Phototransformations of C-Benzoylaziridines
J . Org. Chem., Vol. 61, No. 13, 1996 4245
gave 75 mg (68%) of 17, mp 145-146 °C (mixture mp), after
recrystallization from a mixture (1:9) of benzene and petroleum
ether.
Anal. Calcd for C28H27NO6: C, 71.03; H, 5.70; N, 2.95.
Found: C, 71.42; H, 5.46; N, 2.84.
Tr a n sfor m a tion of 28 to 27. A solution of 28 (20 mg,
0.054 mmol) in methanol (5 mL) was refluxed for 1 h. Removal
of the solvent gave 19 mg (95%) of 27, mp 147-148 °C, after
recrystallization from a mixture (1:1) of benzene and petroleum
ether: IR νmax 3350, 2850, 1720, 1680, 1575 cm-1; UV λmax
(methanol) 215 nm (ꢀ 18 000), 245 (12 000), 280 (5000); 1H
NMR (CDCl3) δ 1.15-2.65 (10H, m), 3.80 (3H, s), 3.91 (3H, s),
7.25-7.65 (6H, m), 8.30-8.55 (1H, D2O-exchangeable); mass
spectrum m/e (rel intensity) 369 (M+, 1), 264 (18), 232 (100),
200 (12), 105 (25), 77 (30).
Ir r a d ia tion of 1a in th e P r esen ce of DMAD. A mixture
of 1a (1.0 g, 3.0 mmol) and DMAD (0.85 g, 6.0 mmol) in
acetonitrile (350 mL) was irradiated (Hanovia 450-W, medium-
pressure Hg lamp) for 45 min at 15-20 °C. Removal of the
solvent under vacuum gave an oily residue, which was chro-
matographed over Florisil. Elution with a mixture (1:9) of
benzene and petroleum ether gave 0.33 g of the unchanged
DMAD, bp 95-98 °C (19 mm). Further elution with a mixture
(2:3) of benzene and petroleum ether gave 100 mg (9%) of
dimethyl meso-2,3-dibenzoylsuccinate, mp 189-190 °C (lit.18
mp 183-184 °C), after recrystallization from a mixture (1:9)
of benzene and petroleum ether: IR νmax (KBr) 3080, 2940,
1725, 1665, 1588 cm-1; UV λmax (methanol) 222 nm (ꢀ 12 000),
258 (23 500), 290 (16 400), 298 (15 000); 1H NMR (CDCl3) δ
3.75 (6H, s), 5.83 (2H, s), 7.58-7.97 (6H, m), 8.18-8.56 (4H,
m); 13C NMR (CDCl3) δ 52.79, 53.41, 128.66, 129.35, 133.74,
136.21, 167.67, 193.77; mass spectrum m/e (rel intensity) 354
(M+, 11), 338 (7), 337 (62), 323 (8), 305 (17), 291 (78), 232 (99),
105 (100).
Anal. Calcd for C21H23NO5: C, 68.29; H, 6.23; N, 3.79.
Found: C, 68.02; H, 6.42; N, 3.55.
P h ototr a n sfor m a tion of 25 to 27. A solution of 25 (110
mg; 0.3 mmol) in acetonitrile (15 mL) was irradiated (RPR 300
nm) for 5 h. Removal of the solvent under vacuum gave a
residue which was separated over chromatotron. Elution with
a mixture (1:3) of ethyl acetate and petroleum ether gave 95
mg (86%) of 27, mp 147-148 °C (mixture mp), after recrys-
tallization from a mixture (1:1) of benzene and petroleum
ether.
In a separate experiment, irradiation of a solution of 25 in
acetonitrile for 3 h and separation of the product mixture over
chromatotron gave a mixture of 28 (62%) and 27 (7%), along
with some unchanged starting material 25 (23%).
In a blank run, a solution of 25 (20 mg; 0.054 mmol) in
methylene chloride (5 mL) was refluxed for 3 h. Removal of
the solvent gave a quantitative recovery (98%) of the un-
changed starting material 25.
Anal. Calcd for C20H18O6: C, 67.79; H, 5.08. Found: C,
67.85; H, 5.18.
Further elution with a mixture (1:1) of benzene and petro-
leum ether gave 25 mg (2%) of dimethyl 1-cyclohexyl-2-
benzoylpyrrole-3,4-dicarboxylate (25), mp 109-110 °C, after
recrystallization from a mixture (1:9) of benzene and petroleum
ether: IR νmax (KBr) 3075, 2860, 1730, 1720, 1640, 1595 cm-1
;
UV λmax (methanol) 244 nm (ꢀ 23 300), 250 (22 400), 298
(12 500); 1H NMR (CDCl3) δ 1.08-2.33 (10H, m), 3.23 (3H, s),
3.84 (3H, s), 4.23-4.68 (1H, m), 7.28-7.93 (6H, m); 13C NMR
(CDCl3) δ 25.23, 25.53, 34.54, 51.49, 57.22, 114.14, 122.52,
127.15, 128.40, 129.01, 133.0, 138.75, 164.29, 188.02; mass
spectrum m/e (rel intensity) 369 (M+, 15), 338 (100), 307 (71),
224 (40), 105 (40).
Ir r a d ia tion of 1b in th e P r esen ce of DMAD. A mixture
of 1b (1.0 g, 3.0 mmol) and DMAD (0.85 g, 6.0 mmol) in
acetonitriel (350 mL) was irradiated (Hanovia 450-W, medium-
pressure Hg lamp) for 1 h at 15-20 °C. Removal of the solvent
under vacuum gave an oily substance, which was chromato-
graphed over Florisil. Elution with a mixture (1:9) of benzene
and petroleum ether gave unchanged DMAD (0.36 g), bp 95-
98 °C (19 mm). Continued elution with a mixture (1:1) of
benzene and petroleum ether gave 90 mg (8%) of dimethyl
meso-2,3-dibenzoylsuccinate, mp 189-190 °C (mixture mp),18
after recrystallization from a mixture (1:9) of benzene and
petroleum ether. Continued elution with a mixture (1:1) of
benzene and petroleum ether gave 50 mg (3%) of the pyrrole
25, mp 109-110 °C (mixture mp), after recrystallization from
a mixture (1:9) of benzene and petroleum ether. Further
elution with benzene gave 770 mg (54%) of the pyrroline 22b
(superimposable ir spectrum). Subsequent elution with a
mixture (7:3) of benzene and ethyl acetate gave 100 mg (9%)
of 28, mp 153-154 °C (mixture mp), after recrystallization
from a mixture (3:7) of benzene and petroleum ether.
Ir r a d ia tion of 3a in th e P r esen ce of DMAD. A mixture
of 3a (1.0 g, 3.27 mmol) and DMAD (0.93 g, 6.55 mmol) in
acetonitrile (350 mL) was irradiated (Hanovia 450-W, medium-
pressure Hg lamp) for 1 h at 15-20 °C. Removal of the solvent
under vacuum gave an oily substance, which was chromato-
graphed over Florisil. Elution with a mixture (1:9) of benzene
and petroleum ether gave 0.4 g of the unchanged DMAD, bp
95-98 °C (19 mm). Continued elution with benzene gave 380
mg (26%) of 32,3f mp 142-143 °C (mixture mp), after recrys-
tallization from methanol. Subsequent elution with a mixture
(9:1) of benzene and ethyl acetate gave 750 mg (51%) of 33a
as a viscous liquid: IR νmax (neat) 3080, 2960, 1715, 1680, 1590
cm-1; UV λmax (methanol) 225 nm (ꢀ 44 000), 268 (29 500), 284
Anal. Calcd for C21H23NO5: C, 68.29; H, 6.23; N, 3.79.
Found: C, 68.45; H, 6.01; N, 3.75.
Continued elution with benzene gave 880 mg (62%) of
dimethyl cis-1-cyclohexyl-2,5-dibenzoyl-3-pyrroline-3,4-dicar-
boxylate (22b) as a viscous liquid: IR νmax (neat) 3066, 2950,
1730, 1685, 1595 cm-1; UV λmax (methanol) 225 (ꢀ 53 000), 258
(47 500), 295 (18 000); 1H NMR (CDCl3) δ 1.12-2.08 (11H, m),
3.68 (2H, s), 3.85 (6H, s), 7.15-8.30 (10H, m).
Anal. Calcd for C29H29NO6: C, 70.73; H, 6.10; N, 2.98.
Found: C, 71.10; H, 5.87; N, 2.68.
Subsequent elution with a mixture (7:3) of benzene and
ethyl acetate gave 132 mg (12%) of the spiro compound 28,
mp 153-154 °C, after recrystallization from a mixture (3:7)
of benzene and petroleum ether: IR δmax (KBr) 3450, 3110,
2980, 1720, 1695, 1600 cm-1; UV λmax (methanol) 228 nm (ꢀ
47 600), 273 (26 000); 1H NMR (CDCl3) δ 1.08-2.43 (10H, m),
3.63 (3H, s), 3.69 (1H, s, D2O-exchangeable), 3.88 (3H, s), 7.20-
7.68 (6H, m); 13C NMR (CDCl3) δ 23.01, 23.22, 24.77, 32.03,
33.97, 51.25, 51.42, 84.25, 85.19, 108.79, 118.52, 122.59,
127.18, 128.08, 128.35, 138.47, 144.62, 163.25, 164.17; mass
spectrum m/e (rel intensity) 369 (M+, 7), 338 (18), 337 (46),
264 (100), 233 (12), 232 (65), 105 (67).
Anal. Calcd for C21H23NO5: C, 68.29; H, 6.23; N, 3.79.
Found: C, 68.39; H, 6.25; N, 3.80.
Nick el P er oxid e Oxid a tion of 22b to 23. A mixture of
22b (238 mg, 0.5 mmol) and freshly prepared nickel peroxide17
(90 mg, 1 mmol) in benzene (15 mL) was stirred at 20 °C for
40 h. Workup of the mixture as in the previous case gave 180
mg (76%) of 23 mp 182-183 °C, after recrystallization from a
mixture (1:9) of benzene and petroleum ether: IR νmax (KBr)
3040, 2920, 1700, 1645, 1585 cm-1; UV λmax (methanol) 227
1
(3500); H NMR (CDCl3) δ 0.75-2.38 (11H, m), 3.32 (1H, s),
3.63 (1H, s), 3.75 (3H, s), 3.92 (3H, s), 7.08-7.95 (10H, m).
Anal. Calcd for C27H29NO5: C, 72.48; H, 6.48; N, 3.13.
Found: C, 72.08; H, 6.27; N, 3.27.
Air Oxid a tion of 33a to 32. A solution of 33a (200 mg,
0.41 mmol) in benzene (10 mL) was refluxed for 5 h under
oxygen saturation. Removal of the solvent under vacuum gave
190 mg (96%) of 32, mp 142-143 °C (mixture mp),3f after
recrystallization from methanol.
Ir r a d ia tion of 3b in th e P r esen ce of DMAD. A mixture
of 3b (1.0 g, 3.27 mmol) and DMAD (0.93 g, 6.55 mmol) in
acetonitrile (350 mL) was irradiated for 3 h and worked up as
in the earlier case by chromatographing over Florisil to give
1
nm (ꢀ 52 000), 267 (62 500), 300 (31 500); H NMR (CDCl3) δ
0.93-2.13 (10H, m), 3.31 (6H, s), 4.05-4.50 (1H, m), 7.33-
8.21 (10H, m); 13C NMR (CDCl3) δ 24.67, 26.07, 32.99, 51.58,
60.62, 109.78, 128.73, 129.30, 133.83, 134.85, 137.98, 163.04,
189.45; mass spectrum m/e (rel intensity) 473 (M+, 3), 442 (6),
441 (16), 336 (2), 105 (100).
(18) Pfleger, R.; Reinhardt, F. Chem. Ber. 1957, 90, 2404-2411.