Article
Dalal et al.
7.030 (dbroad, 1H, J 9.0 Hz, H-3¢), 5.149 (s, 2H, 2¢-OCH2), 4.449
(s, 1H, H-2) and 4.015 (s, 1H, H-3). (2-Benzyloxy-5-chloro-
phenyl){3-(4-methoxyphenyl) oxiran-2-yl}methanone 5d:
Yield 78%, white solid, mp 134-136 °C; UV-Vis (CHCl3) l/nm
354; IR (KBr) n/cm-1 1669 (C=O); 1H NMR (300 MHz, CDCl3) d
7.803 (d, 1H, J 2.7 Hz, H-6¢), 7.431 (dd, 1H, J 9.0, 2.7 Hz, H-4¢),
7.253-7.160 (m, 5H, Ar-H), 6.970 (d, 1H, J 9.0 Hz, H-3¢),
6.858-6.772 (m, 2H, Ar-H), 6.652-6.642 (m, 2H, Ar-H), 5.093 (s,
2H, 2¢-OCH2), 4.409 (d, 1H, J 1.5 Hz, H-2), 3.906 (s, 3H, 4²-
OCH3) and 3.378 (d, 1H, J 1.5 Hz, H-3). (2-Benzyloxy-5-chloro-
phenyl){3-(4-chlorophenyl) oxiran-2-yl}methanone 5e: Yield
81%, white solid, mp 92-94 °C; UV-Vis (CHCl3) l/nm 352; IR
(KBr) n/cm-1 1670 (C=O); 1H NMR (300 MHz, CDCl3) d 7.808
(d, 1H, J 2.7 Hz, H-6¢), 7.434 (dd, 1H, J 9.0, 2.7 Hz, H-4¢), 7.259-
7.136 (m, 7H, Ar-H), 6.969 (d, 1H, J 9.0 Hz, H-3¢), 6.865-6.779
(m, 2H, Ar-H), 5.003 (s, 2H, 2¢-OCH2), 4.411 (d, 1H, J 1.5 Hz,
H-2) and 3.980 (d, 1H, J 1.5 Hz, H-3). (2-Benzyloxy-5-chloro-
phenyl){3-(4-bromophenyl) oxiran-2-yl}methanone 5f: Yield
74%, white solid, mp 90-92 °C; UV-Vis (CHCl3) l/nm 350; IR
(KBr) n/cm-1 1666 (C=O); 1H NMR (400 MHz, CDCl3) d 7.81 (d,
1H, J 2.76 Hz, H-6¢), 7.56-7.13 (m, 10H, H-4¢ and Ar-H), 7.02 (d,
1H, J 9.0 Hz, H-3¢), 4.99 (s, 2H, 2¢-OCH2), 4.37 (d, 1H, J 1.76 Hz,
H-2) and 3.95 (d, 1H, J 1.68, H-3). (5-Chloro-2-methoxy-
phenyl){3-(4-chlorophenyl) oxiran-2-yl}methanone 5g: Yield
72%, white solid, mp 132-134 °C; UV-Vis (CHCl3) l/nm 353; IR
(KBr) n/cm-1 1669 (C=O); 1H NMR (400 MHz, CDCl3) d 7.70 (d,
1H, J 2.70 Hz, H-6¢), 7.39 (d, 2H, J 6.6 Hz, H-3² & 5²), 7.30 (d,
2H, J 6.6 Hz, H-2² & 6²), 7.40 (dd, 1H, J 8.80, 2.70, H-4¢), 6.82
(d, 1H, J 8.84 Hz, H-3¢), 4.16 (d, 1H, J 2.2 Hz, H-2), 3.90 (d, 1H, J
2.2 Hz, H-3) and 3.55 (s, 3H, 2¢-OCH3). (5-Chloro-2-methoxy-
phenyl){3-(4-methoxyphenyl) oxiran-2-yl}methanone 5h:
Yield 62%, white solid, mp 188-190 °C; UV-Vis (CHCl3) l/nm
349; IR (KBr) n/cm-1 1665 (C=O); 1H NMR (400 MHz, CDCl3) d
7.69 (d, 1H, J 2.68 Hz, H-6¢), 7.37 (dd, 1H, J 8.84, 2.80, H-4¢)
7.21 (d, 2H, J 8.6 Hz, H-3² & 5²), 6.84 (d, 2H, J 8.6 Hz, H-2² &
6²), 6.82 (d, 1H, J 8.84 Hz, H-3¢), 4.20 (d, 1H, J 1.8 Hz, H-2), 3.87
(d, 1H, J 1.8, H-3), 3.75 (s, 3H, 2¢-OCH3), 3.54 (s, 3H, 4²-OCH3).
(5-Chloro-2-methoxyphenyl){3-(4-bromophenyl) oxiran-2-
yl}methanone 5i: Yield 79%, white solid, mp 58-60 °C; UV-Vis
(CHCl3) l/nm 351; IR (KBr) n/cm-1 1667 (C=O); 1H NMR (400
MHz, CDCl3) d 7.70 (d, 1H, J 2.64 Hz, H-6¢), 7.45 (d, 2H, J 8.8
Hz, H-3² & 5²), 7.39 (dd, 1H, J 8.8, 2.6, H-4¢), 7.18 (d, 2H, J 8.0
Hz, H-2² & 6²), 6.82 (d, 1H, J 8.84 Hz, H-3¢), 4.15 (d, 1H, J 1.5
Hz, H-2), 3.89 (d, 1H, J 1.5, H-3) and 3.55 (s, 3H, 2¢-OCH3).
Photolysis of a,b-epoxyketones 5(a-i): A deoxygenated
trogen for 15 min and then irradiated under nitrogen with light
from a 125 W Hg vapor lamp. A TLC examination of the photo-
lysate showed no more consumption of the substrate after 30 min.
The removal of solvent under reduced pressure produced a pale
yellow mass that was chromatographed over a column of silica
gel. The column was eluted with hexane-ethyl acetate mixture
(9:1) to obtain the respective photoproducts 6(a-i). Photopro-
duct 6a: Yield 63%, off-white solid, mp 138-140 °C; IR (KBr)
n/cm-1 1601 (C=O); 1H NMR (300 MHz, CDCl3) d 7.983 (d, 1H, J
2.4 Hz, H-6¢), 7.582 (s, 1H, H-2), 7.495-7.398 (m, 6H, H-4¢ and
C3-Ph), 6.994 (d, 1H, J 9.0 Hz, H-3¢) and 3.622 (s, 3H, 2¢-OCH3);
13C NMR (75 MHz, CDCl3) d 186.85 (C-1), 179.87 (C-3), 156.43
(C-2¢), 135.42, 132.65, 132.23, 128.96, 128.55, 128.32, 125.70,
122.09, 116.08, 98.10 (C-2), 58.53 (2¢-OCH3); MS m/z (%)
288/290 (M+, 100%); anal. calcd. for C16H13ClO3: C, 66.56; H,
4.54; found: C, 66.48; H, 4.45. Photoproduct 6b: Yield 57%,
cream colored solid, mp 126-128 °C; IR (KBr) n/cm-1 1600
1
(C=O); H NMR (300 MHz, CDCl3) d 8.081 (d, 1H, J 2.7 Hz,
H-6¢), 7.602 (s, 1H, H-2), 7.577-7.428 (m, 8H, Ar-H), 7.348-
7.257 (m, 3H, Ar-H), 7.068 (d, 1H, J 9.0 Hz, H-3¢) and 5.170 (s,
2H, 2¢-OCH2); 13C NMR (75 MHz, CDCl3) d 187.02 (C-1),
180.59 (C-2), 156.51 (C-2¢), 135.66, 135.60, 132.64, 132.26,
130.22, 128.93, 128.63, 128.48, 128.45, 127.28, 126.55, 125.71,
114.05, 98.74 (C-2), 71.45 (2¢-OCH2); MS m/z (%) 364/366 (M+,
100%); anal. calcd. for C22H17ClO3: C, 72.43; H, 4.70; found: C,
72.39; H, 4.63. Photoproduct 6c: Yield 51%, light yellow solid,
1
mp 148-150 °C; IR (KBr) n/cm-1 1601 (C=O); H NMR (300
MHz, CDCl3) d 8.010-7.705 (m, 5H, H-6’ and Ar-H), 7.607 (bs,
1H, H-2), 7.550-7.520 (m, 3H, Ar-H), 7.442 (dbroad, 1H, J 9.0 Hz,
H-4’), 7.109-7.078 (m, 5H, Ar-H), 7.032 (d, 1H, J 9.0 Hz, H-3’)
and 5.148 (s, 2H, 2’-OCH2); 13C NMR (75 MHz, CDCl3) d 187.03
(C-1), 180.58 (C-2), 156.61 (C-2¢), 135.64, 135.58, 135.26,
133.83, 132.60, 132.32, 131.97, 130.25, 129.75, 128.91, 128.62,
128.43, 128.39, 127.97, 127.62, 127.26, 126.64, 125.76, 114.64,
98.77 (C-2), 72.18 (2¢-OCH2); MS m/z (%) 414/416 (M+, 100%);
anal. calcd. for C26H19ClO3: C, 75.27; H, 4.62; found: C, 75.16; H,
4.56. Photoproduct 6d: Yield 49%, cream colored solid, mp
1
96-98 °C; IR (KBr) n/cm-1 1598 (C=O); H NMR (300 MHz,
CDCl3) d 7.992 (d, 1H, J 2.7 Hz, H-6¢), 7.605 (s, 1H, H-2),
7.553-7.414 (m, 7H, Ar-H), 7.228-7.192 (m, 3H, Ar-H), 6.998 (d,
1H, J 8.7 Hz, H-3¢) 5.162 (s, 2H, 2¢-OCH2) and 3.909 (s, 3H,
4²-OCH3); 13C NMR (75 MHz, CDCl3) d 187.00 (C-1), 180.56
(C-3), 158.01 (C-2¢), 156.49, 135.67, 135.63, 132.23, 130.23,
128.92, 128.55, 128.43, 127.42, 126.54, 125.70, 115.70, 114.01,
98.72 (C-2), 71.73 (2¢-OCH2), 58.31(4²-OCH3); MS m/z (%)
394/396 (M+, 100%); anal. calcd. for C23H19ClO4: C, 69.96; H,
4.85; found: C, 69.89; H, 4.76. Photoproduct 6e: Yield 52%,
solution (0.001 mol L-1) of suitable epoxy ketone 5(a-i) in dry
acetonitrile contained in a Pyrex glass vessel was purged with ni-
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© 2015 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J. Chin. Chem. Soc. 2015, 62, 1114-1120