcd 59.58 C, 7.14 H; 4.96 N. Found:
59.40 C, 7.27 H; 5.09 N.
2-(ter t-Bu toxym eth yl)-1-[(4-ch lor op h en yl)m eth yl]a zir -
id in e (9c). Isolated by flash chromatography using silica gel,
ethyl acetate:hexane 1:4; Rf 0.24. Yield: 13%. 1H NMR (270
MHz, CDCl3) δ 1.18 (9H, s, Me3); 1.45 (1H, d, J ) 6.11 Hz,
Hb); 1.69-1.78 (2H, m, Ha and Hc); 3.29 and 3.38 (each 1H,
ABX, J AB ) 10.01 Hz, J AX ) 5.62 Hz, J BX ) 4.64 Hz, CH2O);
7.28 and 7.34 (each 2H, each d, J ) 8.42 Hz, C6H4). 13C NMR
(68 MHz, CDCl3) δ 27.5 (Me3); 32.1 (CHCH2N); 39.8 (CHN);
63.4 and 64.4 (ArCH2N and CH2O); 72.9 (CO); 128.2 and 129.2
(Carom); 132.6 and 137.8 (each Cquat). IR (NaCl): 2975, 1493,
Syn th esis of 2-Meth ylen ea zir id in es 8. A stirred solution
of 0.05 mol of 1-(arylmethyl)-2-(bromomethyl)aziridine 7 in 100
mL of dry tetrahydrofuran was treated portionwise with 0.075
mol of potassium tert-butoxide. The heterogeneous mixture
was stirred for 24 h at room temperature after which it was
poured in 300 mL of water. Extraction was performed three
times with diethyl ether, and the combined extracts were
washed with 50 mL of brine, dried (MgSO4), and evaporated
in vacuo to give an oil. Vacuum distillation of the reaction
mixture afforded 40-48% yield of 2-methyleneaziridines 8 and
18% of 2-(tert-butoxymethyl)aziridines 9a ,b. 2-(tert-butoxy-
methyl)-1-[(4-chlorophenyl)methyl]aziridine (9c) was isolated
from the residue of distillation by flash chromatography (silica
gel; ethyl acetate:hexane 1:4; Rf 0.24, yield 13%) after the
corresponding 2-methyleneaziridine 8c had been removed by
vacuum distillation.
1365, 1196, 1081, 910 cm-1
. MS m/ z (relative intensity):
253/7 (M+; 0.5); 196/8 (M+ - 57, 17); 197(8); 180/2(28); 181(5);
167(9); 166(6); 127(22); 126(8); 125(60); 89(10); 72(57); 58(7);
57(100); 55(5); 44(9); 42(13); 41(28). Anal. Calcd 5.53 N.
Found: 5.66 N.
1-(2,2-Dim e t h yl-3-p h e n ylp r op yl)-2-m e t h yle n e a zir i-
d in e (8d ): bp 61-65 °C/0.06 mmHg. Yield: 46%. 1H NMR
(270 MHz, CDCl3) δ 0.87 (6H, s); 2.02 (2H, s); 2.22 (2H, s);
2.58 (2H, s); 4.57-4.58 (2H, m); 7.07-7.22 (5H, m). 13C NMR
(68 MHz, CDCl3) δ 25.4 (Me2); 32.2 (NCH2CdCH2); 36.0
(CMe2); 46.3 (CH2C6H5); 70.2 (NCH2CMe2); 81.8 (CH2dC);
125.8 (Cpara); 127.7 and 130.6 (Cortho and Cmeta); 137.2 and 138.9
1-Ben zyl-2-m eth ylen ea zir id in e (8a ): bp 46-54 °C/0.05
mmHg. Yield: 40%. 1H NMR (60 MHz, CDCl3) δ 2.06 (2H, t,
J ) 1 Hz); 3.66 (2H, s); 4.72 (2H, t, J ) 1 Hz); 7.34 (5H, s). 13
C
NMR (20 MHz, CDCl3) δ 30.6 (t, CH2dCCH2N); 62.8 (t,