Med Chem Res
General procedure for the synthesis of (E)-3,4-
diacetoxylstyryl phenethyl ketones (5a–i)
(E)-4-(3-oxo-5-(4-(trifluoromethyl)phenyl)pent-1-enyl)-1,
2-phenylene diacetate (5e) Yellow solid (71.4 %), m.p.
1
68–69 °C; HPLC purity, 8.19 min, 99.1 %; H NMR
(E)-3,4-dihydroxystyryl phenethyl ketones 4a–i (0.06 mmol)
(400 MHz, CDCl3) d = 7.56–7.21 (m, 8H, ArH,
ArCH=CH), 6.66 (d, J = 16 Hz, 1H, ArCH=CH),
3.06–2.98 (m, 4H, CH CH ), 2.30 (d, J = 2.0 Hz, 6H,
and pyridine (catalytic amount) were added to acetic anhy-
dride (3 mL) and stirred at RT until absence of the (E)-3,4-
dihydroxystyryl phenethyl ketones (checked by TLC). The
2
2
1
3
(CH COO) Ar); C NMR (100 MHz, CDCl ) d = 198.1,
3
2
3
reaction mixture was diluted with H O and extracted with
2
168.0, 167.9, 145.3, 143.7, 142.5, 140.9, 133.2, 128.8,
ethyl acetate. The combined organic fractions were washed
with brine, dried (Na SO ) and concentrated under reduced
126.7, 126.7, 125.4, 124.0, 122.9, 42.1, 29.7, 20.6; MS
?
(ESI) m/z: 443.29 [M ? Na] .
2
4
pressure. Purification of the crude residue by column chro-
matography (petroleum ether/ethyl acetate) afforded the title
compounds.
(
E)-4-(3-oxo-5-p-tolylpent-1-enyl)-1,2-phenylene diacetate
(
5f) White solid (78.6 %), m.p. 109 °C; HPLC purity,
1
7
.64 min, 99.9 %;
H
NMR (400 MHz, CDCl3)
(
E)-4-(5-(4-chlorophenyl)-3-oxopent-1-enyl)-1,2-phenylene
d = 7.48–7.09 (m, 8H, ArH, ArCH=CH), 6.65 (d,
J = 16 Hz, 1H, ArCH=CH), 2.95 (s, 4H, CH CH ), 2.31 (t,
13
diacetate (5a) Yellow solid (93.9 %), m.p. 97–98 °C;
HPLC purity, 7.88 min, 97.9 %; H NMR (400 MHz,
2
2
1
9H, ArCH , (CH COO) Ar); C NMR (100 MHz, CDCl3)
3 3 2
CDCl ) d = 7.49–7.14 (m, 8H, ArH, ArCH=CH), 6.65 (d,
d = 199.1, 168.1, 168.0, 143.6, 142.5, 140.6, 138.0, 135.7,
133.4, 129.2, 128.3, 127.0, 126.6, 124.0, 122.8, 42.9, 29.7,
?
21.0, 20.7, 20.6; MS (ESI) m/z: 389.33 [M ? Na] .
3
J = 16 Hz, 1H, ArCH=CH), 2.96 (s, 4H, CH CH ), 2.30
2
2
1
d, J = 3.2 Hz, 6H, (CH COO) Ar); C NMR (100 MHz,
3
(
3
2
CDCl ) d = 198.4, 168.0, 167.9, 143.7, 142.5, 140.8,
3
(
E)-4-(5-(4-ethylphenyl)-3-oxopent-1-enyl)-1,2-phenylene
1
39.6, 133.3, 131.9, 129.8, 128.6, 126.8, 126.6, 124.0,
?
22.9, 42.5, 29.3, 20.7; MS (ESI) m/z: 409.51 [M ? Na] .
diacetate (5g) White solid (84.0 %), m.p. 58–59 °C;
HPLC purity, 12.02 min, 99.8 %; H NMR (400 MHz,
1
1
(
E)-4-(5-(4-fluorophenyl)-3-oxopent-1-enyl)-1,2-phenylene
CDCl ) d = 7.48–7.13 (m, 8H, ArH, ArCH=CH), 6.65 (d,
3
diacetate (5b) Yellow solid (86.8 %), m.p. 74–75 °C;
HPLC purity, 4.97 min, 98.5 %; H NMR (400 MHz,
J = 16 Hz, 1H, ArCH=CH), 2.96 (s, 4H, CH CH ),
2
2
1
2.64–2.58 (m, 2H, CH CH Ar), 2.29 (d, J = 3.6 Hz, 6H,
3 2
1
3
CDCl ) d = 7.51–6.97 (m, 8H, ArH, ArCH = CH), 6.67
(CH COO) Ar), 1.22 (t, 3H, CH CH Ar); C NMR
3 2 3 2
3
(
d, J = 16 Hz, 1H, ArCH = CH), 2.98 (s, 4H, CH CH ),
2
(100 MHz, CDCl ) d = 199.1, 168.1, 168.0, 143.6, 142.5,
142.1, 140.6, 138.2, 133.4, 128.3, 128.0, 127.0, 126.6,
2
3
1
3
2
.32 (d, J = 2.8 Hz, 6H, (CH COO) Ar);
3
C NMR
2
(
100 MHz, CDCl ) d = 198.6, 168.1, 167.9, 143.7, 142.5,
40.7, 136.7, 133.3, 129.8, 129.8, 126.9, 126.6, 124.0,
124.0, 122.8, 42.8, 29.7, 28.5, 20.7, 20.6, 15.7; MS (ESI)
?
m/z: 403.53 [M ? Na] .
3
1
1
22.9, 115.4, 115.2, 42.7, 29.2, 20.6; MS (ESI) m/z: 393.31
?
(E)-4-(5-(4-isopropylphenyl)-3-oxopent-1-enyl)-1,2-pheny-
[
M ? Na] .
lene diacetate (5h) White solid (82.8 %), m.p. 69 °C;
HPLC purity, 16.24 min, 98.3 %; H NMR (400 MHz,
1
(
E)-4-(5-(4-bromophenyl)-3-oxopent-1-enyl)-1,2-phenylene
diacetate (5c) Yellow solid (83.4 %), m.p. 95–96 °C;
HPLC purity, 9.24 min, 94.8 %; H NMR (400 MHz,
CDCl ) d = 7.48–7.16 (m, 8H, ArH, ArCH=CH), 6.65 (d,
3
1
J = 16 Hz, 1H, ArCH=CH), 2.96 (s, 4H, CH CH ),
2
2
CDCl ) d = 7.49–7.09 (m, 8H, ArH, ArCH = CH), 6.65
2.93–2.83 (m, 1H, (CH ) CHAr), 2.30 (d, J = 3.6 Hz, 6H,
3 2
3
(
d, J = 16 Hz, 1H, ArCH = CH), 2.95 (s, 4H, CH CH ),
2
(CH COO) Ar), 1.23 (d, J = 6.8 Hz, 6H, (CH ) CHAr);
3 2
2
3
2
1
.30 (s, 6H, (CH COO) Ar); C NMR (100 MHz, CDCl3)
3
13
2
C NMR (100 MHz, CDCl ) d = 199.2, 168.1, 168.0,
3
2
3
d = 198.4, 168.1, 168.0, 143.7, 142.5, 140.8, 140.1, 133.3,
146.8, 143.7, 142.5, 140.9, 138.4, 133.5, 128.4, 127.1,
1
31.6, 130.2, 126.8, 126.7, 124.0, 122.9, 119.9, 42.4, 29.4,
?
0.7; MS (ESI) m/z: 455.24 [M ? Na] .
126.7, 126.6, 124.0, 122.9, 42.8, 33.8, 29.8, 24.1, 20.7,
?
20.7; MS (ESI) m/z: 417.35 [M ? Na] .
2
(
E)-4-(5-(4-methoxyphenyl)-3-oxopent-1-enyl)-1,2-phenylene
(E)-4-(5-(4-tert-butylphenyl)-3-oxopent-1-enyl)-1,2-pheny-
lene diacetate (5i) Yellow solid (87.7 %), m.p.
diacetate (5d) Yellow solid (65.4 %), m.p. 94–95 °C;
HPLC purity, 4.45 min, 99.7 %; H NMR (400 MHz,
1
1
88–89 °C; HPLC purity, 23.52 min, 99.9 %; H NMR
CDCl ) d = 7.48–6.82 (m, 8H, ArH, ArCH=CH), 6.65 (d,
J = 16 Hz, 1H, ArCH=CH), 3.78 (s, 3H, OCH ), 2.94 (s,
3
(400 MHz, CDCl3) d = 7.47–7.15 (m, 8H, ArH,
ArCH=CH), 6.64 (d, J = 16 Hz, 1H, ArCH=CH), 2.96 (s,
4H,CH CH ), 2.28 (s, 6H, (CH COO) Ar), 1.30 (s, 9H,
3
4
H, CH CH ), 2.30 (d, J = 3.2 Hz, 6H, (CH COO) Ar);
2 2 3 2
2
2
3
2
1
3
13
C NMR (100 MHz, CDCl ) d = 199.1, 168.0, 167.9,
(CH ) CAr); C NMR (100 MHz, CDCl ) d = 199.1,
3
3 3
3
1
1
58.0, 143.6, 142.5, 140.6, 133.4, 129.3, 127.0, 126.6,
168.1, 167.9, 149.0, 143.6, 142.5, 140.6, 138.0, 133.4,
24.0, 122.8, 114.0, 55.3, 43.0, 29.3, 20.7, 20.6; MS (ESI)
?
128.1, 127.1, 126.6, 125.4, 124.0, 122.8, 42.9, 34.4, 31.4,
?
29.6, 20.6; MS (ESI) m/z: 431.40 [M ? Na] .
m/z: 405.53 [M ? Na] .
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23