A. Dalal et al. / Journal of Photochemistry and Photobiology A: Chemistry 329 (2016) 238–245
243
(C-20), 184.9(C-1). ESI–MS: m/z calculated for C19H12BrF3O4
reduced pressure yielded
a
gummy mass that was
(399.0899), found (423.9922) [M + Na]+.
chromatographed over a column of silica gel. The column was
eluted with increasing proportion of ethyl-acetate in pet. ether-
ethyl acetate mixture to obtain photoproducts 5a and 6a.
4.3.1.3.
trifluoromethyl-phenyl)oxirane 4c. Yield 80%, white solid, mp
165–170 ꢁC; nmax(cmꢀ1): 2129 (CRC), 1674 (C
O); dH(CDCl3):
2-{5-Chloro-4-methyl-2-(prop-2-ynyloxy)benzoyl}-3-(4-
¼
4.4.1.2.
1-{5-Chloro-2-(prop-2-ynyloxy)phenyl}-3-hydroxy-3-(40-
7.76 (1H, s, H-60), 7.59 (2H, d, Jo = 8.4 Hz, H-300, 500), 7.43 (2H, d,
Jo = 8.4 Hz, H-200, 600), 6.84 (1H, s, H-30), 4.40 (2H, d, Jallylic = 2.4 Hz, H-
1000), 4.26 (1H, s, H-2), 3.98 (1H, s, H-3), 2.33 (3H, s, CH3), 2.20 (1H, t,
Jallylic = 2.4 Hz, H-3000). dC(CDCl3): 20.9(CꢀꢀCH3), 56.6(C-1000), 59.0(C-
3), 63.9(C-3000), 64.1(C-2), 115.6(C-2000), 125.2(C-30), 125.6(C-10),
125.6(CF3ꢀꢀC), 126.2(C-300,500), 128.0(C-50), 130.3(C-200,600), 130.9
(C-60), 131.0(C-400), 131.3(C-40), 140.3(C-100), 143.8(C-20), 155.6(C-1).
ESI–MS: m/z calculated for C20H14ClF3O3 (394.0584), found
(417.0553) [M + Na]+.
trifluoromethyl-phenyl)prop-2-en-1-one 5a. Yield 35.13%, pale
yellow solid, mp 110–112 ꢁC; nmax(cmꢀ1): 3418 (-OH), 2150
(CRC), 1713 (C
¼
O), 1605 (C C); dH(CDCl3): 8.08 (2H, d,
¼
Jo = 8.1 Hz, H-300, 500), 7.95 (1H, d, Jm = 2.7 Hz, H-60), 7.73 (2H, d,
Jo = 8.1 Hz, H-200, 600), 7.44 (1H, dd, Jo = 8.7 Hz, Jm = 2.7 Hz, H-40), 7.23
(1H, s, H-2), 7.03 (1H, d, Jo = 8.7 Hz, H-30), 4.82 (2H, d, Jallylic = 2.4 Hz,
H-1000), 2.63 (1H, t, Jallylic = 2.4 Hz, H-3000). dC(CDCl3): 57.0, 99.2, 114.6,
122.3, 125.0, 125.6, 126.5, 127.4, 127.6, 130.3, 132.8, 133.5, 133.8,
138.7, 154.9, 183.2, 183.6. ESI–MS: m/z calculated for C19H12ClF3O3
(380.0427), found (403.0393) [M + Na]+.
4.3.1.4. 2-{2-(Prop-2-ynyloxy)benzoyl}-3-(4-trifluoromethyl-phenyl)
oxirane 4d. Yield 81%, white solid, mp 85–90 ꢁC; nmax(cmꢀ1): 2129
4.4.1.3. 8-Chloro-2-phenyl-4,10-dihydrofuro[3,2-c][1]benzoxepin-10-
(CRC), 1674 (C
¼
O); dH(CDCl3): 7.80 (1H, dd, Jo = 7.8 Hz,Jm = 1.6 Hz,
one 6a. Yield 64.86%, white solid, mp 138–140 ꢁC; nmax(cmꢀ1):
H-60), 7.053 (1H, t, Jo = 7.6 Hz, H-40), 6.97 (1H, t, Jo = 8.0 Hz, H-50),
7.42 (2H, d, Jo = 7.6 Hz, H-200, 600), 7.49 (1H, d, Jo = 7.6 Hz, Jm = 1.7 Hz,H-
30), 7.58 (2H, d, Jo = 8.2 Hz, H-300, 500), 4.43 (2H, d, Jallylic = 2.7 Hz, H-
1000), 4.29 (1H, s, H-2), 4.02 (1H, s, H-3), 2.18 (1H, t, Jallylic = 2.4 Hz, H-
3000). dC(CDCl3): 56.3(C-1000), 59.0(C-3), 64.0(C-2), 76.2(C-3000), 112.9
(C-2000),122.1(C-30),125.5(C-10),125.6(C-300,500),125.6(CF3ꢀꢀC),126.2
(C-50), 126.4(C-200,600),127.1(C-60),130.6(C-400),133.4(C-40),134.9 (C-
100), 140.5(C-20), 157.3(C-1). ESI–MS: m/z calculated for C19H13F3O3
(346.0817), found (369.00783) [M + Na]+.
1622 (C O); dH(CDCl3): 8.16 (1H, d, Jm = 2.7 Hz, H-9), 7.97 (2H, d,
¼
Jo = 8.1 Hz, H-30, 50), 7.71 (2H, d, Jo = 8.1 Hz, H-20, 60), 7.46 (1H, dd,
Jo = 8.7 Hz, Jm = 2.7 Hz, H-7), 7.14 (1H, d, Jo = 8.7 Hz, H-6), 6.85 (1H, s,
H-3), 5.14(2H, s, H-4). dC(CDCl3): 66.7, 107.1, 124.0, 125.1, 125.6,
126.0, 126.0, 130.0, 130.2, 130.6 131.8, 134.5, 136.0, 149.3, 156.4,
156.6, 157.1. ESI–MS: m/z calculated for C20H15F3O4 (378.0271),
found (379.0424) [M + H]+, (401.0251) [M + Na]+.
4.4.1.4. Photolysis of 2-{5-bromo-2-(prop-2-ynyloxy)benzoyl}-3-(4-
trifluoromethyl-phenyl)oxirane 4b.. A 1.0 mM solution of 4b in dry
acetonitrile on photolysis for 90 min followed by processing as
above furnished 5b and 6b.
4.3.1.5.
trifluoromethyl-phenyl)oxirane 4e. Yield 82%, white solid, mp
140–142 ꢁC; nmax(cmꢀ1): 2129 (CRC), 1674 (C
O); dH(CDCl3):
2-{5-Methyl-2-(prop-2-ynyloxy)benzoyl}-3-(4-
¼
7.66 (1H, d, Jm = 1.96 Hz, H-60), 7.65 (2H, d, Jo = 8.1 Hz, H-200, 600), 7.51
(2H, d, Jo = 8.1 Hz, H-300, 500), 7.34 (1H, dd, Jo = 8.4 Hz, Jm = 2.3 Hz, H-
40), 6.93 (1H, d, Jo = 8.4 Hz, H-30), 4.43 (2H, d, Jallylic = 2.1 Hz, H-1000),
4.23 (1H, s, H-2), 3.92 (1H, s, H-3), 2.52 (1H, d, Jallylic = 2.1 Hz, H-3000).
dC(CDCl3): 20.2(CH3ꢀꢀC), 56.4(C-1000), 59.0(C-3), 64.1(C-2), 76.1(C-
3000), 113.1(C-2000), 125.3(C-30), 125.5(C-10), 125.5(CF3ꢀꢀC), 125.6(C-
300,500), 123.1(C-50), 126.2(C-200,600), 130.9(C-60), 131.0(C-400), 131.7(C-
40), 135.5(C-100), 140.5(C-20), 155.3(C-1). ESI–MS: m/z calculated for
4.4.1.5.
1-{5-Bromo-2-(prop-2-ynyloxy)phenyl}-3-hydroxy-3-(40-
trifluoromethyl-phenyl)prop-2-en-1-one 5b. Yield 21.8%, white
solid, mp 115–117 ꢁC; nmax(cmꢀ1): 3432 (-OH), 2150 (CRC),
1713 (C
¼
O), 1605 (C
C); dH(CDCl3): 8.08 (2H, d, Jo = 9.0 Hz, H-300,
¼
500), 7.98 (1H, d, Jm = 1.5 Hz, H-60), 7.72 (2H, d, Jo = 8.4 Hz, H-200, 600),
7.47 (1H, dd, Jo = 8.7 Hz, Jm = 2.7 Hz, H-40), 7.16 (1H, s, H-2), 6.83 (1H,
d, Jo = 8.4 Hz, H-30), 4.84 (2H, d, Jallylic = 2.4 Hz, H-1000), 2.62 (1H, t,
Jallylic = 2.4 Hz, H-3000). dC(CDCl3): 57.0, 99.2, 114.6, 122.3, 125.0,
125.6, 126.5, 127.4, 127.6, 130.3, 132.8, 133.54, 133.8, 138.7, 154.9,
183.2, 183.6. ESI–MS: m/z calculated for C20H15F3O4 (423.9922),
found (424.9883) [M + H]+.
C
20H15F3O3 (360.0973), found (383.0942) [M + Na]+.
4.3.1.6.
trifluoromethyl-phenyl)oxirane 4f. Yield 87%, white solid, mp
98–100 ꢁC; nmax(cmꢀ1): 2127 (CRC), 1682 (C
O); dH(CDCl3):
2-{5-Methoxy-2-(prop-2-ynyloxy)benzoyl}-3-(4-
¼
4.4.1.6. 8-Bromo-2-(4’trifluoromethyl-phenyl)-4,10-dihydrofuro[3,2-
c][1]benzoxepin-10-one 6b. Yield 71.8%, white solid, mp 143–
7.57 (2H, d, Jo = 8.1 Hz, H-300, 500), 7.44 (2H, d, Jo = 7.9 Hz, H-200, 600),
7.30 (1H, d, Jm = 3.2 Hz, H-60) 7.04 (1H, dd, Jo = 9.0 Hz, Jm = 3.2 Hz, H-
40), 6.92 (1H, d, Jo = 9.0 Hz, H-30), 4.37 (2H, d, Jallylic = 2.1 Hz, H-1000),
4.31 (1H, s, H-2), 4.01 (1H, s, H-3), 3.75 (3H, s, ꢀOCH3) 2.18 (1H, d,
Jallylic = 2.1 Hz, H-3000). dC(CDCl3): 29.7(CꢀꢀOCH3), 31.2(C-1000), 55.8
(C-3), 57.0(C-2), 59.1(C-3000), 64.1(C-2000), 76.2(C-30), 113.9(C-10),
115.1(CF3ꢀꢀC), 120.1(C-300,500), 121.9(C-50), 125.5(C-200,600), 126.2(C-
60), 127.1(C-400), 130.6(C-40), 140.5(C-100), 151.6(C-20), 154.5(C-1).
ESI–MS: m/z calculated for C20H15F3O4 (376.0922), found
(399.0899) [M + Na]+.
145 ꢁC; nmax(cmꢀ1): 1612 (C
O); dH(CDCl3): 8.30 (1H, d, Jm = 2.6 Hz,
¼
H-9), 7.96 (2H, d, Jo = 8.4 Hz, H-30, 50), 7.70 (2H, d, Jo = 8.7 Hz, H-20,
60), 7.61 (1H, dd, Jo = 8.5 Hz, Jm = 2.7 Hz, H-7), 7.07 (1H, d, Jo = 8.7 Hz,
H-6), 6.84 (1H, s, H-3), 5.07(2H, s, H-4). dC(CDCl3): 66.7,107.1,124.3,
125.6, 126.0, 126.5, 128.2, 128.5, 129.1, 130.4 131.9, 132.8, 134.5,
136.0, 137.5, 149.3, 174.3. ESI–MS: m/z calculated for C19H10BrF3O3
(421.9765), found (423.6) [M + H]+, (444.0) [M + Na]+.
4.4.1.7. Photolysis of 2-{5-chloro-4-methyl-2-(prop-2-ynyloxy)
benzoyl}-3-(4-trifluoromethyl-phenyl)oxirane
4c.
A
1.0 mM
4.4. Photolysis of benzoyl oxiranes 4(a-f)
solution of 4c in dry acetonitrile on photolysis for 90 min
followed by processing as above furnished two photoproduct 5c
and 6c
4.4.1. Photolysis of 2-{5-chloro-2-(prop-2-ynyloxy)benzoyl}-3-(4-
trifluoromethyl-phenyl)oxirane 4a.
4.4.1.8.
1-{5-Chloro-4-methyl-2-(prop-2-ynyloxy)phenyl}-3-
4.4.1.1. General procedure. A deoxygenated 1.0 mM solution in dry
acetonitrile of the benzoyl oxirane 4a contained in a pyrex glass
vessel was purged with nitrogen for 30 min and then irradiated
under nitrogen atmosphere with light from a 125 W medium
pressure Hg vapor lamp for 90 min. The removal of solvent under
hydroxy-3-(40-trifluoromethyl-phenyl)prop-2-en-1-one 5c. Yield
37.5%, white solid, mp 194–196 ꢁC; nmax(cmꢀ1): 1612 (C
O);
¼
dH(CDCl3): 8.17 (1H, s, H-9), 7.98 (2H, d, Jo = 8.1 Hz, H-30, 50), 7.72
(2H, d, Jo = 8.1 Hz, H-20, 60), 7.07 (1H, s, H-6), 6.82 (1H, s, H-3), 5.13
(2H, s, H-4), 2.42 (3H, s, CH3). dC(CDCl3): 20.2, 66.8, 77.3, 105.5,