NATURAL PRODUCT RESEARCH
3
four methylenes at d 3.89 (1H, dd, J ¼ 12.0, 5.8 Hz), 3.73 (1H, dd, J ¼ 12.0, 3.2 Hz), 2.61
2H, dd, J ¼ 8.9, 6.7 Hz), 1.81 (2H, dddd, J ¼ 13.9, 7.9, 6.7, 1.4 Hz) and 3.57 (2H, t,
J ¼ 6.5 Hz), a methyl at d 3.81 (3H, s), six aromatic protons at d 7.05 (1H, d, J ¼ 2.0 Hz),
(
7
.01 (1H, d, J ¼ 1.9 Hz), 6.86 (1H, dd, J ¼ 8.2, 1.9 Hz), 6.82 (1H, d, J ¼ 8.2 Hz), 6.79 (1H,
dd, J ¼ 8.2, 2.0 Hz), 6.76 (1H, d, J ¼ 8.2 Hz) as well as seven protons for one glucose at
0
4
2
.77 (1H, d, J ¼ 7.7 Hz), 3.53 (1H, ddd, J ¼ 9.9, 6.2, 2.2 Hz, H-2 ’), 3.36 (1H, dd, J ¼ 9.3,
0
0
0
.8 Hz, H-3 ’) 3.45 (1H, t, J ¼ 9.0 Hz, H-4 ’), 3.49 (1H, dd, J ¼ 9.3, 7.6 Hz, H-5 ’), 3.83 (1H,
0
0
dd, J ¼ 7.6, 5.8 Hz, H -6 ’), 3.73 (1H, dd, J ¼ 5.6, 3.2 Hz, H -6 ’), and six protons for one
a
b
0
0
arabinose at d 4.93 (1H, d, J ¼ 1.3 Hz, H-1 ’’), 4.00 (1H, dd, J ¼ 3.3, 1.4 Hz, H-2 ’’), 3.82
0
0
(
2
1H, d, J ¼ 3.3 Hz, H-3 ’’), 3.95 (1H, td, J ¼ 5.6, 3.3 Hz, H-4 ’’), 4.06 (1H, dd, J ¼ 10.9,
0
0
13
.2 Hz, H -5 ’’) and 3.62 (1H, dd, J ¼ 10.9, 5.4 Hz, H -5 ’’). The interpretation of the
C
a
b
NMR and HSQC spectra (Table S1) of 1 revealed the presence of thirty carbon signals,
including two methine carbons at d 73.4 (C-7) and 87.1 (C-8), four methylene carbons
at d 61.6 (C-9), 32.6 (C-7 ), 35.5 (C-8 ) and 62.3 (C-9 ), a methyl carbon at d 56.5 (C-
0
0
0
OCH ), twelve aromatic carbons at d134.1 (C-1), 111.7 (C-2), 148.8 (C-3), 147.3 (C-4),
3
0 0 0 0 0
1
15.9 (C-5), 120.9 (C-6), 138.3 (C-1 ), 120.4 (C-2 ), 149.4 (C-3 ), 147.9 (C-4 ), 120.2 (C-5 )
0
0
0
and 124.5 (C-6 ) and six carbons for one glucose at d 103.7 (C-1 ’), 76.9 (C-2 ’), 71.9 (C-
0
0
0 0 0
3
1
’), 77.7 (C-4 ’), 75.3 (C-5 ’), 63.1 (C-6 ’) and five carbons for one arabinose at 109.7 (C-
’’), 83.2 (C-2 ’’), 79.0 (C-3 ’’), 85.9 (C-4 ’’) and 68.0 (C-5 ’’). The HMBC correlations from
0
0
0
0
1
1
H-7 to C-1, C-2, C-6, C-8 and C-9 and from -OCH to C-3 as well as the H- H COSY
3
correlations of H-7/H-8, H-8/H-9 and H-5/H-6 can determine the structure of a phenyl-
0
0
0
0
0
propanoid. Further analysis of the HMBC correlations from H-7 to C-1 , C-2 , C-6 , C-8
0
1
1
0
0
0
and C-9 and the H– H COSY correlations (Figure S1) from H-7 to H-8 , from H-8 to
H-9 and from H-5 to H-6 can determine the structure of the second phenylpropanoid
unit.
0
0
0
The absolute configurations at C-7 and C-8 of the 1-phenyl-2-aryloxypropane-1,3-
diol moiety in 1 were confirmed by the analyses of its nuclear Overhauser effect (NOE)
spectrum and CD spectroscopic evidence (Figure S2). The cross peaks between H-8
and H-2/H-6, and H-8 and H-7 in NOESY spectrum (Matsuda and Kikuchi 1996) as well
as the coupling constant constant (J ¼ 5.6 Hz) between H-7 and H-8 (Greca et al. 1994)
indicated 1 has a relative threo-configuration. The absolute configuration at C-7 and C-
8
was determined to be 7 R and 8 R from the CD spectrum of 1 showing a negative
Cotton effect in the region 220-250 nm (Lee et al. 2015). The sugar component was
identified as a D-glucose and an L-arabinose by HPLC analysis after acid hydrolysis
and derivatization of 1 combined with optical rotation comparison. Finally, the struc-
0
ture of compound 1 was confirmed to be 7 R,8R-threo-4,7,9,9 -tetrahydroxy-3-methoxy-
0
0
0
8
-O-4 -neolignan-3 -O-(3 ’-a-L-arabinofuranosyl)-b-D-glucopyranoside.
Compound 2 was obtained as a colorless gum. Its molecular formula was defined
þ
as C H O by HRESIMS ion peak at m/z 481.16779 [M þ Na] (calcd 481.17881). The
2
1 30 11
1
H NMR and HSQC spectrum (Table S2) of 2 showed signals of a two methylenes at d
.76-2.79 (2H, m, H-7) and 2.79-2.82 (2H, m, H-8), one methyl at d2.12 (3H, s), four aro-
2
matic protons at d 7.12-7.16 (2H, m, H-2, 6) and 7.01-7.04 (2H, m, H-3, 5) and seven
0
protons for one glucose at d 4.85 (overlapped with solvent signal, H-1 ), 3.43-3.44 (1H,
0
0
0
m, H-2 ), 3.42-3.43 (1H, m, H-3 ), 3.35-3.39 (1H, m, H-4 ), 3.63 (1H, ddd, J ¼ 9.9, 6.2,
0
0
0
2
.1 Hz, H-5 ), 4.10 (1H, dd, J ¼ 11.5, 2.1 Hz, H-6 ), 3.75 (1H, dd, J ¼ 11.6, 6.2 Hz, H-6 ), and