K. Ajay Kumar et al. / Tetrahedron 57 &2001) 6993±6996
6995
In support of the formation of pyrrolines 4, we carried out
the base-induced cycloelimination reaction of oxime tosyl-
ate 6 in the presence of solid sodium ethoxide to form
azirine 7. Furthermore, the azirine 7 was subjected to ring
expansion reaction with acrylo nitrile in the presence of
solid sodium hydroxide as the base in tetrahydrofuran as
the solvent under re¯ux conditions in a sealed tube and
obtained pyrroline 811 'Scheme 4), which supports the
formation of the products 4.
C17H17NO4S: C, 61.63, H, 5.13, N, 4.22%. Found: C,
61.51, H, 5.02, N, 4.13%.
2.1.4. 2-Phenyl-N-tosyl-aziridine 2d. Obtained from
styrene 1d '0.51g, 5.0 mmol) and chloramine-T '1.4 g,
5.0 mmol) as a white solid in 58% '0.94 g) yield. Mp
1
113±1158C, IR 'Nujol): in cm21 1162, 1318; H NMR
CDCl3: d 0.55 'd, 2H, CH2, J7.71Hz), 2.6 's, 3H, Ar±
CH3), 3.35 't, 1H, CH, J7.36 Hz), 7.3±7.5 'm, 9H, Ar±H).
MS 'relative abundance) m/z: 274 'MH1, 52), 181 '28), 117
'48), 77 '100). Anal. Calcd for C15H15NO2S: C, 65.93, H,
5.49, N, 5.12%. Found: C, 65.81, H, 5.39, N, 4.97%.
In summary, we have demonstrated for the ®rst time that
pyrrolines can be synthesized via silver nitrate catalyzed
aziridination of alkenes using inexpensive chloramine-T
followed by pyrolysis in presence of alkenes in a sealed
tube.
2.1.5. Typical procedure for the preparation of 2,3-
dicyano-1-pyrroline 4a.
A mixture of 2a '0.44 g,
2.0 mmol) and alkene 3a '0.10 g, 2.0 mmol) and sodium
hydroxide '1±2 pellets) in tetrahydrofuran '10 mL) were
re¯uxed on a water bath in a sealed tube for 3 h. The mixture
was then cooled to room temperature and the solvent was
concentrated in vacuo. The pasty mass was extracted into
ether '50 mL). The ethereal solution was washed succes-
sively with 10% aqueous sodium hydroxide '2£15 mL),
water '2£20 mL), and brine solution '1£15 mL) and dried
over anhydrous sodium sulphate. Evaporation of the solvent
yielded an oily substance. The TLC of the product showed
one major spot corresponding to the product and one minor
spot related to the unreacted starting materials, which was
puri®ed by column chromatography using hexane/ethyl
acetate '8:2) as eluent, which afforded 4a as a colourless
oil in 56% '0.125 g) yield. IR 'Nujol) in cm21: 1685, 2245;
1H NMR CDCl3: d 1.90 'm, 2H, 4-H), 3.90 't, 2H, 5-H,
J5.26 Hz), 5.67 't, 1H, 3-H, J6.42 Hz). 13C NMR
'CDCl3): d 42.12 't, 1C, 5-C), 46.28 't, 1C, 4-C), 95.22
'd, 1C, 3-C), 115.62 's, 1C, CN), 117.28 's, 1C, CN),
159.42 's, 1C, 2-C). MS 'relative abundance) m/z: 1 1 9
'M1, 16), 117 '33), 92 '100), 67 '54). Anal. Calcd for
C6H5N3: C, 60.50, H, 4.20, N, 35.29%. Found: C, 60.42,
H, 4.10, N, 35.21%. The same procedure was used in all
cases.
2. Experimental
2.1. Data for compounds
2.1.1. A typical procedure for the preparation of 2-
cyano-N-tosyl-aziridine 2a. To a well stirred mixture of
chloramine-T trihydrate '1.4 g, 5.0 mmol), silver nitrate
'0.34 g, 2 mmol) in tetrahydrofuran '20 mL), acrylo nitrile
1a '0.26 g, 5 mmol) was added dropwise and the reaction
mixture was kept in dark at room temperature for 6±8 h with
constant stirring. The AgCl formed in the reaction was
®ltered off. The ®ltrate was extracted into ether '25 mL),
washed successively with water '2£20 mL), brine solution
'1£15 mL) and dried over anhydrous sodium sulphate.
After usual workup, 2a obtained as white solid in 42%
'1.37 g) yield. Mp 83±858C, IR 'Nujol): in cm21 1161,
1322, 1748; 1H NMR CDCl3: d 0.4 'd, 2H, CH2,
J7.71Hz), 2.3 's, 3H, Ar±CH 3), 2.9 't, 1H, CH,
J7.45 Hz), 7.2 's, 4H, Ar±H). MS 'relative abundance)
m/z: 223 'MH1, 71), 195 '52), 91 '100), 66 '16). Anal.
Calcd for C10H10N2O2S: C, 54.05, H, 4.50, N, 12.61%.
Found: C, 54.00, H, 4.41, N, 12.46%. The same procedure
was used in all cases.
2.1.6.
Diethyl-1-pyrrolinyl-2,3-dicarboxylate
4b.
Obtained from 2b '0.49 g, 2.0 mmol) and 3b '0.20 g,
2.0 mmol) as a colourless oil in 46% '0.19 g) yield. IR
2.1.2. Ethyl-N-tosyl-aziridine-2-carboxylate 2b. Obtained
from ethyl acrylate 1b '0.49 g, 5.0 mmol), and chloramine-
T '1.4 g, 5.0 mmol) as a colourless solid in 51% '0.82 g)
yield. Mp 91±938C, IR 'Nujol): in cm21 1166, 1324, 1741;
1H NMR CDCl3: d 0.3 'd, 2H, CH2, J7.74 Hz), 1.2 't, 3H,
CH3, J3.83 Hz), 2.35 's, 3H, Ar±CH3), 3.0 't, 1H, CH,
J7.41Hz), 4.50 'q, 2H, OCH 2, J3.91Hz), 7.3 's, 4H,
Ar±H). MS 'relative abundance) m/z: 270 'MH1, 62), 241
'38), 197 '44), 114 '12), 91 '100). Anal. Calcd for
C12H15NO4S: C, 53.53, H, 5.57, N, 5.20%. Found: C,
53.44, H, 5.41, N, 5.08%.
1
'Nujol) in cm21: 1682, 1742; H NMR CDCl3: d 1.20±
1.30 'm, 6H, CH3), 1.95 'm, 2H, 4-H), 3.23 'q, 2H, CH2,
J3.91Hz), 3.90 't, 2H, 5-H, J5.31Hz), 5.67 't, 1H, 3-H,
J5.09 Hz). 13C NMR 'CDCl3): d 13.52 'CH3), 42.86 't,
1C, 5-C), 46.86 't, 1C, 4-C), 62.32 't, 1C, CH2), 95.86 'd,
1C, 3-C), 158.96 's, 1C, 2-C), 168.72 's, 1C, CO). MS
1
'relative abundance) m/z: 21 3 'M, 12), 211 '48), 184
'10), 140 '08), 139 '100). Anal. Calcd for C10H15NO4: C,
56.33, H, 7.04, N, 6.97%. Found: C, 56.24, H, 6.97, N,
6.86%.
2.1.3. 2-(30,40-Methylenedioxybenzyl)-N-tosyl-aziridine
2c. Obtained from 4-allyl-'1,2-methylenedioxy)benzene 1c
'0.80 g, 5.0 mmol) and chloramine-T '1.4 g, 5.0 mmol) as a
white solid in 45% '0.86 g) yield. Mp 119±1218C, IR
2.1.7. Ethyl-2-cyano-1-pyrrolinyl-3-carboxylate 4c.
Obtained from 1a '0.62 g, 1.5 mmol) and 3b '0.15 g,
1.5 mmol) as a colourless oil in 42% '0.180 g) yield. IR
1
'Nujol) in cm21: 1680, 1745, 2230; H NMR CDCl3: d
1
'Nujol): in cm21 1171, 1328; H NMR CDCl3: d 0.6 'd,
1.35 't, 3H, CH3, J3.86 Hz), 1.90 'm, 2H, 4-H), 3.30 'q,
2H, CH2, J3.94 Hz), 4.0 't, 2H, 5-H, J5.24 Hz), 5.67 't,
1H, 3-H, J5.23 Hz). 13C NMR 'CDCl3): d 13.65 'q, 1C,
CH3), 42.56 't, 1C, 5-C), 46.66 't, 1C, 4-C), 62.46 't, 1C,
CH2), 95.47 'd, 1C, 3-C), 115.26 's, 1C, CN), 159.22 's, 1C,
2H, CH2, J7.78 Hz), 2.45 's, 3H, Ar±CH3), 2.75 's, 2H,
Ar±CH2), 3.3 't, 1H, CH, J7.38 Hz), 5.90 's, 2H, OCH2O),
7.2±7.4 'm, 7H, Ar±H). MS 'relative abundance) m/z: 332
'MH1, 64), 175 '40), 135 '100). Anal. Calcd for