C. Wan et al. / Phytochemistry Letters 12 (2015) 267–272
271
21.251,18.756. HRMS (ESI) calcd. for C25H32O4 (M + NH4)+ 414.2639,
measured 414.2635.
3.2.14. Synthesis of decan-1-ol ABA ester 2n
1H NMR of the alcoholic residue (300 MHz, CDCl3, 25 ꢀC)
d
: 4.11
(t, J = 6.6 Hz, 2H), 2.49 (d, J = 17.0 Hz, 1H), 1.71–1.48 (m, 4H), 1.28
13
3.2.7. Synthesis of 3-(trifluoromethyl) phenol ABA ester 2g
(s, 12H), 0.89 (t, J = 6.3 Hz, 3H). C NMR (75 MHz, CDCl3, 25 ꢀC)
Yield: 92%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
d:197.69, 166.18, 162.56, 148.97, 136.23, 128.05, 126.89, 118.70,
25 ꢀC)
d
: 7.50–7.48 (m, 2H), 7.38 (s, 1H), 7.32–7.28 (m, 1H). 13C NMR
79.54, 77.39, 76.97, 76.55, 64.23, 63.01, 49.76, 41.46, 32.76, 31.84,
29.56, 29.50, 29.48, 29.38, 29.26 28.94, 25.70, 24.29, 22.61, 21.10,
14.03. Yield: 77%. HRMS (ESI) calcd. for C25H40O4 (M + Na)+
427.2819, measured 427.2814.
(75 MHz, CDCl3, 25 ꢀC)
d: 197.895, 163.626, 162.632, 153.043,
150.575, 138.023, 129.833, 127.648, 126.889, 125.313, 125.282,
122.443, 118.997, 116.482, 112.275. HRMS (ESI) calcd. for
C
22H23F3O4 (M + Na)+ 431.1441, measured 431.1449.
3.2.15. Synthesis of (2-nitrophenyl) methanol ABA ester 2p
Yield: 83%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
3.2.8. Synthesis of methyl salicylate ABA ester 2h
25 ꢀC)
d
: 8.11 (m, 1H), 7.68–7.60 (m, 2H), 7.52–7.47 (m, 1H), 5.57 (s,
Yield: 81%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
2H). 13C NMR (75 MHz, CDCl3, 25 ꢀC)
d
: 197.543, 165.137, 162.263,
25 ꢀC)
d: 8.02 (m, 1H), 7.59–7.54 (m 1H), 7.34–7.28 (m, 1H), 7.12 (m,
150.705, 147.657, 137.024, 133.661, 132.321, 129.198, 128.729,
127.928, 127.020, 125.029, 117.566, 79.595, 62.489, 49.765,
41.474, 24.331, 23.036, 21.258, 18.778. HRMS (ESI) calcd. for
13
1H), 3.83 (s, 3H). C NMR (75 MHz, CDCl3, 25 ꢀC)
d: 197.651,
164.928, 164.174, 162.435, 151.735, 150.358, 137.300, 133.698,
131.571, 127.883, 126.881, 125.837, 123.893, 123.312, 117.297,
79.490, 52.079, 49.695, 41.441, 24.272, 22.953, 21.312, 18.749.
HRMS (ESI) calcd. for C23H26O6 (M + NH4)+ 416.2068, measured
416.2070.
C
22H22O6 (M + NH4)+ 400.1755, measured 400.1751.
3.2.16. Synthesis of 3-(pyridin-2-yl)propan-1-ol ABA ester 2o (method
b)
Triohenylphosphane (TPP, 100 mg, 0.38 mmol) and diisopropy-
lazodicarboxylate (DIAD, 77 mg, 0.38 mmol) were added to a
cooled solution of (+)-ABA (100 mg, 0.38 mmol) and 2-(3-
hydroxypropyl)pyridine (156 mg, 1.14 mmol) in THF (10 mL). After
stirring at room temperature for 48 h, the reaction was worked up
by removal of the solvent in vacuo, and the residue was partitioned
between EtOAc and saturated NaHCO3. The organic phase was
washed with brine and dried with Na2SO4 and then evaporated.
The residue was purified by silica gel chromatography with CH2Cl2/
CH3OH (50:1) to furnish the product ester 0.08 g, yield 56%. 1H
3.2.9. Synthesis of 4-nitrophenol ABA ester 2i
Yield: 80%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
25 ꢀC)
d
: 8.28–8.23 (m, 2H), 7.32–7.28 (m, 2H). 13C NMR (75 MHz,
CDCl3, 25 ꢀC)
d
: 197.889, 162.901, 162.545, 155.355, 153.844,
145.029, 138.377, 127.624, 126.945, 125.984, 124.983, 122.435,
116.111, 115.558, 79.495, 49.579, 41.471, 24.211, 22.911, 18.805.
HRMS (ESI) calcd. for C21H23N1O6 (M + NH4)+ 403.1864, measured
403.1863.
3.2.10. Synthesis of 2-methoxyphenol ABA ester 2j
NMR of the alcoholic residue (300 MHz, CDCl3, 25 ꢀC)
d: 8.49 (dd,
Yield: 88%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
J = 0.8 Hz, 4.9 Hz, 1H), 7.62 (td, J = 1.8 Hz, 7.7 Hz, 1H), 7.20–7.11 (m,
2H), 4.19 (t, J = 6.0 Hz, 2H), 2.95 (t, J = 7.6 Hz, 2H), 2.16–2.07 (m, 2H).
25 ꢀC) : 7.20 (m, 1H), 7.05–6.91 (m, 3H), 3.81 (s, 3H). 13C NMR
d
(75 MHz, CDCl3, 25 ꢀC)
d: 197.783, 163.726, 162.580, 151.576,
13C NMR (75 MHz, CDCl3, 25 ꢀC)
d: 197.869, 166.167, 162.723,
151.054, 139.316, 137.243, 127.752, 126.809, 126.709, 122.894,
120.610, 117.100, 112.256, 79.437, 55.709, 49.637, 41.421, 24.213,
22.891, 21.258, 18.784. HRMS (ESI) calcd. for C22H26O5 (M + Na)+
393.1672, measured 393.1675.
161.009, 149.091, 148.614, 136.611, 136.565, 128.339, 126.762,
122.895, 121.308, 118.839, 79.484, 63.405, 49.787, 41.493, 34.717,
29.007, 24.392, 23.149, 21.285, 19.094. HRMS (ESI) calcd. for
C
23H30NO4 (M + H)+ 384.2169, measured 384.2170.
3.2.11. Synthesis of 2-methoxy-4-nitrophenol ABA ester 2k
3.3. Bioassays
Yield: 86%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
25 ꢀC) : 7.88–7.79 (m, 2H), 7.21 (m, 1H), 3.91 (s, 3H). 13C NMR
d
3.3.1. Thaliana seed germination
Twenty-five seeds of A. thaliana (Col.) were sterilized succes-
sively with 70% (v/v) EtOH for 30 min and reagent grade EtOH for
(75 MHz, CDCl3, 25 ꢀC)
d: 197.689, 162.407, 153.153, 151.493,
145.854, 144.682, 138.073, 127.523, 126.754, 123.186, 116.107,
115.859, 107.377, 79.302, 56.173, 49.446, 41.345, 24.062, 22.770,
21.168, 18.710. HRMS (ESI) calcd. for C22H25N1O7 (M + NH4)+
433.1969, measured 433.1966.
1 min. The sterilized seeds were soaked in 400 mL of a test solution
and incubated in the dark for 3 days at 4 ꢀC. The vernalized seeds
were transferred to plates in which two sheets of filter paper had
been placed and allowed to germinate under day for 16 h and night
for 8 h at 22ꢀC. The percentage of seeds with an emerged radical
was calculated.
3.2.12. Synthesis of biphenyl-2-ol ABA ester 2l
Yield: 82%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
25 ꢀC)
25 ꢀC)
d
: 7.44–7.26 (m, 8H), 7.15 (m, 1H). 13C NMR (75 MHz, CDCl3,
3.3.2. Lettuce seed germination
d
: 197.590, 164.150, 162.311, 151.548, 147.496, 137.619,
Twenty-five seeds of lettuce (Lactuca sativa L. cv. Grand Rapids)
were placed on two sheets of filter paper soaked in 2 mL of a test
solution in a petri dish and allowed to germinate under continuous
night for 24 h at 25 ꢀC. The percentage of seeds with an emerged
radical was calculated.
137.218, 134.759, 130.862, 128.901, 128.358, 128.157, 127.735,
127.242, 126.830, 126.200, 122.982, 117.217, 79.457, 49.711,
41.430, 24.284, 22.974, 21.231, 18.745. HRMS (ESI) calcd. for
C
27H28O4 (M + NH4)+ 434.2326, measured 434.2324.
3.2.13. Synthesis of methanol ABA ester 2m
3.3.3. Rice seedling growth
Yield: 95%. 1H NMR of the alcoholic residue (300 MHz, CDCl3,
Seeds of rice (Oryza sativa L. cv. Nipponbare) were sterilized
with EtOH for 5 min and washed with running tap water. The
sterilized seeds were soaked in water to germinate for 3 days at
25 ꢀC. The seeds were then placed in a glass tube containing 2 mL of
a test solution and grown with the tube sealed with a plastic cap
25 ꢀC) : 3.70 (s, 3H). 13C NMR (75 MHz, CDCl3, 25 ꢀC)
d d: 197.706,
166.357, 162.432, 149.340, 136.320, 128.073, 126.992, 118.170,
79.597, 51.106, 49.713, 41.496, 24.264, 23.010, 21.091,18.868. HRMS
(ESI) calcd. for C16H22O4 (M + Na)+ 301.141, measured 301.1409.